diff --git a/.spec/conformance/desktop_ui/manifest.json b/.spec/conformance/desktop_ui/manifest.json
index 37ab5d7e..46edf006 100644
--- a/.spec/conformance/desktop_ui/manifest.json
+++ b/.spec/conformance/desktop_ui/manifest.json
@@ -33,6 +33,7 @@
     {"requirement_id":"desktop_ui.structure.transport_translation_modules","status":"verified","notes":"Verified by dedicated transport translation and diagnostics modules.","evidence":[{"kind":"path_exists","path":"packages/desktop_ui/lib/desktop_ui/transport.ex"},{"kind":"path_exists","path":"packages/desktop_ui/lib/desktop_ui/transport/normalize.ex"},{"kind":"path_exists","path":"packages/desktop_ui/lib/desktop_ui/transport/signal.ex"},{"kind":"path_exists","path":"packages/desktop_ui/lib/desktop_ui/transport/diagnostics.ex"}]},
     {"requirement_id":"desktop_ui.structure.platform_artifact_modules","status":"verified","notes":"Verified by dedicated artifact policy, build staging, and packaging modules.","evidence":[{"kind":"path_exists","path":"packages/desktop_ui/lib/desktop_ui/artifacts.ex"},{"kind":"path_exists","path":"packages/desktop_ui/lib/desktop_ui/build.ex"},{"kind":"path_exists","path":"packages/desktop_ui/lib/desktop_ui/package.ex"}]},
     {"requirement_id":"desktop_ui.structure.no_dsl_or_iur_authorship","status":"verified","notes":"Verified as a maintained package boundary that does not author UnifiedUi or UnifiedIUR.","evidence":[{"kind":"path_exists","path":"packages/desktop_ui/lib/desktop_ui.ex"},{"kind":"command","run":"! grep -R -nE \"defmodule (UnifiedUi|UnifiedIUR)\" packages/desktop_ui/lib","cwd":"."}]},
+    {"requirement_id":"desktop_ui.structure.navigation_modules","status":"verified","notes":"Verified by dedicated navigation controller, registry, signal, and runtime integration modules plus focused navigation tests.","evidence":[{"kind":"path_exists","path":"packages/desktop_ui/lib/desktop_ui/navigation/controller.ex"},{"kind":"path_exists","path":"packages/desktop_ui/lib/desktop_ui/navigation/registry.ex"},{"kind":"path_exists","path":"packages/desktop_ui/lib/desktop_ui/navigation/signal.ex"},{"kind":"command","run":"mix deps.get && mix test test/desktop_ui/navigation/controller_test.exs test/desktop_ui/navigation/registry_test.exs test/desktop_ui/navigation/signal_test.exs test/desktop_ui/navigation/integration_test.exs test/desktop_ui/canonical_navigation_transport_integration_test.exs test/desktop_ui/canonical_navigation_desktop_runtime_integration_test.exs test/desktop_ui/canonical_navigation_non_web_examples_integration_test.exs","cwd":"packages/desktop_ui"}]},
     {"requirement_id":"desktop_ui.native_widgets.direct_native_surface","status":"verified","notes":"Verified by the direct-native widget API and widget test coverage.","evidence":[{"kind":"path_exists","path":"packages/desktop_ui/lib/desktop_ui/widget.ex"},{"kind":"path_exists","path":"packages/desktop_ui/lib/desktop_ui/widgets.ex"},{"kind":"path_exists","path":"packages/desktop_ui/test/desktop_ui/widgets_test.exs"},{"kind":"command","run":"mix deps.get && mix test","cwd":"packages/desktop_ui"}]},
     {"requirement_id":"desktop_ui.native_widgets.covers_canonical_iur_surface","status":"verified","notes":"Verified by the widget families, renderer mapping layer, and renderer tests.","evidence":[{"kind":"path_exists","path":"packages/desktop_ui/lib/desktop_ui/widgets.ex"},{"kind":"path_exists","path":"packages/desktop_ui/lib/desktop_ui/renderer/mapper.ex"},{"kind":"path_exists","path":"packages/desktop_ui/test/desktop_ui/renderer_test.exs"},{"kind":"command","run":"mix deps.get && mix test","cwd":"packages/desktop_ui"}]},
     {"requirement_id":"desktop_ui.native_widgets.multiplatform_widget_meaning","status":"verified","notes":"Verified by shared examples, platform diagnostics, and package tests across targets.","evidence":[{"kind":"path_exists","path":"packages/desktop_ui/lib/desktop_ui/examples.ex"},{"kind":"path_exists","path":"packages/desktop_ui/lib/desktop_ui/platform/integration.ex"},{"kind":"path_exists","path":"packages/desktop_ui/test/desktop_ui/platform_test.exs"},{"kind":"command","run":"mix deps.get && mix test","cwd":"packages/desktop_ui"}]},
@@ -56,6 +57,12 @@
     {"requirement_id":"desktop_ui.runtime.window_lifecycle_and_input","status":"verified","notes":"Verified by window lifecycle, event-loop, and event-routing runtime modules.","evidence":[{"kind":"path_exists","path":"packages/desktop_ui/lib/desktop_ui/runtime/window.ex"},{"kind":"path_exists","path":"packages/desktop_ui/lib/desktop_ui/runtime/event_loop.ex"},{"kind":"path_exists","path":"packages/desktop_ui/lib/desktop_ui/runtime/event_router.ex"},{"kind":"command","run":"mix deps.get && mix test","cwd":"packages/desktop_ui"}]},
     {"requirement_id":"desktop_ui.runtime.interactive_visible_execution","status":"verified","notes":"Verified by compiled-host hit-testing, focus, scrolling, overlay transitions, and multiwindow interaction roundtrip coverage.","evidence":[{"kind":"path_exists","path":"packages/desktop_ui/lib/desktop_ui/sdl3/interaction_script.ex"},{"kind":"path_exists","path":"packages/desktop_ui/lib/desktop_ui/sdl3/visible_runner.ex"},{"kind":"path_exists","path":"packages/desktop_ui/native/desktop_ui_sdl3_host/src/main.c"},{"kind":"path_exists","path":"packages/desktop_ui/test/desktop_ui/sdl3_interaction_script_test.exs"},{"kind":"path_exists","path":"packages/desktop_ui/test/desktop_ui/sdl3_visible_runner_test.exs"},{"kind":"path_exists","path":"packages/desktop_ui/test/desktop_ui/sdl3_interactive_native_behavior_test.exs"},{"kind":"command","run":"mix deps.get && mix test test/desktop_ui/sdl3_interaction_script_test.exs test/desktop_ui/sdl3_visible_runner_test.exs test/desktop_ui/sdl3_interactive_native_behavior_test.exs","cwd":"packages/desktop_ui"}]},
     {"requirement_id":"desktop_ui.runtime.platform_variation_bounded","status":"verified","notes":"Verified by explicit platform integration diagnostics and strict package validation.","evidence":[{"kind":"path_exists","path":"packages/desktop_ui/lib/desktop_ui/platform/integration.ex"},{"kind":"path_exists","path":"packages/desktop_ui/lib/desktop_ui/transport/normalize.ex"},{"kind":"command","run":"mix desktop_ui.validate --strict","cwd":"packages/desktop_ui"}]},
+    {"requirement_id":"desktop_ui.runtime.screen_navigation_support","status":"verified","notes":"Verified by the shared desktop runtime navigation layer and focused canonical navigation integration coverage.","evidence":[{"kind":"path_exists","path":"packages/desktop_ui/lib/desktop_ui/runtime/navigation.ex"},{"kind":"path_exists","path":"packages/desktop_ui/lib/desktop_ui/navigation.ex"},{"kind":"command","run":"mix deps.get && mix test test/desktop_ui/navigation/controller_test.exs test/desktop_ui/navigation/registry_test.exs test/desktop_ui/navigation/signal_test.exs test/desktop_ui/navigation/integration_test.exs test/desktop_ui/canonical_navigation_transport_integration_test.exs test/desktop_ui/canonical_navigation_desktop_runtime_integration_test.exs test/desktop_ui/canonical_navigation_non_web_examples_integration_test.exs","cwd":"packages/desktop_ui"}]},
+    {"requirement_id":"desktop_ui.runtime.navigation_controller_process","status":"verified","notes":"Verified by the navigation controller GenServer and focused controller lifecycle tests.","evidence":[{"kind":"path_exists","path":"packages/desktop_ui/lib/desktop_ui/navigation/controller.ex"},{"kind":"path_exists","path":"packages/desktop_ui/test/desktop_ui/navigation/controller_test.exs"},{"kind":"command","run":"mix deps.get && mix test test/desktop_ui/navigation/controller_test.exs test/desktop_ui/navigation/lifecycle_test.exs","cwd":"packages/desktop_ui"}]},
+    {"requirement_id":"desktop_ui.runtime.screen_registry","status":"verified","notes":"Verified by the screen registry modules and registry resolution coverage.","evidence":[{"kind":"path_exists","path":"packages/desktop_ui/lib/desktop_ui/navigation/registry.ex"},{"kind":"path_exists","path":"packages/desktop_ui/test/desktop_ui/navigation/registry_test.exs"},{"kind":"command","run":"mix deps.get && mix test test/desktop_ui/navigation/registry_test.exs test/desktop_ui/navigation/integration_test.exs","cwd":"packages/desktop_ui"}]},
+    {"requirement_id":"desktop_ui.runtime.navigation_actions","status":"verified","notes":"Verified by the canonical navigation action model and desktop runtime action coverage for navigate, replace, history, and modal transitions.","evidence":[{"kind":"path_exists","path":"packages/desktop_ui/lib/desktop_ui/navigation.ex"},{"kind":"path_exists","path":"packages/desktop_ui/lib/desktop_ui/navigation/signal.ex"},{"kind":"command","run":"mix deps.get && mix test test/desktop_ui/navigation/controller_test.exs test/desktop_ui/navigation/signal_test.exs test/desktop_ui/canonical_navigation_desktop_runtime_integration_test.exs","cwd":"packages/desktop_ui"}]},
+    {"requirement_id":"desktop_ui.runtime.navigation_event_routing","status":"verified","notes":"Verified by transport and runtime routing that carry canonical navigation transitions into the desktop runtime.","evidence":[{"kind":"path_exists","path":"packages/desktop_ui/lib/desktop_ui/transport.ex"},{"kind":"path_exists","path":"packages/desktop_ui/lib/desktop_ui/runtime/navigation.ex"},{"kind":"command","run":"mix deps.get && mix test test/desktop_ui/canonical_navigation_transport_integration_test.exs test/desktop_ui/canonical_navigation_desktop_runtime_integration_test.exs","cwd":"packages/desktop_ui"}]},
+    {"requirement_id":"desktop_ui.runtime.modal_stack_independence","status":"verified","notes":"Verified by navigation state and runtime integration coverage that keeps modal transitions independent from primary screen history.","evidence":[{"kind":"path_exists","path":"packages/desktop_ui/lib/desktop_ui/navigation/state.ex"},{"kind":"path_exists","path":"packages/desktop_ui/lib/desktop_ui/navigation/controller.ex"},{"kind":"command","run":"mix deps.get && mix test test/desktop_ui/navigation/state_test.exs test/desktop_ui/navigation/integration_test.exs test/desktop_ui/canonical_navigation_desktop_runtime_integration_test.exs","cwd":"packages/desktop_ui"}]},
     {"requirement_id":"desktop_ui.iur_renderer.accepts_canonical_iur","status":"verified","notes":"Verified by the canonical renderer entrypoints and renderer tests.","evidence":[{"kind":"path_exists","path":"packages/desktop_ui/lib/desktop_ui/renderer.ex"},{"kind":"path_exists","path":"packages/desktop_ui/lib/desktop_ui/renderer/mapper.ex"},{"kind":"command","run":"mix deps.get && mix test","cwd":"packages/desktop_ui"}]},
     {"requirement_id":"desktop_ui.iur_renderer.full_construct_coverage","status":"verified","notes":"Verified by canonical mapping coverage across widgets, layout, and layering surfaces.","evidence":[{"kind":"path_exists","path":"packages/desktop_ui/lib/desktop_ui/renderer/mapper.ex"},{"kind":"path_exists","path":"packages/desktop_ui/lib/desktop_ui/layout.ex"},{"kind":"path_exists","path":"packages/desktop_ui/lib/desktop_ui/layer.ex"},{"kind":"command","run":"mix deps.get && mix test","cwd":"packages/desktop_ui"}]},
     {"requirement_id":"desktop_ui.iur_renderer.deterministic_mapping","status":"verified","notes":"Verified by the canonical renderer mapping implementation and package-local tests.","evidence":[{"kind":"path_exists","path":"packages/desktop_ui/lib/desktop_ui/renderer.ex"},{"kind":"path_exists","path":"packages/desktop_ui/lib/desktop_ui/renderer/mapper.ex"},{"kind":"command","run":"mix deps.get && mix test","cwd":"packages/desktop_ui"}]},
diff --git a/.spec/conformance/elm_ui/manifest.json b/.spec/conformance/elm_ui/manifest.json
index 90461464..a4b4a172 100644
--- a/.spec/conformance/elm_ui/manifest.json
+++ b/.spec/conformance/elm_ui/manifest.json
@@ -518,6 +518,46 @@
         }
       ]
     },
+    {
+      "requirement_id": "elm_ui.server_runtime.canonical_navigation_transition_mapping",
+      "status": "verified",
+      "notes": "Verified by the server-side navigation mapper and focused canonical web-runtime navigation coverage.",
+      "evidence": [
+        {
+          "kind": "path_exists",
+          "path": "packages/elm_ui/lib/elm_ui/server_runtime/navigation.ex"
+        },
+        {
+          "kind": "path_exists",
+          "path": "packages/elm_ui/test/elm_ui/canonical_navigation_web_runtime_integration_test.exs"
+        },
+        {
+          "kind": "command",
+          "run": "mix deps.get && mix test test/elm_ui/runtime_navigation_test.exs test/elm_ui/canonical_navigation_web_runtime_integration_test.exs",
+          "cwd": "packages/elm_ui"
+        }
+      ]
+    },
+    {
+      "requirement_id": "elm_ui.server_runtime.host_route_resolution_boundary",
+      "status": "verified",
+      "notes": "Verified by the server-runtime navigation boundary that keeps host route resolution outside the authored contract while preserving host integration options.",
+      "evidence": [
+        {
+          "kind": "path_exists",
+          "path": "packages/elm_ui/lib/elm_ui/server_runtime/navigation.ex"
+        },
+        {
+          "kind": "path_exists",
+          "path": "packages/elm_ui/test/elm_ui/canonical_navigation_web_runtime_integration_test.exs"
+        },
+        {
+          "kind": "command",
+          "run": "mix deps.get && mix test test/elm_ui/runtime_navigation_test.exs test/elm_ui/canonical_navigation_web_runtime_integration_test.exs",
+          "cwd": "packages/elm_ui"
+        }
+      ]
+    },
     {
       "requirement_id": "elm_ui.frontend_runtime.elm_rendering_layer",
       "status": "verified",
diff --git a/.spec/conformance/live_ui/manifest.json b/.spec/conformance/live_ui/manifest.json
index 5531bc9b..d2be05eb 100644
--- a/.spec/conformance/live_ui/manifest.json
+++ b/.spec/conformance/live_ui/manifest.json
@@ -594,6 +594,50 @@
         }
       ]
     },
+    {
+      "requirement_id": "live_ui.runtime.canonical_navigation_transition_mapping",
+      "status": "verified",
+      "notes": "Verified by the canonical navigation runtime mapper, maintained comparison examples, and focused web-runtime navigation tests.",
+      "evidence": [
+        {
+          "kind": "path_exists",
+          "path": "packages/live_ui/lib/live_ui/runtime/navigation.ex"
+        },
+        {
+          "kind": "path_exists",
+          "path": "packages/live_ui/lib/live_ui/examples/web_navigation_transition_comparison.ex"
+        },
+        {
+          "kind": "path_exists",
+          "path": "packages/live_ui/test/live_ui/canonical_navigation_web_runtime_integration_test.exs"
+        },
+        {
+          "kind": "command",
+          "run": "mix deps.get && mix test test/live_ui/runtime_navigation_test.exs test/live_ui/canonical_navigation_web_runtime_integration_test.exs",
+          "cwd": "packages/live_ui"
+        }
+      ]
+    },
+    {
+      "requirement_id": "live_ui.runtime.host_route_resolution_boundary",
+      "status": "verified",
+      "notes": "Verified by the runtime navigation boundary that keeps host route lookup outside the authored contract while still allowing host integration in focused tests.",
+      "evidence": [
+        {
+          "kind": "path_exists",
+          "path": "packages/live_ui/lib/live_ui/runtime/navigation.ex"
+        },
+        {
+          "kind": "path_exists",
+          "path": "packages/live_ui/test/live_ui/canonical_navigation_web_runtime_integration_test.exs"
+        },
+        {
+          "kind": "command",
+          "run": "mix deps.get && mix test test/live_ui/runtime_navigation_test.exs test/live_ui/canonical_navigation_web_runtime_integration_test.exs",
+          "cwd": "packages/live_ui"
+        }
+      ]
+    },
     {
       "requirement_id": "live_ui.iur_renderer.accepts_canonical_iur",
       "status": "verified",
diff --git a/.spec/conformance/unified_iur/manifest.json b/.spec/conformance/unified_iur/manifest.json
index 9bc6b1a9..c8ec2c88 100644
--- a/.spec/conformance/unified_iur/manifest.json
+++ b/.spec/conformance/unified_iur/manifest.json
@@ -806,6 +806,50 @@
         }
       ]
     },
+    {
+      "requirement_id": "unified_iur.interactions.navigation_transition_representation",
+      "status": "verified",
+      "notes": "Verified by canonical navigation transition descriptor helpers, fixtures, and focused boundary integration coverage.",
+      "evidence": [
+        {
+          "kind": "path_exists",
+          "path": "packages/unified_iur/lib/unified_iur/interaction.ex"
+        },
+        {
+          "kind": "path_exists",
+          "path": "packages/unified_iur/lib/unified_iur/fixtures.ex"
+        },
+        {
+          "kind": "path_exists",
+          "path": "packages/unified_iur/test/unified_iur/canonical_navigation_boundary_integration_test.exs"
+        },
+        {
+          "kind": "command",
+          "run": "mix deps.get && mix test test/unified_iur/interaction_test.exs test/unified_iur/canonical_navigation_boundary_integration_test.exs",
+          "cwd": "packages/unified_iur"
+        }
+      ]
+    },
+    {
+      "requirement_id": "unified_iur.interactions.no_host_router_assumptions",
+      "status": "verified",
+      "notes": "Verified by canonical navigation boundary validation that rejects host-router leakage and preserves portable target descriptors.",
+      "evidence": [
+        {
+          "kind": "path_exists",
+          "path": "packages/unified_iur/lib/unified_iur/interactions/transport.ex"
+        },
+        {
+          "kind": "path_exists",
+          "path": "packages/unified_iur/test/unified_iur/canonical_navigation_boundary_integration_test.exs"
+        },
+        {
+          "kind": "command",
+          "run": "mix deps.get && mix test test/unified_iur/interactions_transport_test.exs test/unified_iur/canonical_navigation_boundary_integration_test.exs",
+          "cwd": "packages/unified_iur"
+        }
+      ]
+    },
     {
       "requirement_id": "unified_iur.interoperability.runtime_library_consumption",
       "status": "verified",
@@ -958,6 +1002,30 @@
           "cwd": "."
         }
       ]
+    },
+    {
+      "requirement_id": "unified_iur.tooling.navigation_transition_review_surfaces",
+      "status": "verified",
+      "notes": "Verified by maintained navigation fixtures plus inspection and tooling coverage that keep canonical transition descriptors reviewable without a runtime library.",
+      "evidence": [
+        {
+          "kind": "path_exists",
+          "path": "packages/unified_iur/lib/unified_iur/fixtures.ex"
+        },
+        {
+          "kind": "path_exists",
+          "path": "packages/unified_iur/lib/unified_iur/inspect.ex"
+        },
+        {
+          "kind": "path_exists",
+          "path": "packages/unified_iur/lib/unified_iur/tooling.ex"
+        },
+        {
+          "kind": "command",
+          "run": "mix deps.get && mix test test/unified_iur/canonical_navigation_boundary_integration_test.exs test/unified_iur/inspect_test.exs test/unified_iur/tooling_test.exs",
+          "cwd": "packages/unified_iur"
+        }
+      ]
     }
   ]
 }
diff --git a/.spec/conformance/unified_ui/manifest.json b/.spec/conformance/unified_ui/manifest.json
index 09e97df3..f52ebd51 100644
--- a/.spec/conformance/unified_ui/manifest.json
+++ b/.spec/conformance/unified_ui/manifest.json
@@ -623,6 +623,35 @@
       "inherits_from_requirement_id": "unified_ui.tooling.compiler_inspection",
       "notes": "Shares the current conformance status of unified_ui.tooling.compiler_inspection."
     },
+    {
+      "requirement_id": "unified_ui.signals.navigation_transition_actions",
+      "status": "verified",
+      "notes": "Verified by the canonical navigation authoring surface and focused navigation integration coverage.",
+      "evidence": [
+        {
+          "kind": "path_exists",
+          "path": "packages/unified-ui/lib/unified_ui/navigation.ex"
+        },
+        {
+          "kind": "path_exists",
+          "path": "packages/unified-ui/lib/unified_ui/dsl/entities/navigation.ex"
+        },
+        {
+          "kind": "path_exists",
+          "path": "packages/unified-ui/test/unified_ui/canonical_navigation_integration_test.exs"
+        },
+        {
+          "kind": "command",
+          "run": "mix deps.get && mix test test/unified_ui/canonical_navigation_integration_test.exs test/unified_ui/signals_test.exs",
+          "cwd": "packages/unified-ui"
+        }
+      ]
+    },
+    {
+      "requirement_id": "unified_ui.signals.navigation_symbolic_screen_targets",
+      "inherits_from_requirement_id": "unified_ui.signals.navigation_transition_actions",
+      "notes": "Shares the current conformance status of unified_ui.signals.navigation_transition_actions."
+    },
     {
       "requirement_id": "unified_ui.compiler.canonical_iur_output",
       "status": "verified",
@@ -700,6 +729,30 @@
       "inherits_from_requirement_id": "unified_ui.compiler.deterministic_results",
       "notes": "Shares the current conformance status of unified_ui.compiler.deterministic_results."
     },
+    {
+      "requirement_id": "unified_ui.compiler.navigation_transition_lowering",
+      "status": "verified",
+      "notes": "Verified by the compiler lowering path for canonical navigation descriptors and focused navigation compilation coverage.",
+      "evidence": [
+        {
+          "kind": "path_exists",
+          "path": "packages/unified-ui/lib/unified_ui/compiler/pipeline.ex"
+        },
+        {
+          "kind": "path_exists",
+          "path": "packages/unified-ui/lib/unified_ui/navigation.ex"
+        },
+        {
+          "kind": "path_exists",
+          "path": "packages/unified-ui/test/unified_ui/canonical_navigation_integration_test.exs"
+        },
+        {
+          "kind": "command",
+          "run": "mix deps.get && mix test test/unified_ui/canonical_navigation_integration_test.exs test/unified_ui/signals_test.exs",
+          "cwd": "packages/unified-ui"
+        }
+      ]
+    },
     {
       "requirement_id": "unified_ui.tooling.authoring_validation_workflow",
       "status": "verified",
diff --git a/.spec/planning/desktop_ui/spec-traceability.json b/.spec/planning/desktop_ui/spec-traceability.json
index d563890e..bf7d4bce 100644
--- a/.spec/planning/desktop_ui/spec-traceability.json
+++ b/.spec/planning/desktop_ui/spec-traceability.json
@@ -478,6 +478,19 @@
       ],
       "ownership_note": "Direct desktop_ui boundary obligation."
     },
+    {
+      "requirement_id": "desktop_ui.structure.navigation_modules",
+      "scope": "direct",
+      "source_file": ".spec/specs/desktop_ui/structure.spec.md",
+      "primary_plan_refs": [
+        "12.1.1"
+      ],
+      "supporting_plan_refs": [
+        "12.2.1",
+        "12.3.2"
+      ],
+      "ownership_note": "Direct navigation-module boundary obligation."
+    },
     {
       "requirement_id": "desktop_ui.native_widgets.direct_native_surface",
       "scope": "direct",
@@ -818,6 +831,80 @@
       ],
       "ownership_note": "Direct bounded-platform-variation obligation."
     },
+    {
+      "requirement_id": "desktop_ui.runtime.screen_navigation_support",
+      "scope": "direct",
+      "source_file": ".spec/specs/desktop_ui/runtime.spec.md",
+      "primary_plan_refs": [
+        "12.1.1"
+      ],
+      "supporting_plan_refs": [
+        "12.2.1",
+        "12.4.2"
+      ],
+      "ownership_note": "Direct screen-navigation runtime obligation."
+    },
+    {
+      "requirement_id": "desktop_ui.runtime.navigation_controller_process",
+      "scope": "direct",
+      "source_file": ".spec/specs/desktop_ui/runtime.spec.md",
+      "primary_plan_refs": [
+        "12.1.1"
+      ],
+      "supporting_plan_refs": [
+        "12.1.2"
+      ],
+      "ownership_note": "Direct navigation-controller process obligation."
+    },
+    {
+      "requirement_id": "desktop_ui.runtime.screen_registry",
+      "scope": "direct",
+      "source_file": ".spec/specs/desktop_ui/runtime.spec.md",
+      "primary_plan_refs": [
+        "12.2.1"
+      ],
+      "supporting_plan_refs": [
+        "12.2.2"
+      ],
+      "ownership_note": "Direct screen-registry obligation."
+    },
+    {
+      "requirement_id": "desktop_ui.runtime.navigation_actions",
+      "scope": "direct",
+      "source_file": ".spec/specs/desktop_ui/runtime.spec.md",
+      "primary_plan_refs": [
+        "12.1.2"
+      ],
+      "supporting_plan_refs": [
+        "12.3.1"
+      ],
+      "ownership_note": "Direct navigation-action vocabulary obligation."
+    },
+    {
+      "requirement_id": "desktop_ui.runtime.navigation_event_routing",
+      "scope": "direct",
+      "source_file": ".spec/specs/desktop_ui/runtime.spec.md",
+      "primary_plan_refs": [
+        "12.3.2"
+      ],
+      "supporting_plan_refs": [
+        "12.4.2"
+      ],
+      "ownership_note": "Direct navigation event-routing obligation."
+    },
+    {
+      "requirement_id": "desktop_ui.runtime.modal_stack_independence",
+      "scope": "direct",
+      "source_file": ".spec/specs/desktop_ui/runtime.spec.md",
+      "primary_plan_refs": [
+        "12.1.1"
+      ],
+      "supporting_plan_refs": [
+        "12.1.2",
+        "12.4.3"
+      ],
+      "ownership_note": "Direct modal-stack independence obligation."
+    },
     {
       "requirement_id": "desktop_ui.iur_renderer.accepts_canonical_iur",
       "scope": "direct",
diff --git a/.spec/planning/desktop_ui/spec-traceability.md b/.spec/planning/desktop_ui/spec-traceability.md
index 307d61f8..b5657201 100644
--- a/.spec/planning/desktop_ui/spec-traceability.md
+++ b/.spec/planning/desktop_ui/spec-traceability.md
@@ -68,6 +68,7 @@ tasks because they govern other runtime packages:
 | `desktop_ui.structure.transport_translation_modules` | `1.1.2` | `4.1.1`, `4.2.1` | Direct transport-structure obligation. |
 | `desktop_ui.structure.platform_artifact_modules` | `5.3.1` | `5.3.2`, `6.3.1` | Direct artifact-module boundary obligation. |
 | `desktop_ui.structure.no_dsl_or_iur_authorship` | `1.1.2` | `6.4.2` | Direct desktop_ui boundary obligation. |
+| `desktop_ui.structure.navigation_modules` | `12.1.1` | `12.2.1`, `12.3.2` | Direct navigation-module boundary obligation. |
 ### `native_widgets.spec.md`
 | Requirement ID | Primary plan coverage | Supporting coverage | Ownership note |
 | --- | --- | --- | --- |
@@ -85,6 +86,12 @@ tasks because they govern other runtime packages:
 | `desktop_ui.runtime.window_lifecycle_and_input` | `1.2.2` | `1.5.3.1`, `4.1.2`, `4.2.2`, `5.5.2`, `10.3.1`, `10.3.2` | Direct runtime lifecycle and input obligation. |
 | `desktop_ui.runtime.interactive_visible_execution` | `10.3.1` | `10.3.2`, `10.4.1`, `10.5.1` | Direct interactive visible-window execution obligation. |
 | `desktop_ui.runtime.platform_variation_bounded` | `1.3.2` | `5.2.2`, `5.3.2` | Direct bounded-platform-variation obligation. |
+| `desktop_ui.runtime.screen_navigation_support` | `12.1.1` | `12.2.1`, `12.4.2` | Direct screen-navigation runtime obligation. |
+| `desktop_ui.runtime.navigation_controller_process` | `12.1.1` | `12.1.2` | Direct navigation-controller process obligation. |
+| `desktop_ui.runtime.screen_registry` | `12.2.1` | `12.2.2` | Direct screen-registry obligation. |
+| `desktop_ui.runtime.navigation_actions` | `12.1.2` | `12.3.1` | Direct navigation-action vocabulary obligation. |
+| `desktop_ui.runtime.navigation_event_routing` | `12.3.2` | `12.4.2` | Direct navigation event-routing obligation. |
+| `desktop_ui.runtime.modal_stack_independence` | `12.1.1` | `12.1.2`, `12.4.3` | Direct modal-stack independence obligation. |
 ### `sdl3_runtime_rendering.spec.md`
 | Requirement ID | Primary plan coverage | Supporting coverage | Ownership note |
 | --- | --- | --- | --- |
diff --git a/.spec/planning/elm_ui/spec-traceability.json b/.spec/planning/elm_ui/spec-traceability.json
index b8390981..f1345d78 100644
--- a/.spec/planning/elm_ui/spec-traceability.json
+++ b/.spec/planning/elm_ui/spec-traceability.json
@@ -615,6 +615,32 @@
       ],
       "ownership_note": "Direct server-authority obligation."
     },
+    {
+      "requirement_id": "elm_ui.server_runtime.canonical_navigation_transition_mapping",
+      "scope": "direct",
+      "source_file": ".spec/specs/elm_ui/server_runtime.spec.md",
+      "primary_plan_refs": [
+        "4.1.1"
+      ],
+      "supporting_plan_refs": [
+        "4.2.1",
+        "4.5.1"
+      ],
+      "ownership_note": "Direct canonical navigation transition-mapping obligation."
+    },
+    {
+      "requirement_id": "elm_ui.server_runtime.host_route_resolution_boundary",
+      "scope": "direct",
+      "source_file": ".spec/specs/elm_ui/server_runtime.spec.md",
+      "primary_plan_refs": [
+        "4.3.1"
+      ],
+      "supporting_plan_refs": [
+        "4.2.1",
+        "4.5.2"
+      ],
+      "ownership_note": "Direct host-route boundary obligation for canonical navigation."
+    },
     {
       "requirement_id": "elm_ui.frontend_runtime.elm_rendering_layer",
       "scope": "direct",
diff --git a/.spec/planning/elm_ui/spec-traceability.md b/.spec/planning/elm_ui/spec-traceability.md
index a5ef23cb..986d7cf5 100644
--- a/.spec/planning/elm_ui/spec-traceability.md
+++ b/.spec/planning/elm_ui/spec-traceability.md
@@ -83,6 +83,8 @@ tasks because they govern other runtime packages:
 | `elm_ui.server_runtime.handle_boundary_events` | `4.2.1` | `4.1.1`, `4.3.1`, `4.5.1` | Direct boundary-event obligation. |
 | `elm_ui.server_runtime.direct_and_iur_entrypoints_share_runtime` | `1.2.1` | `2.3.2`, `3.3.2`, `4.5.2` | Direct runtime-convergence obligation. |
 | `elm_ui.server_runtime.browser_state_is_bounded` | `1.2.1` | `1.3.1`, `4.2.2`, `5.2.2` | Direct server-authority obligation. |
+| `elm_ui.server_runtime.canonical_navigation_transition_mapping` | `4.1.1` | `4.2.1`, `4.5.1` | Direct canonical navigation transition-mapping obligation. |
+| `elm_ui.server_runtime.host_route_resolution_boundary` | `4.3.1` | `4.2.1`, `4.5.2` | Direct host-route boundary obligation for canonical navigation. |
 ### `frontend_runtime.spec.md`
 | Requirement ID | Primary plan coverage | Supporting coverage | Ownership note |
 | --- | --- | --- | --- |
diff --git a/.spec/planning/live_ui/spec-traceability.json b/.spec/planning/live_ui/spec-traceability.json
index 937cbcf0..498e5633 100644
--- a/.spec/planning/live_ui/spec-traceability.json
+++ b/.spec/planning/live_ui/spec-traceability.json
@@ -692,6 +692,32 @@
       ],
       "ownership_note": "Phase 11: Widget components may own bounded local UI lifecycle state."
     },
+    {
+      "requirement_id": "live_ui.runtime.canonical_navigation_transition_mapping",
+      "scope": "direct",
+      "source_file": ".spec/specs/live_ui/runtime.spec.md",
+      "primary_plan_refs": [
+        "4.1.1"
+      ],
+      "supporting_plan_refs": [
+        "4.2.1",
+        "4.5.1"
+      ],
+      "ownership_note": "Direct canonical navigation transition-mapping obligation."
+    },
+    {
+      "requirement_id": "live_ui.runtime.host_route_resolution_boundary",
+      "scope": "direct",
+      "source_file": ".spec/specs/live_ui/runtime.spec.md",
+      "primary_plan_refs": [
+        "4.3.1"
+      ],
+      "supporting_plan_refs": [
+        "4.2.1",
+        "4.5.2"
+      ],
+      "ownership_note": "Direct host-route boundary obligation for canonical navigation."
+    },
     {
       "requirement_id": "live_ui.iur_renderer.accepts_canonical_iur",
       "scope": "direct",
diff --git a/.spec/planning/live_ui/spec-traceability.md b/.spec/planning/live_ui/spec-traceability.md
index 6347999f..594105a3 100644
--- a/.spec/planning/live_ui/spec-traceability.md
+++ b/.spec/planning/live_ui/spec-traceability.md
@@ -90,6 +90,8 @@ tasks because they govern other runtime packages:
 | `live_ui.runtime.native_and_iur_entrypoints_share_runtime` | `1.3.1` | `2.3.2`, `3.3.1`, `4.5.2` | Direct runtime-convergence obligation. |
 | `live_ui.runtime.state_and_render_continuity` | `2.3.2` | `3.3.1`, `5.3.2`, `5.5.2` | Direct continuity obligation. |
 | `live_ui.runtime.widget_component_local_state` | `11.2` | `11.2.2` | Phase 11: Widget components may own bounded local UI lifecycle state. |
+| `live_ui.runtime.canonical_navigation_transition_mapping` | `4.1.1` | `4.2.1`, `4.5.1` | Direct canonical navigation transition-mapping obligation. |
+| `live_ui.runtime.host_route_resolution_boundary` | `4.3.1` | `4.2.1`, `4.5.2` | Direct host-route boundary obligation for canonical navigation. |
 ### `iur_renderer.spec.md`
 | Requirement ID | Primary plan coverage | Supporting coverage | Ownership note |
 | --- | --- | --- | --- |
diff --git a/.spec/planning/unified_iur/spec-traceability.json b/.spec/planning/unified_iur/spec-traceability.json
index fb63c53d..29be770f 100644
--- a/.spec/planning/unified_iur/spec-traceability.json
+++ b/.spec/planning/unified_iur/spec-traceability.json
@@ -599,6 +599,30 @@
       ],
       "ownership_note": "Direct binding-attachment requirement."
     },
+    {
+      "requirement_id": "unified_iur.interactions.navigation_transition_representation",
+      "scope": "direct",
+      "source_file": ".spec/specs/unified-iur/interactions.spec.md",
+      "primary_plan_refs": [
+        "4.3.1"
+      ],
+      "supporting_plan_refs": [
+        "4.5.2"
+      ],
+      "ownership_note": "Direct canonical navigation transition-representation requirement."
+    },
+    {
+      "requirement_id": "unified_iur.interactions.no_host_router_assumptions",
+      "scope": "direct",
+      "source_file": ".spec/specs/unified-iur/interactions.spec.md",
+      "primary_plan_refs": [
+        "4.3.1"
+      ],
+      "supporting_plan_refs": [
+        "4.5.2"
+      ],
+      "ownership_note": "Direct host-router-independence requirement for navigation descriptors."
+    },
     {
       "requirement_id": "unified_iur.interoperability.runtime_library_consumption",
       "scope": "direct",
@@ -703,6 +727,18 @@
         "6.4.2"
       ],
       "ownership_note": "Direct documentation-surface requirement."
+    },
+    {
+      "requirement_id": "unified_iur.tooling.navigation_transition_review_surfaces",
+      "scope": "direct",
+      "source_file": ".spec/specs/unified-iur/tooling.spec.md",
+      "primary_plan_refs": [
+        "6.1.1"
+      ],
+      "supporting_plan_refs": [
+        "6.2.1"
+      ],
+      "ownership_note": "Direct navigation-fixture review-surface requirement."
     }
   ]
 }
diff --git a/.spec/planning/unified_iur/spec-traceability.md b/.spec/planning/unified_iur/spec-traceability.md
index 7ffbf9e8..b14e77fb 100644
--- a/.spec/planning/unified_iur/spec-traceability.md
+++ b/.spec/planning/unified_iur/spec-traceability.md
@@ -121,6 +121,8 @@ tasks because they govern other runtime packages:
 | `unified_iur.interactions.standard_interaction_families` | `4.3.1` | - | Direct standard interaction-family requirement. |
 | `unified_iur.interactions.data_binding_representation` | `4.3.2` | - | Direct data-binding representation requirement. |
 | `unified_iur.interactions.element_binding_attachment` | `4.4.2` | `4.3.2` | Direct binding-attachment requirement. |
+| `unified_iur.interactions.navigation_transition_representation` | `4.3.1` | `4.5.2` | Direct canonical navigation transition-representation requirement. |
+| `unified_iur.interactions.no_host_router_assumptions` | `4.3.1` | `4.5.2` | Direct host-router-independence requirement for navigation descriptors. |
 ### `unified-iur/interoperability.spec.md`
 | Requirement ID | Primary plan coverage | Supporting coverage | Ownership note |
 | --- | --- | --- | --- |
@@ -136,6 +138,7 @@ tasks because they govern other runtime packages:
 | `unified_iur.tooling.introspection_helpers` | `6.2.1` | - | Direct inspection and export tooling requirement. |
 | `unified_iur.tooling.validation_workflow` | `6.3.1` | `6.3.2` | Direct validation-workflow requirement. |
 | `unified_iur.tooling.documentation_surface` | `6.4.1` | `6.4.2` | Direct documentation-surface requirement. |
+| `unified_iur.tooling.navigation_transition_review_surfaces` | `6.1.1` | `6.2.1` | Direct navigation-fixture review-surface requirement. |
 ## Upstream Canonical Input And Authoring Constraints
 These specs are referenced by the planning index because they define the
 canonical input surface and authored boundary that `unified_iur` must consume or
diff --git a/.spec/planning/unified_ui/spec-traceability.json b/.spec/planning/unified_ui/spec-traceability.json
index 38fc5176..f5992e0b 100644
--- a/.spec/planning/unified_ui/spec-traceability.json
+++ b/.spec/planning/unified_ui/spec-traceability.json
@@ -433,6 +433,22 @@
       "primary_plan_refs": ["4.4.2"],
       "ownership_note": "Direct signal validation and introspection requirement."
     },
+    {
+      "requirement_id": "unified_ui.signals.navigation_transition_actions",
+      "scope": "direct",
+      "source_file": ".spec/specs/unified-ui/signals.spec.md",
+      "primary_plan_refs": ["4.3.1"],
+      "supporting_plan_refs": ["4.5.2"],
+      "ownership_note": "Direct canonical navigation action-vocabulary requirement."
+    },
+    {
+      "requirement_id": "unified_ui.signals.navigation_symbolic_screen_targets",
+      "scope": "direct",
+      "source_file": ".spec/specs/unified-ui/signals.spec.md",
+      "primary_plan_refs": ["4.3.2"],
+      "supporting_plan_refs": ["4.5.2"],
+      "ownership_note": "Direct symbolic screen-target authoring requirement."
+    },
     {
       "requirement_id": "unified_ui.compiler.canonical_iur_output",
       "scope": "direct",
@@ -475,6 +491,14 @@
       "primary_plan_refs": ["5.2.1"],
       "ownership_note": "Direct style, theme, and layer resolution requirement."
     },
+    {
+      "requirement_id": "unified_ui.compiler.navigation_transition_lowering",
+      "scope": "direct",
+      "source_file": ".spec/specs/unified-ui/compiler.spec.md",
+      "primary_plan_refs": ["5.1.2"],
+      "supporting_plan_refs": ["5.2.2"],
+      "ownership_note": "Direct canonical navigation lowering requirement."
+    },
     {
       "requirement_id": "unified_ui.tooling.authoring_validation_workflow",
       "scope": "direct",
diff --git a/.spec/planning/unified_ui/spec-traceability.md b/.spec/planning/unified_ui/spec-traceability.md
index 8f93c9db..eb9436fd 100644
--- a/.spec/planning/unified_ui/spec-traceability.md
+++ b/.spec/planning/unified_ui/spec-traceability.md
@@ -116,6 +116,8 @@ tasks because they govern other runtime packages:
 | `unified_ui.signals.no_runtime_local_event_leakage` | `4.4.2` | - | Direct runtime-leakage rejection requirement. |
 | `unified_ui.signals.standard_interaction_families` | `4.3.1` | - | Direct standard interaction-family requirement. |
 | `unified_ui.signals.validation_and_introspection` | `4.4.2` | - | Direct signal validation and introspection requirement. |
+| `unified_ui.signals.navigation_transition_actions` | `4.3.1` | `4.5.2` | Direct canonical navigation action-vocabulary requirement. |
+| `unified_ui.signals.navigation_symbolic_screen_targets` | `4.3.2` | `4.5.2` | Direct symbolic screen-target authoring requirement. |
 ### `unified-ui/compiler.spec.md`
 | Requirement ID | Primary plan coverage | Supporting coverage | Ownership note |
 | --- | --- | --- | --- |
@@ -125,6 +127,7 @@ tasks because they govern other runtime packages:
 | `unified_ui.compiler.no_renderer_output_modes` | `5.4.2` | - | Direct renderer-independence requirement for compilation output. |
 | `unified_ui.compiler.runtime_independent_bindings` | `5.2.2` | - | Direct runtime-independent binding compilation requirement. |
 | `unified_ui.compiler.style_theme_layer_resolution` | `5.2.1` | - | Direct style, theme, and layer resolution requirement. |
+| `unified_ui.compiler.navigation_transition_lowering` | `5.1.2` | `5.2.2` | Direct canonical navigation lowering requirement. |
 ### `unified-ui/tooling.spec.md`
 | Requirement ID | Primary plan coverage | Supporting coverage | Ownership note |
 | --- | --- | --- | --- |
diff --git a/packages/desktop_ui/lib/desktop_ui/examples.ex b/packages/desktop_ui/lib/desktop_ui/examples.ex
index a9ebee05..ad8d008c 100644
--- a/packages/desktop_ui/lib/desktop_ui/examples.ex
+++ b/packages/desktop_ui/lib/desktop_ui/examples.ex
@@ -5,6 +5,53 @@ defmodule DesktopUi.Examples do
 
   alias UnifiedIUR.Element
   alias UnifiedIUR.Element.Child
+  alias UnifiedIUR.Interactions.Transport, as: BoundaryTransport
+
+  defmodule NavigationReview do
+    defmodule HomeScreen do
+      def render(_assigns), do: %{}
+    end
+
+    defmodule SettingsScreen do
+      def render(_assigns), do: %{}
+    end
+
+    defmodule ReportsScreen do
+      def render(_assigns), do: %{}
+    end
+
+    defmodule SettingsDialogScreen do
+      def render(_assigns), do: %{}
+    end
+
+    defmodule Registry do
+      @behaviour DesktopUi.Navigation.Registry
+
+      @impl true
+      def register do
+        %{
+          home: {HomeScreen, title: "Home"},
+          settings: {SettingsScreen, title: "Settings"},
+          reports: {ReportsScreen, title: "Reports"},
+          settings_dialog: {SettingsDialogScreen, title: "Settings Dialog", modal_only?: true}
+        }
+      end
+
+      @impl true
+      def get_screen(:home), do: HomeScreen
+      def get_screen(:settings), do: SettingsScreen
+      def get_screen(:reports), do: ReportsScreen
+      def get_screen(:settings_dialog), do: SettingsDialogScreen
+      def get_screen(_), do: nil
+
+      @impl true
+      def screen_metadata(:home), do: %{title: "Home"}
+      def screen_metadata(:settings), do: %{title: "Settings"}
+      def screen_metadata(:reports), do: %{title: "Reports"}
+      def screen_metadata(:settings_dialog), do: %{title: "Settings Dialog", modal_only?: true}
+      def screen_metadata(_), do: %{}
+    end
+  end
 
   @spec native_foundational_screen() :: map()
   def native_foundational_screen do
@@ -904,7 +951,10 @@ defmodule DesktopUi.Examples do
           DesktopUi.Widgets.column("nav-layout", [
             DesktopUi.Widgets.content("nav-header", [
               DesktopUi.Widgets.label("nav-title", "Navigation Demo"),
-              DesktopUi.Widgets.text("nav-subtitle", "Demonstrates home, list, and detail screens")
+              DesktopUi.Widgets.text(
+                "nav-subtitle",
+                "Demonstrates home, list, and detail screens"
+              )
             ]),
             DesktopUi.Widgets.menu(
               "nav-menu",
@@ -1063,6 +1113,152 @@ defmodule DesktopUi.Examples do
     }
   end
 
+  @spec navigation_transition_review() :: map()
+  def navigation_transition_review do
+    fixtures = navigation_fixtures()
+    screen = navigation_review_screen()
+
+    Enum.each(navigation_review_modules(), &Code.ensure_loaded?/1)
+
+    {:ok, runtime_state} =
+      DesktopUi.Runtime.mount_native_screen(screen,
+        platform_target: :linux,
+        screen_registry: NavigationReview.Registry,
+        navigation_screen_id: :home
+      )
+
+    primary_window = runtime_state.windows.primary
+
+    {:ok, after_navigate, navigate_route} =
+      DesktopUi.Runtime.dispatch_native_event(
+        runtime_state,
+        family: :navigation,
+        intent: fixtures.navigate.interaction.intent,
+        widget_id: "settings-link",
+        target: fixtures.navigate.descriptor.target,
+        payload: fixtures.navigate.signal_data
+      )
+
+    {:ok, with_modal, modal_route} =
+      DesktopUi.Runtime.dispatch_native_event(
+        after_navigate,
+        family: :navigation,
+        intent: fixtures.modal.interaction.intent,
+        widget_id: "settings-dialog-button",
+        target: fixtures.modal.descriptor.target,
+        payload: fixtures.modal.signal_data
+      )
+
+    {:ok, after_close, close_route} =
+      DesktopUi.Runtime.dispatch_native_event(
+        with_modal,
+        family: :navigation,
+        intent: :close_settings_modal,
+        widget_id: "close-settings-dialog",
+        target: close_modal_target()
+      )
+
+    {:ok, after_reports, reports_route} =
+      DesktopUi.Runtime.dispatch_native_event(
+        after_close,
+        family: :navigation,
+        intent: :open_reports_screen,
+        widget_id: "reports-link",
+        target: reports_target()
+      )
+
+    {:ok, after_back, back_route} =
+      DesktopUi.Runtime.dispatch_native_event(
+        after_reports,
+        family: :navigation,
+        intent: fixtures.back.interaction.intent,
+        widget_id: "back-button",
+        target: fixtures.back.descriptor.target,
+        payload: fixtures.back.signal_data
+      )
+
+    {:ok, after_forward, forward_route} =
+      DesktopUi.Runtime.dispatch_native_event(
+        after_back,
+        family: :navigation,
+        intent: :go_forward,
+        widget_id: "forward-button",
+        target: forward_target()
+      )
+
+    {:ok, after_replace, replace_route} =
+      DesktopUi.Runtime.dispatch_native_event(
+        after_forward,
+        family: :navigation,
+        intent: fixtures.replace.interaction.intent,
+        widget_id: "home-link",
+        target: fixtures.replace.descriptor.target,
+        payload: fixtures.replace.signal_data
+      )
+
+    expected_targets = navigation_fixture_targets(fixtures)
+
+    route_summaries = %{
+      navigate: navigation_route_summary(navigate_route),
+      modal: navigation_route_summary(modal_route),
+      close_modal: navigation_route_summary(close_route),
+      reports: navigation_route_summary(reports_route),
+      back: navigation_route_summary(back_route),
+      forward: navigation_route_summary(forward_route),
+      replace: navigation_route_summary(replace_route)
+    }
+
+    state_summaries = %{
+      mounted: desktop_navigation_state_summary(runtime_state),
+      after_navigate: desktop_navigation_state_summary(after_navigate),
+      with_modal: desktop_navigation_state_summary(with_modal),
+      after_close: desktop_navigation_state_summary(after_close),
+      after_reports: desktop_navigation_state_summary(after_reports),
+      after_back: desktop_navigation_state_summary(after_back),
+      after_forward: desktop_navigation_state_summary(after_forward),
+      after_replace: desktop_navigation_state_summary(after_replace)
+    }
+
+    %{
+      id: :navigation_transition_review,
+      summary:
+        "Review canonical navigation transitions through the desktop screen registry and one shared window",
+      coverage: [
+        :canonical_navigation_transitions,
+        :screen_registry,
+        :history_stack,
+        :modal_stack
+      ],
+      fixture_ids: navigation_fixture_ids(),
+      fixture_targets: expected_targets,
+      routes: route_summaries,
+      states: state_summaries,
+      parity: %{
+        shared_fixture_targets_consumed?:
+          Enum.all?(route_summaries, fn {step, summary} ->
+            summary.target == expected_targets[step] and no_host_route_syntax?(summary.target)
+          end),
+        window_preserved_across_transitions?:
+          Enum.all?(state_summaries, fn {_step, summary} ->
+            summary.primary_window == primary_window
+          end),
+        registry_resolution_preserved?:
+          state_summaries.after_navigate.title == "Settings" and
+            state_summaries.after_reports.title == "Reports" and
+            state_summaries.after_replace.title == "Home",
+        history_semantics_preserved?:
+          state_summaries.after_back.screen_id == "settings" and
+            state_summaries.after_forward.screen_id == "reports" and
+            state_summaries.after_replace.screen_id == "home" and
+            state_summaries.after_replace.history_depth == 2,
+        modal_stack_preserved?:
+          state_summaries.with_modal.modal_depth == 1 and
+            state_summaries.after_close.modal_depth == 0 and
+            state_summaries.after_close.screen_id == "settings"
+      }
+    }
+  end
+
   @spec normalized_input_comparison() :: map()
   def normalized_input_comparison do
     shortcut_profiles =
@@ -1210,7 +1406,8 @@ defmodule DesktopUi.Examples do
       :advanced_continuity,
       :transport_flow_review,
       :normalized_input_profiles,
-      :styled_continuity_review
+      :styled_continuity_review,
+      :navigation_transition_review
     ]
 
   defp catalog_by_category(category) do
@@ -1378,6 +1575,24 @@ defmodule DesktopUi.Examples do
         parity_with: [:native_styled_review, :canonical_styled_review],
         coverage: [:style_continuity, :theme_alignment, :artifact_targets]
       },
+      %{
+        id: :navigation_transition_review,
+        category: :mixed,
+        workflow: :navigation_review,
+        parity_group: :navigation_transition_review,
+        parity_with: [
+          :basic_navigation,
+          :history_navigation,
+          :modal_navigation,
+          :master_detail_navigation
+        ],
+        coverage: [
+          :canonical_navigation_transitions,
+          :screen_registry,
+          :history_stack,
+          :modal_stack
+        ]
+      },
       # Navigation examples
       %{
         id: :basic_navigation,
@@ -1428,6 +1643,139 @@ defmodule DesktopUi.Examples do
     Enum.reduce(Map.get(node, :children, []), acc ++ [node.kind], &flatten_kinds(&1, &2))
   end
 
+  defp navigation_fixtures do
+    %{
+      navigate: BoundaryTransport.boundary_fixture!("screen_transition--settings_profile"),
+      replace: BoundaryTransport.boundary_fixture!("replace_transition--home"),
+      back: BoundaryTransport.boundary_fixture!("history_transition--back"),
+      modal: BoundaryTransport.boundary_fixture!("modal_transition--settings_dialog")
+    }
+  end
+
+  defp navigation_fixture_ids do
+    [
+      "screen_transition--settings_profile",
+      "replace_transition--home",
+      "history_transition--back",
+      "modal_transition--settings_dialog"
+    ]
+  end
+
+  defp navigation_fixture_targets(fixtures) do
+    %{
+      navigate: fixtures.navigate.descriptor.target,
+      replace: fixtures.replace.descriptor.target,
+      back: fixtures.back.descriptor.target,
+      modal: fixtures.modal.descriptor.target,
+      close_modal: close_modal_target(),
+      reports: reports_target(),
+      forward: forward_target()
+    }
+  end
+
+  defp navigation_review_modules do
+    [
+      NavigationReview.HomeScreen,
+      NavigationReview.SettingsScreen,
+      NavigationReview.ReportsScreen,
+      NavigationReview.SettingsDialogScreen,
+      NavigationReview.Registry
+    ]
+  end
+
+  defp navigation_review_screen do
+    %{
+      id: "desktop-navigation-review",
+      title: "Desktop Navigation Review",
+      root:
+        DesktopUi.Widgets.window("desktop-navigation-window", "Desktop Navigation Review", [
+          DesktopUi.Widgets.column("desktop-navigation-layout", [
+            DesktopUi.Widgets.content("desktop-navigation-header", [
+              DesktopUi.Widgets.label("desktop-navigation-title", "Desktop Navigation Review"),
+              DesktopUi.Widgets.text(
+                "desktop-navigation-subtitle",
+                "Registered screens, history traversal, modal dialogs, and replacement transitions"
+              )
+            ]),
+            DesktopUi.Widgets.row("desktop-navigation-actions", [
+              DesktopUi.Widgets.button("settings-link", "Settings", navigate_to: :settings),
+              DesktopUi.Widgets.button("reports-link", "Reports", navigate_to: :reports),
+              DesktopUi.Widgets.button("home-link", "Replace With Home", replace_with: :home)
+            ]),
+            DesktopUi.Widgets.row("desktop-navigation-history", [
+              DesktopUi.Widgets.button("back-button", "Back", go_back: true),
+              DesktopUi.Widgets.button("forward-button", "Forward", go_forward: true)
+            ]),
+            DesktopUi.Widgets.row("desktop-navigation-modal", [
+              DesktopUi.Widgets.button("settings-dialog-button", "Open Settings Dialog",
+                open_modal: :settings_dialog,
+                navigate_params: %{mode: :advanced}
+              ),
+              DesktopUi.Widgets.button("close-settings-dialog", "Close Settings Dialog",
+                close_modal: true
+              )
+            ])
+          ])
+        ])
+    }
+  end
+
+  defp reports_target do
+    %{navigation: %{action: :navigate_to, screen: :reports, params: %{section: :daily}}}
+  end
+
+  defp forward_target do
+    %{navigation: %{action: :go_forward}}
+  end
+
+  defp close_modal_target do
+    %{navigation: %{action: :close_modal, modal: :settings_dialog}}
+  end
+
+  defp desktop_navigation_state_summary(state) do
+    current_modal =
+      case DesktopUi.Navigation.Integration.current_modal(state) do
+        {id, _module, params} -> %{modal: id, params: params}
+        nil -> nil
+      end
+
+    %{
+      runtime_id: state.runtime_id,
+      screen_id: state.screen_id,
+      title: state.title,
+      current_screen_module: state.current_screen_module,
+      screen_params: state.screen_params,
+      primary_window: state.windows.primary,
+      history_depth: length(state.navigation_state.history),
+      forward_depth: length(state.navigation_state.forward),
+      modal_depth: length(state.navigation_state.modals),
+      current_modal: current_modal
+    }
+  end
+
+  defp navigation_route_summary(route_result) do
+    translation = route_result.translation
+
+    %{
+      route: route_result.route,
+      family: route_result.family,
+      input_family: route_result.input_family,
+      boundary: route_result.boundary,
+      target: Map.get(translation, :target),
+      signal_type:
+        case Map.get(translation, :signal) do
+          nil -> nil
+          signal -> signal.type
+        end
+    }
+  end
+
+  defp no_host_route_syntax?(%{navigation: navigation}) when is_map(navigation) do
+    not Map.has_key?(navigation, :route)
+  end
+
+  defp no_host_route_syntax?(_other), do: true
+
   defp root_for_sequence(%{kind: :window, children: [child | _rest]}), do: child
   defp root_for_sequence(tree), do: tree
 end
diff --git a/packages/desktop_ui/lib/desktop_ui/inspect.ex b/packages/desktop_ui/lib/desktop_ui/inspect.ex
index 741d65f0..4cff7851 100644
--- a/packages/desktop_ui/lib/desktop_ui/inspect.ex
+++ b/packages/desktop_ui/lib/desktop_ui/inspect.ex
@@ -48,7 +48,7 @@ defmodule DesktopUi.Inspect do
          shutdown: %{acknowledgement: shutdown_ack, final_state: host.state},
          resource_contracts: %{
            text: DesktopUi.Sdl3.Text.contract(),
-            images: DesktopUi.Sdl3.Images.contract()
+           images: DesktopUi.Sdl3.Images.contract()
          },
          resource_support: %{
            text: DesktopUi.Sdl3.Text.native_support(capabilities),
@@ -148,6 +148,10 @@ defmodule DesktopUi.Inspect do
     DesktopUi.Examples.styled_comparison()
   end
 
+  defp preview_surface(%{category: :mixed, id: :navigation_transition_review}) do
+    DesktopUi.Examples.navigation_transition_review()
+  end
+
   defp launch_host(%{category: :native, id: :native_foundational}, opts) do
     DesktopUi.Sdl3.App.launch_native_screen(
       DesktopUi.Examples.native_foundational_screen(),
diff --git a/packages/desktop_ui/lib/desktop_ui/navigation/controller.ex b/packages/desktop_ui/lib/desktop_ui/navigation/controller.ex
index 77f34b0a..6ebeb4a0 100644
--- a/packages/desktop_ui/lib/desktop_ui/navigation/controller.ex
+++ b/packages/desktop_ui/lib/desktop_ui/navigation/controller.ex
@@ -105,6 +105,14 @@ defmodule DesktopUi.Navigation.Controller do
     |> State.current_screen()
   end
 
+  @doc """
+  Returns the configured screen registry module, if any.
+  """
+  @spec registry(GenServer.server() | atom()) :: module() | nil
+  def registry(server) do
+    GenServer.call(server, :registry)
+  end
+
   @doc """
   Stops the navigation controller.
 
@@ -233,6 +241,10 @@ defmodule DesktopUi.Navigation.Controller do
     {:reply, state.nav_state, state}
   end
 
+  def handle_call(:registry, _from, state) do
+    {:reply, state.registry, state}
+  end
+
   # State transition functions
 
   defp navigate_to(%State{} = nav, screen_id, screen_module, params) do
diff --git a/packages/desktop_ui/lib/desktop_ui/navigation/integration.ex b/packages/desktop_ui/lib/desktop_ui/navigation/integration.ex
index a9b95068..8d018e2d 100644
--- a/packages/desktop_ui/lib/desktop_ui/navigation/integration.ex
+++ b/packages/desktop_ui/lib/desktop_ui/navigation/integration.ex
@@ -206,17 +206,26 @@ defmodule DesktopUi.Navigation.Integration do
     end
   end
 
+  defp signal_from_event(%{family: :navigation, target: target}) when is_map(target) do
+    Signal.from_map(target)
+  end
+
   defp signal_from_event(_event), do: {:error, :not_a_navigation_event}
 
   defp update_runtime_for_navigation(%RuntimeState{} = runtime, %State{} = nav_state) do
     # Extract current screen from navigation state
-    {_screen_id, screen_module, params} = State.current_screen(nav_state)
+    {screen_id, screen_module, params} = State.current_screen(nav_state)
 
     %RuntimeState{
       runtime
       | navigation_state: nav_state,
+        screen_id: normalize_screen_id(screen_id, runtime.screen_id),
         current_screen_module: screen_module,
         screen_params: params
     }
   end
+
+  defp normalize_screen_id(screen_id, _fallback) when is_binary(screen_id), do: screen_id
+  defp normalize_screen_id(screen_id, _fallback) when is_atom(screen_id), do: to_string(screen_id)
+  defp normalize_screen_id(_screen_id, fallback), do: fallback
 end
diff --git a/packages/desktop_ui/lib/desktop_ui/navigation/signal.ex b/packages/desktop_ui/lib/desktop_ui/navigation/signal.ex
index 7ebec2eb..cc4cd756 100644
--- a/packages/desktop_ui/lib/desktop_ui/navigation/signal.ex
+++ b/packages/desktop_ui/lib/desktop_ui/navigation/signal.ex
@@ -189,6 +189,52 @@ defmodule DesktopUi.Navigation.Signal do
     end
   end
 
+  def from_map(%{"type" => _type} = map) do
+    map
+    |> normalize_map_keys()
+    |> from_map()
+  end
+
+  def from_map(%{action: action} = map) when is_atom(action) or is_binary(action) do
+    descriptor = normalize_descriptor(map)
+
+    case normalize_action(action) do
+      :navigate_to ->
+        {:ok, navigate(Map.get(descriptor, :screen), Map.get(descriptor, :params, %{}))}
+
+      :replace_with ->
+        {:ok, replace(Map.get(descriptor, :screen), Map.get(descriptor, :params, %{}))}
+
+      :go_back ->
+        {:ok, go_back()}
+
+      :go_forward ->
+        {:ok, go_forward()}
+
+      :open_modal ->
+        {:ok, open_modal(Map.get(descriptor, :modal), Map.get(descriptor, :params, %{}))}
+
+      :close_modal ->
+        {:ok, close_modal()}
+
+      _other ->
+        {:error, :unknown_navigation_type}
+    end
+  end
+
+  def from_map(%{"action" => _action} = map) do
+    map
+    |> normalize_map_keys()
+    |> from_map()
+  end
+
+  def from_map(%{navigation: navigation}) when is_map(navigation), do: from_map(navigation)
+  def from_map(%{"navigation" => navigation}) when is_map(navigation), do: from_map(navigation)
+  def from_map(%{target: %{navigation: navigation}}) when is_map(navigation), do: from_map(navigation)
+
+  def from_map(%{"target" => %{"navigation" => navigation}}) when is_map(navigation),
+    do: from_map(navigation)
+
   def from_map(_), do: {:error, :invalid_signal_format}
 
   @doc """
@@ -254,6 +300,31 @@ defmodule DesktopUi.Navigation.Signal do
 
   # Private helpers
 
+  defp normalize_action(action) when is_atom(action), do: action
+  defp normalize_action(action) when is_binary(action), do: String.to_atom(action)
+  defp normalize_action(_action), do: nil
+
+  defp normalize_descriptor(map) do
+    map = normalize_map_keys(map)
+
+    %{}
+    |> maybe_put(:action, normalize_action(Map.get(map, :action)))
+    |> maybe_put(:screen, Map.get(map, :screen))
+    |> maybe_put(:modal, Map.get(map, :modal))
+    |> maybe_put(:params, normalize_params(Map.get(map, :params, %{})))
+  end
+
+  defp normalize_map_keys(map) do
+    Map.new(map, fn
+      {key, value} when is_binary(key) -> {String.to_atom(key), value}
+      pair -> pair
+    end)
+  end
+
+  defp maybe_put(map, _key, nil), do: map
+  defp maybe_put(map, _key, ""), do: map
+  defp maybe_put(map, key, value), do: Map.put(map, key, value)
+
   defp normalize_params(params) when is_map(params), do: params
   defp normalize_params(params) when is_list(params), do: Map.new(params)
   defp normalize_params(_), do: %{}
diff --git a/packages/desktop_ui/lib/desktop_ui/renderer.ex b/packages/desktop_ui/lib/desktop_ui/renderer.ex
index 93177c5e..d849a080 100644
--- a/packages/desktop_ui/lib/desktop_ui/renderer.ex
+++ b/packages/desktop_ui/lib/desktop_ui/renderer.ex
@@ -23,7 +23,7 @@ defmodule DesktopUi.Renderer do
   end
 
   @doc """
-  All 45 canonical IUR widget kinds supported by the desktop_ui renderer.
+  All canonical renderer kinds supported by the `desktop_ui` renderer.
   Each kind has dedicated native widget mapping, draw kind handling, and
   SDL3 rendering implementation.
   """
@@ -88,6 +88,7 @@ defmodule DesktopUi.Renderer do
       :canvas,
       :gauge,
       :line_chart,
+      :sparkline,
       :timeline,
       # Layout & Structure (3)
       :column,
diff --git a/packages/desktop_ui/lib/desktop_ui/runtime.ex b/packages/desktop_ui/lib/desktop_ui/runtime.ex
index 6b92880f..49d7a5ae 100644
--- a/packages/desktop_ui/lib/desktop_ui/runtime.ex
+++ b/packages/desktop_ui/lib/desktop_ui/runtime.ex
@@ -4,7 +4,16 @@ defmodule DesktopUi.Runtime do
   """
 
   alias DesktopUi.Renderer
-  alias DesktopUi.Runtime.{Boot, Error, EventLoop, EventRouter, Shutdown, State, StyleResolver}
+  alias DesktopUi.Runtime.{
+    Boot,
+    Error,
+    EventLoop,
+    EventRouter,
+    Navigation,
+    Shutdown,
+    State,
+    StyleResolver
+  }
   alias UnifiedIUR.Element
   alias Jido.Signal
 
@@ -22,6 +31,7 @@ defmodule DesktopUi.Runtime do
       DesktopUi.Runtime.Frame,
       DesktopUi.Runtime.Window,
       DesktopUi.Runtime.Screen,
+      Navigation,
       StyleResolver,
       DesktopUi.Runtime.State,
       DesktopUi.Runtime.Shutdown,
@@ -51,6 +61,7 @@ defmodule DesktopUi.Runtime do
       :canonical_boundary_events,
       :normalized_desktop_inputs,
       :shared_event_routing,
+      :screen_navigation,
       :event_polling_scaffold,
       :frame_coordination,
       :focus_callback_placeholders,
@@ -137,8 +148,9 @@ defmodule DesktopUi.Runtime do
       |> Map.put_new(:source_kind, runtime_state.source_kind)
 
     with {:ok, translation} <- DesktopUi.Transport.from_native_event(attrs),
-         {:ok, route_result} <- EventRouter.route(runtime_state, translation) do
-      {:ok, apply_route(runtime_state, route_result), route_result}
+         {:ok, route_result} <- EventRouter.route(runtime_state, translation),
+         {:ok, routed_state} <- apply_route(runtime_state, route_result) do
+      {:ok, routed_state, route_result}
     end
   end
 
@@ -159,20 +171,24 @@ defmodule DesktopUi.Runtime do
           {:ok, State.t(), map()} | {:error, Error.t() | term()}
   def handle_boundary_signal(%State{} = runtime_state, signal) do
     with {:ok, translation} <- DesktopUi.Transport.from_boundary_signal(signal),
-         {:ok, route_result} <- EventRouter.route(runtime_state, translation) do
-      {:ok, apply_route(runtime_state, route_result), route_result}
+         {:ok, route_result} <- EventRouter.route(runtime_state, translation),
+         {:ok, routed_state} <- apply_route(runtime_state, route_result) do
+      {:ok, routed_state, route_result}
     end
   end
 
   defp apply_route(%State{} = runtime_state, route_result) do
     translation = route_result.translation
 
-    %{
-      runtime_state
-      | focus: apply_focus(runtime_state.focus, translation, route_result.route),
-        event_loop: EventLoop.record_route(runtime_state.event_loop, route_result),
-        event_log: runtime_state.event_log ++ [event_log_entry(route_result)]
-    }
+    with {:ok, transitioned_state} <- maybe_apply_navigation(runtime_state, translation) do
+      {:ok,
+       %{
+         transitioned_state
+         | focus: apply_focus(transitioned_state.focus, translation, route_result.route),
+           event_loop: EventLoop.record_route(transitioned_state.event_loop, route_result),
+           event_log: transitioned_state.event_log ++ [event_log_entry(route_result)]
+       }}
+    end
   end
 
   defp apply_focus(nil, _translation, _route), do: nil
@@ -220,4 +236,12 @@ defmodule DesktopUi.Runtime do
 
   defp normalize_map(attrs) when is_map(attrs), do: Map.new(attrs)
   defp normalize_map(attrs) when is_list(attrs), do: Enum.into(attrs, %{})
+
+  defp maybe_apply_navigation(%State{} = runtime_state, translation) do
+    if Navigation.transition?(translation) do
+      Navigation.apply_transition(runtime_state, translation)
+    else
+      {:ok, runtime_state}
+    end
+  end
 end
diff --git a/packages/desktop_ui/lib/desktop_ui/runtime/boot.ex b/packages/desktop_ui/lib/desktop_ui/runtime/boot.ex
index 61879f6d..1085787e 100644
--- a/packages/desktop_ui/lib/desktop_ui/runtime/boot.ex
+++ b/packages/desktop_ui/lib/desktop_ui/runtime/boot.ex
@@ -13,16 +13,18 @@ defmodule DesktopUi.Runtime.Boot do
   @spec prepare_native_screen(map(), keyword()) :: {:ok, State.t()} | {:error, Error.t()}
   def prepare_native_screen(screen, opts \\ []) do
     with :ok <- validate_screen(screen),
-         {:ok, root} <- normalize_root(Map.fetch!(screen, :root)) do
-      build_state(Map.put(screen, :root, root), :native, opts)
+         {:ok, root} <- normalize_root(Map.fetch!(screen, :root)),
+         {:ok, state} <- build_state(Map.put(screen, :root, root), :native, opts) do
+      maybe_start_navigation_controller(state, screen, opts)
     end
   end
 
   @spec prepare_rendered_screen(Widget.t() | map(), keyword()) ::
           {:ok, State.t()} | {:error, Error.t()}
   def prepare_rendered_screen(rendered_root, opts \\ []) do
-    with {:ok, root} <- normalize_root(rendered_root) do
-      build_state(
+    with {:ok, root} <- normalize_root(rendered_root),
+         {:ok, state} <-
+           build_state(
         %{
           id: Keyword.get(opts, :screen_id, "canonical-screen"),
           title: Keyword.get(opts, :title, "Canonical Screen"),
@@ -30,13 +32,14 @@ defmodule DesktopUi.Runtime.Boot do
         },
         :canonical,
         opts
-      )
+      ) do
+      maybe_start_navigation_controller(state, %{id: Keyword.get(opts, :screen_id)}, opts)
     end
   end
 
   @spec start_navigation_controller(State.t(), keyword()) :: {:ok, State.t()} | {:error, term()}
   def start_navigation_controller(state, opts \\ []) do
-    registry = Keyword.get(opts, :registry)
+    registry = Keyword.get(opts, :screen_registry) || Keyword.get(opts, :registry)
     initial_screen = Keyword.get(opts, :initial_screen)
 
     cond do
@@ -45,7 +48,6 @@ defmodule DesktopUi.Runtime.Boot do
         {:ok, state}
 
       initial_screen ->
-        screen_module = elem(initial_screen, 1)
         params = elem(initial_screen, 2)
 
         case Controller.start_link(
@@ -60,7 +62,7 @@ defmodule DesktopUi.Runtime.Boot do
              %{
                state
                | navigation_controller: controller,
-                 current_screen_module: screen_module,
+                 current_screen_module: nav_state.current_module,
                  navigation_state: nav_state,
                  screen_params: params
              }}
@@ -175,4 +177,32 @@ defmodule DesktopUi.Runtime.Boot do
   defp normalize_root(root) do
     {:error, Error.new(:invalid_screen_root, %{root: root}, :runtime_boot)}
   end
+
+  defp maybe_start_navigation_controller(state, screen, opts) do
+    initial_screen =
+      Keyword.get(opts, :initial_screen) ||
+        inferred_initial_screen(screen, opts, Keyword.get(opts, :screen_registry) || Keyword.get(opts, :registry))
+
+    start_navigation_controller(
+      state,
+      screen_registry: Keyword.get(opts, :screen_registry),
+      registry: Keyword.get(opts, :registry),
+      initial_screen: initial_screen
+    )
+  end
+
+  defp inferred_initial_screen(_screen, _opts, nil), do: nil
+
+  defp inferred_initial_screen(screen, opts, _registry) do
+    screen_id =
+      Keyword.get(opts, :navigation_screen_id) ||
+        Keyword.get(opts, :screen_id) ||
+        Map.get(screen, :navigation_screen_id)
+
+    if is_nil(screen_id) do
+      nil
+    else
+      {screen_id, Keyword.get(opts, :screen_module), Keyword.get(opts, :screen_params, %{})}
+    end
+  end
 end
diff --git a/packages/desktop_ui/lib/desktop_ui/runtime/navigation.ex b/packages/desktop_ui/lib/desktop_ui/runtime/navigation.ex
new file mode 100644
index 00000000..4e7fac9e
--- /dev/null
+++ b/packages/desktop_ui/lib/desktop_ui/runtime/navigation.ex
@@ -0,0 +1,222 @@
+defmodule DesktopUi.Runtime.Navigation do
+  @moduledoc """
+  Canonical screen-transition handling for the shared `desktop_ui` runtime.
+  """
+
+  alias DesktopUi.Navigation.{Controller, Integration, Registry, Signal}
+  alias DesktopUi.Navigation.State, as: NavigationState
+  alias DesktopUi.Runtime.{Error, Screen, State}
+  alias UnifiedIUR.Interaction
+  alias UnifiedIUR.Interactions.Transport, as: BoundaryTransport
+
+  @spec transition?(map()) :: boolean()
+  def transition?(%{family: :navigation, target: target}) when is_map(target) do
+    not is_nil(Interaction.navigation_descriptor(target))
+  end
+
+  def transition?(_other), do: false
+
+  @spec apply_transition(State.t(), map()) :: {:ok, State.t()} | {:error, Error.t()}
+  def apply_transition(%State{navigation_controller: nil}, translation) when is_map(translation) do
+    if transition?(translation) do
+      {:error,
+       Error.new(
+         :no_navigation_controller,
+         %{action: descriptor_action(translation)},
+         :event_routing
+       )}
+    else
+      {:error, Error.new(:invalid_navigation_transition, %{reason: :missing_navigation_target}, :event_routing)}
+    end
+  end
+
+  def apply_transition(%State{} = runtime_state, translation) when is_map(translation) do
+    with {:ok, descriptor} <- validate_navigation_descriptor(translation),
+         :ok <- validate_transition_context(runtime_state, descriptor),
+         {:ok, signal} <- Signal.from_map(descriptor),
+         {:ok, updated_runtime, nav_state, _transition} <-
+           Integration.handle_navigation(runtime_state, signal) do
+      {:ok, synchronize_runtime(updated_runtime, nav_state, runtime_state, descriptor)}
+    else
+      {:error, %Error{} = error} ->
+        {:error, error}
+
+      {:error, {:unknown_screen, screen_id}} ->
+        {:error,
+         Error.new(
+           :unresolved_navigation_target,
+           %{action: descriptor_action(translation), screen_id: screen_id},
+           :event_routing
+         )}
+
+      {:error, :no_modal} ->
+        {:error,
+         Error.new(
+           :invalid_modal_transition,
+           %{action: descriptor_action(translation), reason: :no_modal},
+           :event_routing
+         )}
+
+      {:error, :empty_history} ->
+        {:error,
+         Error.new(
+           :unsupported_navigation_context,
+           %{action: descriptor_action(translation), reason: :empty_history},
+           :event_routing
+         )}
+
+      {:error, :empty_forward} ->
+        {:error,
+         Error.new(
+           :unsupported_navigation_context,
+           %{action: descriptor_action(translation), reason: :empty_forward},
+           :event_routing
+         )}
+
+      {:error, reason} ->
+        {:error,
+         Error.new(
+           :invalid_navigation_transition,
+           %{action: descriptor_action(translation), reason: inspect(reason)},
+           :event_routing
+         )}
+    end
+  end
+
+  defp validate_navigation_descriptor(translation) do
+    descriptor = boundary_descriptor(translation)
+
+    case BoundaryTransport.validate_boundary_descriptor(descriptor) do
+      :ok ->
+        {:ok, navigation_descriptor(translation)}
+
+      {:error, {:forbidden_navigation_keys, keys}} ->
+        {:error, Error.new(:host_route_navigation_syntax, %{keys: keys}, :event_routing)}
+
+      {:error, reason} ->
+        {:error, Error.new(:invalid_navigation_transition, %{reason: inspect(reason)}, :event_routing)}
+    end
+  end
+
+  defp validate_transition_context(%State{} = runtime_state, descriptor) do
+    action = Map.get(descriptor, :action)
+
+    cond do
+      action in [:close_modal, "close_modal"] and modal_mismatch?(runtime_state, descriptor) ->
+        {:error,
+         Error.new(
+           :invalid_modal_transition,
+           %{action: action, requested_modal: Map.get(descriptor, :modal)},
+           :event_routing
+         )}
+
+      true ->
+        :ok
+    end
+  end
+
+  defp synchronize_runtime(updated_runtime, %NavigationState{} = nav_state, previous_runtime, descriptor) do
+    screen_id = current_screen_id(nav_state, updated_runtime.screen_id)
+    title = resolve_screen_title(previous_runtime, screen_id, updated_runtime.current_screen_module)
+
+    %{
+      updated_runtime
+      | screen_id: screen_id,
+        title: title,
+        screen: synchronize_screen(updated_runtime.screen, screen_id, title, descriptor, nav_state)
+    }
+  end
+
+  defp synchronize_screen(%Screen{} = screen, screen_id, title, descriptor, nav_state) do
+    metadata =
+      screen.metadata
+      |> Map.put(:current_screen_id, screen_id)
+      |> Map.put(:navigation_action, Map.get(descriptor, :action))
+      |> Map.put(:modal_depth, NavigationState.modal_depth(nav_state))
+
+    %{screen | id: screen_id, title: title, metadata: metadata}
+  end
+
+  defp resolve_screen_title(runtime_state, screen_id, current_screen_module) do
+    metadata =
+      case Controller.registry(runtime_state.navigation_controller) do
+        registry when is_atom(registry) ->
+          Registry.metadata(registry, normalize_registry_id(screen_id))
+
+        _other ->
+          %{}
+      end
+
+    Map.get(metadata, :title) ||
+      Map.get(metadata, "title") ||
+      default_title(screen_id, current_screen_module)
+  end
+
+  defp current_screen_id(%NavigationState{current: current}, fallback),
+    do: normalize_screen_id(current, fallback)
+
+  defp normalize_screen_id(screen_id, _fallback) when is_binary(screen_id), do: screen_id
+  defp normalize_screen_id(screen_id, _fallback) when is_atom(screen_id), do: to_string(screen_id)
+  defp normalize_screen_id(_screen_id, fallback), do: fallback
+
+  defp normalize_registry_id(screen_id) when is_binary(screen_id), do: String.to_atom(screen_id)
+  defp normalize_registry_id(screen_id), do: screen_id
+
+  defp default_title(screen_id, _current_screen_module) when is_atom(screen_id) do
+    screen_id
+    |> Atom.to_string()
+    |> String.split("_")
+    |> Enum.map(&String.capitalize/1)
+    |> Enum.join(" ")
+  end
+
+  defp default_title(screen_id, _current_screen_module) when is_binary(screen_id) and screen_id != "" do
+    screen_id
+    |> String.split(~r/[_-]+/)
+    |> Enum.map(&String.capitalize/1)
+    |> Enum.join(" ")
+  end
+
+  defp default_title(_screen_id, current_screen_module) when is_atom(current_screen_module) do
+    current_screen_module
+    |> Module.split()
+    |> List.last()
+  end
+
+  defp default_title(_screen_id, _current_screen_module), do: "Screen"
+
+  defp modal_mismatch?(%State{navigation_state: nil}, %{modal: modal}) when not is_nil(modal), do: true
+
+  defp modal_mismatch?(%State{navigation_state: nav_state}, %{modal: modal})
+       when not is_nil(modal) and modal != "" do
+    case NavigationState.top_modal(nav_state) do
+      {current_modal, _module, _params} -> current_modal != modal
+      nil -> true
+    end
+  end
+
+  defp modal_mismatch?(_runtime_state, _descriptor), do: false
+
+  defp boundary_descriptor(translation) do
+    %{
+      family: :navigation,
+      intent: Map.get(translation, :intent),
+      source_context: %{
+        element_id: Map.get(translation, :widget_id),
+        scope: :screen
+      },
+      target: Map.get(translation, :target, %{}),
+      metadata: %{}
+    }
+  end
+
+  defp navigation_descriptor(translation) do
+    Interaction.navigation_descriptor(Map.get(translation, :target, %{})) || %{}
+  end
+
+  defp descriptor_action(translation) do
+    translation
+    |> navigation_descriptor()
+    |> Map.get(:action)
+  end
+end
diff --git a/packages/desktop_ui/lib/desktop_ui/transport/diagnostics.ex b/packages/desktop_ui/lib/desktop_ui/transport/diagnostics.ex
index 0f49a270..22dcd788 100644
--- a/packages/desktop_ui/lib/desktop_ui/transport/diagnostics.ex
+++ b/packages/desktop_ui/lib/desktop_ui/transport/diagnostics.ex
@@ -6,6 +6,8 @@ defmodule DesktopUi.Transport.Diagnostics do
   alias Jido.Signal
   alias DesktopUi.Transport.{Error, Normalize}
   alias DesktopUi.Transport.Signal, as: TransportSignal
+  alias UnifiedIUR.Interaction
+  alias UnifiedIUR.Interactions.Transport, as: BoundaryTransport
 
   @payload_leak_keys [
     :backend_payload,
@@ -50,6 +52,7 @@ defmodule DesktopUi.Transport.Diagnostics do
   def validate_translation(%{} = translation) do
     with :ok <- validate_payload(Map.get(translation, :payload, %{}), :translation_payload),
          :ok <- validate_payload(Map.get(translation, :target, %{}), :translation_target),
+         :ok <- validate_navigation_target(translation),
          :ok <- maybe_validate_boundary_signal(translation) do
       if Map.get(translation, :boundary) == :boundary do
         validate_boundary_context(translation)
@@ -144,6 +147,33 @@ defmodule DesktopUi.Transport.Diagnostics do
 
   defp leaked_key?(_key), do: false
 
+  defp validate_navigation_target(%{family: :navigation, target: target}) when is_map(target) do
+    descriptor = Interaction.navigation_descriptor(target)
+
+    if is_nil(descriptor) do
+      :ok
+    else
+      case BoundaryTransport.validate_boundary_descriptor(%{
+             family: :navigation,
+             intent: nil,
+             source_context: %{},
+             target: target,
+             metadata: %{}
+           }) do
+        :ok ->
+          :ok
+
+        {:error, {:forbidden_navigation_keys, keys}} ->
+          {:error, Error.host_route_navigation_syntax(keys)}
+
+        {:error, reason} ->
+          {:error, Error.invalid_navigation_target(reason)}
+      end
+    end
+  end
+
+  defp validate_navigation_target(_translation), do: :ok
+
   defp maybe_missing(fields, field, nil), do: fields ++ [field]
   defp maybe_missing(fields, field, ""), do: fields ++ [field]
   defp maybe_missing(fields, _field, _value), do: fields
diff --git a/packages/desktop_ui/lib/desktop_ui/transport/error.ex b/packages/desktop_ui/lib/desktop_ui/transport/error.ex
index 5fd37ce0..4368c7ce 100644
--- a/packages/desktop_ui/lib/desktop_ui/transport/error.ex
+++ b/packages/desktop_ui/lib/desktop_ui/transport/error.ex
@@ -83,4 +83,22 @@ defmodule DesktopUi.Transport.Error do
       details: %{platform_target: inspect(target)}
     }
   end
+
+  @spec host_route_navigation_syntax([atom() | String.t()]) :: t()
+  def host_route_navigation_syntax(keys) do
+    %__MODULE__{
+      reason: :host_route_navigation_syntax,
+      message: "canonical desktop navigation targets must not contain host-route syntax",
+      details: %{keys: keys}
+    }
+  end
+
+  @spec invalid_navigation_target(term()) :: t()
+  def invalid_navigation_target(reason) do
+    %__MODULE__{
+      reason: :invalid_navigation_target,
+      message: "desktop_ui navigation targets must satisfy the canonical screen-transition contract",
+      details: %{reason: inspect(reason)}
+    }
+  end
 end
diff --git a/packages/desktop_ui/lib/desktop_ui/transport/normalize.ex b/packages/desktop_ui/lib/desktop_ui/transport/normalize.ex
index 5d5a6552..d0b685e2 100644
--- a/packages/desktop_ui/lib/desktop_ui/transport/normalize.ex
+++ b/packages/desktop_ui/lib/desktop_ui/transport/normalize.ex
@@ -114,11 +114,24 @@ defmodule DesktopUi.Transport.Normalize do
 
     case Enum.uniq(matches) do
       [family] -> {:ok, family}
-      [] -> {:error, Error.invalid_native_event(attrs)}
+      [] -> infer_input_family_from_family(attrs)
       _many -> {:error, Error.ambiguous_native_event(attrs)}
     end
   end
 
+  defp infer_input_family_from_family(attrs) do
+    case normalize_family(fetch(attrs, :family)) do
+      :command -> {:ok, :shortcut}
+      :navigation -> {:ok, :keyboard}
+      :selection -> {:ok, :pointer}
+      :click -> {:ok, :pointer}
+      :submit -> {:ok, :keyboard}
+      :change -> {:ok, :keyboard}
+      :focus -> {:ok, :focus}
+      _other -> {:error, Error.invalid_native_event(attrs)}
+    end
+  end
+
   defp resolve_canonical_family(attrs, input_family) do
     case normalize_family(fetch(attrs, :family)) do
       nil ->
diff --git a/packages/desktop_ui/lib/desktop_ui/validate.ex b/packages/desktop_ui/lib/desktop_ui/validate.ex
index a1084b78..9949dbaf 100644
--- a/packages/desktop_ui/lib/desktop_ui/validate.ex
+++ b/packages/desktop_ui/lib/desktop_ui/validate.ex
@@ -82,7 +82,7 @@ defmodule DesktopUi.Validate do
         :renderer_supports_all_iur_kinds,
         iur_widget_coverage_complete?(),
         %{
-          expected_count: 45,
+          expected_count: expected_renderer_kind_count(),
           actual_count: length(DesktopUi.Renderer.supported_kinds()),
           supported_kinds: DesktopUi.Renderer.supported_kinds()
         }
@@ -822,10 +822,10 @@ defmodule DesktopUi.Validate do
 
   defp traceability_includes_direct_prefix?(_result, _prefix), do: false
 
-  # Verifies that all 45 canonical IUR widget kinds are supported by the renderer.
-  # Returns true when the renderer supports the complete set of IUR widget kinds.
+  # Verifies that the renderer supports the complete native/canonical widget
+  # surface exposed through DesktopUi.Widgets.
   defp iur_widget_coverage_complete? do
-    expected_count = 45
+    expected_count = expected_renderer_kind_count()
     actual_count = length(DesktopUi.Renderer.supported_kinds())
 
     actual_count >= expected_count and
@@ -835,6 +835,10 @@ defmodule DesktopUi.Validate do
       )
   end
 
+  defp expected_renderer_kind_count do
+    DesktopUi.Widgets.kinds() |> length()
+  end
+
   defp package_root do
     Path.expand("../..", __DIR__)
   end
diff --git a/packages/desktop_ui/lib/desktop_ui/widgets/foundational.ex b/packages/desktop_ui/lib/desktop_ui/widgets/foundational.ex
index f81be770..80c21ef3 100644
--- a/packages/desktop_ui/lib/desktop_ui/widgets/foundational.ex
+++ b/packages/desktop_ui/lib/desktop_ui/widgets/foundational.ex
@@ -4,6 +4,7 @@ defmodule DesktopUi.Widgets.Foundational do
   """
 
   alias DesktopUi.Widget
+  alias DesktopUi.Widgets.Navigation, as: NavigationWidget
 
   @spec kinds() :: [atom()]
   def kinds do
@@ -144,6 +145,10 @@ defmodule DesktopUi.Widgets.Foundational do
 
   @spec button(String.t() | atom(), String.t(), keyword()) :: Widget.t()
   def button(id, label, opts \\ []) do
+    click_event =
+      NavigationWidget.event_payload(opts) ||
+        event_payload(opts, :on_click, %{intent: Keyword.get(opts, :intent, :activate)})
+
     Widget.new(:button,
       id: id,
       metadata: metadata(opts, focusable: true, role: :button),
@@ -152,7 +157,7 @@ defmodule DesktopUi.Widgets.Foundational do
       styles: styles(opts),
       events:
         %{
-          click: event_payload(opts, :on_click, %{intent: Keyword.get(opts, :intent, :activate)}),
+          click: click_event,
           shortcut: shortcut_event(opts)
         }
         |> Enum.reject(fn {_key, value} -> is_nil(value) end)
@@ -182,6 +187,10 @@ defmodule DesktopUi.Widgets.Foundational do
 
   @spec link(String.t() | atom(), String.t(), String.t(), keyword()) :: Widget.t()
   def link(id, label, href, opts \\ []) do
+    click_event =
+      NavigationWidget.event_payload(opts) ||
+        event_payload(opts, :on_follow, %{intent: Keyword.get(opts, :intent, :open_link)})
+
     Widget.new(:link,
       id: id,
       metadata: metadata(opts, focusable: true, role: :link),
@@ -189,13 +198,17 @@ defmodule DesktopUi.Widgets.Foundational do
       attributes: %{label: label, href: href},
       styles: styles(opts),
       events: %{
-        click: event_payload(opts, :on_follow, %{intent: Keyword.get(opts, :intent, :open_link)})
+        click: click_event
       }
     )
   end
 
   @spec command(String.t() | atom(), String.t(), keyword()) :: Widget.t()
   def command(id, label, opts \\ []) do
+    click_event =
+      NavigationWidget.event_payload(opts) ||
+        event_payload(opts, :on_press, %{intent: Keyword.get(opts, :intent, :run_command)})
+
     Widget.new(:command,
       id: id,
       metadata:
@@ -210,8 +223,7 @@ defmodule DesktopUi.Widgets.Foundational do
       styles: styles(opts),
       events:
         %{
-          click:
-            event_payload(opts, :on_press, %{intent: Keyword.get(opts, :intent, :run_command)}),
+          click: click_event,
           shortcut: shortcut_event(opts)
         }
         |> Enum.reject(fn {_key, value} -> is_nil(value) end)
diff --git a/packages/desktop_ui/lib/desktop_ui/widgets/navigation.ex b/packages/desktop_ui/lib/desktop_ui/widgets/navigation.ex
index 80dfd2c4..13ad54ea 100644
--- a/packages/desktop_ui/lib/desktop_ui/widgets/navigation.ex
+++ b/packages/desktop_ui/lib/desktop_ui/widgets/navigation.ex
@@ -125,42 +125,75 @@ defmodule DesktopUi.Widgets.Navigation do
   def event_payload(opts) when is_list(opts), do: opts |> Enum.into(%{}) |> event_payload()
 
   def event_payload(%{navigate_to: screen_id} = opts) when is_atom(screen_id) or is_binary(screen_id) do
+    params = Map.get(opts, :navigate_params, %{})
+
     %{
       family: :navigation,
+      intent: Map.get(opts, :intent, :navigate_to),
       type: :navigate_to,
       screen_id: screen_id,
-      params: Map.get(opts, :navigate_params, %{})
+      params: params,
+      target: %{navigation: %{action: :navigate_to, screen: screen_id, params: params}},
+      payload: Map.get(opts, :payload, %{})
     }
   end
 
   def event_payload(%{replace_with: screen_id} = opts) when is_atom(screen_id) or is_binary(screen_id) do
+    params = Map.get(opts, :navigate_params, %{})
+
     %{
       family: :navigation,
+      intent: Map.get(opts, :intent, :replace_with),
       type: :replace_with,
       screen_id: screen_id,
-      params: Map.get(opts, :navigate_params, %{})
+      params: params,
+      target: %{navigation: %{action: :replace_with, screen: screen_id, params: params}},
+      payload: Map.get(opts, :payload, %{})
     }
   end
 
   def event_payload(%{go_back: true}) do
-    %{family: :navigation, type: :go_back}
+    %{
+      family: :navigation,
+      intent: :go_back,
+      type: :go_back,
+      target: %{navigation: %{action: :go_back}},
+      payload: %{}
+    }
   end
 
   def event_payload(%{go_forward: true}) do
-    %{family: :navigation, type: :go_forward}
+    %{
+      family: :navigation,
+      intent: :go_forward,
+      type: :go_forward,
+      target: %{navigation: %{action: :go_forward}},
+      payload: %{}
+    }
   end
 
   def event_payload(%{open_modal: screen_id} = opts) when is_atom(screen_id) or is_binary(screen_id) do
+    params = Map.get(opts, :navigate_params, %{})
+
     %{
       family: :navigation,
+      intent: Map.get(opts, :intent, :open_modal),
       type: :open_modal,
       screen_id: screen_id,
-      params: Map.get(opts, :navigate_params, %{})
+      params: params,
+      target: %{navigation: %{action: :open_modal, modal: screen_id, params: params}},
+      payload: Map.get(opts, :payload, %{})
     }
   end
 
   def event_payload(%{close_modal: true}) do
-    %{family: :navigation, type: :close_modal}
+    %{
+      family: :navigation,
+      intent: :close_modal,
+      type: :close_modal,
+      target: %{navigation: %{action: :close_modal}},
+      payload: %{}
+    }
   end
 
   def event_payload(_), do: nil
diff --git a/packages/desktop_ui/test/desktop_ui/canonical_navigation_desktop_runtime_integration_test.exs b/packages/desktop_ui/test/desktop_ui/canonical_navigation_desktop_runtime_integration_test.exs
new file mode 100644
index 00000000..a9ad0b3b
--- /dev/null
+++ b/packages/desktop_ui/test/desktop_ui/canonical_navigation_desktop_runtime_integration_test.exs
@@ -0,0 +1,214 @@
+defmodule DesktopUi.CanonicalNavigationDesktopRuntimeIntegrationTest do
+  use ExUnit.Case, async: true
+
+  alias DesktopUi.Runtime
+  alias UnifiedIUR.Interactions.Transport, as: BoundaryTransport
+
+  defmodule HomeScreen do
+    def render(_assigns), do: %{}
+  end
+
+  defmodule SettingsScreen do
+    def render(_assigns), do: %{}
+  end
+
+  defmodule SettingsDialogScreen do
+    def render(_assigns), do: %{}
+  end
+
+  defmodule ScreenRegistry do
+    def register do
+      %{
+        home: {HomeScreen, title: "Home"},
+        settings: {SettingsScreen, title: "Settings"},
+        settings_dialog: {SettingsDialogScreen, title: "Settings Dialog", modal_only?: true}
+      }
+    end
+
+    def get_screen(:home), do: HomeScreen
+    def get_screen(:settings), do: SettingsScreen
+    def get_screen(:settings_dialog), do: SettingsDialogScreen
+    def get_screen(_), do: nil
+
+    def screen_metadata(:home), do: %{title: "Home"}
+    def screen_metadata(:settings), do: %{title: "Settings"}
+    def screen_metadata(:settings_dialog), do: %{title: "Settings Dialog", modal_only?: true}
+    def screen_metadata(_), do: %{}
+  end
+
+  test "desktop runtime maps canonical navigation fixtures through the controller while preserving window state" do
+    navigate_fixture = BoundaryTransport.boundary_fixture!("screen_transition--settings_profile")
+    replace_fixture = BoundaryTransport.boundary_fixture!("replace_transition--home")
+
+    assert {:ok, runtime_state} =
+             Runtime.mount_native_screen(base_screen(),
+               platform_target: :linux,
+               screen_registry: ScreenRegistry,
+               navigation_screen_id: :home
+             )
+
+    primary_window = runtime_state.windows.primary
+    initial_runtime_id = runtime_state.runtime_id
+
+    assert {:ok, after_navigate, navigate_route} =
+             Runtime.dispatch_native_event(
+               runtime_state,
+               family: :navigation,
+               intent: navigate_fixture.interaction.intent,
+               widget_id: "settings-link",
+               target: navigate_fixture.descriptor.target,
+               payload: navigate_fixture.signal_data
+             )
+
+    assert navigate_route.route == :canonical_boundary
+    assert navigate_route.translation.target == navigate_fixture.descriptor.target
+    assert after_navigate.screen_id == "settings"
+    assert after_navigate.current_screen_module == SettingsScreen
+    assert after_navigate.screen_params == %{tab: :profile}
+    assert after_navigate.title == "Settings"
+    assert after_navigate.runtime_id == initial_runtime_id
+    assert after_navigate.windows.primary == primary_window
+    assert after_navigate.navigation_state.history == [{:home, HomeScreen, %{}}]
+
+    assert {:ok, replace_translation} =
+             DesktopUi.Transport.from_interaction(
+               replace_fixture.interaction,
+               platform_target: :linux,
+               widget_id: "home-link",
+               runtime_id: after_navigate.runtime_id,
+               screen: after_navigate.screen_id,
+               payload: replace_fixture.signal_data
+             )
+
+    assert {:ok, after_replace, replace_route} =
+             Runtime.handle_boundary_signal(after_navigate, replace_translation.signal)
+
+    assert replace_route.route == :canonical_boundary
+    assert after_replace.screen_id == "home"
+    assert after_replace.current_screen_module == HomeScreen
+    assert after_replace.screen_params == %{source: :command_palette}
+    assert after_replace.windows.primary == primary_window
+    assert after_replace.navigation_state.history == [{:home, HomeScreen, %{}}]
+    assert after_replace.screen.metadata.navigation_action == :replace_with
+  end
+
+  test "desktop runtime preserves history and modal semantics across canonical actions" do
+    navigate_fixture = BoundaryTransport.boundary_fixture!("screen_transition--settings_profile")
+    modal_fixture = BoundaryTransport.boundary_fixture!("modal_transition--settings_dialog")
+    history_fixture = BoundaryTransport.boundary_fixture!("history_transition--back")
+
+    assert {:ok, runtime_state} =
+             Runtime.mount_native_screen(base_screen(),
+               platform_target: :linux,
+               screen_registry: ScreenRegistry,
+               navigation_screen_id: :home
+             )
+
+    assert {:ok, after_navigate, _route} =
+             Runtime.dispatch_native_event(
+               runtime_state,
+               family: :navigation,
+               intent: navigate_fixture.interaction.intent,
+               widget_id: "settings-link",
+               target: navigate_fixture.descriptor.target,
+               payload: navigate_fixture.signal_data
+             )
+
+    assert {:ok, with_modal, modal_route} =
+             Runtime.dispatch_native_event(
+               after_navigate,
+               family: :navigation,
+               intent: modal_fixture.interaction.intent,
+               widget_id: "settings-dialog-button",
+               target: modal_fixture.descriptor.target,
+               payload: modal_fixture.signal_data
+             )
+
+    assert modal_route.translation.target == modal_fixture.descriptor.target
+    assert with_modal.screen_id == "settings"
+    assert with_modal.navigation_state.modal_open?
+    assert with_modal.navigation_state.modals == [
+             {:settings_dialog, SettingsDialogScreen, %{mode: :advanced}}
+           ]
+
+    assert {:ok, after_close, _close_route} =
+             Runtime.dispatch_native_event(
+               with_modal,
+               family: :navigation,
+               intent: :close_settings_modal,
+               widget_id: "close-settings-dialog",
+               target: %{navigation: %{action: :close_modal, modal: :settings_dialog}}
+             )
+
+    refute after_close.navigation_state.modal_open?
+    assert after_close.navigation_state.modals == []
+    assert after_close.screen_id == "settings"
+
+    assert {:ok, after_back, back_route} =
+             Runtime.dispatch_native_event(
+               after_close,
+               family: :navigation,
+               intent: history_fixture.interaction.intent,
+               widget_id: "back-button",
+               target: history_fixture.descriptor.target,
+               payload: history_fixture.signal_data
+             )
+
+    assert back_route.translation.target == history_fixture.descriptor.target
+    assert after_back.screen_id == "home"
+    assert after_back.current_screen_module == HomeScreen
+    assert after_back.navigation_state.forward == [{:settings, SettingsScreen, %{tab: :profile}}]
+  end
+
+  test "desktop runtime reports invalid screen targets, leaked route syntax, and modal mismatches deterministically" do
+    assert {:ok, runtime_state} =
+             Runtime.mount_native_screen(base_screen(),
+               platform_target: :linux,
+               screen_registry: ScreenRegistry,
+               navigation_screen_id: :home
+             )
+
+    assert {:error, %Runtime.Error{reason: :unresolved_navigation_target}} =
+             Runtime.dispatch_native_event(
+               runtime_state,
+               family: :navigation,
+               intent: :open_missing_screen,
+               widget_id: "missing-link",
+               target: %{navigation: %{action: :navigate_to, screen: :missing}}
+             )
+
+    assert {:error, %Runtime.Error{reason: :host_route_navigation_syntax}} =
+             Runtime.dispatch_native_event(
+               runtime_state,
+               family: :navigation,
+               intent: :open_settings_screen,
+               widget_id: "settings-link",
+               target: %{
+                 navigation: %{action: :navigate_to, screen: :settings, route: "/settings"}
+               }
+             )
+
+    assert {:error, %Runtime.Error{reason: :invalid_modal_transition}} =
+             Runtime.dispatch_native_event(
+               runtime_state,
+               family: :navigation,
+               intent: :close_settings_modal,
+               widget_id: "close-settings-dialog",
+               target: %{navigation: %{action: :close_modal, modal: :settings_dialog}}
+             )
+  end
+
+  defp base_screen do
+    %{
+      id: "workspace",
+      title: "Workspace",
+      root:
+        DesktopUi.Widgets.window("workspace-window", "Workspace", [
+          DesktopUi.Widgets.column("workspace-layout", [
+            DesktopUi.Widgets.text("workspace-title", "Workspace"),
+            DesktopUi.Widgets.button("settings-link", "Settings", navigate_to: :settings)
+          ])
+        ])
+    }
+  end
+end
diff --git a/packages/desktop_ui/test/desktop_ui/canonical_navigation_non_web_examples_integration_test.exs b/packages/desktop_ui/test/desktop_ui/canonical_navigation_non_web_examples_integration_test.exs
new file mode 100644
index 00000000..00a9bf4a
--- /dev/null
+++ b/packages/desktop_ui/test/desktop_ui/canonical_navigation_non_web_examples_integration_test.exs
@@ -0,0 +1,45 @@
+defmodule DesktopUi.CanonicalNavigationNonWebExamplesIntegrationTest do
+  use ExUnit.Case, async: true
+
+  test "desktop maintained navigation review preserves shared canonical targets through one-window navigation" do
+    review = DesktopUi.Examples.navigation_transition_review()
+    metadata = DesktopUi.Examples.metadata(:navigation_transition_review)
+    reference = DesktopUi.reference()
+    summary = DesktopUi.info()
+
+    assert review.fixture_ids == [
+             "screen_transition--settings_profile",
+             "replace_transition--home",
+             "history_transition--back",
+             "modal_transition--settings_dialog"
+           ]
+
+    assert review.parity.shared_fixture_targets_consumed?
+    assert review.parity.window_preserved_across_transitions?
+    assert review.parity.registry_resolution_preserved?
+    assert review.parity.history_semantics_preserved?
+    assert review.parity.modal_stack_preserved?
+    assert review.states.after_navigate.title == "Settings"
+    assert review.states.after_reports.screen_id == "reports"
+    assert review.states.after_reports.history_depth == 2
+    assert review.states.after_back.forward_depth == 1
+    assert review.states.after_replace.screen_params == %{source: :command_palette}
+    assert review.states.mounted.primary_window == review.states.after_replace.primary_window
+    assert review.routes.replace.target == review.fixture_targets.replace
+    assert review.routes.forward.target == review.fixture_targets.forward
+    assert metadata.workflow == :navigation_review
+    assert metadata.parity_group == :navigation_transition_review
+    assert :navigation_transition_review in reference.examples.comparison_ids
+    assert :navigation_transition_review in summary.examples.comparison_ids
+    assert :navigation_review in summary.examples.workflows
+  end
+
+  test "desktop maintained navigation review keeps canonical targets free of host route syntax" do
+    review = DesktopUi.Examples.navigation_transition_review()
+
+    assert Enum.all?(review.routes, fn {_step, route} ->
+             match?(%{navigation: _}, route.target) and
+               get_in(route.target, [:navigation, :route]) == nil
+           end)
+  end
+end
diff --git a/packages/desktop_ui/test/desktop_ui/examples_test.exs b/packages/desktop_ui/test/desktop_ui/examples_test.exs
index f0382743..8d3c706c 100644
--- a/packages/desktop_ui/test/desktop_ui/examples_test.exs
+++ b/packages/desktop_ui/test/desktop_ui/examples_test.exs
@@ -61,7 +61,11 @@ defmodule DesktopUi.ExamplesTest do
              :native_foundational,
              :native_advanced_operations,
              :native_transport_review,
-             :native_styled_review
+             :native_styled_review,
+             :basic_navigation,
+             :history_navigation,
+             :modal_navigation,
+             :master_detail_navigation
            ]
 
     assert reference.examples.canonical_ids == [
@@ -76,14 +80,19 @@ defmodule DesktopUi.ExamplesTest do
              :advanced_continuity,
              :transport_flow_review,
              :normalized_input_profiles,
-             :styled_continuity_review
+             :styled_continuity_review,
+             :navigation_transition_review
            ]
 
     assert summary.examples.native_ids == [
              :native_foundational,
              :native_advanced_operations,
              :native_transport_review,
-             :native_styled_review
+             :native_styled_review,
+             :basic_navigation,
+             :history_navigation,
+             :modal_navigation,
+             :master_detail_navigation
            ]
 
     assert summary.examples.comparison_ids == [
@@ -91,7 +100,8 @@ defmodule DesktopUi.ExamplesTest do
              :advanced_continuity,
              :transport_flow_review,
              :normalized_input_profiles,
-             :styled_continuity_review
+             :styled_continuity_review,
+             :navigation_transition_review
            ]
   end
 
@@ -149,4 +159,55 @@ defmodule DesktopUi.ExamplesTest do
                  "desktop_ui.examples.styled_continuity_review.comparison"
            end)
   end
+
+  test "navigation review exposes shared canonical fixtures through one-window desktop navigation" do
+    review = DesktopUi.Examples.navigation_transition_review()
+    metadata = DesktopUi.Examples.metadata(:navigation_transition_review)
+    matrix = DesktopUi.Examples.coverage_matrix()
+
+    assert review.id == :navigation_transition_review
+
+    assert review.fixture_ids == [
+             "screen_transition--settings_profile",
+             "replace_transition--home",
+             "history_transition--back",
+             "modal_transition--settings_dialog"
+           ]
+
+    assert review.fixture_targets.navigate ==
+             %{
+               navigation: %{
+                 action: :navigate_to,
+                 kind: :screen_transition,
+                 params: %{tab: :profile},
+                 screen: :settings
+               }
+             }
+
+    assert %{navigation: modal_target} = review.fixture_targets.modal
+    assert modal_target.action == :open_modal
+    assert modal_target.kind == :modal_transition
+    assert modal_target.modal == :settings_dialog
+    assert modal_target.params == %{mode: :advanced}
+    assert modal_target.metadata == %{surface: :workspace}
+
+    assert review.parity.shared_fixture_targets_consumed?
+    assert review.parity.window_preserved_across_transitions?
+    assert review.parity.registry_resolution_preserved?
+    assert review.parity.history_semantics_preserved?
+    assert review.parity.modal_stack_preserved?
+    assert review.states.after_navigate.screen_id == "settings"
+    assert review.states.after_reports.screen_id == "reports"
+    assert review.states.after_replace.screen_id == "home"
+
+    assert review.states.with_modal.current_modal == %{
+             modal: :settings_dialog,
+             params: %{mode: :advanced}
+           }
+
+    assert review.routes.forward.target == %{navigation: %{action: :go_forward}}
+    assert metadata.workflow == :navigation_review
+    assert metadata.parity_group == :navigation_transition_review
+    assert matrix.parity_groups.navigation_transition_review == [:navigation_transition_review]
+  end
 end
diff --git a/packages/desktop_ui/test/desktop_ui/navigation/signal_test.exs b/packages/desktop_ui/test/desktop_ui/navigation/signal_test.exs
index a8f347bd..71fd473d 100644
--- a/packages/desktop_ui/test/desktop_ui/navigation/signal_test.exs
+++ b/packages/desktop_ui/test/desktop_ui/navigation/signal_test.exs
@@ -136,6 +136,27 @@ defmodule DesktopUi.Navigation.SignalTest do
       assert signal.type == :close_modal
     end
 
+    test "creates navigation signals from canonical transition descriptors" do
+      assert {:ok, navigate_signal} =
+               Signal.from_map(%{
+                 target: %{navigation: %{action: :navigate_to, screen: :settings, params: %{tab: :profile}}}
+               })
+
+      assert {:ok, modal_signal} =
+               Signal.from_map(%{
+                 action: :open_modal,
+                 modal: :settings_dialog,
+                 params: %{mode: :advanced}
+               })
+
+      assert navigate_signal.type == :navigate_to
+      assert navigate_signal.screen_id == :settings
+      assert navigate_signal.params == %{tab: :profile}
+      assert modal_signal.type == :open_modal
+      assert modal_signal.screen_id == :settings_dialog
+      assert modal_signal.params == %{mode: :advanced}
+    end
+
     test "returns error for unknown navigation type" do
       assert {:error, :unknown_navigation_type} = Signal.from_map(%{type: :invalid})
     end
diff --git a/packages/desktop_ui/test/desktop_ui/phase_eleven_integration_test.exs b/packages/desktop_ui/test/desktop_ui/phase_eleven_integration_test.exs
index 79f33b20..256b2a07 100644
--- a/packages/desktop_ui/test/desktop_ui/phase_eleven_integration_test.exs
+++ b/packages/desktop_ui/test/desktop_ui/phase_eleven_integration_test.exs
@@ -8,8 +8,6 @@ defmodule DesktopUi.PhaseElevenIntegrationTest do
 
   @moduletag :phase_eleven
 
-  @iur_widget_count 45
-
   @all_iur_kinds MapSet.new([
     # Foundational (13)
     :badge, :button, :command, :content, :hero, :icon, :image, :label, :link, :separator, :spacer,
@@ -21,8 +19,8 @@ defmodule DesktopUi.PhaseElevenIntegrationTest do
     :breadcrumbs, :list, :menu, :tabs,
     # Data (7)
     :inspector, :info_list, :key_value, :markdown_viewer, :stat, :table, :tree_view,
-    # Feedback (6)
-    :alert_dialog, :dialog, :inline_feedback, :progress, :status, :toast,
+    # Feedback (7)
+    :alert_dialog, :dialog, :inline_feedback, :progress, :sparkline, :status, :toast,
     # Operational (7)
     :cluster_dashboard, :command_palette, :log_viewer, :process_monitor, :stream_widget,
     :supervision_tree_viewer, :window_command,
@@ -34,6 +32,8 @@ defmodule DesktopUi.PhaseElevenIntegrationTest do
     :window
   ])
 
+  @iur_widget_count MapSet.size(@all_iur_kinds)
+
   setup_all do
     {:ok, capabilities: ensure_visible_runner_capabilities()}
   end
@@ -238,17 +238,17 @@ defmodule DesktopUi.PhaseElevenIntegrationTest do
   end
 
   describe "11.5 Mapper coverage and diagnostics scenarios" do
-    test "canonical mapper handles all 45 IUR widget kinds without fallback" do
+    test "canonical mapper handles the full maintained renderer kind surface without fallback" do
       supported = Renderer.supported_kinds() |> MapSet.new()
 
       # All IUR widget kinds should be supported
       missing_kinds = MapSet.difference(@all_iur_kinds, supported)
 
       assert MapSet.size(missing_kinds) == 0,
-             "Expected all 45 IUR kinds to be supported, but missing: #{inspect(MapSet.to_list(missing_kinds))}"
+             "Expected all maintained renderer kinds to be supported, but missing: #{inspect(MapSet.to_list(missing_kinds))}"
     end
 
-    test "renderer.supported_kinds returns exactly 45 kinds" do
+    test "renderer.supported_kinds returns the full maintained renderer kind surface" do
       count = length(Renderer.supported_kinds())
 
       assert count >= @iur_widget_count,
diff --git a/packages/desktop_ui/test/desktop_ui/phase_one_five_integration_test.exs b/packages/desktop_ui/test/desktop_ui/phase_one_five_integration_test.exs
index 85ff5cf4..384beb3a 100644
--- a/packages/desktop_ui/test/desktop_ui/phase_one_five_integration_test.exs
+++ b/packages/desktop_ui/test/desktop_ui/phase_one_five_integration_test.exs
@@ -29,7 +29,7 @@ defmodule DesktopUi.PhaseOneFiveIntegrationTest do
     assert canonical_boot.runtime.direct_native_and_canonical_share_runtime
 
     assert canonical_boot.frame_request.presentation.render_plan.presentation.validation_state ==
-             :render_plan_ready
+             :iur_renderer_complete
   end
 
   test "minimal native screens can produce native-window state and widget-complete draw plans" do
diff --git a/packages/desktop_ui/test/desktop_ui/sdl3_render_plan_test.exs b/packages/desktop_ui/test/desktop_ui/sdl3_render_plan_test.exs
index 9056eff5..1e8989b7 100644
--- a/packages/desktop_ui/test/desktop_ui/sdl3_render_plan_test.exs
+++ b/packages/desktop_ui/test/desktop_ui/sdl3_render_plan_test.exs
@@ -48,7 +48,7 @@ defmodule DesktopUi.Sdl3RenderPlanTest do
     assert plan.presentation.logical_units
     refute plan.presentation.placeholder_draw_operations
     assert plan.presentation.widget_complete_draw_operations
-    assert plan.presentation.validation_state == :render_plan_ready
+    assert plan.presentation.validation_state == :iur_renderer_complete
     assert plan.diagnostics.window_count == 2
     assert plan.diagnostics.draw_operation_count > 0
     assert plan.diagnostics.draw_kind_counts.window_chrome >= 1
diff --git a/packages/desktop_ui/test/desktop_ui/transport_test.exs b/packages/desktop_ui/test/desktop_ui/transport_test.exs
index 845c1e7e..4f5775ea 100644
--- a/packages/desktop_ui/test/desktop_ui/transport_test.exs
+++ b/packages/desktop_ui/test/desktop_ui/transport_test.exs
@@ -142,4 +142,28 @@ defmodule DesktopUi.TransportTest do
     assert Transport.diagnostics().mapping_summary.platform_targets ==
              DesktopUi.Platform.targets()
   end
+
+  test "transport diagnostics reject leaked host-route syntax on canonical navigation targets" do
+    interaction =
+      Interaction.navigation_transition(
+        intent: :open_settings_screen,
+        action: :navigate_to,
+        screen: :settings
+      )
+
+    assert {:ok, translation} =
+             Transport.from_interaction(
+               interaction,
+               platform_target: :linux,
+               widget_id: "settings-link",
+               runtime_id: "desktop-ui:workspace",
+               screen: "workspace"
+             )
+
+    translation =
+      put_in(translation.target.navigation[:route], "/settings")
+
+    assert {:error, %DesktopUi.Transport.Error{reason: :host_route_navigation_syntax}} =
+             Transport.validate_translation(translation)
+  end
 end
diff --git a/packages/desktop_ui/test/desktop_ui/widgets/navigation_test.exs b/packages/desktop_ui/test/desktop_ui/widgets/navigation_test.exs
index fdff57f9..cea5bd99 100644
--- a/packages/desktop_ui/test/desktop_ui/widgets/navigation_test.exs
+++ b/packages/desktop_ui/test/desktop_ui/widgets/navigation_test.exs
@@ -166,5 +166,31 @@ defmodule DesktopUi.Widgets.NavigationTest do
       assert widget.id == :item_list
       assert widget.metadata.role == :list
     end
+
+    test "foundational action widgets can emit canonical navigation targets" do
+      button =
+        DesktopUi.Widgets.button("open-settings", "Settings",
+          navigate_to: :settings,
+          navigate_params: %{tab: :profile}
+        )
+
+      command =
+        DesktopUi.Widgets.command("open-dialog", "Open Dialog",
+          open_modal: :settings_dialog,
+          navigate_params: %{mode: :advanced}
+        )
+
+      assert button.events.click.target.navigation == %{
+               action: :navigate_to,
+               screen: :settings,
+               params: %{tab: :profile}
+             }
+
+      assert command.events.click.target.navigation == %{
+               action: :open_modal,
+               modal: :settings_dialog,
+               params: %{mode: :advanced}
+             }
+    end
   end
 end
diff --git a/packages/live_ui/lib/live_ui/demo/screen.ex b/packages/live_ui/lib/live_ui/demo/screen.ex
index 52300a5c..8712dbc3 100644
--- a/packages/live_ui/lib/live_ui/demo/screen.ex
+++ b/packages/live_ui/lib/live_ui/demo/screen.ex
@@ -9,6 +9,22 @@ defmodule LiveUi.Demo.Screen do
   alias LiveUi.Demo
   alias LiveUi.Demo.{Catalog, Style, WidgetPreview}
 
+  @widget_demo_runtime_events [
+    "click:widget_demo_button",
+    "navigation:widget_demo_link",
+    "change:widget_demo_text_input",
+    "change:widget_demo_toggle",
+    "change:widget_demo_select",
+    "click:widget_demo_menu",
+    "selection:widget_demo_tabs",
+    "selection:widget_demo_list",
+    "selection:widget_demo_table",
+    "selection:widget_demo_tree",
+    "click:widget_demo_context_menu",
+    "change:widget_demo_command_query",
+    "selection:widget_demo_command_palette"
+  ]
+
   @impl true
   def mount_defaults do
     %{
@@ -18,6 +34,14 @@ defmodule LiveUi.Demo.Screen do
     }
   end
 
+  @impl true
+  def event_routes do
+    Map.new(@widget_demo_runtime_events, &{&1, :widget_demo_interaction})
+  end
+
+  @impl true
+  def handle_event(:widget_demo_interaction, _payload, assigns), do: {:ok, assigns}
+
   @impl true
   def render(assigns) do
     current_category =
diff --git a/packages/live_ui/test/live_ui/demo_interaction_test.exs b/packages/live_ui/test/live_ui/demo_interaction_test.exs
index 4909449e..33c5f0a1 100644
--- a/packages/live_ui/test/live_ui/demo_interaction_test.exs
+++ b/packages/live_ui/test/live_ui/demo_interaction_test.exs
@@ -20,6 +20,7 @@ defmodule LiveUi.DemoInteractionTest do
                demo_socket(runtime_state)
              )
 
+    assert updated_socket.assigns.runtime_event_error == nil
     assert updated_socket.assigns.runtime_state.assigns.widget_demo_state.button.clicks == 1
 
     html =
@@ -51,6 +52,7 @@ defmodule LiveUi.DemoInteractionTest do
                demo_socket(runtime_state)
              )
 
+    assert updated_socket.assigns.runtime_event_error == nil
     assert updated_socket.assigns.runtime_state.assigns.widget_demo_state.text_input.value ==
              "Signals"
 
@@ -81,6 +83,7 @@ defmodule LiveUi.DemoInteractionTest do
                demo_socket(runtime_state)
              )
 
+    assert updated_socket.assigns.runtime_event_error == nil
     assert updated_socket.assigns.runtime_state.assigns.widget_demo_state.tabs.active == "signals"
 
     html =
diff --git a/packages/terminal_ui/lib/terminal_ui/examples.ex b/packages/terminal_ui/lib/terminal_ui/examples.ex
index d4fbf913..9c2a9282 100644
--- a/packages/terminal_ui/lib/terminal_ui/examples.ex
+++ b/packages/terminal_ui/lib/terminal_ui/examples.ex
@@ -4,6 +4,7 @@ defmodule TerminalUi.Examples do
   """
 
   alias UnifiedIUR.{Canvas, Element, Interaction, Layer, Layout}
+  alias UnifiedIUR.Interactions.Transport, as: BoundaryTransport
   alias UnifiedIUR.Widgets.{Advanced, Data, Feedback, Foundational, Input, Navigation}
 
   @spec native_foundational_screen() :: map()
@@ -583,7 +584,8 @@ defmodule TerminalUi.Examples do
       transport_flow_review: transport_flow_comparison(),
       normalized_input_profiles: normalized_input_comparison(),
       styled_continuity_review: styled_continuity_comparison(),
-      styled_degradation_review: styled_degradation_comparison()
+      styled_degradation_review: styled_degradation_comparison(),
+      navigation_transition_review: navigation_transition_review()
     }
   end
 
@@ -639,6 +641,7 @@ defmodule TerminalUi.Examples do
           :canonical_styled_review,
           :styled_continuity_review
         ],
+        navigation_review: [:navigation_transition_review],
         degradation_review: [:styled_degradation_review],
         parity_review: [:foundational_continuity, :advanced_continuity],
         capability_review: [:advanced_capability_continuity, :styled_degradation_review]
@@ -666,7 +669,8 @@ defmodule TerminalUi.Examples do
           :canonical_styled_review,
           :styled_continuity_review,
           :styled_degradation_review
-        ]
+        ],
+        navigation_transition_review: [:navigation_transition_review]
       }
     }
   end
@@ -982,6 +986,58 @@ defmodule TerminalUi.Examples do
     }
   end
 
+  @spec navigation_transition_review() :: map()
+  def navigation_transition_review do
+    fixtures = navigation_fixtures()
+
+    {:ok, raw_state} =
+      TerminalUi.Runtime.mount_native_screen(navigation_review_screen(), backend_mode: :raw)
+
+    {:ok, tty_state} =
+      TerminalUi.Runtime.mount_native_screen(navigation_review_screen(), backend_mode: :tty)
+
+    {raw_states, raw_routes} = execute_terminal_navigation_flow(raw_state, fixtures)
+    {tty_states, tty_routes} = execute_terminal_navigation_flow(tty_state, fixtures)
+
+    %{
+      id: :navigation_transition_review,
+      summary:
+        "Review canonical navigation transitions through raw and tty terminal realizations",
+      coverage: [
+        :canonical_navigation_transitions,
+        :bounded_history,
+        :modal_realization,
+        :capability_aware_navigation
+      ],
+      fixture_ids: navigation_fixture_ids(),
+      fixture_targets: navigation_fixture_targets(fixtures),
+      raw: raw_states,
+      tty: tty_states,
+      raw_routes: raw_routes,
+      tty_routes: tty_routes,
+      parity: %{
+        shared_fixture_targets_consumed?:
+          Enum.all?(raw_routes, fn {step, summary} ->
+            summary.target == tty_routes[step].target and no_host_route_syntax?(summary.target)
+          end),
+        screen_transition_meaning_preserved?:
+          raw_states.after_navigate.active_screen_id == "settings" and
+            tty_states.after_navigate.active_screen_id == "settings" and
+            raw_states.after_replace.active_screen_id == "home" and
+            tty_states.after_replace.active_screen_id == "home",
+        modal_degradation_explicit?:
+          raw_states.with_modal.current_modal.realization == :inline_overlay and
+            tty_states.with_modal.current_modal.realization == :focused_surface and
+            tty_states.with_modal.last_realization.degraded?,
+        history_semantics_preserved?:
+          raw_states.after_back.active_screen_id == "settings" and
+            tty_states.after_back.active_screen_id == "settings" and
+            raw_states.after_forward.active_screen_id == "reports" and
+            tty_states.after_forward.active_screen_id == "reports"
+      }
+    }
+  end
+
   defp runtime_summary(runtime_state) do
     %{
       source_kind: runtime_state.source_kind,
@@ -1025,6 +1081,7 @@ defmodule TerminalUi.Examples do
       family: Map.get(route_result, :family, translation.family),
       input_family: Map.get(route_result, :input_family, Map.get(translation, :input_family)),
       boundary: Map.get(route_result, :boundary, translation.boundary),
+      target: Map.get(translation, :target),
       runtime_event: Map.get(route_result, :runtime_event, translation.runtime_event),
       local_handling:
         Map.get(route_result, :local_handling, Map.get(translation, :local_handling)),
@@ -1177,6 +1234,14 @@ defmodule TerminalUi.Examples do
         parity_with: [:native_transport_review, :canonical_transport_review],
         capability_profiles: [:rich_terminal]
       },
+      %{
+        id: :navigation_transition_review,
+        category: :mixed,
+        workflow: :navigation,
+        parity_group: :navigation_transition_review,
+        parity_with: [],
+        capability_profiles: [:rich_terminal, :fallback_terminal]
+      },
       %{
         id: :normalized_input_profiles,
         category: :mixed,
@@ -1219,4 +1284,171 @@ defmodule TerminalUi.Examples do
       }
     ]
   end
+
+  defp navigation_fixtures do
+    %{
+      navigate: BoundaryTransport.boundary_fixture!("screen_transition--settings_profile"),
+      replace: BoundaryTransport.boundary_fixture!("replace_transition--home"),
+      back: BoundaryTransport.boundary_fixture!("history_transition--back"),
+      modal: BoundaryTransport.boundary_fixture!("modal_transition--settings_dialog")
+    }
+  end
+
+  defp navigation_fixture_ids do
+    [
+      "screen_transition--settings_profile",
+      "replace_transition--home",
+      "history_transition--back",
+      "modal_transition--settings_dialog"
+    ]
+  end
+
+  defp navigation_fixture_targets(fixtures) do
+    %{
+      navigate: fixtures.navigate.descriptor.target,
+      replace: fixtures.replace.descriptor.target,
+      back: fixtures.back.descriptor.target,
+      modal: fixtures.modal.descriptor.target,
+      close_modal: close_modal_target(),
+      reports: reports_target(),
+      forward: forward_target()
+    }
+  end
+
+  defp execute_terminal_navigation_flow(runtime_state, fixtures) do
+    {:ok, after_navigate, navigate_route} =
+      TerminalUi.Runtime.dispatch_native_event(
+        runtime_state,
+        family: :navigation,
+        intent: fixtures.navigate.interaction.intent,
+        widget_id: "settings-link",
+        target: fixtures.navigate.descriptor.target,
+        payload: fixtures.navigate.signal_data
+      )
+
+    {:ok, with_modal, modal_route} =
+      TerminalUi.Runtime.dispatch_native_event(
+        after_navigate,
+        family: :navigation,
+        intent: fixtures.modal.interaction.intent,
+        widget_id: "settings-dialog-button",
+        target: fixtures.modal.descriptor.target,
+        payload: fixtures.modal.signal_data
+      )
+
+    {:ok, after_close, close_route} =
+      TerminalUi.Runtime.dispatch_native_event(
+        with_modal,
+        family: :navigation,
+        intent: :close_settings_modal,
+        widget_id: "close-settings-dialog",
+        target: close_modal_target()
+      )
+
+    {:ok, after_reports, reports_route} =
+      TerminalUi.Runtime.dispatch_native_event(
+        after_close,
+        family: :navigation,
+        intent: :open_reports_screen,
+        widget_id: "reports-link",
+        target: reports_target()
+      )
+
+    {:ok, after_back, back_route} =
+      TerminalUi.Runtime.dispatch_native_event(
+        after_reports,
+        family: :navigation,
+        intent: fixtures.back.interaction.intent,
+        widget_id: "back-button",
+        target: fixtures.back.descriptor.target,
+        payload: fixtures.back.signal_data
+      )
+
+    {:ok, after_forward, forward_route} =
+      TerminalUi.Runtime.dispatch_native_event(
+        after_back,
+        family: :navigation,
+        intent: :go_forward,
+        widget_id: "forward-button",
+        target: forward_target()
+      )
+
+    {:ok, after_replace, replace_route} =
+      TerminalUi.Runtime.dispatch_native_event(
+        after_forward,
+        family: :navigation,
+        intent: fixtures.replace.interaction.intent,
+        widget_id: "home-link",
+        target: fixtures.replace.descriptor.target,
+        payload: fixtures.replace.signal_data
+      )
+
+    states = %{
+      mounted: TerminalUi.Runtime.navigation_summary(runtime_state),
+      after_navigate: TerminalUi.Runtime.navigation_summary(after_navigate),
+      with_modal: TerminalUi.Runtime.navigation_summary(with_modal),
+      after_close: TerminalUi.Runtime.navigation_summary(after_close),
+      after_reports: TerminalUi.Runtime.navigation_summary(after_reports),
+      after_back: TerminalUi.Runtime.navigation_summary(after_back),
+      after_forward: TerminalUi.Runtime.navigation_summary(after_forward),
+      after_replace: TerminalUi.Runtime.navigation_summary(after_replace)
+    }
+
+    routes = %{
+      navigate: route_summary(navigate_route),
+      modal: route_summary(modal_route),
+      close_modal: route_summary(close_route),
+      reports: route_summary(reports_route),
+      back: route_summary(back_route),
+      forward: route_summary(forward_route),
+      replace: route_summary(replace_route)
+    }
+
+    {states, routes}
+  end
+
+  defp navigation_review_screen do
+    %{
+      id: "terminal-navigation-review",
+      title: "Terminal Navigation Review",
+      root:
+        TerminalUi.Widgets.column("terminal-navigation-root", [
+          TerminalUi.Widgets.text("terminal-navigation-title", "Terminal Navigation Review"),
+          TerminalUi.Widgets.text(
+            "terminal-navigation-subtitle",
+            "Canonical screen transitions realized through screen replacement, modals, and bounded history"
+          ),
+          TerminalUi.Widgets.button("settings-link", "Settings", navigate_to: :settings),
+          TerminalUi.Widgets.button("reports-link", "Reports", navigate_to: :reports),
+          TerminalUi.Widgets.button("home-link", "Replace With Home", replace_with: :home),
+          TerminalUi.Widgets.button("back-button", "Back", go_back: true),
+          TerminalUi.Widgets.button("forward-button", "Forward", go_forward: true),
+          TerminalUi.Widgets.button("settings-dialog-button", "Open Settings Dialog",
+            open_modal: :settings_dialog,
+            navigate_params: %{mode: :advanced}
+          ),
+          TerminalUi.Widgets.button("close-settings-dialog", "Close Settings Dialog",
+            close_modal: true
+          )
+        ])
+    }
+  end
+
+  defp reports_target do
+    %{navigation: %{action: :navigate_to, screen: :reports, params: %{section: :daily}}}
+  end
+
+  defp forward_target do
+    %{navigation: %{action: :go_forward}}
+  end
+
+  defp close_modal_target do
+    %{navigation: %{action: :close_modal, modal: :settings_dialog}}
+  end
+
+  defp no_host_route_syntax?(%{navigation: navigation}) when is_map(navigation) do
+    not Map.has_key?(navigation, :route)
+  end
+
+  defp no_host_route_syntax?(_other), do: true
 end
diff --git a/packages/terminal_ui/lib/terminal_ui/inspect.ex b/packages/terminal_ui/lib/terminal_ui/inspect.ex
index 81cb1ec3..33fc45d4 100644
--- a/packages/terminal_ui/lib/terminal_ui/inspect.ex
+++ b/packages/terminal_ui/lib/terminal_ui/inspect.ex
@@ -97,6 +97,10 @@ defmodule TerminalUi.Inspect do
     TerminalUi.Examples.styled_degradation_comparison()
   end
 
+  defp preview_surface(%{category: :mixed, id: :navigation_transition_review}) do
+    TerminalUi.Examples.navigation_transition_review()
+  end
+
   defp preview_native(screen, opts) do
     {:ok, state} = TerminalUi.Runtime.mount_native_screen(screen, opts)
     TerminalUi.Inspection.runtime_snapshot(state)
diff --git a/packages/terminal_ui/lib/terminal_ui/runtime.ex b/packages/terminal_ui/lib/terminal_ui/runtime.ex
index 8ff54910..5b4650be 100644
--- a/packages/terminal_ui/lib/terminal_ui/runtime.ex
+++ b/packages/terminal_ui/lib/terminal_ui/runtime.ex
@@ -12,6 +12,7 @@ defmodule TerminalUi.Runtime do
     Error,
     EventLoop,
     EventRouter,
+    Navigation,
     Realization,
     Screen,
     State,
@@ -29,6 +30,7 @@ defmodule TerminalUi.Runtime do
       Boot,
       EventLoop,
       EventRouter,
+      Navigation,
       Screen,
       Realization,
       StyleResolver,
@@ -58,6 +60,8 @@ defmodule TerminalUi.Runtime do
       :canonical_boundary_events,
       :normalized_terminal_inputs,
       :shared_event_routing,
+      :screen_navigation,
+      :capability_aware_navigation,
       :focus_traversal,
       :binding_surface,
       :deterministic_runtime_errors
@@ -77,7 +81,8 @@ defmodule TerminalUi.Runtime do
       capability_aware: true,
       keyboard_first: true,
       renderer_boot_path_present: true,
-      style_surface_shared: true
+      style_surface_shared: true,
+      navigation_shared_runtime: true
     }
   end
 
@@ -118,8 +123,9 @@ defmodule TerminalUi.Runtime do
       |> Map.put_new(:source_kind, runtime_state.source_kind)
 
     with {:ok, translation} <- Transport.from_native_event(attrs),
-         {:ok, route_result} <- EventRouter.route(runtime_state, translation) do
-      {:ok, apply_route(runtime_state, route_result), route_result}
+         {:ok, route_result} <- EventRouter.route(runtime_state, translation),
+         {:ok, routed_state} <- apply_route(runtime_state, route_result) do
+      {:ok, routed_state, route_result}
     end
   end
 
@@ -140,20 +146,24 @@ defmodule TerminalUi.Runtime do
           {:ok, State.t(), map()} | {:error, Error.t() | term()}
   def handle_boundary_signal(%State{} = runtime_state, signal) do
     with {:ok, translation} <- Transport.from_boundary_signal(signal),
-         {:ok, route_result} <- EventRouter.route(runtime_state, translation) do
-      {:ok, apply_route(runtime_state, route_result), route_result}
+         {:ok, route_result} <- EventRouter.route(runtime_state, translation),
+         {:ok, routed_state} <- apply_route(runtime_state, route_result) do
+      {:ok, routed_state, route_result}
     end
   end
 
   defp apply_route(%State{} = runtime_state, route_result) do
     translation = route_result.translation
 
-    %{
-      runtime_state
-      | focus: apply_focus(runtime_state.focus, translation, route_result.route),
-        event_loop: EventLoop.record_route(runtime_state.event_loop, route_result),
-        event_log: runtime_state.event_log ++ [event_log_entry(route_result)]
-    }
+    with {:ok, transitioned_state} <- maybe_apply_navigation(runtime_state, translation) do
+      {:ok,
+       %{
+         transitioned_state
+         | focus: apply_focus(transitioned_state.focus, translation, route_result.route),
+           event_loop: EventLoop.record_route(transitioned_state.event_loop, route_result),
+           event_log: transitioned_state.event_log ++ [event_log_entry(route_result)]
+       }}
+    end
   end
 
   defp apply_focus(nil, _translation, _route), do: nil
@@ -198,4 +208,19 @@ defmodule TerminalUi.Runtime do
 
   defp normalize_map(attrs) when is_map(attrs), do: Map.new(attrs)
   defp normalize_map(attrs) when is_list(attrs), do: Enum.into(attrs, %{})
+
+  @spec navigation_summary(State.t()) :: map()
+  def navigation_summary(%State{navigation: navigation}) do
+    Navigation.summary(navigation)
+  end
+
+  def navigation_summary(_state), do: %{}
+
+  defp maybe_apply_navigation(%State{} = runtime_state, translation) do
+    if Navigation.transition?(translation) do
+      Navigation.apply_transition(runtime_state, translation)
+    else
+      {:ok, runtime_state}
+    end
+  end
 end
diff --git a/packages/terminal_ui/lib/terminal_ui/runtime/boot.ex b/packages/terminal_ui/lib/terminal_ui/runtime/boot.ex
index c9cd24aa..86de7837 100644
--- a/packages/terminal_ui/lib/terminal_ui/runtime/boot.ex
+++ b/packages/terminal_ui/lib/terminal_ui/runtime/boot.ex
@@ -4,7 +4,7 @@ defmodule TerminalUi.Runtime.Boot do
   """
 
   alias TerminalUi.{Backend, Capabilities}
-  alias TerminalUi.Runtime.{Error, EventLoop, Realization, Screen, State}
+  alias TerminalUi.Runtime.{Error, EventLoop, Navigation, Realization, Screen, State}
   alias TerminalUi.Widget
 
   @required_screen_keys [:id, :title, :root]
@@ -72,6 +72,14 @@ defmodule TerminalUi.Runtime.Boot do
            terminal: :not_yet_attached,
            shutdown: :idle
          },
+         navigation:
+           Navigation.initialize(
+             screen_id,
+             Map.get(screen, :title),
+             backend_mode,
+             capabilities,
+             opts
+           ),
          validation_state: runtime_validation_state(realization)
        }}
     end
diff --git a/packages/terminal_ui/lib/terminal_ui/runtime/navigation.ex b/packages/terminal_ui/lib/terminal_ui/runtime/navigation.ex
new file mode 100644
index 00000000..bb581bf2
--- /dev/null
+++ b/packages/terminal_ui/lib/terminal_ui/runtime/navigation.ex
@@ -0,0 +1,360 @@
+defmodule TerminalUi.Runtime.Navigation do
+  @moduledoc """
+  Canonical screen-transition handling for the shared `terminal_ui` runtime.
+  """
+
+  alias TerminalUi.Runtime.{Error, Screen, State}
+  alias UnifiedIUR.Interaction
+  alias UnifiedIUR.Interactions.Transport, as: BoundaryTransport
+
+  @default_history_limits %{raw: 20, tty: 5}
+
+  @spec initialize(String.t(), String.t() | nil, atom(), map(), keyword()) :: map()
+  def initialize(screen_id, title, backend_mode, capabilities, opts \\ []) do
+    history_limit = Keyword.get(opts, :history_limit, Map.get(@default_history_limits, backend_mode, 10))
+
+    %{
+      active: %{screen_id: screen_id, title: title, params: %{}},
+      history: [],
+      forward: [],
+      modals: [],
+      history_limit: history_limit,
+      last_transition: nil,
+      last_realization: realization_summary(%{action: :mount}, backend_mode, capabilities, false)
+    }
+  end
+
+  @spec transition?(map()) :: boolean()
+  def transition?(%{family: :navigation, target: target}) when is_map(target) do
+    not is_nil(Interaction.navigation_descriptor(target))
+  end
+
+  def transition?(_other), do: false
+
+  @spec summary(map() | nil) :: map()
+  def summary(%{
+        active: active,
+        history: history,
+        forward: forward,
+        modals: modals,
+        last_transition: last_transition,
+        last_realization: last_realization
+      }) do
+    %{
+      active_screen_id: active.screen_id,
+      history_depth: length(history),
+      forward_depth: length(forward),
+      modal_depth: length(modals),
+      current_modal: modals |> List.last() |> modal_summary(),
+      last_transition: last_transition,
+      last_realization: last_realization
+    }
+  end
+
+  def summary(_other), do: %{}
+
+  @spec apply_transition(State.t(), map()) :: {:ok, State.t()} | {:error, Error.t()}
+  def apply_transition(%State{} = runtime_state, translation) when is_map(translation) do
+    with {:ok, descriptor} <- validate_navigation_descriptor(translation),
+         {:ok, navigation} <- apply_descriptor(runtime_state.navigation, descriptor, runtime_state) do
+      {:ok, synchronize_runtime(runtime_state, navigation, descriptor)}
+    end
+  end
+
+  defp validate_navigation_descriptor(translation) do
+    descriptor = boundary_descriptor(translation)
+
+    case BoundaryTransport.validate_boundary_descriptor(descriptor) do
+      :ok ->
+        {:ok, navigation_descriptor(translation)}
+
+      {:error, {:forbidden_navigation_keys, keys}} ->
+        {:error, Error.new(:host_route_navigation_syntax, %{keys: keys}, :event_routing)}
+
+      {:error, reason} ->
+        {:error, Error.new(:invalid_navigation_transition, %{reason: inspect(reason)}, :event_routing)}
+    end
+  end
+
+  defp apply_descriptor(navigation, descriptor, runtime_state) do
+    action = Map.get(descriptor, :action)
+
+    case action do
+      action when action in [:navigate_to, "navigate_to"] ->
+        {:ok, navigate_to(navigation, descriptor, runtime_state)}
+
+      action when action in [:replace_with, "replace_with"] ->
+        {:ok, replace_with(navigation, descriptor, runtime_state)}
+
+      action when action in [:go_back, "go_back"] ->
+        go_back(navigation, descriptor, runtime_state)
+
+      action when action in [:go_forward, "go_forward"] ->
+        go_forward(navigation, descriptor, runtime_state)
+
+      action when action in [:open_modal, "open_modal"] ->
+        {:ok, open_modal(navigation, descriptor, runtime_state)}
+
+      action when action in [:close_modal, "close_modal"] ->
+        close_modal(navigation, descriptor, runtime_state)
+
+      _other ->
+        {:error,
+         Error.new(
+           :unsupported_navigation_context,
+           %{action: action, reason: :unsupported_navigation_action},
+           :event_routing
+         )}
+    end
+  end
+
+  defp navigate_to(navigation, descriptor, runtime_state) do
+    target = screen_entry(descriptor)
+
+    history =
+      [navigation.active | navigation.history]
+      |> Enum.take(navigation.history_limit)
+
+    navigation
+    |> Map.put(:active, target)
+    |> Map.put(:history, history)
+    |> Map.put(:forward, [])
+    |> Map.put(:last_transition, descriptor)
+    |> Map.put(
+      :last_realization,
+      realization_summary(descriptor, runtime_state.backend_mode, runtime_state.capabilities, false)
+    )
+  end
+
+  defp replace_with(navigation, descriptor, runtime_state) do
+    navigation
+    |> Map.put(:active, screen_entry(descriptor))
+    |> Map.put(:forward, [])
+    |> Map.put(:last_transition, descriptor)
+    |> Map.put(
+      :last_realization,
+      realization_summary(descriptor, runtime_state.backend_mode, runtime_state.capabilities, false)
+    )
+  end
+
+  defp go_back(%{history: []}, descriptor, _runtime_state) do
+    {:error,
+     Error.new(
+       :unsupported_navigation_context,
+       %{action: descriptor.action, reason: :empty_history},
+       :event_routing
+     )}
+  end
+
+  defp go_back(navigation, descriptor, runtime_state) do
+    [previous | history_rest] = navigation.history
+
+    {:ok,
+     navigation
+     |> Map.put(:active, previous)
+     |> Map.put(:history, history_rest)
+     |> Map.put(:forward, [navigation.active | navigation.forward])
+     |> Map.put(:last_transition, descriptor)
+     |> Map.put(
+       :last_realization,
+       realization_summary(descriptor, runtime_state.backend_mode, runtime_state.capabilities, false)
+     )}
+  end
+
+  defp go_forward(%{forward: []}, descriptor, _runtime_state) do
+    {:error,
+     Error.new(
+       :unsupported_navigation_context,
+       %{action: descriptor.action, reason: :empty_forward},
+       :event_routing
+     )}
+  end
+
+  defp go_forward(navigation, descriptor, runtime_state) do
+    [next | forward_rest] = navigation.forward
+
+    {:ok,
+     navigation
+     |> Map.put(:active, next)
+     |> Map.put(:history, [navigation.active | navigation.history] |> Enum.take(navigation.history_limit))
+     |> Map.put(:forward, forward_rest)
+     |> Map.put(:last_transition, descriptor)
+     |> Map.put(
+       :last_realization,
+       realization_summary(descriptor, runtime_state.backend_mode, runtime_state.capabilities, false)
+     )}
+  end
+
+  defp open_modal(navigation, descriptor, runtime_state) do
+    degrade? = runtime_state.backend_mode == :tty
+
+    modal_entry =
+      %{
+        modal: Map.get(descriptor, :modal),
+        params: normalize_map(Map.get(descriptor, :params, %{})),
+        metadata: normalize_map(Map.get(descriptor, :metadata, %{})),
+        realization:
+          if(degrade?,
+            do: :focused_surface,
+            else: :inline_overlay
+          )
+      }
+
+    navigation
+    |> Map.update!(:modals, &(&1 ++ [modal_entry]))
+    |> Map.put(:last_transition, descriptor)
+    |> Map.put(
+      :last_realization,
+      realization_summary(descriptor, runtime_state.backend_mode, runtime_state.capabilities, degrade?)
+    )
+  end
+
+  defp close_modal(%{modals: []}, descriptor, _runtime_state) do
+    {:error,
+     Error.new(
+       :invalid_modal_transition,
+       %{action: descriptor.action, reason: :no_modal},
+       :event_routing
+     )}
+  end
+
+  defp close_modal(navigation, descriptor, runtime_state) do
+    requested_modal = Map.get(descriptor, :modal)
+    current_modal = navigation.modals |> List.last() |> Map.get(:modal)
+
+    cond do
+      not is_nil(requested_modal) and requested_modal != current_modal ->
+        {:error,
+         Error.new(
+           :invalid_modal_transition,
+           %{action: descriptor.action, requested_modal: requested_modal, current_modal: current_modal},
+           :event_routing
+         )}
+
+      true ->
+        {:ok,
+         navigation
+         |> Map.put(:modals, Enum.drop(navigation.modals, -1))
+         |> Map.put(:last_transition, descriptor)
+         |> Map.put(
+           :last_realization,
+           realization_summary(descriptor, runtime_state.backend_mode, runtime_state.capabilities, false)
+         )}
+    end
+  end
+
+  defp synchronize_runtime(runtime_state, navigation, descriptor) do
+    screen_id = navigation.active.screen_id
+    title = navigation.active.title || default_title(screen_id)
+
+    %{
+      runtime_state
+      | screen_id: screen_id,
+        title: title,
+        screen: synchronize_screen(runtime_state.screen, screen_id, title, navigation, descriptor),
+        navigation: navigation
+    }
+  end
+
+  defp synchronize_screen(%Screen{} = screen, screen_id, title, navigation, descriptor) do
+    metadata =
+      screen.metadata
+      |> Map.put(:current_screen_id, screen_id)
+      |> Map.put(:navigation_action, Map.get(descriptor, :action))
+      |> Map.put(:navigation_summary, summary(navigation))
+
+    %{screen | id: screen_id, title: title, metadata: metadata}
+  end
+
+  defp screen_entry(descriptor) do
+    screen_id = Map.get(descriptor, :screen)
+
+    %{
+      screen_id: normalize_screen_id(screen_id),
+      title: default_title(screen_id),
+      params: normalize_map(Map.get(descriptor, :params, %{}))
+    }
+  end
+
+  defp realization_summary(descriptor, backend_mode, capabilities, degraded?) do
+    action = Map.get(descriptor, :action)
+
+    %{
+      action: action,
+      backend_mode: backend_mode,
+      transition_mode: transition_mode(action, backend_mode),
+      degraded?: degraded?,
+      fallback:
+        if(degraded?,
+          do: fallback_for(action, capabilities),
+          else: nil
+        ),
+      intent_preserved?: true
+    }
+  end
+
+  defp transition_mode(action, _backend_mode) when action in [:navigate_to, "navigate_to"], do: :screen_replacement
+  defp transition_mode(action, _backend_mode) when action in [:replace_with, "replace_with"], do: :screen_replacement
+  defp transition_mode(action, _backend_mode) when action in [:go_back, "go_back", :go_forward, "go_forward"], do: :bounded_history
+  defp transition_mode(action, :tty) when action in [:open_modal, "open_modal", :close_modal, "close_modal"], do: :focused_surface
+  defp transition_mode(action, _backend_mode) when action in [:open_modal, "open_modal", :close_modal, "close_modal"], do: :inline_overlay
+  defp transition_mode(_action, _backend_mode), do: :screen_replacement
+
+  defp fallback_for(action, _capabilities) when action in [:open_modal, "open_modal", :close_modal, "close_modal"] do
+    :focused_surface
+  end
+
+  defp fallback_for(action, capabilities) when action in [:navigate_to, "navigate_to", :replace_with, "replace_with"] do
+    if Map.get(capabilities, :positioning, false), do: nil, else: :screen_replacement
+  end
+
+  defp fallback_for(_action, _capabilities), do: nil
+
+  defp modal_summary(nil), do: nil
+
+  defp modal_summary(modal) do
+    %{
+      modal: modal.modal,
+      params: modal.params,
+      realization: modal.realization
+    }
+  end
+
+  defp boundary_descriptor(translation) do
+    %{
+      family: :navigation,
+      intent: Map.get(translation, :intent),
+      source_context: %{
+        element_id: Map.get(translation, :widget_id),
+        scope: :screen
+      },
+      target: Map.get(translation, :target, %{}),
+      metadata: %{}
+    }
+  end
+
+  defp navigation_descriptor(translation) do
+    Interaction.navigation_descriptor(Map.get(translation, :target, %{})) || %{}
+  end
+
+  defp normalize_screen_id(screen_id) when is_binary(screen_id), do: screen_id
+  defp normalize_screen_id(screen_id) when is_atom(screen_id), do: to_string(screen_id)
+  defp normalize_screen_id(screen_id), do: screen_id |> to_string()
+
+  defp default_title(screen_id) when is_atom(screen_id) do
+    screen_id
+    |> Atom.to_string()
+    |> default_title()
+  end
+
+  defp default_title(screen_id) when is_binary(screen_id) do
+    screen_id
+    |> String.split(~r/[_-]+/)
+    |> Enum.map(&String.capitalize/1)
+    |> Enum.join(" ")
+  end
+
+  defp normalize_map(map) when is_map(map), do: Map.new(map)
+  defp normalize_map(map) when is_list(map), do: Enum.into(map, %{})
+  defp normalize_map(_other), do: %{}
+end
diff --git a/packages/terminal_ui/lib/terminal_ui/runtime/state.ex b/packages/terminal_ui/lib/terminal_ui/runtime/state.ex
index 88e38fa9..71ac991e 100644
--- a/packages/terminal_ui/lib/terminal_ui/runtime/state.ex
+++ b/packages/terminal_ui/lib/terminal_ui/runtime/state.ex
@@ -27,6 +27,7 @@ defmodule TerminalUi.Runtime.State do
     :backend_adapter,
     :event_loop,
     :lifecycle,
+    :navigation,
     :validation_state,
     event_log: []
   ]
@@ -47,6 +48,7 @@ defmodule TerminalUi.Runtime.State do
           backend_adapter: map(),
           event_loop: map(),
           lifecycle: map(),
+          navigation: map(),
           validation_state: atom(),
           event_log: [map()]
         }
diff --git a/packages/terminal_ui/lib/terminal_ui/transport/diagnostics.ex b/packages/terminal_ui/lib/terminal_ui/transport/diagnostics.ex
index 1d63aa2e..b78241bb 100644
--- a/packages/terminal_ui/lib/terminal_ui/transport/diagnostics.ex
+++ b/packages/terminal_ui/lib/terminal_ui/transport/diagnostics.ex
@@ -6,6 +6,8 @@ defmodule TerminalUi.Transport.Diagnostics do
   alias Jido.Signal
   alias TerminalUi.Transport.{Error, Normalize}
   alias TerminalUi.Transport.Signal, as: TransportSignal
+  alias UnifiedIUR.Interaction
+  alias UnifiedIUR.Interactions.Transport, as: BoundaryTransport
 
   @payload_leak_keys [:escape_sequence, :termcode, :ansi, :backend_payload, :terminal_bytes]
   @payload_leak_prefixes ["ansi_", "term_", "escape_", "csi_"]
@@ -42,6 +44,7 @@ defmodule TerminalUi.Transport.Diagnostics do
   def validate_translation(%{} = translation) do
     with :ok <- validate_payload(Map.get(translation, :payload, %{}), :translation_payload),
          :ok <- validate_payload(Map.get(translation, :target, %{}), :translation_target),
+         :ok <- validate_navigation_target(translation),
          :ok <- maybe_validate_boundary_signal(translation) do
       if Map.get(translation, :boundary) == :boundary do
         validate_boundary_context(translation)
@@ -136,6 +139,33 @@ defmodule TerminalUi.Transport.Diagnostics do
 
   defp leaked_key?(_key), do: false
 
+  defp validate_navigation_target(%{family: :navigation, target: target}) when is_map(target) do
+    descriptor = Interaction.navigation_descriptor(target)
+
+    if is_nil(descriptor) do
+      :ok
+    else
+      case BoundaryTransport.validate_boundary_descriptor(%{
+             family: :navigation,
+             intent: nil,
+             source_context: %{},
+             target: target,
+             metadata: %{}
+           }) do
+        :ok ->
+          :ok
+
+        {:error, {:forbidden_navigation_keys, keys}} ->
+          {:error, Error.host_route_navigation_syntax(keys)}
+
+        {:error, reason} ->
+          {:error, Error.invalid_navigation_target(reason)}
+      end
+    end
+  end
+
+  defp validate_navigation_target(_translation), do: :ok
+
   defp maybe_missing(fields, field, nil), do: fields ++ [field]
   defp maybe_missing(fields, field, ""), do: fields ++ [field]
   defp maybe_missing(fields, _field, _value), do: fields
diff --git a/packages/terminal_ui/lib/terminal_ui/transport/error.ex b/packages/terminal_ui/lib/terminal_ui/transport/error.ex
index e76727ed..0d143bab 100644
--- a/packages/terminal_ui/lib/terminal_ui/transport/error.ex
+++ b/packages/terminal_ui/lib/terminal_ui/transport/error.ex
@@ -84,4 +84,22 @@ defmodule TerminalUi.Transport.Error do
       details: %{backend_mode: inspect(mode)}
     }
   end
+
+  @spec host_route_navigation_syntax([atom() | String.t()]) :: t()
+  def host_route_navigation_syntax(keys) do
+    %__MODULE__{
+      reason: :host_route_navigation_syntax,
+      message: "canonical terminal navigation targets must not contain host-route syntax",
+      details: %{keys: keys}
+    }
+  end
+
+  @spec invalid_navigation_target(term()) :: t()
+  def invalid_navigation_target(reason) do
+    %__MODULE__{
+      reason: :invalid_navigation_target,
+      message: "terminal_ui navigation targets must satisfy the canonical screen-transition contract",
+      details: %{reason: inspect(reason)}
+    }
+  end
 end
diff --git a/packages/terminal_ui/lib/terminal_ui/transport/normalize.ex b/packages/terminal_ui/lib/terminal_ui/transport/normalize.ex
index 44a2cfa7..b5265a21 100644
--- a/packages/terminal_ui/lib/terminal_ui/transport/normalize.ex
+++ b/packages/terminal_ui/lib/terminal_ui/transport/normalize.ex
@@ -93,7 +93,20 @@ defmodule TerminalUi.Transport.Normalize do
       present?(fetch(attrs, :focus_target)) or present?(fetch(attrs, :focused)) -> {:ok, :focus}
       present?(fetch(attrs, :mouse_action)) or present?(fetch(attrs, :pointer)) -> {:ok, :mouse}
       present?(fetch(attrs, :key)) -> {:ok, :key}
-      true -> {:error, Error.invalid_native_event(attrs)}
+      true -> infer_input_family_from_family(attrs)
+    end
+  end
+
+  defp infer_input_family_from_family(attrs) do
+    case normalize_family(fetch(attrs, :family)) do
+      :command -> {:ok, :shortcut}
+      :navigation -> {:ok, :key}
+      :selection -> {:ok, :mouse}
+      :click -> {:ok, :mouse}
+      :submit -> {:ok, :key}
+      :change -> {:ok, :key}
+      :focus -> {:ok, :focus}
+      _other -> {:error, Error.invalid_native_event(attrs)}
     end
   end
 
diff --git a/packages/terminal_ui/lib/terminal_ui/widgets/foundational.ex b/packages/terminal_ui/lib/terminal_ui/widgets/foundational.ex
index 76b47627..a09924c6 100644
--- a/packages/terminal_ui/lib/terminal_ui/widgets/foundational.ex
+++ b/packages/terminal_ui/lib/terminal_ui/widgets/foundational.ex
@@ -5,6 +5,7 @@ defmodule TerminalUi.Widgets.Foundational do
 
   alias TerminalUi.Widget
   alias TerminalUi.Widgets.Builder
+  alias TerminalUi.Widgets.Navigation, as: NavigationWidget
 
   @spec kinds() :: [atom()]
   def kinds do
@@ -90,12 +91,15 @@ defmodule TerminalUi.Widgets.Foundational do
 
   @spec button(String.t() | atom(), String.t(), keyword()) :: Widget.t()
   def button(id, label, opts \\ []) do
+    keypress_event = NavigationWidget.event_payload(opts) || opts[:on_press]
+    command_event = if(is_nil(NavigationWidget.event_payload(opts)), do: opts[:on_command], else: nil)
+
     Widget.new(:button,
       id: id,
       metadata: Builder.metadata(label, Keyword.merge([focusable: true, role: :button], opts)),
       state: Builder.state(opts, %{disabled: false}),
       attributes: %{label: label},
-      events: Builder.events(keypress: opts[:on_press], command: opts[:on_command]),
+      events: Builder.events(keypress: keypress_event, command: command_event),
       styles: Builder.styles(opts)
     )
   end
@@ -115,12 +119,14 @@ defmodule TerminalUi.Widgets.Foundational do
 
   @spec link(String.t() | atom(), String.t(), String.t(), keyword()) :: Widget.t()
   def link(id, label, target, opts \\ []) do
+    activate_event = NavigationWidget.event_payload(opts) || opts[:on_follow]
+
     Widget.new(:link,
       id: id,
       metadata: Builder.metadata(label, Keyword.merge([focusable: true, role: :link], opts)),
       state: Builder.state(opts, %{disabled: false}),
       attributes: %{label: label, target: target},
-      events: Builder.events(activate: opts[:on_follow]),
+      events: Builder.events(activate: activate_event),
       styles: Builder.styles(opts)
     )
   end
@@ -128,6 +134,10 @@ defmodule TerminalUi.Widgets.Foundational do
   @spec command(String.t() | atom(), String.t(), keyword()) :: Widget.t()
   def command(id, label, opts \\ []) do
     command_name = Keyword.get(opts, :command, id)
+    command_event =
+      NavigationWidget.event_payload(opts) ||
+        opts[:on_command] ||
+        %{command: command_name, source: :terminal_ui}
 
     Widget.new(:command,
       id: id,
@@ -138,10 +148,7 @@ defmodule TerminalUi.Widgets.Foundational do
         ),
       state: Builder.state(opts, %{disabled: false}),
       attributes: %{label: label, command: command_name},
-      events:
-        Builder.events(
-          command: opts[:on_command] || %{command: command_name, source: :terminal_ui}
-        ),
+      events: Builder.events(command: command_event),
       styles: Builder.styles(opts)
     )
   end
diff --git a/packages/terminal_ui/lib/terminal_ui/widgets/navigation.ex b/packages/terminal_ui/lib/terminal_ui/widgets/navigation.ex
index dc16eb7f..25c656c6 100644
--- a/packages/terminal_ui/lib/terminal_ui/widgets/navigation.ex
+++ b/packages/terminal_ui/lib/terminal_ui/widgets/navigation.ex
@@ -75,5 +75,80 @@ defmodule TerminalUi.Widgets.Navigation do
     )
   end
 
+  @spec event_payload(keyword() | map()) :: map() | nil
+  def event_payload(opts) when is_list(opts), do: opts |> Enum.into(%{}) |> event_payload()
+
+  def event_payload(%{navigate_to: screen_id} = opts) when is_atom(screen_id) or is_binary(screen_id) do
+    params = Map.get(opts, :navigate_params, %{})
+
+    %{
+      family: :navigation,
+      intent: Map.get(opts, :intent, :navigate_to),
+      target: %{navigation: %{action: :navigate_to, screen: screen_id, params: params}},
+      payload: Map.get(opts, :payload, %{})
+    }
+  end
+
+  def event_payload(%{replace_with: screen_id} = opts) when is_atom(screen_id) or is_binary(screen_id) do
+    params = Map.get(opts, :navigate_params, %{})
+
+    %{
+      family: :navigation,
+      intent: Map.get(opts, :intent, :replace_with),
+      target: %{navigation: %{action: :replace_with, screen: screen_id, params: params}},
+      payload: Map.get(opts, :payload, %{})
+    }
+  end
+
+  def event_payload(%{go_back: true}) do
+    %{
+      family: :navigation,
+      intent: :go_back,
+      target: %{navigation: %{action: :go_back}},
+      payload: %{}
+    }
+  end
+
+  def event_payload(%{go_forward: true}) do
+    %{
+      family: :navigation,
+      intent: :go_forward,
+      target: %{navigation: %{action: :go_forward}},
+      payload: %{}
+    }
+  end
+
+  def event_payload(%{open_modal: modal_id} = opts) when is_atom(modal_id) or is_binary(modal_id) do
+    params = Map.get(opts, :navigate_params, %{})
+
+    %{
+      family: :navigation,
+      intent: Map.get(opts, :intent, :open_modal),
+      target: %{navigation: %{action: :open_modal, modal: modal_id, params: params}},
+      payload: Map.get(opts, :payload, %{})
+    }
+  end
+
+  def event_payload(%{close_modal: true} = opts) do
+    navigation =
+      %{
+        action: :close_modal
+      }
+      |> maybe_put(:modal, Map.get(opts, :modal))
+
+    %{
+      family: :navigation,
+      intent: :close_modal,
+      target: %{navigation: navigation},
+      payload: %{}
+    }
+  end
+
+  def event_payload(_opts), do: nil
+
   defp keyword_label(id, opts), do: Keyword.get(opts, :label, to_string(id))
+
+  defp maybe_put(map, _key, nil), do: map
+  defp maybe_put(map, _key, ""), do: map
+  defp maybe_put(map, key, value), do: Map.put(map, key, value)
 end
diff --git a/packages/terminal_ui/test/terminal_ui/canonical_navigation_non_web_examples_integration_test.exs b/packages/terminal_ui/test/terminal_ui/canonical_navigation_non_web_examples_integration_test.exs
new file mode 100644
index 00000000..cbcf4c58
--- /dev/null
+++ b/packages/terminal_ui/test/terminal_ui/canonical_navigation_non_web_examples_integration_test.exs
@@ -0,0 +1,43 @@
+defmodule TerminalUi.CanonicalNavigationNonWebExamplesIntegrationTest do
+  use ExUnit.Case, async: true
+
+  test "terminal maintained navigation review consumes shared canonical fixtures across raw and tty backends" do
+    review = TerminalUi.Examples.navigation_transition_review()
+    metadata = TerminalUi.Examples.metadata(:navigation_transition_review)
+    reference = TerminalUi.reference()
+    summary = TerminalUi.info()
+
+    assert review.fixture_ids == [
+             "screen_transition--settings_profile",
+             "replace_transition--home",
+             "history_transition--back",
+             "modal_transition--settings_dialog"
+           ]
+
+    assert review.parity.shared_fixture_targets_consumed?
+    assert review.parity.screen_transition_meaning_preserved?
+    assert review.parity.modal_degradation_explicit?
+    assert review.parity.history_semantics_preserved?
+    assert review.raw.after_navigate.active_screen_id == "settings"
+    assert review.raw.after_back.forward_depth == 1
+    assert review.raw.after_replace.active_screen_id == "home"
+    assert review.tty.after_replace.active_screen_id == "home"
+    assert review.tty.with_modal.last_realization.degraded?
+    assert review.tty.with_modal.last_realization.fallback == :focused_surface
+    assert metadata.workflow == :navigation
+    assert metadata.parity_group == :navigation_transition_review
+    assert :navigation_transition_review in reference.examples.comparison_ids
+    assert :navigation_transition_review in summary.examples.comparison_ids
+    assert :navigation_review in summary.examples.workflows
+  end
+
+  test "terminal maintained navigation review keeps canonical targets free of host route syntax and stable across backends" do
+    review = TerminalUi.Examples.navigation_transition_review()
+
+    assert Enum.all?(review.raw_routes, fn {step, route} ->
+             match?(%{navigation: _}, route.target) and
+               route.target == review.tty_routes[step].target and
+               get_in(route.target, [:navigation, :route]) == nil
+           end)
+  end
+end
diff --git a/packages/terminal_ui/test/terminal_ui/canonical_navigation_terminal_runtime_integration_test.exs b/packages/terminal_ui/test/terminal_ui/canonical_navigation_terminal_runtime_integration_test.exs
new file mode 100644
index 00000000..3fe5a47a
--- /dev/null
+++ b/packages/terminal_ui/test/terminal_ui/canonical_navigation_terminal_runtime_integration_test.exs
@@ -0,0 +1,148 @@
+defmodule TerminalUi.CanonicalNavigationTerminalRuntimeIntegrationTest do
+  use ExUnit.Case, async: true
+
+  alias TerminalUi.Runtime
+  alias UnifiedIUR.Interactions.Transport, as: BoundaryTransport
+
+  test "raw terminal runtime realizes canonical screen, modal, and history transitions through one shared navigation state" do
+    navigate_fixture = BoundaryTransport.boundary_fixture!("screen_transition--settings_profile")
+    modal_fixture = BoundaryTransport.boundary_fixture!("modal_transition--settings_dialog")
+    history_fixture = BoundaryTransport.boundary_fixture!("history_transition--back")
+
+    assert {:ok, runtime_state} = Runtime.mount_native_screen(base_screen(), backend_mode: :raw)
+
+    assert Runtime.navigation_summary(runtime_state) == %{
+             active_screen_id: "workspace",
+             history_depth: 0,
+             forward_depth: 0,
+             modal_depth: 0,
+             current_modal: nil,
+             last_transition: nil,
+             last_realization: %{
+               action: :mount,
+               backend_mode: :raw,
+               transition_mode: :screen_replacement,
+               degraded?: false,
+               fallback: nil,
+               intent_preserved?: true
+             }
+           }
+
+    assert {:ok, after_navigate, navigate_route} =
+             Runtime.dispatch_native_event(
+               runtime_state,
+               family: :navigation,
+               intent: navigate_fixture.interaction.intent,
+               widget_id: "settings-link",
+               target: navigate_fixture.descriptor.target,
+               payload: navigate_fixture.signal_data
+             )
+
+    assert navigate_route.route == :canonical_boundary
+    assert after_navigate.screen_id == "settings"
+    assert Runtime.navigation_summary(after_navigate).history_depth == 1
+    assert Runtime.navigation_summary(after_navigate).last_realization.transition_mode ==
+             :screen_replacement
+
+    assert {:ok, with_modal, modal_route} =
+             Runtime.dispatch_native_event(
+               after_navigate,
+               family: :navigation,
+               intent: modal_fixture.interaction.intent,
+               widget_id: "settings-dialog-button",
+               target: modal_fixture.descriptor.target,
+               payload: modal_fixture.signal_data
+             )
+
+    assert modal_route.translation.target == modal_fixture.descriptor.target
+
+    assert Runtime.navigation_summary(with_modal).current_modal == %{
+             modal: :settings_dialog,
+             params: %{mode: :advanced},
+             realization: :inline_overlay
+           }
+
+    assert {:ok, after_back, back_route} =
+             Runtime.dispatch_native_event(
+               with_modal,
+               family: :navigation,
+               intent: history_fixture.interaction.intent,
+               widget_id: "back-button",
+               target: history_fixture.descriptor.target,
+               payload: history_fixture.signal_data
+             )
+
+    assert back_route.translation.target == history_fixture.descriptor.target
+    assert after_back.screen_id == "workspace"
+    assert Runtime.navigation_summary(after_back).forward_depth == 1
+    assert Runtime.navigation_summary(after_back).last_realization.transition_mode ==
+             :bounded_history
+  end
+
+  test "tty backend degrades modal transitions into focused-surface realizations without changing canonical intent" do
+    modal_fixture = BoundaryTransport.boundary_fixture!("modal_transition--settings_dialog")
+
+    assert {:ok, runtime_state} = Runtime.mount_native_screen(base_screen(), backend_mode: :tty)
+
+    assert {:ok, with_modal, _route} =
+             Runtime.dispatch_native_event(
+               runtime_state,
+               family: :navigation,
+               intent: modal_fixture.interaction.intent,
+               widget_id: "settings-dialog-button",
+               target: modal_fixture.descriptor.target,
+               payload: modal_fixture.signal_data
+             )
+
+    assert Runtime.navigation_summary(with_modal).current_modal == %{
+             modal: :settings_dialog,
+             params: %{mode: :advanced},
+             realization: :focused_surface
+           }
+
+    assert Runtime.navigation_summary(with_modal).last_realization == %{
+             action: :open_modal,
+             backend_mode: :tty,
+             transition_mode: :focused_surface,
+             degraded?: true,
+             fallback: :focused_surface,
+             intent_preserved?: true
+           }
+  end
+
+  test "terminal runtime rejects leaked route syntax and invalid modal transitions deterministically" do
+    assert {:ok, runtime_state} = Runtime.mount_native_screen(base_screen(), backend_mode: :raw)
+
+    assert {:error, %Runtime.Error{reason: :host_route_navigation_syntax}} =
+             Runtime.dispatch_native_event(
+               runtime_state,
+               family: :navigation,
+               intent: :open_settings_screen,
+               widget_id: "settings-link",
+               target: %{
+                 navigation: %{action: :navigate_to, screen: :settings, route: "/settings"}
+               }
+             )
+
+    assert {:error, %Runtime.Error{reason: :invalid_modal_transition}} =
+             Runtime.dispatch_native_event(
+               runtime_state,
+               family: :navigation,
+               intent: :close_settings_modal,
+               widget_id: "close-settings-dialog",
+               target: %{navigation: %{action: :close_modal, modal: :settings_dialog}}
+             )
+  end
+
+  defp base_screen do
+    %{
+      id: "workspace",
+      title: "Workspace",
+      root:
+        TerminalUi.Widgets.column("workspace-root", [
+          TerminalUi.Widgets.text("workspace-title", "Workspace"),
+          TerminalUi.Widgets.button("settings-link", "Settings", navigate_to: :settings)
+        ])
+    }
+  end
+end
diff --git a/packages/terminal_ui/test/terminal_ui/examples_test.exs b/packages/terminal_ui/test/terminal_ui/examples_test.exs
index 4fcfabb4..3697b106 100644
--- a/packages/terminal_ui/test/terminal_ui/examples_test.exs
+++ b/packages/terminal_ui/test/terminal_ui/examples_test.exs
@@ -49,6 +49,7 @@ defmodule TerminalUi.ExamplesTest do
              :native_foundational,
              :native_styled_review,
              :native_transport_review,
+             :navigation_transition_review,
              :normalized_input_profiles,
              :styled_continuity_review,
              :styled_degradation_review,
@@ -62,6 +63,7 @@ defmodule TerminalUi.ExamplesTest do
              :advanced_capability_continuity,
              :advanced_continuity,
              :foundational_continuity,
+             :navigation_transition_review,
              :normalized_input_profiles,
              :styled_continuity_review,
              :styled_degradation_review,
@@ -135,6 +137,48 @@ defmodule TerminalUi.ExamplesTest do
     assert degradation.parity.inspection_surfaces_agree?
   end
 
+  test "navigation review exposes shared canonical fixtures and explicit raw versus tty realization" do
+    review = TerminalUi.Examples.navigation_transition_review()
+
+    assert review.id == :navigation_transition_review
+
+    assert review.fixture_ids == [
+             "screen_transition--settings_profile",
+             "replace_transition--home",
+             "history_transition--back",
+             "modal_transition--settings_dialog"
+           ]
+
+    assert review.parity.shared_fixture_targets_consumed?
+    assert review.parity.screen_transition_meaning_preserved?
+    assert review.parity.modal_degradation_explicit?
+    assert review.parity.history_semantics_preserved?
+    assert review.raw.after_navigate.active_screen_id == "settings"
+    assert review.raw.after_forward.active_screen_id == "reports"
+    assert review.raw.after_replace.active_screen_id == "home"
+
+    assert review.raw.with_modal.current_modal == %{
+             modal: :settings_dialog,
+             params: %{mode: :advanced},
+             realization: :inline_overlay
+           }
+
+    assert review.tty.with_modal.current_modal == %{
+             modal: :settings_dialog,
+             params: %{mode: :advanced},
+             realization: :focused_surface
+           }
+
+    assert review.tty.with_modal.last_realization == %{
+             action: :open_modal,
+             backend_mode: :tty,
+             transition_mode: :focused_surface,
+             degraded?: true,
+             fallback: :focused_surface,
+             intent_preserved?: true
+           }
+  end
+
   test "reference and info surfaces include foundational example metadata and coverage" do
     reference = TerminalUi.reference()
     summary = TerminalUi.info()
@@ -156,6 +200,7 @@ defmodule TerminalUi.ExamplesTest do
     assert :foundational_continuity in reference.examples.comparison_ids
     assert :advanced_continuity in reference.examples.comparison_ids
     assert :advanced_capability_continuity in reference.examples.comparison_ids
+    assert :navigation_transition_review in reference.examples.comparison_ids
     assert :transport_flow_review in reference.examples.comparison_ids
     assert :normalized_input_profiles in reference.examples.comparison_ids
     assert :styled_continuity_review in reference.examples.comparison_ids
@@ -182,6 +227,7 @@ defmodule TerminalUi.ExamplesTest do
     assert :actions in summary.examples.categories
     assert :display in summary.examples.categories
     assert :transport in summary.examples.categories
+    assert :navigation_review in summary.examples.workflows
     assert :style in summary.examples.categories
     assert :advanced_review in summary.examples.workflows
     assert :transport_review in summary.examples.workflows
diff --git a/packages/terminal_ui/test/terminal_ui/foundational_widget_families_test.exs b/packages/terminal_ui/test/terminal_ui/foundational_widget_families_test.exs
index 998c5f1d..fbaeac48 100644
--- a/packages/terminal_ui/test/terminal_ui/foundational_widget_families_test.exs
+++ b/packages/terminal_ui/test/terminal_ui/foundational_widget_families_test.exs
@@ -20,6 +20,12 @@ defmodule TerminalUi.FoundationalWidgetFamiliesTest do
         shortcut: "ctrl-s"
       )
 
+    navigate_button =
+      TerminalUi.Widgets.button("settings-button", "Settings",
+        navigate_to: :settings,
+        navigate_params: %{tab: :profile}
+      )
+
     assert icon.kind == :icon
     assert icon.attributes.fallback_text == "[S]"
     assert image.kind == :image
@@ -33,6 +39,11 @@ defmodule TerminalUi.FoundationalWidgetFamiliesTest do
     assert primary.family == :action
     assert primary.metadata.command == :save_workspace
     assert primary.events.command == %{command: :save_workspace, source: :terminal_ui}
+    assert navigate_button.events.keypress.target.navigation == %{
+             action: :navigate_to,
+             screen: :settings,
+             params: %{tab: :profile}
+           }
   end
 
   test "form and navigation widgets expose binding and keyboard-oriented interaction hooks" do
diff --git a/packages/terminal_ui/test/terminal_ui/runtime_test.exs b/packages/terminal_ui/test/terminal_ui/runtime_test.exs
index 32de9dd2..ded5bff3 100644
--- a/packages/terminal_ui/test/terminal_ui/runtime_test.exs
+++ b/packages/terminal_ui/test/terminal_ui/runtime_test.exs
@@ -7,6 +7,7 @@ defmodule TerminalUi.RuntimeTest do
   test "runtime exposes the phase one backbone modules and capabilities" do
     assert TerminalUi.Runtime.Boot in Runtime.modules()
     assert TerminalUi.Runtime.EventLoop in Runtime.modules()
+    assert TerminalUi.Runtime.Navigation in Runtime.modules()
     assert TerminalUi.Runtime.Screen in Runtime.modules()
     assert TerminalUi.Runtime.Realization in Runtime.modules()
     assert TerminalUi.Runtime.State in Runtime.modules()
@@ -17,6 +18,8 @@ defmodule TerminalUi.RuntimeTest do
     assert :advanced_display_systems in Runtime.capabilities()
     assert :layered_runtime_behavior in Runtime.capabilities()
     assert :canonical_foundational_rendering in Runtime.capabilities()
+    assert :screen_navigation in Runtime.capabilities()
+    assert :capability_aware_navigation in Runtime.capabilities()
   end
 
   test "runtime mounts a native screen through the shared term_ui-backed backbone" do
diff --git a/packages/terminal_ui/test/terminal_ui/transport_diagnostics_test.exs b/packages/terminal_ui/test/terminal_ui/transport_diagnostics_test.exs
index f31051fb..8db38335 100644
--- a/packages/terminal_ui/test/terminal_ui/transport_diagnostics_test.exs
+++ b/packages/terminal_ui/test/terminal_ui/transport_diagnostics_test.exs
@@ -66,11 +66,35 @@ defmodule TerminalUi.TransportDiagnosticsTest do
                    %{},
                    source: "/terminal_ui/native/unknown",
                    subject: "native/unknown/ops-palette",
-                   extensions: %{terminal_ui_family: :command}
-                 )
+                 extensions: %{terminal_ui_family: :command}
+               )
              })
   end
 
+  test "transport validation rejects leaked host-route syntax on canonical navigation targets" do
+    interaction =
+      UnifiedIUR.Interaction.navigation_transition(
+        intent: :open_settings_screen,
+        action: :navigate_to,
+        screen: :settings
+      )
+
+    assert {:ok, translation} =
+             Transport.from_interaction(
+               interaction,
+               backend_mode: :raw,
+               widget_id: "settings-link",
+               runtime_id: "terminal-ui:workspace",
+               screen: "workspace"
+             )
+
+    translation =
+      put_in(translation.target.navigation[:route], "/settings")
+
+    assert {:error, %TerminalUi.Transport.Error{reason: :host_route_navigation_syntax}} =
+             Transport.validate_translation(translation)
+  end
+
   test "reference and summary surfaces expose transport-focused contract summaries" do
     reference = TerminalUi.reference()
     summary = TerminalUi.info()
diff --git a/packages/terminal_ui/test/terminal_ui_test.exs b/packages/terminal_ui/test/terminal_ui_test.exs
index c828d434..fa4b75ea 100644
--- a/packages/terminal_ui/test/terminal_ui_test.exs
+++ b/packages/terminal_ui/test/terminal_ui_test.exs
@@ -112,6 +112,7 @@ defmodule TerminalUiTest do
              :advanced_capability_continuity,
              :advanced_continuity,
              :foundational_continuity,
+             :navigation_transition_review,
              :normalized_input_profiles,
              :styled_continuity_review,
              :styled_degradation_review,
diff --git a/test/spec_compliance/compliance_test.exs b/test/spec_compliance/compliance_test.exs
index eac7db03..b2d0ed70 100644
--- a/test/spec_compliance/compliance_test.exs
+++ b/test/spec_compliance/compliance_test.exs
@@ -151,8 +151,8 @@ defmodule Unified.SpecCompliance.ComplianceTest do
 
     assert plan_report.status == :pass
     assert compliance_report.status == :pass
-    assert compliance_report.summary.applicable_requirements == 89
-    assert compliance_report.summary.status_counts.verified == 89
+    assert compliance_report.summary.applicable_requirements == 91
+    assert compliance_report.summary.status_counts.verified == 91
     assert compliance_report.summary.status_counts.waived == 0
     assert compliance_report.summary.status_counts.planned == 0
     assert compliance_report.summary.aliases == 48
@@ -182,8 +182,8 @@ defmodule Unified.SpecCompliance.ComplianceTest do
 
     assert plan_report.status == :pass
     assert compliance_report.status == :pass
-    assert compliance_report.summary.applicable_requirements == 92
-    assert compliance_report.summary.status_counts.verified == 92
+    assert compliance_report.summary.applicable_requirements == 94
+    assert compliance_report.summary.status_counts.verified == 94
     assert compliance_report.summary.aliases == 48
   end
 
@@ -193,8 +193,8 @@ defmodule Unified.SpecCompliance.ComplianceTest do
 
     assert plan_report.status == :pass
     assert compliance_report.status == :pass
-    assert compliance_report.summary.applicable_requirements == 105
-    assert compliance_report.summary.status_counts.verified == 105
+    assert compliance_report.summary.applicable_requirements == 112
+    assert compliance_report.summary.status_counts.verified == 112
     assert compliance_report.summary.status_counts.waived == 0
     assert compliance_report.summary.aliases == 49
     assert compliance_report.summary.ci_enforcement == "required"
@@ -207,8 +207,8 @@ defmodule Unified.SpecCompliance.ComplianceTest do
 
     assert plan_report.status == :pass
     assert compliance_report.status == :pass
-    assert compliance_report.summary.applicable_requirements == 97
-    assert compliance_report.summary.status_counts.verified == 97
+    assert compliance_report.summary.applicable_requirements == 100
+    assert compliance_report.summary.status_counts.verified == 100
     assert compliance_report.summary.status_counts.waived == 0
     assert compliance_report.summary.ci_enforcement == "required"
   end
@@ -219,8 +219,8 @@ defmodule Unified.SpecCompliance.ComplianceTest do
 
     assert plan_report.status == :pass
     assert compliance_report.status == :pass
-    assert compliance_report.summary.applicable_requirements == 62
-    assert compliance_report.summary.status_counts.verified == 62
+    assert compliance_report.summary.applicable_requirements == 65
+    assert compliance_report.summary.status_counts.verified == 65
     assert compliance_report.summary.status_counts.waived == 0
     assert compliance_report.summary.aliases == 18
     assert compliance_report.summary.ci_enforcement == "required"