diff --git a/python/packages/azurefunctions/agent_framework_azurefunctions/_app.py b/python/packages/azurefunctions/agent_framework_azurefunctions/_app.py
index dc90d13..88f409d 100644
--- a/python/packages/azurefunctions/agent_framework_azurefunctions/_app.py
+++ b/python/packages/azurefunctions/agent_framework_azurefunctions/_app.py
@@ -22,6 +22,7 @@
 import azure.durable_functions as df
 import azure.functions as func
 from agent_framework import SupportsAgentRun, Workflow
+from agent_framework._telemetry import mark_feature_used
 from agent_framework_durabletask import (
     DEFAULT_MAX_POLL_RETRIES,
     DEFAULT_POLL_INTERVAL_SECONDS,
@@ -58,6 +59,7 @@
 
 from ._entities import create_agent_entity
 from ._errors import IncomingRequestError
+from ._feature_usage import FeatureIndex
 from ._orchestration import AgentOrchestrationContextType, AgentTask, AzureFunctionsAgentExecutor
 from ._routes import build_workflow_respond_url, build_workflow_status_url, split_request_url
 from ._workflow import run_workflow_orchestrator
@@ -315,6 +317,7 @@ def __init__(
         if self.enable_health_check:
             self._setup_health_route()
 
+        mark_feature_used(FeatureIndex.AZUREFUNCTIONS)
         logger.debug("[AgentFunctionApp] Initialization complete")
 
     def _collect_workflows(
diff --git a/python/packages/azurefunctions/agent_framework_azurefunctions/_context.py b/python/packages/azurefunctions/agent_framework_azurefunctions/_context.py
index 4912fe4..66ecff1 100644
--- a/python/packages/azurefunctions/agent_framework_azurefunctions/_context.py
+++ b/python/packages/azurefunctions/agent_framework_azurefunctions/_context.py
@@ -115,6 +115,18 @@ async def create_checkpoint(
         """Checkpointing not supported in activity context."""
         raise NotImplementedError("Checkpointing is not supported in Azure Functions activity context")
 
+    async def build_checkpoint(
+        self,
+        workflow_name: str,
+        graph_signature_hash: str,
+        state: State,
+        previous_checkpoint_id: str | None,
+        iteration_count: int,
+        metadata: dict[str, Any] | None = None,
+    ) -> WorkflowCheckpoint:
+        """Checkpointing not supported in activity context."""
+        raise NotImplementedError("Checkpointing is not supported in Azure Functions activity context")
+
     async def load_checkpoint(self, checkpoint_id: str) -> WorkflowCheckpoint | None:
         """Checkpointing not supported in activity context."""
         raise NotImplementedError("Checkpointing is not supported in Azure Functions activity context")
diff --git a/python/packages/azurefunctions/agent_framework_azurefunctions/_feature_usage.py b/python/packages/azurefunctions/agent_framework_azurefunctions/_feature_usage.py
new file mode 100644
index 0000000..4bc0ffe
--- /dev/null
+++ b/python/packages/azurefunctions/agent_framework_azurefunctions/_feature_usage.py
@@ -0,0 +1,9 @@
+# Copyright (c) Microsoft. All rights reserved.
+
+from enum import IntEnum
+
+
+class FeatureIndex(IntEnum):
+    """Azure Functions-owned feature-usage indexes."""
+
+    AZUREFUNCTIONS = 78
diff --git a/python/packages/azurefunctions/pyproject.toml b/python/packages/azurefunctions/pyproject.toml
index cd6c343..ff7bff8 100644
--- a/python/packages/azurefunctions/pyproject.toml
+++ b/python/packages/azurefunctions/pyproject.toml
@@ -22,7 +22,7 @@ classifiers = [
   "Typing :: Typed",
 ]
 dependencies = [
-    "agent-framework-core>=1.11.0,<2",
+    "agent-framework-core>=1.13.0,<2",
     "agent-framework-durabletask>=1.0.0b260709,<2",
     "azure-functions>=1.24.0,<2",
     "azure-functions-durable>=1.3.1,<2",
diff --git a/python/packages/azurefunctions/tests/test_app.py b/python/packages/azurefunctions/tests/test_app.py
index 15fff90..5751d3a 100644
--- a/python/packages/azurefunctions/tests/test_app.py
+++ b/python/packages/azurefunctions/tests/test_app.py
@@ -32,6 +32,7 @@
 )
 from agent_framework_azurefunctions._entities import create_agent_entity
 from agent_framework_azurefunctions._errors import IncomingRequestError
+from agent_framework_azurefunctions._feature_usage import FeatureIndex
 
 FuncT = TypeVar("FuncT", bound=Callable[..., Any])
 
@@ -63,8 +64,11 @@ def test_init_with_defaults(self) -> None:
         mock_agent = Mock()
         mock_agent.name = "TestAgent"
 
-        app = AgentFunctionApp(agents=[mock_agent])
+        with patch("agent_framework_azurefunctions._app.mark_feature_used") as mark_feature_used:
+            app = AgentFunctionApp(agents=[mock_agent])
 
+        mark_feature_used.assert_called_once_with(FeatureIndex.AZUREFUNCTIONS)
+        assert FeatureIndex.AZUREFUNCTIONS == 78
         assert len(app.agents) == 1
         assert "TestAgent" in app.agents
         assert app.enable_health_check is True
diff --git a/python/packages/azurefunctions/tests/test_func_utils.py b/python/packages/azurefunctions/tests/test_func_utils.py
index 80add1d..4d80feb 100644
--- a/python/packages/azurefunctions/tests/test_func_utils.py
+++ b/python/packages/azurefunctions/tests/test_func_utils.py
@@ -149,6 +149,14 @@ async def test_create_checkpoint_raises_not_implemented(self, context: Capturing
         with pytest.raises(NotImplementedError):
             await context.create_checkpoint("test_workflow", "abc123", State(), None, 1)
 
+    @pytest.mark.asyncio
+    async def test_build_checkpoint_raises_not_implemented(self, context: CapturingRunnerContext) -> None:
+        """Test that checkpoint construction is not supported."""
+        from agent_framework._workflows._state import State
+
+        with pytest.raises(NotImplementedError):
+            await context.build_checkpoint("test_workflow", "abc123", State(), None, 1)
+
     @pytest.mark.asyncio
     async def test_load_checkpoint_raises_not_implemented(self, context: CapturingRunnerContext) -> None:
         """Test that load_checkpoint raises NotImplementedError."""
diff --git a/python/packages/durabletask/agent_framework_durabletask/_feature_usage.py b/python/packages/durabletask/agent_framework_durabletask/_feature_usage.py
new file mode 100644
index 0000000..fba5fc3
--- /dev/null
+++ b/python/packages/durabletask/agent_framework_durabletask/_feature_usage.py
@@ -0,0 +1,9 @@
+# Copyright (c) Microsoft. All rights reserved.
+
+from enum import IntEnum
+
+
+class FeatureIndex(IntEnum):
+    """Durable Task-owned feature-usage indexes."""
+
+    DURABLETASK = 77
diff --git a/python/packages/durabletask/agent_framework_durabletask/_shim.py b/python/packages/durabletask/agent_framework_durabletask/_shim.py
index e6e9f5d..ed8a752 100644
--- a/python/packages/durabletask/agent_framework_durabletask/_shim.py
+++ b/python/packages/durabletask/agent_framework_durabletask/_shim.py
@@ -13,9 +13,11 @@
 from typing import Any, Generic, Literal, TypeVar
 
 from agent_framework import AgentSession, ServiceSessionId, SupportsAgentRun, normalize_messages
+from agent_framework._telemetry import mark_feature_used
 from agent_framework._types import AgentRunInputs
 
 from ._executors import DurableAgentExecutor
+from ._feature_usage import FeatureIndex
 from ._models import DurableAgentSession
 
 # TypeVar for the task type returned by executors
@@ -127,6 +129,7 @@ def run(  # type: ignore[override]
             options=options,
         )
 
+        mark_feature_used(FeatureIndex.DURABLETASK)
         return self._executor.run_durable_agent(
             agent_name=self.name,
             run_request=run_request,
diff --git a/python/packages/durabletask/agent_framework_durabletask/_worker.py b/python/packages/durabletask/agent_framework_durabletask/_worker.py
index 3eed81f..77fae09 100644
--- a/python/packages/durabletask/agent_framework_durabletask/_worker.py
+++ b/python/packages/durabletask/agent_framework_durabletask/_worker.py
@@ -13,12 +13,14 @@
 from typing import Any
 
 from agent_framework import SupportsAgentRun, Workflow
+from agent_framework._telemetry import mark_feature_used
 from durabletask.task import ActivityContext, OrchestrationContext
 from durabletask.worker import TaskHubGrpcWorker
 
 from ._async_bridge import run_agent_coroutine
 from ._callbacks import AgentResponseCallbackProtocol
 from ._entities import AgentEntity, DurableTaskEntityStateProvider
+from ._feature_usage import FeatureIndex
 from ._workflows.activity import execute_workflow_activity
 from ._workflows.dt_context import DurableTaskWorkflowContext
 from ._workflows.naming import (
@@ -157,6 +159,7 @@ def start(self) -> None:
             The worker will block until stopped.
         """
         logger.info("[DurableAIAgentWorker] Starting worker with %d registered agents", len(self._registered_agents))
+        mark_feature_used(FeatureIndex.DURABLETASK)
         self._worker.start()
 
     def stop(self) -> None:
diff --git a/python/packages/durabletask/agent_framework_durabletask/_workflows/runner_context.py b/python/packages/durabletask/agent_framework_durabletask/_workflows/runner_context.py
index d364616..b68de25 100644
--- a/python/packages/durabletask/agent_framework_durabletask/_workflows/runner_context.py
+++ b/python/packages/durabletask/agent_framework_durabletask/_workflows/runner_context.py
@@ -109,6 +109,17 @@ async def create_checkpoint(
     ) -> str:
         raise NotImplementedError("Checkpointing is not supported in activity context")
 
+    async def build_checkpoint(
+        self,
+        workflow_name: str,
+        graph_signature_hash: str,
+        state: State,
+        previous_checkpoint_id: str | None,
+        iteration_count: int,
+        metadata: dict[str, Any] | None = None,
+    ) -> WorkflowCheckpoint:
+        raise NotImplementedError("Checkpointing is not supported in activity context")
+
     async def load_checkpoint(self, checkpoint_id: str) -> WorkflowCheckpoint | None:
         raise NotImplementedError("Checkpointing is not supported in activity context")
 
diff --git a/python/packages/durabletask/pyproject.toml b/python/packages/durabletask/pyproject.toml
index f937c6b..6e5ca54 100644
--- a/python/packages/durabletask/pyproject.toml
+++ b/python/packages/durabletask/pyproject.toml
@@ -22,7 +22,7 @@ classifiers = [
   "Typing :: Typed",
 ]
 dependencies = [
-    "agent-framework-core>=1.11.0,<2",
+    "agent-framework-core>=1.13.0,<2",
     "durabletask>=1.5.0,<2",
     "durabletask-azuremanaged>=1.4.0,<2",
     "python-dateutil>=2.8.0,<3",
diff --git a/python/packages/durabletask/tests/test_runner_context.py b/python/packages/durabletask/tests/test_runner_context.py
new file mode 100644
index 0000000..158cca7
--- /dev/null
+++ b/python/packages/durabletask/tests/test_runner_context.py
@@ -0,0 +1,15 @@
+# Copyright (c) Microsoft. All rights reserved.
+
+import pytest
+from agent_framework._workflows._state import State
+
+from agent_framework_durabletask._workflows.runner_context import CapturingRunnerContext
+
+
+@pytest.mark.asyncio
+async def test_build_checkpoint_raises_not_implemented() -> None:
+    """Checkpoint construction must not fall through to the protocol stub."""
+    context = CapturingRunnerContext()
+
+    with pytest.raises(NotImplementedError):
+        await context.build_checkpoint("test_workflow", "abc123", State(), None, 1)
diff --git a/python/packages/durabletask/tests/test_shim.py b/python/packages/durabletask/tests/test_shim.py
index de343f3..83dff6c 100644
--- a/python/packages/durabletask/tests/test_shim.py
+++ b/python/packages/durabletask/tests/test_shim.py
@@ -7,7 +7,7 @@
 """
 
 from typing import Any, cast
-from unittest.mock import Mock
+from unittest.mock import Mock, patch
 
 import pytest
 from agent_framework import Message, SupportsAgentRun
@@ -15,6 +15,7 @@
 
 from agent_framework_durabletask import DurableAgentSession
 from agent_framework_durabletask._executors import DurableAgentExecutor
+from agent_framework_durabletask._feature_usage import FeatureIndex
 from agent_framework_durabletask._models import RunRequest
 from agent_framework_durabletask._shim import DurableAgentProvider, DurableAIAgent
 
@@ -67,8 +68,10 @@ class TestDurableAIAgentMessageNormalization:
 
     def test_run_accepts_string_message(self, test_agent: DurableAIAgent[Any], mock_executor: Mock) -> None:
         """Verify run accepts and normalizes string messages."""
-        test_agent.run("Hello, world!")
+        with patch("agent_framework_durabletask._shim.mark_feature_used") as mark_feature_used:
+            test_agent.run("Hello, world!")
 
+        mark_feature_used.assert_called_once_with(FeatureIndex.DURABLETASK)
         mock_executor.run_durable_agent.assert_called_once()
         # Verify agent_name and run_request were passed correctly as kwargs
         _, kwargs = mock_executor.run_durable_agent.call_args
diff --git a/python/packages/durabletask/tests/test_worker.py b/python/packages/durabletask/tests/test_worker.py
index 24f7ccb..fc96ffb 100644
--- a/python/packages/durabletask/tests/test_worker.py
+++ b/python/packages/durabletask/tests/test_worker.py
@@ -5,11 +5,12 @@
 Focuses on critical worker flows: agent registration, validation, callbacks, and lifecycle.
 """
 
-from unittest.mock import Mock
+from unittest.mock import Mock, patch
 
 import pytest
 
 from agent_framework_durabletask import DurableAIAgentWorker
+from agent_framework_durabletask._feature_usage import FeatureIndex
 
 
 @pytest.fixture
@@ -131,8 +132,11 @@ def test_start_delegates_to_underlying_worker(
         self, agent_worker: DurableAIAgentWorker, mock_grpc_worker: Mock
     ) -> None:
         """Verify start() delegates to wrapped worker."""
-        agent_worker.start()
+        with patch("agent_framework_durabletask._worker.mark_feature_used") as mark_feature_used:
+            agent_worker.start()
 
+        mark_feature_used.assert_called_once_with(FeatureIndex.DURABLETASK)
+        assert FeatureIndex.DURABLETASK == 77
         mock_grpc_worker.start.assert_called_once()
 
     def test_stop_delegates_to_underlying_worker(
diff --git a/python/packages/durabletask/tests/test_workflow_activity.py b/python/packages/durabletask/tests/test_workflow_activity.py
index de6650f..2b33bee 100644
--- a/python/packages/durabletask/tests/test_workflow_activity.py
+++ b/python/packages/durabletask/tests/test_workflow_activity.py
@@ -54,6 +54,7 @@ async def mutate(message: Any, source_executor_ids: Any, state: Any, runner_cont
             config = state.get("Local.config")
             config["code"] = "SOMECODEXXX"
             config["enabled"] = True
+            state.set("Local.config", config)
             state.commit()
 
         executor = _make_executor("test-exec", mutate)
@@ -68,7 +69,9 @@ def test_new_key_in_nested_dict_detected(self) -> None:
         """Adding a key to a nested dict is reported as an update."""
 
         async def mutate(message: Any, source_executor_ids: Any, state: Any, runner_context: Any) -> None:
-            state.get("Local.data")["code"] = "NEW_CODE"
+            data = state.get("Local.data")
+            data["code"] = "NEW_CODE"
+            state.set("Local.data", data)
             state.commit()
 
         executor = _make_executor("test-exec", mutate)
@@ -80,7 +83,9 @@ def test_nested_list_mutation_detected(self) -> None:
         """Appending to a nested list is reported as an update."""
 
         async def mutate(message: Any, source_executor_ids: Any, state: Any, runner_context: Any) -> None:
-            state.get("Local.items").append(4)
+            items = state.get("Local.items")
+            items.append(4)
+            state.set("Local.items", items)
             state.commit()
 
         executor = _make_executor("test-exec", mutate)
diff --git a/python/uv.lock b/python/uv.lock
index f7fff65..19e5653 100644
--- a/python/uv.lock
+++ b/python/uv.lock
@@ -56,7 +56,7 @@ dependencies = [
 
 [package.metadata]
 requires-dist = [
-    { name = "agent-framework-core", specifier = ">=1.11.0,<2" },
+    { name = "agent-framework-core", specifier = ">=1.13.0,<2" },
     { name = "agent-framework-durabletask", editable = "packages/durabletask" },
     { name = "azure-functions", specifier = ">=1.24.0,<2" },
     { name = "azure-functions-durable", specifier = ">=1.3.1,<2" },
@@ -64,17 +64,18 @@ requires-dist = [
 
 [[package]]
 name = "agent-framework-core"
-version = "1.11.0"
+version = "1.16.0"
 source = { registry = "https://pypi.org/simple" }
 dependencies = [
+    { name = "msgspec", marker = "sys_platform == 'darwin' or sys_platform == 'linux' or sys_platform == 'win32'" },
     { name = "opentelemetry-api", marker = "sys_platform == 'darwin' or sys_platform == 'linux' or sys_platform == 'win32'" },
     { name = "pydantic", marker = "sys_platform == 'darwin' or sys_platform == 'linux' or sys_platform == 'win32'" },
     { name = "python-dotenv", marker = "sys_platform == 'darwin' or sys_platform == 'linux' or sys_platform == 'win32'" },
     { name = "typing-extensions", marker = "sys_platform == 'darwin' or sys_platform == 'linux' or sys_platform == 'win32'" },
 ]
-sdist = { url = "https://files.pythonhosted.org/packages/96/c2/e42a2ee46c1c30acc1082dd4881c032170f315f18355486094ee689925f1/agent_framework_core-1.11.0.tar.gz", hash = "sha256:758a06812b27cdba2a6c3d02ef6785971bd7b627a5b9482fb6defb3f0caf88ec", size = 498640, upload-time = "2026-07-10T03:42:25.475Z" }
+sdist = { url = "https://files.pythonhosted.org/packages/b0/96/14e04d00dfc2653677f3f97fa6b348bd202dc4bf4eba4621caabd93ee607/agent_framework_core-1.16.0.tar.gz", hash = "sha256:47ee37b4f6201add7a8a8f9cc39ffe43438c24360b53b116f61ba075e6962d94", size = 584318, upload-time = "2026-08-28T01:10:39.244Z" }
 wheels = [
-    { url = "https://files.pythonhosted.org/packages/3c/92/bad6983d03aee0323f56266d63d520347cd48e0b914b9b567fcd779bdb06/agent_framework_core-1.11.0-py3-none-any.whl", hash = "sha256:37e589e6086cf4a6ae6c7d2eaf4178f9fd1a81c13f863c81ad83df95258ce0a3", size = 551737, upload-time = "2026-07-10T03:35:55.239Z" },
+    { url = "https://files.pythonhosted.org/packages/ed/17/7abbfc9e560911967dd5b96a8b6cea537d35efab18f8f77367429159b637/agent_framework_core-1.16.0-py3-none-any.whl", hash = "sha256:382a6a0332cdc3144ffcf14b07a9a38c3ef42afc06dde8230226b850fe4cc76e", size = 641893, upload-time = "2026-08-28T01:10:29.875Z" },
 ]
 
 [[package]]
@@ -162,7 +163,7 @@ dev = [
 
 [package.metadata]
 requires-dist = [
-    { name = "agent-framework-core", specifier = ">=1.11.0,<2" },
+    { name = "agent-framework-core", specifier = ">=1.13.0,<2" },
     { name = "durabletask", specifier = ">=1.5.0,<2" },
     { name = "durabletask-azuremanaged", specifier = ">=1.4.0,<2" },
     { name = "python-dateutil", specifier = ">=2.8.0,<3" },
@@ -1920,6 +1921,12 @@ wheels = [
     { url = "https://files.pythonhosted.org/packages/15/cf/f2966a2638144491f8696c27320d5219f48a072715075d168b31d3237720/msrest-0.7.1-py3-none-any.whl", hash = "sha256:21120a810e1233e5e6cc7fe40b474eeb4ec6f757a15d7cf86702c369f9567c32", size = 85384, upload-time = "2022-06-13T22:41:22.42Z" },
 ]
 
+[[package]]
+name = "msgspec"
+version = "0.21.1"
+source = { registry = "https://pypi.org/simple" }
+sdist = { url = "https://files.pythonhosted.org/packages/e3/60/f79b9b013a16fa3a58350c9295ddc6789f2e335f36ea61ed10a21b215364/msgspec-0.21.1.tar.gz", hash = "sha256:2313508e394b0d208f8f56892ca9b2799e2561329de9763b19619595a6c0f72c", size = 319193, upload-time = "2026-04-12T21:44:50.394Z" }
+
 [[package]]
 name = "multidict"
 version = "6.7.1"