ci: limit policy setup to its pinned tools

.github/workflows/ci.yml

@@ -21,17 +21,18 @@ jobs:
       - uses: actions/checkout@93cb6efe18208431cddfb8368fd83d5badbf9bfd # v5
         with:
           persist-credentials: false
+      # Keep the same explicit selection in every exec below to avoid lazy tool installs.
       - uses: jdx/mise-action@c37c93293d6b742fc901e1406b8f764f6fb19dac # v2
         with:
           version: 2026.5.5
-          install_args: --jobs=1
+          install_args: --jobs=1 python uv github:rhysd/actionlint
           cache: false
       - run: >-
-          mise exec -- uv run --frozen --project . pytest -q
+          mise exec --no-deps python uv github:rhysd/actionlint -- uv run --frozen --project . pytest -q
           tools/ci/tests/test_required_ci.py tools/ci/tests/test_public_tree.py
-      - run: mise exec -- python tools/ci/check_public_tree.py
+      - run: mise exec --no-deps python uv github:rhysd/actionlint -- python tools/ci/check_public_tree.py
       - run: >-
-          mise exec -- actionlint
+          mise exec --no-deps python uv github:rhysd/actionlint -- actionlint
           -ignore '^unexpected key "queue" for "concurrency" section\. expected one of "cancel-in-progress", "group"$'
 
   bootstrap:

tools/ci/tests/test_required_ci.py

@@ -100,8 +100,8 @@ def test_mise_workflow_setups_pin_concrete_versions():
                     )
 
 
-def test_mise_bootstrap_serializes_the_complete_toolset():
-    # Partial installs defer the other tools to `mise exec`, outside install_args.
+def test_mise_bootstrap_serializes_required_toolsets():
+    # Unqualified `mise exec` installs missing tools outside install_args.
     for path in sorted((ROOT / ".github/workflows").glob("*.y*ml")):
         workflow = yaml.safe_load(path.read_text())
         for name, job in workflow["jobs"].items():
@@ -110,11 +110,36 @@ def test_mise_bootstrap_serializes_the_complete_toolset():
                     continue
                 inputs = step.get("with", {})
                 if inputs.get("install", True) is not False:
-                    assert shlex.split(inputs.get("install_args", "")) == ["--jobs=1"], (
-                        f"{path.name}: {name} must serialize the full tool install to avoid Node GPG races"
+                    expected = ["--jobs=1"]
+                    if path.name == "ci.yml" and name == "policy":
+                        expected += ["python", "uv", "github:rhysd/actionlint"]
+                    assert shlex.split(inputs.get("install_args", "")) == expected, (
+                        f"{path.name}: {name} must serialize its tool install to avoid Node GPG races"
                     )
 
 
+def test_policy_exec_does_not_lazily_install_unrelated_tools():
+    workflow = yaml.safe_load((ROOT / ".github/workflows/ci.yml").read_text())
+    policy = workflow["jobs"]["policy"]
+    commands = [shlex.split(step["run"]) for step in policy["steps"] if "run" in step]
+    prefix = ["mise", "exec", "--no-deps", "python", "uv", "github:rhysd/actionlint", "--"]
+    assert len(commands) == 3
+    assert all(command[: len(prefix)] == prefix for command in commands)
+    assert commands[0][len(prefix) :] == [
+        "uv",
+        "run",
+        "--frozen",
+        "--project",
+        ".",
+        "pytest",
+        "-q",
+        "tools/ci/tests/test_required_ci.py",
+        "tools/ci/tests/test_public_tree.py",
+    ]
+    assert commands[1][len(prefix) :] == ["python", "tools/ci/check_public_tree.py"]
+    assert commands[2][len(prefix)] == "actionlint"
+
+
 @pytest.mark.parametrize("install_status", [0, 1])
 def test_init_serializes_install_and_stops_on_failure(tmp_path, install_status):
     log = tmp_path / "mise.log"