Add ExtensionContext.paths to expose resolved TauPaths

src/tau_coding/extensions/api.py

@@ -20,6 +20,7 @@
     from tau_coding.extensions.providers import DynamicProvider
     from tau_coding.extensions.runtime import ExtensionRuntime
     from tau_coding.local_backends import LocalBackend
+    from tau_coding.paths import TauPaths
     from tau_coding.tui.config import TuiTheme
 
 AGENT_EVENT_TYPES: frozenset[str] = frozenset(
@@ -890,6 +891,12 @@ def cwd(self) -> Path:
         self._generation.assert_active()
         return self._runtime.session_view.cwd
 
+    @property
+    def paths(self) -> TauPaths:
+        """Return the resolved Tau filesystem paths for this session."""
+        self._generation.assert_active()
+        return self._runtime.paths
+
     @property
     def model(self) -> str:
         """Return the active model name."""

src/tau_coding/extensions/runtime.py

@@ -248,6 +248,7 @@ def __init__(
         self._renderer_failures_reported: set[str] = set()
         self._load_diagnostics: list[ResourceDiagnostic] = []
         self._runtime_diagnostics: list[ResourceDiagnostic] = []
+        self._paths: TauPaths = TauPaths()
         self._session: BoundSession | None = None
         self._ui: UiBridge = ui or NullUiBridge()
         self._turn_requested: TurnRequestedCallback | None = None
@@ -266,6 +267,7 @@ def load(
         include_user_dir: bool = True,
     ) -> None:
         """Load built-ins, then discover extensions and run isolated setup."""
+        self._paths = paths.paths or TauPaths(home=paths.root)
         self._load_built_ins()
         result = load_extensions(
             paths,
@@ -851,6 +853,11 @@ def local_backend_registry(self) -> LocalBackendRegistry:
         """Return this staged runtime generation's local-backend registry."""
         return self._local_backend_registry
 
+    @property
+    def paths(self) -> TauPaths:
+        """Return the resolved Tau filesystem paths for this runtime."""
+        return self._paths
+
     @property
     def extension_names(self) -> tuple[str, ...]:
         """Return visible extension names in load order."""

tests/test_extensions.py

@@ -1939,6 +1939,25 @@ async def executor(
     return AgentTool(name=name, label=name, description="d", parameters={}, execute_fn=executor)
 
 
+def test_context_paths_exposes_resolved_paths_from_load(tmp_path: Path) -> None:
+    runtime = ExtensionRuntime()
+    resolved = TauPaths(home=tmp_path / "custom-home")
+    runtime.load(TauResourcePaths(root=tmp_path / "unused-root", paths=resolved))
+    api = cast(ExtensionAPI, _register_inline_extension(runtime, "reader"))
+    runtime.bind(RecordingSession(tmp_path))
+
+    assert api.context.paths is resolved
+
+
+def test_context_paths_falls_back_to_resource_root_home(tmp_path: Path) -> None:
+    runtime = ExtensionRuntime()
+    runtime.load(TauResourcePaths(root=tmp_path / "home-tau"))
+    api = cast(ExtensionAPI, _register_inline_extension(runtime, "reader"))
+    runtime.bind(RecordingSession(tmp_path))
+
+    assert api.context.paths.home == tmp_path / "home-tau"
+
+
 # -- coding-session integration ---------------------------------------------------
 
 
@@ -2060,6 +2079,16 @@ async def test_session_lifecycle_recreates_built_in_in_a_fresh_generation(
     await session.aclose()
 
 
+async def test_session_exposes_extension_paths_at_moved_home(tmp_path: Path) -> None:
+    await CodingSession.load(
+        _session_config(tmp_path, FakeProvider([]), extension_body=API_CAPTURING_EXTENSION)
+    )
+    module = _loaded_extension_module("integration")
+    api = cast(ExtensionAPI, module.APIS[-1])  # type: ignore[attr-defined]
+
+    assert api.context.paths.home == tmp_path / "home-tau"
+
+
 async def test_session_exposes_extension_tools_and_commands(tmp_path: Path) -> None:
     body = HELLO_TOOL_EXTENSION + (
         "\n\ndef _cmd(args, context):\n"
@@ -2871,6 +2900,8 @@ async def test_reset_for_reload_invalidates_prior_context_and_ui(tmp_path: Path)
 
     with pytest.raises(ExtensionError, match="stale after reload"):
         _ = context.cwd
+    with pytest.raises(ExtensionError, match="stale after reload"):
+        _ = context.paths
     with pytest.raises(ExtensionError, match="stale after reload"):
         _ = context.transcript
     with pytest.raises(ExtensionError, match="stale after reload"):