Add entity lifecycle status MCP tools (apps + components) - #23

README.md:390

• The lifecycle API is introduced specifically with the gateway 0.6.0 contract, so older gateways that do not expose /{entity_type}/{entity_id}/status will return an error for reads as well. Please qualify this statement (for example, “Reading the status works on gateways that expose the 0.6.0 lifecycle API”) so users do not assume compatibility with every gateway version.

Reading the status works on any gateway. Triggering a transition requires the gateway
to have a `LifecycleProvider` plugin registered for the entity; there is no built-in

README.md:392

• The MCP tool does not return the documented 501 prefix here: _call_void stores the status in SovdClientError.status_code, but its message for this error envelope is only [not-implemented] ..., and call_tool does not append status_code. This also conflicts with the exact output documented below on line 411; please describe the actual tool error (or change the formatter if the HTTP status must be exposed).

`501 [not-implemented] Lifecycle control not available for this entity`.

src/ros2_medkit_mcp/mcp_app.py:2643

• This tool description also presents status_get as working on a stock gateway without stating the required gateway version. Since this client is pinned to and the feature is defined for gateway 0.6.0, older gateways can reject the GET endpoint; qualify the claim here so the tool metadata does not overstate compatibility.

                    " LifecycleProvider plugin for the entity; there is no"
                    " built-in provider, so a stock gateway answers every"
                    " transition with 'not-implemented' while status_get still"
                    " works. On success the gateway returns a body-less 202 and"

Previously missed (2) — in code that hasn't changed since the last review.

README.md:392

• SovdClientError keeps the HTTP status in status_code, but call_tool formats only str(e), so the tool output contains [not-implemented] Lifecycle control not available for this entity without the 501 prefix. This example disagrees with the actual response (and with the wording below); please update the documented error text or include status codes in the formatter.

`501 [not-implemented] Lifecycle control not available for this entity`.

src/ros2_medkit_mcp/mcp_app.py:3265

• At this branch, an unsupported entity_type or action raises ValidationError, but the broad handler below converts it into Internal error: .... That mislabels invalid user input as a server failure and does not provide the clear rejection promised for lifecycle arguments. Handle validation errors as input errors (or validate these arguments before dispatch) so the response is not labeled internal.

                status_get_args = StatusGetArgs(**arguments)

Previously missed (1) — in code that hasn't changed since the last review.

src/ros2_medkit_mcp/mcp_app.py:3272

• This validation raises ValidationError before SovdClient.set_status can produce its explicit lifecycle message, but the only matching handler below is the broad except Exception, so an invalid action is returned to MCP as Internal error: ... rather than as a client-input error. Catch lifecycle argument validation separately and format it as an invalid-arguments response so the rejection is not misdiagnosed as a server failure.

                status_set_args = StatusSetArgs(**arguments)

README.md:390

• The phrase Triggering a transition does: is grammatically incomplete; use Triggering a transition does this: so the lifecycle documentation is clear.

for managed lifecycle nodes, from their reported state. Triggering a transition does: the

src/ros2_medkit_mcp/client.py:1522

• This GET still goes through _call, which converts the generated client's None for an undocumented response status into {} (_to_dict(None)). As a result, a gateway/proxy failure such as HTTP 503 can be reported as a successful empty status response instead of an error, so callers cannot distinguish readiness data from an outage. Use a status-aware detailed call here (and require the status payload) before returning.

        return await self._call(fn, **{_entity_id_kwarg(entity_type): entity_id})

src/ros2_medkit_mcp/client.py:569

• The hook is installed after self._medkit is published at line 561. A concurrent first request can therefore take the fast path at line 557 while __aenter__() is still suspended, observe an uninitialized client (or issue a request before this hook exists), and fail to record the response status. Build and fully initialize a local MedkitClient, install the hook, then assign it to self._medkit so initialization is atomic to other callers.

                hooks = self._medkit.http.get_async_httpx_client().event_hooks
                hooks.setdefault("response", []).append(_record_response_status)