The tool list reflects the current session
Home MCP shows tools supported by the signed-in person, selected installation, and its capabilities. The list returned by a client can therefore differ between users and installations.
Tool annotations
Each tool states whether it only reads data, can perform a destructive action, is idempotent, or interacts with an external system. The client uses this information when showing consequences and confirmations. Home MCP still checks permissions on every call.
Check the final state
For a state-changing action, distinguish between sending the request, acceptance by Home MCP, acknowledgement by the home system, and the observed final state. A response from the client does not replace checking the resulting device or installation state.