The Home Automation MCP server provides 5 clearly named tools with consistent verb-noun patterns (list_devices, control_light, set_temperature, control_door_lock, activate_scene). All tools have descriptions and visible JSON schemas with typed parameters and enums for constrained inputs. However, definitions fall short of production grade in several areas: parameter descriptions lack constraint details (ranges, formats), output schemas are not formally documented, error handling is minimal with no recovery guidance, and there are no per-tool security annotations despite write operations on sensitive devices (door locks, thermostats). The descriptions are concise but under-optimized for LLM decision-making, they state WHAT the tool does but lack WHEN/WHY context. Average parameter annotation length is ~40 chars, below the baseline of 72. Tool composition is sound (each tool has one responsibility) but no idempotency or dry-run mechanisms for irreversible operations.

• Add minValue/maxValue/minimum/maximum to brightness and target_temperature schemas instead of relying on text descriptions. Format: {'type': 'integer', 'minimum': 0, 'maximum': 100} and {'type': 'number', 'minimum': 16, 'maximum': 30}.
• Convert all tool responses from unstructured strings to JSON objects with typed fields. Example: control_light should return {"success": true, "state": "on", "brightness": 70, "device": "living_room_light", "timestamp": "2025-01-15T14:30:00Z"} instead of a formatted text string.
• Add tool annotations: mark control_door_lock and activate_scene with destructiveHint=true; mark list_devices and get_device_status with readOnlyHint=true. This signals to agents which calls are safe to retry.
• Enhance error responses with recovery guidance. Change 'Error: Brightness must be between 0 and 100' to 'Invalid brightness 150: must be 0 - 100. Try control_light(action="on", brightness=75) instead.'
• Add permission checks: wrap control_door_lock and set_temperature behind a check like if not user.has_permission('write:home_automation'): return {"error": "Permission denied: write:home_automation required"}.
• Extend tool descriptions to 100 - 200 chars with context hints. Example: 'Control the living room light. Accepts on/off/toggle and optional brightness (0 - 100). Use activate_scene() to override with preset settings like "evening" or "away".'
• Add an idempotency mechanism for control_door_lock: track the last state and timestamp, and return early if called with the same action within 5 seconds, preventing double-locks from retries.