Single tool with basic schema and description, but significant gaps in parameter documentation, error handling guidance, and composition patterns. The tool has a reasonable description (75 chars) and enum constraint on state, but lacks error recovery hints, confirmation for destructive operations, and proper parameter validation messaging. No evidence of tool chaining, pagination, or output schema documentation. The optional durationSeconds parameter lacks validation constraints (range, units clarity).

• Add explicit validation constraints to durationSeconds: 'Duration in seconds (integer, 0-3600). If 0, LED stays on indefinitely. If omitted, defaults to permanent state change.'
• Document output schema: 'Returns {success: boolean, deviceId: string, previousState: "ON"|"OFF", newState: "ON"|"OFF", appliedAt: ISO8601 timestamp}.'
• Add error recovery guidance: 'If Node-RED endpoint is unreachable, verify Node-RED is running at configured address. Retry with exponential backoff. If deviceId is invalid, call list_connected_devices() to discover valid IDs.'
• Clarify deviceId format: 'Device identifier as configured in Node-RED (e.g. "led_01", "bedroom_lamp"). Case-sensitive. Call list_connected_devices() to enumerate valid identifiers.'
• Add confirmation pattern for state changes: 'This operation modifies hardware state immediately. Recommend confirming the change before calling, especially for critical devices.'
• Specify idempotency: 'Calling setLedState twice with the same parameters produces the same result. Safe to retry on transient failures.'