Get Key Light Color

Instructions

Implementation Reference

• server.js:1213-1260 (registration)

  Registration of the 'get_key_light_color' tool via mcpServer.registerTool

  mcpServer.registerTool(
    'get_key_light_color',
    {
      title: 'Get Key Light Color',
      description: 'Get the current key light color as a hex color code (e.g., "#ffffff"). ' +
        'Query this before relative color changes to ensure accuracy. ' +
        'For absolute changes, you may use recently queried state from context if no manual interactions occurred.',
      inputSchema: {}
    },
    async () => {
      const sessionId = getCurrentSessionId();
      if (!sessionId) {
        return {
          content: [
            {
              type: 'text',
              text: 'Error: No active session found.'
            }
          ],
          isError: true
        };
      }
  
      try {
        const { state, metadata } = await getState(sessionId);
        const color = state.keyLight?.color || '#ffffff';
        
        return {
          content: [
            {
              type: 'text',
              text: formatStateResponse(color, 'Key light color', sessionId, metadata)
            }
          ]
        };
      } catch (error) {
        return {
          content: [
            {
              type: 'text',
              text: `Error retrieving key light color: ${error.message}`
            }
          ],
          isError: true
        };
      }
    }
  );

• server.js:1222-1260 (handler)

  Handler function for the 'get_key_light_color' tool. Gets the current key light color from browser state (state.keyLight?.color) and returns it as a hex color code.

    async () => {
      const sessionId = getCurrentSessionId();
      if (!sessionId) {
        return {
          content: [
            {
              type: 'text',
              text: 'Error: No active session found.'
            }
          ],
          isError: true
        };
      }
  
      try {
        const { state, metadata } = await getState(sessionId);
        const color = state.keyLight?.color || '#ffffff';
        
        return {
          content: [
            {
              type: 'text',
              text: formatStateResponse(color, 'Key light color', sessionId, metadata)
            }
          ]
        };
      } catch (error) {
        return {
          content: [
            {
              type: 'text',
              text: `Error retrieving key light color: ${error.message}`
            }
          ],
          isError: true
        };
      }
    }
  );

• server.js:1214-1221 (schema)

  Input schema for 'get_key_light_color' tool - empty object (no input parameters needed)

  'get_key_light_color',
  {
    title: 'Get Key Light Color',
    description: 'Get the current key light color as a hex color code (e.g., "#ffffff"). ' +
      'Query this before relative color changes to ensure accuracy. ' +
      'For absolute changes, you may use recently queried state from context if no manual interactions occurred.',
    inputSchema: {}
  },

• server.js:319-327 (helper)

  formatStateResponse helper function used by the handler to format the response with metadata.

  function formatStateResponse(value, propertyName, sessionId, metadata) {
    const timestamp = metadata.timestamp;
    const source = metadata.source;
    const stalenessWarning = metadata.wasCached 
      ? ' (using cached state - browser may be disconnected)' 
      : '';
    
    return `${propertyName}: ${value} (queried at ${timestamp}, source: ${source}${stalenessWarning})`;
  }

• server.js:284-316 (helper)

  getState helper function used by the handler to fetch current state from the browser (with cache fallback).

  async function getState(sessionId) {
    let state;
    let source;
    let wasCached = false;
    
    // Always query browser for current state
    try {
      state = await queryStateFromBrowser(sessionId);
      source = 'fresh';
    } catch (error) {
      // If query fails, fall back to cache if available (browser may be disconnected)
      const cached = sessionStateCache.get(sessionId);
      if (cached) {
        console.warn(`Browser query failed for session ${sessionId}, returning cached state: ${error.message}`);
        state = cached.state;
        source = 'cache';
        wasCached = true;
      } else {
        // No cache available, throw error
        throw new Error(`Unable to retrieve state: ${error.message}. Browser may be disconnected.`);
      }
    }
    
    // Return state with metadata
    return {
      state,
      metadata: {
        source,
        wasCached,
        timestamp: new Date().toISOString()
      }
    };
  }