Hello3DMCP Server

Instructions

Implementation Reference

• server.js:1860-1906 (registration)

  Registration of the 'get_model_color' tool with its handler implementation. The tool queries the browser state to get the current model color as a hex code, with proper error handling and session management.
  'get_model_color', { title: 'Get Model Color', description: 'Get the current model color as a hex color code (e.g., "#ff0000"). ' + 'Query this before relative color changes (e.g., "darken by 10%") 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.model?.color || '#808080'; return { content: [ { type: 'text', text: formatStateResponse(color, 'Model color', sessionId, metadata) } ] }; } catch (error) { return { content: [ { type: 'text', text: `Error retrieving model color: ${error.message}` } ], isError: true }; } } );
• server.js:1868-1905 (handler)

  The handler function for 'get_model_color' that executes the tool logic: gets the current session ID, queries the browser state for the model color, formats the response with metadata, and handles errors appropriately.
  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.model?.color || '#808080'; return { content: [ { type: 'text', text: formatStateResponse(color, 'Model color', sessionId, metadata) } ] }; } catch (error) { return { content: [ { type: 'text', text: `Error retrieving model color: ${error.message}` } ], isError: true }; } }
• server.js:284-316 (helper)

  Helper function that queries state from the browser with fallback to cached state. Used by get_model_color to retrieve the current model color. Returns state with metadata including source (fresh/cached) and timestamp.
  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() } }; }
• server.js:319-327 (helper)

  Helper function used by get_model_color to format the response with metadata. It formats the state value with property name, timestamp, source info, and a staleness warning if using cached state.
  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:2882-2888 (helper)

  Helper function that retrieves the current session ID, working in both STDIO mode (using a unique ID) and HTTP mode (using AsyncLocalStorage context). Used by get_model_color to identify which browser session to query.
  function getCurrentSessionId() { if (isStdioMode) { return STDIO_SESSION_ID; } else { return sessionContext.getStore(); } }