Gemini MCP Tool

Instructions

Implementation Reference

• src/tools/fetch-chunk.tool.ts:31-79 (handler)

  The main handler function for the 'fetch-chunk' tool. It retrieves cached code edit chunks using the provided cacheKey and chunkIndex, validates inputs, formats the response, and handles errors like cache misses or invalid indices.

    execute: async (args: any, onProgress?: (newOutput: string) => void): Promise<string> => {
      const { cacheKey, chunkIndex } = args;
      
      Logger.toolInvocation('fetch-chunk', args);
      Logger.debug(`Fetching chunk ${chunkIndex} with cache key: ${cacheKey}`);
      
      // Retrieve cached chunks
      const chunks = getChunks(cacheKey);
      
      if (!chunks) {
        return `❌ Cache miss: No chunks found for cache key "${cacheKey}". 
  
    Possible reasons:
    1. The cache key is incorrect, Have you ran ask-gemini with changeMode enabled?
    2. The cache has expired (10 minute TTL)
    3. The MCP server was restarted and the file-based cache was cleared
  
  Please re-run the original changeMode request to regenerate the chunks.`;
      }
      
      // Validate chunk index
      if (chunkIndex < 1 || chunkIndex > chunks.length) {
        return `❌ Invalid chunk index: ${chunkIndex}
  
  Available chunks: 1 to ${chunks.length}
  You requested: ${chunkIndex}
  
  Please use a valid chunk index.`;
      }
      
      // Get the requested chunk
      const chunk = chunks[chunkIndex - 1];
      
      // Format the response
      let result = formatChangeModeResponse(
        chunk.edits,
        { current: chunkIndex, total: chunks.length, cacheKey }
      );
      
      // Add summary for first chunk
      if (chunkIndex === 1 && chunks.length > 1) {
        const allEdits = chunks.flatMap(c => c.edits);
        result = summarizeChangeModeEdits(allEdits, true) + '\n\n' + result;
      }
      
      Logger.debug(`Returning chunk ${chunkIndex} of ${chunks.length} with ${chunk.edits.length} edits`);
      
      return result;
    }

• src/tools/fetch-chunk.tool.ts:7-10 (schema)

  Zod input schema defining the parameters for the fetch-chunk tool: cacheKey (string) and chunkIndex (number >=1). This schema is used for input validation in the tool definition.

  const inputSchema = z.object({
    cacheKey: z.string().describe("The cache key provided in the initial changeMode response"),
    chunkIndex: z.number().min(1).describe("Which chunk to retrieve (1-based index)")
  });

• src/tools/index.ts:9-16 (registration)

  Registration of the fetchChunkTool into the central toolRegistry array, making it available for use in the MCP server.

  toolRegistry.push(
    askGeminiTool,
    pingTool,
    helpTool,
    brainstormTool,
    fetchChunkTool,
    timeoutTestTool
  );

• src/tools/index.ts:6-6 (registration)

  Import statement that brings the fetchChunkTool definition into the index file for registration.

  import { fetchChunkTool } from './fetch-chunk.tool.js';