ChainFETCH MCP Server

Instructions

Implementation Reference

• index.js:340-353 (registration)

  Registration of the 'search_blocks_llm' tool in the ListTools response, defining its name, description, and input schema.

  {
    name: 'search_blocks_llm',
    description: 'LLM-powered block search using LLaMA 3.2 3B to select from 120+ parameters',
    inputSchema: {
      type: 'object',
      properties: {
        query: {
          type: 'string',
          description: 'Natural language query for block search',
        },
      },
      required: ['query'],
    },
  },

• index.js:343-352 (schema)

  Input schema for the 'search_blocks_llm' tool, specifying a required 'query' string parameter.

  inputSchema: {
    type: 'object',
    properties: {
      query: {
        type: 'string',
        description: 'Natural language query for block search',
      },
    },
    required: ['query'],
  },

• index.js:727-728 (handler)

  Handler implementation for 'search_blocks_llm' tool within the handleToolCall switch statement. It calls the shared makeRequest method to forward the tool arguments to the ChainFETCH API endpoint '/api/v1/ethereum/blocks/llm_search'.

  case 'search_blocks_llm':
    return await this.makeRequest('/api/v1/ethereum/blocks/llm_search', 'GET', args, null, token);

• index.js:634-682 (helper)

  Shared helper method 'makeRequest' used by all tool handlers to make authenticated HTTP requests to the ChainFETCH API, including token handling, query parameter construction, and error propagation.

  async makeRequest(endpoint, method = 'GET', params = {}, body = null, token = null) {
    const chainfetchToken = token || process.env.CHAINFETCH_API_TOKEN;
    
    if (!chainfetchToken) {
      throw new McpError(
        ErrorCode.InvalidRequest,
        'CHAINFETCH_API_TOKEN is required'
      );
    }
  
    const url = new URL(`${API_BASE_URL}${endpoint}`);
    
    // Add query parameters for GET requests
    if (method === 'GET' && Object.keys(params).length > 0) {
      Object.entries(params).forEach(([key, value]) => {
        if (value !== undefined && value !== null) {
          if (Array.isArray(value)) {
            value.forEach(v => url.searchParams.append(`${key}[]`, v));
          } else {
            url.searchParams.append(key, value.toString());
          }
        }
      });
    }
  
    const fetchOptions = {
      method,
      headers: {
        'Authorization': `Bearer ${chainfetchToken}`,
        'Content-Type': 'application/json',
      },
    };
  
    if (body && method !== 'GET') {
      fetchOptions.body = JSON.stringify(body);
    }
  
    const response = await fetch(url.toString(), fetchOptions);
    
    if (!response.ok) {
      const errorText = await response.text();
      throw new McpError(
        ErrorCode.InternalError,
        `API request failed: ${response.status} ${response.statusText} - ${errorText}`
      );
    }
  
    return await response.json();
  }