MCP Server Gemini

Instructions

Implementation Reference

• src/enhanced-stdio-server.ts:786-828 (handler)

  Main execution logic for the list_models tool. Filters GEMINI_MODELS based on optional 'filter' parameter and returns JSON-formatted list.

  private listModels(id: any, args: any): MCPResponse {
    const filter = args?.filter || 'all';
    let models = Object.entries(GEMINI_MODELS);
  
    if (filter !== 'all') {
      models = models.filter(([_, info]) => {
        switch (filter) {
          case 'thinking':
            return 'thinking' in info && info.thinking === true;
          case 'vision':
            return info.features.includes('function_calling'); // All current models support vision
          case 'grounding':
            return info.features.includes('grounding');
          case 'json_mode':
            return info.features.includes('json_mode');
          default:
            return true;
        }
      });
    }
  
    const modelList = models.map(([name, info]) => ({
      name,
      ...info
    }));
  
    return {
      jsonrpc: '2.0',
      id,
      result: {
        content: [
          {
            type: 'text',
            text: JSON.stringify(modelList, null, 2)
          }
        ],
        metadata: {
          count: modelList.length,
          filter
        }
      }
    };
  }

• src/enhanced-stdio-server.ts:496-497 (registration)

  Dispatch case in handleToolCall method that routes list_models tool calls to the handler.

  case 'list_models':
    return this.listModels(request.id, args);

• src/enhanced-stdio-server.ts:338-351 (registration)

  Tool registration in getAvailableTools() - defines name, description, and input schema advertised in tools/list response.

  {
    name: 'list_models',
    description: 'List all available Gemini models and their capabilities',
    inputSchema: {
      type: 'object',
      properties: {
        filter: {
          type: 'string',
          description: 'Filter models by capability',
          enum: ['all', 'thinking', 'vision', 'grounding', 'json_mode']
        }
      }
    }
  },

• src/utils/validation.ts:98-100 (schema)

  Zod validation schema for list_models parameters (defined but not explicitly used in handler).

  listModels: z.object({
    filter: z.enum(['all', 'thinking', 'vision', 'grounding', 'json_mode']).optional()
  }),

• src/enhanced-stdio-server.ts:17-66 (helper)

  Data structure of available models used by the list_models handler to generate the response.

  const GEMINI_MODELS = {
    // Thinking models (2.5 series) - latest and most capable
    'gemini-2.5-pro': {
      description: 'Most capable thinking model, best for complex reasoning and coding',
      features: ['thinking', 'function_calling', 'json_mode', 'grounding', 'system_instructions'],
      contextWindow: 2000000, // 2M tokens
      thinking: true
    },
    'gemini-2.5-flash': {
      description: 'Fast thinking model with best price/performance ratio',
      features: ['thinking', 'function_calling', 'json_mode', 'grounding', 'system_instructions'],
      contextWindow: 1000000, // 1M tokens
      thinking: true
    },
    'gemini-2.5-flash-lite': {
      description: 'Ultra-fast, cost-efficient thinking model for high-throughput tasks',
      features: ['thinking', 'function_calling', 'json_mode', 'system_instructions'],
      contextWindow: 1000000,
      thinking: true
    },
  
    // 2.0 series
    'gemini-2.0-flash': {
      description: 'Fast, efficient model with 1M context window',
      features: ['function_calling', 'json_mode', 'grounding', 'system_instructions'],
      contextWindow: 1000000
    },
    'gemini-2.0-flash-lite': {
      description: 'Most cost-efficient model for simple tasks',
      features: ['function_calling', 'json_mode', 'system_instructions'],
      contextWindow: 1000000
    },
    'gemini-2.0-pro-experimental': {
      description: 'Experimental model with 2M context, excellent for coding',
      features: ['function_calling', 'json_mode', 'grounding', 'system_instructions'],
      contextWindow: 2000000
    },
  
    // Legacy models (for compatibility)
    'gemini-1.5-pro': {
      description: 'Previous generation pro model',
      features: ['function_calling', 'json_mode', 'system_instructions'],
      contextWindow: 2000000
    },
    'gemini-1.5-flash': {
      description: 'Previous generation fast model',
      features: ['function_calling', 'json_mode', 'system_instructions'],
      contextWindow: 1000000
    }
  };