SingleStore MCP Server

Instructions

Implementation Reference

• src/index.ts:1619-1652 (handler)

  The handler for 'run_read_query' tool. Validates input, ensures query is SELECT-only, executes on database, returns results as JSON text.

  case 'run_read_query': {
    if (!request.params.arguments || typeof request.params.arguments.query !== 'string') {
      throw new McpError(
        ErrorCode.InvalidParams,
        'Query parameter must be a string'
      );
    }
  
    const query = request.params.arguments.query.trim().toLowerCase();
    if (!query.startsWith('select ')) {
      throw new McpError(
        ErrorCode.InvalidParams,
        'Only SELECT queries are allowed for this tool'
      );
    }
  
    try {
      const [rows] = await conn.query(request.params.arguments.query) as [mysql.RowDataPacket[], mysql.FieldPacket[]];
      return {
        content: [
          {
            type: 'text',
            text: JSON.stringify(rows, null, 2),
          },
        ],
      };
    } catch (error: unknown) {
      const err = error as Error;
      throw new McpError(
        ErrorCode.InternalError,
        `Query error: ${err.message}`
      );
    }
  }

• src/index.ts:1224-1236 (schema)

  Input schema definition for run_read_query tool in MCP ListToolsRequestSchema response.

    name: 'run_read_query',
    description: 'Execute a read-only (SELECT) query on the database',
    inputSchema: {
      type: 'object',
      properties: {
        query: {
          type: 'string',
          description: 'SQL SELECT query to execute',
        },
      },
      required: ['query'],
    },
  },

• src/index.ts:1224-1236 (registration)

  The run_read_query tool is registered here in the tools list returned by ListToolsRequestSchema handler.

    name: 'run_read_query',
    description: 'Execute a read-only (SELECT) query on the database',
    inputSchema: {
      type: 'object',
      properties: {
        query: {
          type: 'string',
          description: 'SQL SELECT query to execute',
        },
      },
      required: ['query'],
    },
  },

• src/index.ts:184-196 (schema)

  Duplicate schema definition for SSE/HTTP API tool listing.

    name: 'run_read_query',
    description: 'Execute a read-only (SELECT) query on the database',
    inputSchema: {
      type: 'object',
      properties: {
        query: {
          type: 'string',
          description: 'SQL SELECT query to execute',
        },
      },
      required: ['query'],
    },
  },