SingleStore MCP Server

Instructions

Implementation Reference

• src/index.ts:1489-1541 (handler)

  Main handler implementation for the 'describe_table' tool. Validates input, queries DESCRIBE for schema, COUNT(*) for statistics, and SELECT LIMIT 5 for sample data, returns structured JSON response.

  case 'describe_table': {
    if (!request.params.arguments || typeof request.params.arguments.table !== 'string') {
      throw new McpError(
        ErrorCode.InvalidParams,
        'Table parameter must be a string'
      );
    }
  
    try {
      // Get table schema
      const [columns] = await conn.query(
        'DESCRIBE ??',
        [request.params.arguments.table]
      ) as [ColumnRowDataPacket[], mysql.FieldPacket[]];
  
      // Get basic table statistics
      const [stats] = await conn.query(
        'SELECT COUNT(*) as total_rows FROM ??',
        [request.params.arguments.table]
      ) as [mysql.RowDataPacket[], mysql.FieldPacket[]];
  
      // Sample some data
      const [sample] = await conn.query(
        'SELECT * FROM ?? LIMIT 5',
        [request.params.arguments.table]
      ) as [mysql.RowDataPacket[], mysql.FieldPacket[]];
  
      const statistics = stats[0] as { total_rows: number };
  
      return {
        content: [
          {
            type: 'text',
            text: JSON.stringify(
              {
                schema: columns,
                statistics,
                sample_data: sample,
              },
              null,
              2
            ),
          },
        ],
      };
    } catch (error: unknown) {
      const err = error as Error;
      throw new McpError(
        ErrorCode.InternalError,
        `Table description error: ${err.message}`
      );
    }
  }

• src/index.ts:1210-1222 (registration)

  Tool registration including name, description, and input schema in the MCP server's ListTools response.

    name: 'describe_table',
    description: 'Get detailed information about a table',
    inputSchema: {
      type: 'object',
      properties: {
        table: {
          type: 'string',
          description: 'Name of the table to describe',
        },
      },
      required: ['table'],
    },
  },

• src/index.ts:1212-1222 (schema)

  Input schema definition for the 'describe_table' tool requiring a 'table' string parameter.

    inputSchema: {
      type: 'object',
      properties: {
        table: {
          type: 'string',
          description: 'Name of the table to describe',
        },
      },
      required: ['table'],
    },
  },

• src/index.ts:22-29 (helper)

  Type interface used in the describe_table handler for typing DESCRIBE query results.

  interface ColumnRowDataPacket extends mysql.RowDataPacket {
    Field: string;
    Type: string;
    Null: string;
    Key: string;
    Default?: string;
    Extra?: string;
  }

• src/index.ts:170-182 (registration)

  Secondary tool registration in SSE handleRequest cached tools list (identical schema).

    name: 'describe_table',
    description: 'Get detailed information about a table',
    inputSchema: {
      type: 'object',
      properties: {
        table: {
          type: 'string',
          description: 'Name of the table to describe',
        },
      },
      required: ['table'],
    },
  },