MCP Server MySQL

Instructions

Implementation Reference

• src/index.ts:272-297 (handler)

  The handler function executes a DESCRIBE query on the specified table (optionally in a database) and returns the column structure including Field, Type, Null, Key, Default, and Extra.

  async ({ table, database }) => {
    const p = await getPool();
  
    const tableName = database ? `\`${database}\`.\`${table}\`` : `\`${table}\``;
    const [rows] = await p.query<RowDataPacket[]>(`DESCRIBE ${tableName}`);
  
    const columns = rows as Array<{
      Field: string;
      Type: string;
      Null: string;
      Key: string;
      Default: string | null;
      Extra: string;
    }>;
    const output = { table, database: database || null, columns };
  
    return {
      content: [
        {
          type: "text" as const,
          text: JSON.stringify(rows, null, 2),
        },
      ],
      structuredContent: output,
    };
  }

• src/index.ts:268-271 (schema)

  Input schema using Zod: required 'table' string and optional 'database' string.

  {
    table: z.string().describe("Table name"),
    database: z.string().optional().describe("Database name (optional)"),
  },

• src/index.ts:265-298 (registration)

  Registration of the describe_table tool via server.tool call, including name, description, input schema, and handler.

  server.tool(
    "describe_table",
    "Get the structure/schema of a table",
    {
      table: z.string().describe("Table name"),
      database: z.string().optional().describe("Database name (optional)"),
    },
    async ({ table, database }) => {
      const p = await getPool();
  
      const tableName = database ? `\`${database}\`.\`${table}\`` : `\`${table}\``;
      const [rows] = await p.query<RowDataPacket[]>(`DESCRIBE ${tableName}`);
  
      const columns = rows as Array<{
        Field: string;
        Type: string;
        Null: string;
        Key: string;
        Default: string | null;
        Extra: string;
      }>;
      const output = { table, database: database || null, columns };
  
      return {
        content: [
          {
            type: "text" as const,
            text: JSON.stringify(rows, null, 2),
          },
        ],
        structuredContent: output,
      };
    }
  );