MCP Postgres Server

Instructions

Implementation Reference

• index.ts:218-248 (handler)

  The handler function that lists all tables in the public schema by querying information_schema.tables and returns a JSON array of table names.

  async () => {
    try {
      debugLog("Listing database tables");
      
      return await executeDbQuery(async (client) => {
        const result = await withTimeout(
          client.query(
            "SELECT table_name FROM information_schema.tables WHERE table_schema = 'public'"
          ),
          API_TIMEOUT_MS,
          "Listing database tables"
        ) as pg.QueryResult;
        
        debugLog(`Found ${result.rows.length} tables`);
        
        const tableList = result.rows.map((row: { table_name: string }) => row.table_name);
        
        return {
          content: [
            {
              type: "text",
              text: JSON.stringify(tableList, null, 2),
            },
          ],
        };
      }, "Failed to list database tables");
    } catch (error) {
      handleError(error, "Failed to list database tables");
      throw error;
    }
  }

• index.ts:215-249 (registration)

  Registration of the postgres_list_tables tool on the MCP server, including empty input schema and inline handler.

  server.tool(
    "postgres_list_tables",
    {},
    async () => {
      try {
        debugLog("Listing database tables");
        
        return await executeDbQuery(async (client) => {
          const result = await withTimeout(
            client.query(
              "SELECT table_name FROM information_schema.tables WHERE table_schema = 'public'"
            ),
            API_TIMEOUT_MS,
            "Listing database tables"
          ) as pg.QueryResult;
          
          debugLog(`Found ${result.rows.length} tables`);
          
          const tableList = result.rows.map((row: { table_name: string }) => row.table_name);
          
          return {
            content: [
              {
                type: "text",
                text: JSON.stringify(tableList, null, 2),
              },
            ],
          };
        }, "Failed to list database tables");
      } catch (error) {
        handleError(error, "Failed to list database tables");
        throw error;
      }
    }
  );

• index.ts:140-142 (schema)

  Input/output schema declaration for the tool in the MCP server capabilities. No parameters required.

  postgres_list_tables: {
    description: "List all tables in the PostgreSQL database",
    parameters: {},