PostgreSQL MCP Server

Instructions

Implementation Reference

• src/index.ts:445-484 (registration)

  Registers the 'disconnect_database' tool with server.tool. Includes empty input schema, description, and an inline async handler that disconnects the PostgreSQL database by calling dbClient.end() if connected, handling success, no-connection, and error cases.

  server.tool(
    "disconnect_database",
    "Disconnect from the current PostgreSQL database",
    {},
    async () => {
      try {
        if (dbClient) {
          await dbClient.end();
          dbClient = null;
          return {
            content: [
              {
                type: "text",
                text: "Successfully disconnected from database.",
              },
            ],
          };
        } else {
          return {
            content: [
              {
                type: "text",
                text: "No active database connection to disconnect.",
              },
            ],
          };
        }
      } catch (error) {
        const errorMessage = error instanceof Error ? error.message : "Unknown error";
        return {
          content: [
            {
              type: "text",
              text: `Error disconnecting from database: ${errorMessage}`,
            },
          ],
        };
      }
    }
  );

• src/index.ts:449-483 (handler)

  Inline handler function for disconnect_database tool. Checks if dbClient exists, ends the connection, sets to null, and returns appropriate text response. Handles no connection and errors gracefully.

  async () => {
    try {
      if (dbClient) {
        await dbClient.end();
        dbClient = null;
        return {
          content: [
            {
              type: "text",
              text: "Successfully disconnected from database.",
            },
          ],
        };
      } else {
        return {
          content: [
            {
              type: "text",
              text: "No active database connection to disconnect.",
            },
          ],
        };
      }
    } catch (error) {
      const errorMessage = error instanceof Error ? error.message : "Unknown error";
      return {
        content: [
          {
            type: "text",
            text: `Error disconnecting from database: ${errorMessage}`,
          },
        ],
      };
    }
  }

• src/index.ts:448-448 (schema)

  Empty input schema object, indicating the tool takes no input parameters.

  {},