connect_database

Establish a connection to a PostgreSQL database using specified host, port, database name, username, password, and SSL settings. Facilitates secure database interactions and query execution.

Instructions

Connect to a PostgreSQL database

Input Schema

TableJSON Schema

Name	Required	Description
`database`	Yes	Database name
`host`	No	Database host (default: localhost)
`password`	No	Database password
`port`	No	Database port (default: 5432)
`ssl`	No	Use SSL connection (default: false)
`username`	Yes	Database username

Implementation Reference

src/index.ts:65-115 (registration)

Registration of the 'connect_database' tool using server.tool(). Includes tool name, description, input schema defined with Zod, and inline asynchronous handler function.

server.tool(
  "connect_database",
  "Connect to a PostgreSQL database",
  {
    host: z.string().describe("Database host (default: localhost)").optional(),
    port: z.number().describe("Database port (default: 5432)").optional(),
    database: z.string().describe("Database name"),
    username: z.string().describe("Database username"),
    password: z.string().describe("Database password").optional(),
    ssl: z.boolean().describe("Use SSL connection (default: false)").optional(),
  },
  async ({ host, port, database, username, password, ssl }) => {
    try {
      // Close existing connection if any
      if (dbClient) {
        await dbClient.end();
      }

      // Create new connection
      dbClient = new Client({
        host: host || "localhost",
        port: port || 5432,
        database,
        user: username,
        password,
        ssl: ssl || false,
      });

      await dbClient.connect();

      return {
        content: [
          {
            type: "text",
            text: `Successfully connected to PostgreSQL database '${database}' on ${host || "localhost"}:${port || 5432}`,
          },
        ],
      };
    } catch (error) {
      const errorMessage = error instanceof Error ? error.message : "Unknown connection error";
      return {
        content: [
          {
            type: "text",
            text: `Failed to connect to database: ${errorMessage}`,
          },
        ],
      };
    }
  }
);

src/index.ts:76-114 (handler)

The handler function for the connect_database tool. It closes any existing database connection, creates a new PostgreSQL Client with the provided configuration (using defaults where applicable), connects to the database, and returns a success message or error details.

async ({ host, port, database, username, password, ssl }) => {
  try {
    // Close existing connection if any
    if (dbClient) {
      await dbClient.end();
    }

    // Create new connection
    dbClient = new Client({
      host: host || "localhost",
      port: port || 5432,
      database,
      user: username,
      password,
      ssl: ssl || false,
    });

    await dbClient.connect();

    return {
      content: [
        {
          type: "text",
          text: `Successfully connected to PostgreSQL database '${database}' on ${host || "localhost"}:${port || 5432}`,
        },
      ],
    };
  } catch (error) {
    const errorMessage = error instanceof Error ? error.message : "Unknown connection error";
    return {
      content: [
        {
          type: "text",
          text: `Failed to connect to database: ${errorMessage}`,
        },
      ],
    };
  }
}

src/index.ts:69-75 (schema)

Input schema for the connect_database tool, defined using Zod object with parameters for PostgreSQL connection: host, port, database, username, password, ssl, including descriptions and optionals.

  host: z.string().describe("Database host (default: localhost)").optional(),
  port: z.number().describe("Database port (default: 5432)").optional(),
  database: z.string().describe("Database name"),
  username: z.string().describe("Database username"),
  password: z.string().describe("Database password").optional(),
  ssl: z.boolean().describe("Use SSL connection (default: false)").optional(),
},

PostgreSQL MCP Server