Postgres: [single/namespace mode] Unable to list db: Password authentication failed

[alzimmermsft]

Description:
When entering the test prompt Show me the PostgreSQL databases in server <server> in mcp server single mode, the operation fails with a password authentication error, even though I provide the correct username and password. This PostgreSQL server is configured with both PostgreSQL authentication and Microsoft Entra authentication methods. The specific error is as follows:

• namespace mode:

• single mode:

Steps to Reproduce:

1. Run git clone https://github.com/azure/azure-mcp.
2. Run dotnet build.
3. Run az login.
4. Configure mcp.json in single/namespace mode.
5. Start mcp server.
6. Open GitHub Copilot in VS Code and switch to Agent mode.
7. Click Refresh on the tools list, and only select the configured MCP Server Tools.
8. Enter test prompts Show me the PostgreSQL databases in server <server>.

Environment:

• OS: Windows.
• Vscode Insiders Version: 1.103.0
• GitHub Copilot Chat Version: 0.30.2025073102

Expected Behavior:
It can successfully list PostgreSQL databases.

@jongio and @joshfree for notification

[alzimmermsft]

Copied from Azure/azure-mcp#804

[joshfree]

@kk-src