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Debug Connectors

The Connectors Debugger helps you test an MCP Connector server before you use it with Studio. Use it to check server reachability, authentication setup, tool discovery, and validation errors from Studio.

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Information

The Connectors Debugger is in public preview. Validation coverage and error details can change as we add more MCP compatibility checks.

Before you start

Before you start

You need access to Studio and the MCP Connector server URL you want to test.

If the server requires authentication, prepare one of the following:

  • A static HTTP header, such as Authorization: Bearer <token>.
  • OAuth2 client credentials for the Connector server.

If your Connector uses OAuth2, configure this redirect URI in your OAuth application:

https://console.mistral.ai/build/connectors/debugger/oauth-callback
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Information

Credentials configured in the Debugger aren't stored. They last only for the current session.

Open the Connectors Debugger

Open the Connectors Debugger

  1. Open Studio.
  2. In the left menu, click Connectors.
  3. Click Debugger in the top-right corner.

Alternatively, use the direct URL: Studio›Connectors›Debugger ↗

Configure the Connector test

Configure the Connector test

  1. In the Connector URL field, enter the MCP server URL.
  2. If the server requires credentials, click the settings icon next to Run diagnostic:
    • In Credentials, select Custom header or OAuth 2.0.
    • For a custom header, set Header name to Authorization and Header value to Bearer <token>.
    • For OAuth, enter Client ID and Client Secret.
  3. Click Run diagnostic.
Caution

Only test Connector servers you trust. The Debugger sends the configured headers or credentials to the server address you provide.

Run a diagnostic

Run a diagnostic

The Debugger runs the diagnostic and generates a report on the right side of the window. If you need to repeat the test after changing the URL or credentials, click Run again.

When a step fails, the report explains which step failed and includes troubleshooting details. Depending on the failure, the report can include:

  • Likely cause
  • Suggested fix
  • Raw response
  • Copy as curl
  • Headers
  • Body
  • A JSON report for the failed step

For example, if the server responds with HTML instead of an MCP JSON-RPC response, the report can show The server responded but does not appear to be an MCP server as the likely cause and Verify the URL points to an MCP server, not a regular web page or REST API as the suggested fix.

A failed step report can look like this:

{
  "step": "transport_detection",
  "status": "error",
  "duration": 259,
  "data": {
    "attempt": {
      "request": {
        "method": "POST",
        "url": "https://chaos-mcp.example.com/"
      },
      "response": {
        "status": 200,
        "headers": {
          "content-type": "text/html; charset=utf-8"
        },
        "body": "<!DOCTYPE html><html lang=\"en\">..."
      }
    }
  },
  "error": {
    "type": "not_mcp_server"
  }
}
Review a successful test

Review a successful test

When all checks pass, the final report shows that the MCP server is ready. The report includes the MCP protocol version, a View official docs link, summary metrics, instructions when available, and discovered MCP content.

A successful report can include:

  • MCP server ready
  • Protocol 2025-11-25
  • View official docs
  • Tools: the number of tools discovered
  • Prompts: the number of prompts discovered
  • Resources: the number of resources discovered
  • Duration: how long the validation took
  • Checks: the number of checks that passed, such as 3/3
  • Instructions: server instructions when the MCP server returns them

The Tools section lists discovered tools. You can use Search... to filter them and select Interactive to inspect them. For example, a test server might return tools named echo, add, and current_time. Selecting echo shows Echo back the provided message. as the description and shows the input schema:

{
  "type": "object",
  "properties": {
    "message": {
      "description": "Text to echo",
      "type": "string"
    }
  },
  "required": ["message"]
}
Troubleshoot typical MCP errors

Troubleshoot typical MCP errors

Use the generated report first. It shows the failed step and the most specific Likely cause and Suggested fix available. The cases below explain common MCP server issues that can appear in the report.

Next steps after a successful test

Next steps after a successful test

After the Debugger validates your Connector server, use the report to confirm compatibility with Studio. The Connector creation flow isn't in scope for this release.