ComposioHQ/composio · error · ValidationError

No server URL generated

Error message

No server URL generated

What it means

Raised during MCP.generate() when the backend's URL-generation response does not contain a usable user_ids_url list. The SDK mirrors the TS behavior (urlResponse.user_ids_url[0]) and treats a missing/empty user_ids_url as a hard failure rather than returning a server instance without a URL.

Source

Thrown at python/composio/core/models/mcp.py:482

            >>> print(mcp['allowed_tools'])  # Available tools
        """

        try:
            # Get server details first (matching TS: this.client.mcp.retrieve)
            server_details = self._client.mcp.retrieve(mcp_config_id)

            # Generate server URLs (matching TS: this.client.mcp.generate.url)
            url_response = self._client.mcp.generate.url(
                mcp_server_id=mcp_config_id,
                user_ids=[user_id],
                managed_auth_by_composio=False if manually_manage_connections else True,
            )

            # Get the generated URL (matching TS: urlResponse.user_ids_url[0])
            if hasattr(url_response, "user_ids_url") and url_response.user_ids_url:
                server_url = url_response.user_ids_url[0]
            else:
                raise ValidationError("No server URL generated")

            # Create structured server instance (matching TS MCPServerInstance)
            server_instance: MCPServerInstance = {
                "id": server_details.id,
                "name": server_details.name,
                "type": "streamable_http",
                "url": server_url,
                "user_id": user_id,
                "allowed_tools": getattr(server_details, "allowed_tools", []),
                "auth_configs": getattr(server_details, "auth_config_ids", []),
            }

            return server_instance

        except Exception as e:
            if isinstance(e, ValidationError):
                raise
            raise ValidationError("Failed to parse MCP server instance") from e

View on GitHub (pinned to 64b1b85502)

Solutions

1. Retry the create/generate call — transient provisioning failures often resolve
2. Upgrade composio so the generated client matches the backend response schema
3. Check your workspace MCP config quota/limits in the dashboard
4. If persistent, capture the raw response by calling client.mcp.get_url directly to inspect fields

for attempt in range(3):
    try:
        inst = composio.mcp.create(name=name, toolkits=tks)
        break
    except ValidationError as e:
        if 'No server URL' not in str(e) or attempt == 2:
            raise
        time.sleep(2 ** attempt)

When it happens

Trigger: Calling composio.mcp.create(...) (which calls generate) or generate() directly, when the backend response lacks the user_ids_url attribute or it's an empty array — typically a partial provisioning failure or backend/API version mismatch.

Common situations: Backend-side provisioning hiccup, SDK pinned to an older generated client that expects a response field the backend no longer returns, rate/quota limits preventing URL assignment.

Related errors

• Failed to fetch file from URL: {_sanitize_url_for_logging(ur
• File size ({content_length} bytes) exceeds maximum allowed s
• Failed to list MCP servers
• Failed to retrieve MCP server {server_id}
• Failed to update MCP server {server_id}

AI-assisted analysis of ComposioHQ/composio@64b1b85502 (2026-08-28). Data as JSON: /api/errors/d142c290c9dc88df. Report an issue: GitHub.