Antigravity say "Error Agent execution terminated due to error." and MCP Error: "Your account does not have the necessary privileges to access this endpoint"

[alejo-ocana]

Describe the bug
When using the Supabase MCP server within the Antigravity IDE with the Claude Opus 4.5 (Thinking) model, the agent fails with a 403 Forbidden error: "Your account does not have the necessary privileges to access this endpoint." This occurs despite using a valid Personal Access Token (PAT) for an account with Owner privileges. Notably, the same configuration works perfectly when switching the model to Gemini 3, suggesting a model-specific handling issue of the Management API calls or the "Thinking" block headers.

To Reproduce
Steps to reproduce the behavior:

1. Configure mcp_config.json in Antigravity with the @supabase/mcp-server-supabase@latest.
2. Provide a valid Personal Access Token (PAT)
3. Start a new chat using Claude Opus 4.5 (Thinking).
4. Ask the model to "List tables from the public schema" or "List projects".
5. See error: Agent execution terminated due to error or the JSON response: Your account does not have the necessary privileges to access this endpoint.

Expected behavior
The model should successfully authenticate via the Management API, list the projects or database schema, and maintain the agent session without termination, as it does with other models (e.g., Gemini).

System information

• Windows 11
• IDE: Antigravity (January 2026 build)
• Model: Claude Opus 4.5 (Thinking)
• Version of Node.js: v20.x or higher (via npx)
• MCP Server: @supabase/mcp-server-supabase@latest

Additional context

• Privileges: The user is the Owner of the organization and project.
• Troubleshooting attempted:
  • Moved credentials from args to env variables (SUPABASE_ACCESS_TOKEN, SUPABASE_PROJECT_ID).
  • Attempted using both @supabase/mcp-server-supabase@latest and @supabase/mcp-server.
  • Verified that the token works via curl/Gemini 3.
• Hypothesis: Claude 4.5's "Thinking" process might be triggering additional discovery calls (like /v1/organizations) that are not permitted for certain PAT scopes or are being malformed by the Antigravity proxy.

Screenshots:

[bhavesh0009]

+1

[alejo-ocana]

I am experiencing a persistent error with the Supabase MCP. Even after a full uninstallation and re-installation, the connector seems to retain legacy configuration or session data, preventing the successful integration of a new Supabase token.

Steps to Reproduce:

• Install the Supabase MCP.
• Uninstall the MCP.
• Generate a new Supabase access token.
• Re-install the MCP and attempt to configure it with the new token.

Expected Behavior: The MCP should perform a clean handshake with the new token, clearing any previous session data or local configuration from the previous installation.

Actual Behavior: The system fails to recognize the new token or remains stuck in a state consistent with the previous installation (as shown in the attached screenshot), suggesting that the uninstallation process is not purging all local files or environment variables related to the MCP.