Gemini CLI replaced by Antigravity CLI: move your Sume MCP entry

If you moved from Gemini CLI to Antigravity CLI, your Sume MCP server does not carry over on its own: the entry has to move from ~/.gemini/settings.json to a standalone mcp_config.json, and the URL key changes from httpUrl to serverUrl. Sume's endpoint stays https://mcp.sume.com/mcp; only the file around it changes.

The Gemini CLI documentation site carries a banner (read 2026-10-10) saying that for unpaid-tier and Google One users, Gemini CLI was replaced by Antigravity CLI on June 18, 2026. If you are one of those users and your Sume tools vanished from a session, this is the likely reason.

What changed in the config

Gemini CLI's MCP page says servers live in settings.json, at ~/.gemini/settings.json for user scope or .gemini/settings.json for a project. Remote servers use url for SSE or httpUrl for HTTP streaming, with an optional headers object.

Antigravity's migration page describes a different layout: it separates MCP servers into dedicated JSON profiles instead of nesting them in your main preferences. The paths are ~/.gemini/config/mcp_config.json (global) and .agents/mcp_config.json (workspace). For remote servers it requires serverUrl, and states that legacy url or httpUrl fields are not supported. Context files such as GEMINI.md and AGENTS.md keep working.

The Sume entry, before and after

Sume's quickstart tells remote HTTP clients to point at the production URL and complete OAuth, or to send an API key as Authorization: Bearer or x-api-key. For Antigravity CLI that becomes the block below. Leave the key out of the file if you can use OAuth, and never commit a real key.

Antigravity's page lists OAuth support (automatic, or manual with clientId and clientSecret) and custom headers. Sume's OAuth needs no pre-registered client secret in the docs we read, so try the plain serverUrl entry first and use the header form only for unattended runs.

// ~/.gemini/config/mcp_config.json
{
  "mcpServers": {
    "sume": {
      "serverUrl": "https://mcp.sume.com/mcp"
    }
  }
}

// CI variant with an API key header (keep the value out of git)
{
  "mcpServers": {
    "sume": {
      "serverUrl": "https://mcp.sume.com/mcp",
      "headers": { "x-api-key": "<your SUME_API_KEY>" }
    }
  }
}

Check it worked

Antigravity says typing /mcp in the prompt panel opens an MCP Manager for status, config reloads and logs. After the entry loads, ask the agent to call Sume's mcp_health and then tools_list, the two read-only calls Sume recommends for a first check.

If the list is short, look at the credential before the file. Sume's OAuth sessions are read-only until the user turns on Write at consent, and write or paid tools return insufficient_scope without it. An API key shows the full set.

• Entry loads but no tools: check serverUrl, not url or httpUrl.
• Only read tools: the OAuth grant has mcp:read only; re-authorize with Write on, or use an API key.
• Paid call refused: Sume requires an idempotency_key on write and paid tools.
• Old Gemini CLI still installed: it keeps reading settings.json, so edit each tool's own file.

Who this applies to

The June 18 replacement applies, per Google's banner, to unpaid-tier and Google One users, not to everyone. If your Gemini CLI still runs and still reads settings.json, keep its httpUrl entry; add the Antigravity file only on machines that moved. Both can point at the same Sume endpoint, https://mcp.sume.com/mcp.