Factory Droid: /compress (session compact) fails on Gemini 2.5 via CLIProxyAPI

[mikez93]

Summary

When using Factory's Droid CLI with Gemini via CLIProxyAPI, attempting to compact a session (/compress / "compact session") fails with an error in the Droid UI, while the same setup works for Anthropic and OpenAI models through the proxy.

Environment

• Client: Factory Droid CLI (BYOK/custom models)
• Proxy: CLIProxyAPI (latest v6.x, Gemini CLI OAuth configured and working for normal chat + tools)
• Model: Gemini 2.5 Flash / gemini-2.5-pro (Gemini CLI OAuth)
• Config (excerpt from ~/.factory/config.json):

  {
    "custom_models": [
      {
        "model": "gemini-2.5-flash",            // or gemini-2.5-pro
        "base_url": "http://127.0.0.1:8317/v1",
        "api_key": "sk-dummy",
        "provider": "openai"                    // or "anthropic" per docs; repro happens with working config
      }
    ]
  }

Reproduction steps

1. Start cliproxyapi with Gemini OAuth configured and working (normal chat + tools OK in Droid).
2. In droid, select the custom Gemini model (e.g. Gemini 2.5 Flash [Proxy] [custom]).
3. Have a non-trivial session (enough turns that Factory would benefit from compaction).
4. Run the session compact command in Droid (e.g. /compress / "Compact session").

Actual behavior

• Droid shows an error instead of compacting the session, e.g.:

  Error: Failed to compact and start a new session

• The same workflow with Anthropic/OpenAI custom models through CLIProxyAPI compacts successfully.

Expected behavior

• Session compaction should work when using Gemini models via CLIProxyAPI in Droid, just as it does for Anthropic/OpenAI via the proxy (or at least fail with a clear, proxied error from Gemini explaining what’s unsupported).

Notes

• Existing issues related to Droid + Gemini (e.g. Gemini + Droid = Bug #123, gemini oauth in droid cli: unknown provider #258) address tool-calling / provider wiring, but I couldn’t find an issue specifically tracking /compress / session compaction behavior for Gemini via CLIProxyAPI.
• Happy to enable request-log: true and provide the exact HTTP request/response for the compaction call if that would help.