Codex app-server protocol detection fails: sends session/list instead of thread/list

[sldx]

Summary

When connecting Agmente iOS to a Codex app-server via stdio-to-ws, Agmente falls back to ACP mode and sends session/list instead of thread/list, causing Codex to reject the request.

Environment

• Agmente iOS: 0.1.0
• Codex CLI: 0.116.0 (codex app-server)
• stdio-to-ws: 0.2.0 (via npx @rebornix/stdio-to-ws)
• macOS: 15.7.3 (arm64)
• Transport: Tailscale serve (TLS) → ws://localhost:9000

Steps to Reproduce

1. Start the bridge:

   npx -y @rebornix/stdio-to-ws --persist --grace-period 604800 "codex app-server" --port 9000
   

2. Expose via TLS (e.g. tailscale serve --bg 9000)
3. Connect from Agmente iOS using wss://<host>
4. Send any message → "initialize needed" error on the phone

Observed Behavior

The initialize handshake succeeds, but the userAgent in the response does not start with codex/:

userAgent: 'Agmente iOS/0.116.0 (Mac OS 15.7.3; arm64) unknown (Agmente iOS; 0.1.0)'

After initialize, Agmente sends session/list (ACP protocol) instead of thread/list (Codex protocol). Codex rejects it:

Error:
{"error":{"code":-32600,"message":"Invalid request: unknown variant session/list, expected one of initialize, thread/start, thread/resume, ..."}}

Expected Behavior

Agmente should detect the Codex app-server and use thread/* methods instead of session/*.

Possible Cause

Protocol detection appears to look for codex/ in the userAgent field of the initialize response. The current Codex 0.116.0 app-server does not seem to include a matching userAgent string, so Agmente defaults to ACP mode.

[sldx]

Additional note: the local agent setup guide does not list Codex as a supported agent, though other parts of the documentation and README mention Codex compatibility.