Claude Desktop gateway routing fails: alias not reverse-mapped to DeepSeek model (400)

[vehiclerentropy]

Summary

Claude Desktop (Cowork, custom3p managed config) pointed at the opencodex gateway fails with HTTP 400 — the desktop client sends the injected alias model id (e.g. claude-opus-4-8-20261210) and opencodex forwards that alias verbatim to the routed provider (deepseek) instead of reverse-mapping it to the real model (deepseek/deepseek-v4-flash).

Expected

opencodex should reverse-map the alias from claudeCode.desktopProfile.assignments (alias → provider/model) before forwarding to the provider, like it does for Claude Code CLI aliases.

Actual

• Claude Desktop sends: model=claude-opus-4-8-20261210
• opencodex forwards to deepseek provider unchanged
• DeepSeek API rejects: The supported API model names are deepseek-v4-pro or deepseek-v4-flash, but you passed claude-opus-4-8-20261210 (400)
• Usage log confirms: provider=deepseek, model=claude-opus-4-8-20261210, requestedModel=claude-opus-4-8-20261210, status=400

Repro

1. ocx login deepseek, add deepseek provider
2. ocx claude desktop apply (injects configLibrary json with inferenceModels: name=claude-opus-4-8-20261210, labelOverride=Deepseek V4 Flash (deepseek))
3. Open Claude Desktop → it shows "Deepseek V4 Flash (deepseek)" in the model picker
4. Send a message → 400, model never reaches DeepSeek

Notes

• Manually changing the configLibrary name to deepseek/deepseek-v4-flash fails Claude Desktop validation ("is not an Anthropic model"); changing to anthropic/deepseek-v4-flash passes validation but opencodex still forwards it verbatim and DeepSeek rejects it.
• Environment: opencodex 2.8.0, Claude Desktop 1.24012.9 (macOS), deepseek provider (openai-chat adapter).

[github-actions]

Issue closed: use an issue template

Thanks for taking the time to submit this issue. It was closed automatically because it was not opened with a recognized issue template (Bug report, Feature request, Documentation, or Provider compatibility). Freeform and API-opened issues cannot skip this check.

• This issue does not use a recognized issue template.

Please edit the issue to add:

• Open a new issue with the Bug report, Feature request, Documentation, or Provider compatibility template.
• Or edit this issue so the body uses the template section headings for the kind of report you are filing.

See the Contributing guide for details.

Once the report passes the automated checks, it will be reopened automatically unless a maintainer has changed its state.

[github-actions]

_{Automated translation bookkeeping — detected language: unknown.}