Bug: `"auto" tool choice requires --enable-auto-tool-choice and --tool-call-parser to be set`

[seleckis]

Environment

• Plugin version: latest (@morphllm/opencode-morph-plugin)
• Model: morph-v3-large
• OpenCode config: default (no custom baseURL, no OPENAI_API_KEY/OPENAI_BASE_URL set)

Steps to reproduce

1. Install the plugin per README
2. Set MORPH_API_KEY
3. Open OpenCode — model shows as morph v3 large
4. Send any message

Error

OpenCode sends tool_choice: "auto" to https://api.morphllm.com/v1/chat/completions, which returns HTTP 400:

{"error":{"message":"\"auto\" tool choice requires --enable-auto-tool-choice and --tool-call-parser to be set","type":"BadRequestError","param":null,"code":400}}

Expected behavior

The API should accept tool_choice: "auto" for morph-v3-large, or the plugin should use a compatible tool_choice value that the endpoint supports.

Notes

The request never reaches any local vLLM — it goes directly to api.morphllm.com. The error message suggests the backend is running vLLM without --enable-auto-tool-choice and --tool-call-parser flags.