[BUG] `opencode agent create` throws error when using OpenAI as provider

[RisaKirisu]

Description

Previous issues mentioned similar issue but was never fixed:
#7995
#7322

Terminal output:

risa@RisaK-Desktop:~$ opencode agent create --log-level=DEBUG --print-logs --pure --model openai/gpt-5.4
INFO  2026-04-03T05:54:49 +373ms service=default version=1.3.13 args=["agent","create","--log-level=DEBUG","--print-logs","--pure","--model","openai/gpt-5.4"] opencode
INFO  2026-04-03T05:54:49 +1ms service=default directory=/home/risa creating instance
INFO  2026-04-03T05:54:49 +5ms service=project directory=/home/risa fromDirectory
INFO  2026-04-03T05:54:49 +12ms service=db path=/home/risa/.local/share/opencode/opencode.db opening database
INFO  2026-04-03T05:54:49 +2ms service=db count=10 mode=bundled applying migrations

┌  Create agent
│
◇  Description
│  General question answering, calculation, and conversational agent. Approximately 70/30 on technical vs general
│
INFO  2026-04-03T05:54:55 +5461ms service=config path=/home/risa/.config/opencode/config.json loading
INFO  2026-04-03T05:54:55 +18ms service=config path=/home/risa/.config/opencode/opencode.json loading
INFO  2026-04-03T05:54:55 +12ms service=config path=/home/risa/.config/opencode/opencode.jsonc loading
DEBUG 2026-04-03T05:54:55 +14ms service=config loading config from /home/risa/.opencode/opencode.jsonc
INFO  2026-04-03T05:54:55 +0ms service=config path=/home/risa/.opencode/opencode.jsonc loading
DEBUG 2026-04-03T05:54:55 +1ms service=config loading config from /home/risa/.opencode/opencode.json
INFO  2026-04-03T05:54:55 +0ms service=config path=/home/risa/.opencode/opencode.json loading
INFO  2026-04-03T05:54:55 +8ms service=provider status=started state
◒  Generating agent configurationINFO  2026-04-03T05:54:55 +38ms service=provider init
INFO  2026-04-03T05:54:55 +13ms service=plugin name=CodexAuthPlugin loading internal plugin
INFO  2026-04-03T05:54:55 +0ms service=plugin name=CopilotAuthPlugin loading internal plugin
INFO  2026-04-03T05:54:55 +1ms service=plugin name=gitlabAuthPlugin loading internal plugin
INFO  2026-04-03T05:54:55 +0ms service=plugin name=PoeAuthPlugin loading internal plugin
INFO  2026-04-03T05:54:55 +0ms service=bus type=* subscribing
INFO  2026-04-03T05:54:55 +16ms service=provider providerID=openrouter found
INFO  2026-04-03T05:54:55 +0ms service=provider providerID=openai found
INFO  2026-04-03T05:54:55 +0ms service=provider providerID=opencode found
INFO  2026-04-03T05:54:55 +0ms service=provider status=completed duration=68 state
INFO  2026-04-03T05:54:55 +1ms service=provider status=started providerID=openai getSDK
INFO  2026-04-03T05:54:55 +1ms service=provider providerID=openai pkg=@ai-sdk/openai using bundled provider
INFO  2026-04-03T05:54:55 +0ms service=provider status=completed duration=1 providerID=openai getSDK
◐  Generating agent configurationINFO  2026-04-03T05:54:55 +11ms service=skill count=0 init
■  LLM failed to generate agent: Bad Request
ERROR 2026-04-03T05:54:55 +321ms service=default name=UICancelledError message=UICancelledError stack=UICancelledError: UICancelledError
    at <anonymous> (/$bunfs/root/src/index.js:451509:17)
    at processTicksAndRejections (native:7:39) fatal



risa@RisaK-Desktop:~$ opencode -v
1.3.13



risa@RisaK-Desktop:~$ cat  ~/.config/opencode/opencode.json
cat: /home/risa/.config/opencode/opencode.json: No such file or directory

risa@RisaK-Desktop:~$ opencode auth list

┌  Credentials ~/.local/share/opencode/auth.json
│
●  OpenRouter api
│
●  OpenAI oauth
│
└  2 credentials

Plugins

None

OpenCode version

1.3.13

Steps to reproduce

1. Authenticate with OpenAI (OAuth)
2. Do opencode agent create --log-level=DEBUG --print-logs --pure --model openai/gpt-5.4
3. Input any description, then enter.
4. Error: LLM failed to generate agent: Bad Request

Screenshot and/or share link

No response

Operating System

Windows 11 WSL2 Ubuntu

Terminal

Windows Terminal

[github-actions]

This issue might be a duplicate of existing issues. Please check:

• opencode agent create fails with OpenAI model (Bad Request`) #19346: opencode agent create fails with OpenAI model (Bad Request) — same error, same command, same provider
• LLM failed to generate agent: Bad Request #8337: LLM failed to generate agent: Bad Request — same error message
• opencode agent create fails due to OpenAI provider #7995: opencode agent create fails due to OpenAI provider — same root cause (referenced in this issue)
• Command: opencode agent create fails #7322: Command: opencode agent create fails — same command failing (referenced in this issue)

If your issue is still reproducible on the latest version and the above issues don't fully cover your case, please add a comment explaining what's different.

[RisaKirisu]

These issues describe similar problem. All of them are closed, and one even have a PR attached that supposedly fix the issue. However the problem still persists in the latest version v1.3.13.

[OpeOginni]

Yeah I am able to reproduce this issue. On logging the error I gott this in the response

responseBody: "{\"detail\":\"Instructions are required\"}",

So It is related to those previous errors, and I might have a fix based on how the logic for openai oauth login works from normal llm textStreaming.