TOKEN_REFRESH_NEEDED error incorrectly thrown for context overflow (400 prompt too long) #12135

Description

When a session exceeds the model's context limit, the GitLab provider throws TOKEN_REFRESH_NEEDED instead of reporting the actual error.

Actual error (from logs):

400 {"type":"invalid_request_error","message":"prompt is too long: 218390 tokens > 200000 maximum"}

Displayed error:

GitLabError: TOKEN_REFRESH_NEEDED

Root cause: The error handling in @gitlab/gitlab-ai-provider appears to catch non-401 errors and incorrectly classify them as token issues.

Impact:

• Users spend significant time debugging authentication issues when the real problem is context overflow
• This also affects fix(provider): add OAuth token refresh support for GitLab provider #9949 (OAuth token refresh support) - if that PR lands, it would attempt to refresh tokens on context overflow errors, which would fail and still not surface the real problem

Expected behavior:

• 400 "prompt too long" errors should be reported as context overflow
• TOKEN_REFRESH_NEEDED should only be thrown for actual 401 authentication errors
• Ideally, suggest starting a new session or compacting context
  Environment:
• opencode version: 1.1.51
• Provider: gitlab/duo-chat-opus-4-5

Related: #9949, #9711

Plugins

@gitlab/opencode-gitlab-plugin

OpenCode version

1.1.51

Steps to reproduce

1. Configure opencode with GitLab Duo as the LLM provider
2. Start a session and have a long conversation (or use tools that return large outputs) until context approaches 200k tokens
3. Send another message
4. Observe GitLabError: TOKEN_REFRESH_NEEDED error instead of a context overflow message

Screenshot and/or share link

Operating System

Ubunut 24.04.3 LTS (Noble Numbat)

Terminal

xterm-256color (ZSH)