Token refresh fails with 400 on initial prompt (Anthropic Max / Claude Opus 4.6)

[vitorpavani]

Description

After sending the initial prompt, the system occasionally returns:

Error: Token refresh failed: 400

A couple of seconds later, the request goes through successfully.

Environment

• Model: Claude Opus 4.6 (anthropic/claude-opus-4-6)
• Subscription: Anthropic Max
• Behavior: Intermittent — likely occurs when the auth token has expired and needs refreshing

Steps to Reproduce

1. Start a new OpenCode session with Claude Opus 4.6 via Anthropic Max
2. Send a prompt (particularly after the session has been idle / token has expired)
3. Observe Token refresh failed: 400 error
4. Wait ~2 seconds — the request then succeeds on retry

Expected Behavior

Token refresh should succeed silently without surfacing an error to the user.

Actual Behavior

When the token needs refreshing, the first refresh attempt fails with a 400 status. The automatic retry succeeds shortly after. This does not happen on every prompt — only when the system needs to refresh an expired token.

[github-actions]

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

• Claude subscription token expires after a period of time #6559: Same symptom — Claude subscription token expires after inactivity, first prompt fails with Token refresh failed: 400, then succeeds on retry (open)
• Daily "Error: Token refresh failed: 400" for Anthropic "Claude Pro/Max" subscription #14083: Same error Token refresh failed: 400 for Anthropic Claude Pro/Max subscription after hours of inactivity (closed)
• OAuth token expires after inactivity causing 'Token refresh failed: 400' #9111: OAuth token expires after inactivity causing Token refresh failed: 400 (closed)