[Bug] Anthropic API Error: frontier_llm - Unauthorized Model Access for Claude Opus 5.5
Status Open
Reported on v2.1.289
Maintainer reply None cached
Activity 0 comments · opened Oct 3, 2026
Bug Description
My Claude Code account can no longer use Claude Opus 5.5, including in any newly created sessions. The error reports Details: [frontier_llm]. My use is legitimate software development and general coding, not training, distilling, reproducing, or extracting another frontier model. Please review whether this is an account-level false positive or an incorrect model-access restriction.
Environment Info
- Platform: darwin
- Terminal: iTerm.app
- Version: 2.1.289
- Feedback ID: 1faee6f4-db47-4e15-902e-f837558376c5