Claude Code may silently fall back from Opus 5 to Opus 4.8 on refusal
steipete · x · 2026-07-25
- A screenshot and repost claim that when Opus 5 hits a policy refusal in Claude Code, the server can silently re-run the same turn on Opus 4.8.
- The fallback is described as server-controlled, with no user-visible dialog if the server is in a “silent lane.”
- The image also says the retry is one-turn only, can cascade if 4.8 also refuses, and is tagged with x-cc-fallback- headers so backend systems can detect the fallback.
- The practical takeaway: an answer that appears to come from Opus 5 may have been generated behind the scenes by Opus 4.8, unless the user enables a visible-lane setting or watches for the x-is-refusal-fallback header.
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