Sweep 19 Sep 2026 · 02:36Z Build v2.1.278 500 read Stable v2.1.267 Latest v2.1.278 Next v2.1.278 Feeds RSS JSON llms.txt Unofficial
Claude Code v2.1.271 ·

New model-capability quirk id: lucky_cerf

New per-model capability flag lucky_cerf added to the internal model quirks list

TierUnder the hoodhow much it should matter to you
Useful1my rating, 1 to 5
Signal1worth watching, 1 to 5
AreaModel Configwhat it touches
KindInternal Changesin v2.1.271,
Under the hood

New per-model capability flag lucky_cerf added to the internal model quirks list

What

A new entry, lucky_cerf, has been added to the list of per-model capability or behavior flags Claude Code tracks, alongside existing entries like refusal_fallback, thinking_display_updates, and quizzical_shore.

Why

This is an internal flag whose purpose is not described; it likely lets Claude Code adjust behavior for models that have this particular quirk.

How sure we are
Something disagreesSomething we can check disagrees with this entry, or the writer said they could not settle it.
The writer flagged doubtWhat `lucky_cerf` controls or which models it applies to is not stated.

See this entry in the whole of v2.1.271 →