Refusal Fallback Tracking / Claude Code v2.1.202

Refusal-continuation retries are now tracked explicitly with a refusalFallbackOccurred flag in session state, allowing downstream code to distinguish sessions where a silent retry occurred.

Details

refusalFallbackOccurred is a boolean in session state initialized to false; it is set to true (Hdr()) only when a silent (non-interactive, ni = true) refusal fallback fires — visible-to-user fallbacks do not set it
When the flag is true and the convolute_arcades GrowthBook feature flag is also active, the HTTP header x-is-refusal-fallback: true is attached to every subsequent Anthropic API request in that query, signalling to the backend that a retry is in progress
The flag is reset to false per-query by XHn(), and is also cleared on session transitions: both SHn() (new session UUID) and pA() (session switch) reset it, ensuring it does not bleed across tasks
During conversation rewind, kCe() is read as latchActive to determine whether the refusalFallbackModelLatch should be cleared and the original model restored; this prevents rewinding past a fallback from leaving the model permanently switched
The refusal_continuation QueryEvent now brackets the retry window with phase: "begin" (carrying salvageText to preserve any partial streamed text visible in the UI) and phase: "end"; the SDK schema describes it as "@internal Emitted when a silent refusal-continuation retry begins … or ends"
The internal QueryEvent 'refusal_continuation' description was updated from "window begins" to "retry begins" to more accurately reflect the mechanism
Session state gains refusalFallbackOccurred: false at initialization, reset per-query via XHn()

Evidence

Refusal fallback state (search for "refusalFallbackOccurred", "x-is-refusal-fallback", and "convolute_arcades")

Strings lifted out of the shipped bundle, so the claim above can be checked against them.