Decode only Retry's HTTP 400 error field for the existing banner. Preserve raw model/key refusal envelopes and other submission-error handling.
Verified on the accepted-main integration: 2424 full-suite tests, typecheck, full ESLint, production build and isolated synthetic production-browser Retry/Submit smoke. No real provider calls.
Keep failed attempts in the saved transcript and omit only trailing failures from Retry's temporary agent history. Use the matching temporary prefix length when persisting genuinely new output.
Preserve the error notice across plan/compaction markers, refuse Retry after later compaction, and avoid synthesizing results for tool calls inside failed generations while retaining Pi's native filtering.
Verified: 173 focused Retry/session/compaction-projection/practice-record tests, typecheck, changed-file lint, and diff --check. No app launch or real provider calls.
amosblomqvist