The three fallback-capture keys (orient_failure, sweep_failure,
handoff_failure) were write-only dead state: captured on LLM-node failure
but interpolated nowhere, so end_failure rendered an empty STEP_FAILED
shell and write_handoff carried no trace a dead sweep.
- new crash-proof script node note_llm_fault distills orient/handoff
'LLM node...' failure text into fault_note (prefix-anchored; empty when
neither key holds a fault); orient and write_handoff fallbacks now route
through it before end_failure
- end_failure renders 'Pipeline fault (if any): {{fault_note}}' (sentinel
and all existing fields preserved; fault_note defaulted in initial_state)
- write_handoff prompt interpolates {{sweep_failure}} with a
PIPELINE-FAULT VISIBILITY instruction mirroring the review_report
treatment (fault -> Deviations entry + step_summary; success/empty
ignored)
- tests: note_llm_fault fault/clean/crash/truncation paths via the
GRAPH_STATE harness; wiring test pins the retargeted fallbacks,
note_llm_fault routing, {{fault_note}} in end_failure, and the
sweep-fault prompt/instruction anchors; warning baseline unchanged
