scripts/codex_arm.py drives OpenAI Codex CLI end-to-end on the same
transcripts: chunk-file reads until its REAL auto-compaction fires (verified
via compacted events in the rollout jsonl; peak 455-483K vs its 258K
window), then quizzes post-compaction with the identical question banks and
judge. Results (results/codex-arm-2026-08-15/): codex 36.7% avg vs lean
closed-book 40.0% vs lean+recovery 68.3%. Codex has no runtime re-access
over its rollout history — the session_search differentiator, measured.
lean+recovery 68.3% avg recall @ 49K retained vs current 45.8% @ 162K —
+22.5pts at 0.30x tokens. Anchor index moved GUI needle-fact recall
23.3->60.0 closed-book, 46.7->80.0 with recovery.
- _build_anchor_index(): regex-harvests PR/issue numbers, SHAs, branches,
file paths, error strings, handles, URLs from the compacted region into a
bounded indexed summary section. LLM-free, so needle identifiers cannot be
paraphrased away (the GUI-lineage failure class: 10/15 verbatim-or-nothing
golds). Doubles as session_search query-anchor map.
- evals/compaction/test_region_scoping.py: sentinel tripwire proving the
summarizer input carries ONLY the compacted region (head/tail sentinels
never reach the serialized turns body) in both legacy and lean modes.
- _digest_worthy() drops no-signal tool rows before chunking (GUI-lineage
digests were starving on tool-noise)
- eval recovery sim now uses in-memory SQLite FTS5 + BM25 (production
session_search engine) instead of term-frequency scoring
- recovery query writer sees the digest section (front of context) so it can
mine anchor identifiers
Measures recall accuracy vs tokens retained across compaction policies.
Real transcripts in, LLM-generated recall exam from the summarized region,
per-policy answer+judge passes, scorecard out.