## Description
Fixes#899. The `reread` signal (#853/#854) counts re-served tool
results but cannot answer the question that motivated it: **did Headroom
cause the re-read?** A re-read after an intact first serve is agent
behavior; a re-read after Headroom markerized the first serve is
over-compression cost. This PR splits the signal so the actionable part
is visible.
Request-local, no store lookups: the client resends full history each
turn and the pipeline recompresses it deterministically, so the current
request already holds the evidence. `TransformPipeline.apply` passes
`current_messages` into `parse_messages(compressed_messages=...)`. For
each counted reread group, if the transformed copy of the **first
serve** carries a CCR retrieval marker and its original text is gone,
the group's counted repeats go into `reread_compressed_tokens`. Lossless
reshaping (no marker) is deliberately not attributed.
Closes#899.
## Type of Change
- [x] New feature (non-breaking change that adds functionality)
## Changes Made
- `parser.py`: `parse_messages` gains an optional `compressed_messages`
param; the content-hash reread loop accumulates per-group
`counted_tokens` and attributes them to `reread_compressed_tokens` when
the first serve's transformed copy carries a CCR marker
(`CCR_RETRIEVAL_MARKER_RE`, kept local to avoid a transforms import
cycle).
- `transforms/pipeline.py`: pass `current_messages` (post-transform
copy) into the existing waste-detection `parse_messages` call.
- `config.py`: new `reread_compressed_tokens` WasteSignals field;
`dashboard.html` + `reporting/generator.py` surface it.
- Tests: `tests/test_reread_attribution.py` + WasteSignals contract
update.
## Testing
- [x] Unit tests pass (`pytest`)
- [x] Linting passes (`ruff check .`)
- [x] New tests added for new functionality
- [x] New and existing unit tests pass locally with my changes
### Test Output
```text
$ pytest tests/test_reread_attribution.py tests/test_parser.py tests/test_gemini_function_response_waste.py tests/test_codex_responses_waste_signals.py -q
122 passed in 1.50s
$ pytest tests/ -k "waste or pipeline or reporting or config or reread" -q
348 passed, 33 skipped, 6010 deselected
# (1 unrelated env-dependent failure: test_proxy_gemini_native_integration::test_generation_config — 404, reproduces on main without these changes; needs a Gemini key locally)
$ ruff check headroom/parser.py headroom/transforms/pipeline.py
All checks passed!
```
## Real Behavior Proof
- Environment: local macOS, repo .venv, Python 3.11.9
- Exact command / steps: rebased onto current main to resolve conflicts
with #909 (merged), then ran the reread + parser + waste suites above
- Observed result: a reread whose first serve is markerized attributes
to `reread_compressed_tokens`; an intact first serve and a lossless
(no-marker) reshape do not. #909's re-issued-call detection (same call,
different bytes) continues to count and dedup correctly alongside it —
all 122 targeted tests pass.
- Not tested: live proxy traffic; the one gemini-native route test above
(environmental 404, not introduced here).
## Review Readiness
- [x] I have performed a self-review
- [x] This PR is ready for human review
## Additional Notes
**Rebased onto current main after #909 merged.** #909 added a
re-issued-call reread pass *after* the original content-hash loop this
PR modifies — the conflict was textual/adjacent, not a re-architecture.
Resolution preserves #909's `counted_results` dedup contract and leaves
its new pass unchanged; #901's attribution stays scoped to the
content-hash groups it was reviewed against (attributing #909's call-key
pass too would be a separate follow-up). The diff differs from the prior
approval only by this reshape — worth a quick re-glance.
