## Description
Close the passive-memory observability loop by recording access for
context rows that survive the final injection budget and tagging
requests where context is actually appended.
Closes#2211
## Type of Change
- [x] Bug fix (non-breaking change that fixes an issue)
- [ ] New feature (non-breaking change that adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality to change)
- [ ] Documentation update
- [ ] Performance improvement
- [ ] Code refactoring (no functional changes)
## Changes Made
- Track only memory IDs retained after ranking, similarity filtering,
entry limits, and final text truncation.
- Call optional backend `record_access` with stable de-duplication and
fail-open error handling.
- Extend structured injection logging to stamp `memory_injected=true`
when injected bytes are positive.
- Thread request tags through successful Anthropic, OpenAI Chat, OpenAI
Responses, Gemini, and Codex WebSocket injection sites.
- Add a static contract test that all current successful handler
injection logs pass tags.
## Testing
- [x] Unit tests pass (`pytest`)
- [x] Linting passes (`ruff check .`)
- [ ] Type checking passes (`mypy headroom`)
- [x] New tests added for new functionality
- [ ] Manual testing performed
### Test Output
```text
$ uv run --with pytest --with pytest-asyncio --with numpy --with fastapi pytest \
tests/test_memory_handler_native_ops.py \
tests/test_memory_auto_tail.py \
tests/test_memory_handler_project_isolation.py \
tests/test_memory_injection_logging.py -q
51 passed
$ uv run --with ruff ruff check <touched Python files>
All checks passed!
$ git diff --check
(no output)
```
## Real Behavior Proof
- Environment: Python 3.13 with synthetic backend and handler fixtures
- Exact command / steps: run the focused test set above
- Observed result: only IDs present after the final text budget are
access-recorded; access-write failures remain fail-open; positive
injection logs stamp `memory_injected=true`; all six current successful
injection call sites pass tags
- Not tested: live provider requests, full repository suite, third-party
backends without `record_access`
## Review Readiness
- [x] I have performed a self-review
- [ ] This PR is ready for human review
## Checklist
- [x] My code follows the project's style guidelines
- [x] I have performed a self-review of my code
- [x] I have commented my code, particularly in hard-to-understand areas
- [ ] I have made corresponding changes to the documentation
- [x] My changes generate no new warnings
- [x] I have added tests that prove my fix is effective or that my
feature works
- [x] New and existing unit tests pass locally with my changes
- [ ] I have updated the CHANGELOG.md if applicable
## Screenshots (if applicable)
N/A
## Additional Notes
Access accounting is intentionally best-effort: unsupported backends and
write failures do not delay or fail the upstream model request.
Documentation and changelog changes are not needed for this internal
observability fix.
Co-authored-by: JerrettDavis <mxjerrett@gmail.com>
