## Summary
- Lazy-import `create_app`/`run_server` in `headroom/proxy/__init__.py`
via PEP 562 `__getattr__` to prevent CLI crash when `fastapi` is not
installed (i.e., installed without `[proxy]` extras)
- Fix `.pre-commit-config.yaml` to use `python3` instead of `python`
(unavailable on macOS Homebrew)
- Add graceful `ImportError` skip in `scripts/sync-plugin-versions.py`
for environments without dev dependencies
Fixes#441
## Test plan
- [x] `headroom --help` works without `[proxy]` extras installed
- [x] `headroom proxy --help` works with `[proxy]` extras installed
- [x] `headroom proxy --port 18787` starts and serves traffic
- [x] Lazy imports resolve correctly: `from headroom.proxy import
create_app, run_server`
- [x] `AttributeError` raised for invalid attributes on `headroom.proxy`
- [x] Pre-commit hooks pass (ruff, ruff-format, mypy,
sync-plugin-versions)
🤖 Generated with [Claude Code](https://claude.com/claude-code)
---------
Co-authored-by: Claude Code Bot <claude-code@smartwatermelon.github>
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
Three independent contract-pattern follow-ons bundled into one PR.
Same frozen-dataclass + factory + apply_to_tags + Rust-portable
shape that PR #473 / #477 / #483 established.
## (1) MemoryRanker + RecencyBoostRanker
Pre-this-PR Headroom ranked memory candidates by pure cosine
similarity. Every other memory system we surveyed (Letta, Mem0,
Cognee, Supermemory) re-ranks beyond cosine.
* ``MemoryRanker`` Protocol — pluggable re-ranker; future PRs add
source-weight + access-count rankers behind the same interface.
* ``RecencyBoostRanker`` — first concrete impl. Final score is
``cosine × exp(-age_days / decay_days)``. Default decay 30 days
(half-life ~21 days; 60-day-old factor 0.135, 90-day-old 0.050).
* ``MemoryCandidate`` — backend-agnostic frozen value type that
flows through the ranker. ``MemoryCandidate.from_backend_result``
adapter converts the existing ``MemoryResult`` shape (with nested
``memory.created_at``) into the ranker's flatter form.
* Wired into ``memory_handler.search_and_format_context`` as an
optional ``ranker=`` kwarg — backwards-compat: ``None`` (default)
preserves the pure-cosine path identically.
Defensive:
* ``created_at=None`` → factor 1.0 (recency-neutral, back-compat with
legacy rows / migrating backends)
* Negative age (clock skew) → clamped to factor 1.0 (a future-dated
row can't outrank a real fresh memory)
* Sort is stable on ties — same input → same output every turn, so
consecutive turns inject memories in the same order (prefix-cache
friendly)
Performance: O(N) over candidates where N=top_k≈10. One ``math.exp``
per candidate. Sub-microsecond. Zero new I/O.
## (2) ImageCompressionDecision
Mirror of :class:`CompressionDecision` for image compression. Two
sites today (``openai.py:1203``, ``anthropic.py:868``) gate inline;
both already respect bypass (no Gemini-class drift bug like text
compression had), but consolidating into a value type:
* Locks bypass-respect via AST contract test — future sites can't
drift on it
* Surfaces ``image_skip_reason`` in ``RequestOutcome.tags`` for
dashboard slicing (same observability surface as
``passthrough_reason`` and ``memory_skip_reason``)
* Same Rust-port shape as the other decision types
Precedence: ``bypass_header`` > ``image_optimize_disabled`` >
``no_messages`` > ``should_compress=True``.
Anthropic's extra ``is_cache_mode`` check stays inline because it's
Anthropic-specific (openai/gemini don't have it). Documented in a
code comment.
## (3) Branch-aware sync-plugin-versions hook
Pre-this-fix the pre-commit ``sync-plugin-versions`` hook ran on
every commit and bumped manifests to the predicted-next-release
version. Every PR ended up carrying the prediction as collateral
("Why are we bumping ``.claude-plugin/marketplace.json`` — we
should not, right??" - user, on PR #483).
Fix: the hook is now a NO-OP unless EITHER:
* We're on the ``main`` branch, OR
* ``HEADROOM_SYNC_VERSIONS=1`` is set explicitly (release workflow)
On feature branches the hook prints a single line explaining the
skip and exits cleanly. The release workflow opts in via the env
var; behaviour on main / at release time is unchanged.
## Test coverage
* 16 new tests on ``MemoryRanker`` / ``RecencyBoostRanker``
(frozen, equal cosine wins by recency, decay configurable, NULL
timestamp neutral, no-mutation contract, Rust-port shape)
* 17 new tests on ``ImageCompressionDecision`` (frozen, all 3
skip reasons, precedence, observability fields, apply_to_tags)
* 1 new AST invariant test (extends
``test_handler_outcome_tag_invariant.py``) — locks "no raw
``if self.config.image_optimize and messages and not _bypass:``
conjunction in any handler"
All existing memory + cache-stability + handler tests pass (203 ✓).
``make ci-precheck`` clean.
## Rust portability
All three new value types port cleanly to frozen Rust structs +
pure functions. Same migration pattern as ``CompressionDecision``
(already locked in for the SmartCrusher Rust port).
## Zero-regression contract
* Default ``ranker=None`` → memory_handler behaves identically to
pre-this-PR (pure cosine; no perf change)
* Image decision migration is identity at the bypass/optimize/messages
gate — no behaviour change, just contract consolidation
* Hook fix is no-op on feature branches (less churn) and unchanged
on main (release flow preserved)
`.gitattributes` declares `*.py text eol=lf` and `*.sh text eol=lf`, but
74 files (73 .py, 1 .sh) are stored in the index with CRLF line endings,
violating that contract. Every macOS/Linux clone reports these files as
"modified" on fresh checkout because git's diff engine sees the stored
bytes don't match the attribute contract, even though the working tree
and index match byte-for-byte.
Running `git add --renormalize .` rewrites each affected blob so the
stored form matches the attribute declaration. No semantic changes —
every affected file's diff is "N insertions, N deletions" with inserts
and deletes being the same lines modulo line endings.
Follow-up commit adds `.git-blame-ignore-revs` so `git blame` / GitHub
blame skip this mechanical commit.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
