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Author	SHA1	Message	Date
Tejas Chopra	ad56dd382b	fix(router): compare token quantities in one unit (#2759) ... ## Description Two places compared a token quantity against something measured in a **different unit**. Both changed compression **behaviour**, not just reporting — which is the worse class. ### 1. The CONFIG branch put a word count in a token ratio `compressed_tokens = len(compressed.split())` was divided by `original_tokens`, which comes from `_estimate_tokens(content)`. Words run ~2.8× fewer than estimator tokens on config text, so a compressor that returned its input **byte-identically** scored ~0.36. `min_ratio` is 1.0 — accept any real shrink — so the router **accepted the no-op**: cached the result, pinned a frozen "compress" verdict, emitted a `router:config_compressor` label into `transforms_applied`, and recorded a fabricated saving to TOIN. ```text mkdocs.yml, compressor returns its input unchanged denominator (_estimate_tokens) = 936 OLD numerator len(split()) = 334 -> ratio 0.357 claims 64% saved ACCEPTED NEW numerator (_estimate_tokens) = 936 -> ratio 1.000 correctly rejected ``` The sibling TABULAR branch already used `_estimate_tokens`; CONFIG was the outlier. ### 2. The Kompress size gate tested a token cap in chars/4 `len(text_to_compress) > self._kompress_max_tokens * 4` under-counts anything denser than 4 chars/token, and compact JSON runs ~3.2. Against the 50,000-token default there is a band where an oversized payload passes: ```text records chars old_gate(len/4) new_gate(tokens) 2700 119,281 False False 4000 177,781 False True <- 44,445 vs 55,557 tokens, 11% over 4400 195,781 False True <- 48,945 vs 61,182 tokens, 22% over 5000 222,781 True True ``` Those payloads entered ONNX inference — exactly the >30s non-preemptible worker stall the gate exists to prevent (#1171). Closes # ## Type of Change - [x] Bug fix (non-breaking change that fixes an issue) ## Changes Made - `content_router.py` CONFIG branch — `compressed_tokens` now from `_estimate_tokens(compressed)`, matching its denominator and every sibling branch. - `content_router.py` Kompress gate — compared with `_estimate_tokens`, the unit the cap is actually expressed in. The extra O(n) char scan is negligible against the inference it guards. ## Testing - [x] Unit tests pass - [x] Linting passes (`ruff check` + `format --check`, pinned 0.15.17) - [x] New tests added - [x] Manual testing performed ### Test Output ```text $ pytest tests/test_content_router_token_units.py -q 4 passed in 0.33s $ uvx ruff@0.15.17 check headroom/transforms/content_router.py tests/test_content_router_token_units.py All checks passed! ``` **Regression check against clean `upstream/main` in the same environment:** ```text tests/test_transforms/ + test_transforms_content_router.py + kompress suites upstream/main : 2 failed, 468 passed, 78 skipped this branch : 2 failed, 468 passed, 78 skipped failure sets : identical ``` The 2 failures are `test_kompress_failsafe`'s artifact-selection tests, which need a real `onnxruntime` this throwaway env lacks. Unrelated to this change. The 4 new tests pin the unit contract *and* the bounds of the disagreement band — including the cases where both formulations agree, so the band is demonstrated rather than assumed. ## Real Behavior Proof - **Environment:** macOS 26.4 arm64, isolated worktree off `upstream/main`. `content_router` needs the compiled `headroom._core`, which isn't in a fresh worktree (gitignored, built in-place); I copied the built `.so` in to run these, then removed it before committing. - **Observed:** both tables above are from running the real `_estimate_tokens` against the real thresholds, not reconstructed arithmetic. - **Not tested:** no live ONNX inference — the >30s stall the gate prevents is cited from #1171, not reproduced. The CONFIG no-op was demonstrated at the ratio level rather than by driving a stubbed compressor through `apply()`. ## Review Readiness - [x] I have performed a self-review - [x] 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 - [x] My changes generate no new warnings - [x] I have added tests that prove my fix is effective - [x] I did **not** edit `CHANGELOG.md` ## Related Third of three PRs from one tokenizer-consistency audit — see #2757 (litellm total-prompt / `--budget`) and #2758 (HuggingFace chat templates, `gpt-5`, gateway-wrapped names). Separate subsystems, separate risk. Known remaining from the same audit, not in any of the three: `_netcost_message_tokens` pricing an image by Python `repr` (34× over-count, flag-gated), three transforms reporting via `count_text(str(content))` where the pipeline uses `count_messages` (19% apart in one log file), `frozen_message_count` walking a chars/3.5 estimate against provider-reported cached tokens, and `target_ratio` honoured in words while documented as tokens. 🤖 Generated with [Claude Code](https://claude.com/claude-code)	2026-08-03 22:49:47 -07:00