Benchmark Methodology

Benchmark methodology

Authority: docs/harness/ARCHAEOLOGY.md (the benchmark rows), benchmarks/METHODOLOGY.md, benchmarks/REPRODUCING.md, CLAUDE.md Practice 4, docs/harness/FINDINGS.md F-10, F-13, F-17.

Rules, each a pointer, none restated:

1. Never hand-type a number. Every figure comes from a run in THIS session or the CI-captured artifact benchmarks/jcm_reference.json (Practice 4). The comparators read that file; there is no estimator.
2. Per row, never per total (F-13): the total hid one cause behind another. Diff threshold ids one by one.
3. Five mirrors move together (Practice 4): results.md, METHODOLOGY.md, README, provenance/measured.json, REPRODUCING.md; tests/test_provenance.py is the gate and --reference rewrites them.
4. The reference is captured where the gate runs (F-13): benchmark.yml dispatch with reference=true; a dev-box number differs by CRLF, walk order and a HOME ledger (F-17).
5. Deterministic configuration is the bench tier itself: --offline, pinned corpora (benchmarks/tasks.json), the no-network fixture. Add no flags.
6. A refusal is not a zero: an absent value prints n/a.
7. Floors live only in harness/thresholds.json; read one with uv run python -m harness threshold <id>.
8. benchmarks/schema_baseline.json is the only source for schema-token figures (CLAUDE.md "Tier-switch pricing"); the harness counts a different payload and the two never agree digit for digit.