Commits the 2026-05-19 probe as a durable, replayable eval lane.
This is *step 1* of the gloss-feature rollout sequence agreed
upstream: establish a stable measurement substrate before any
further intent/grounding changes, so the 52%→0% lift (and any
future regression) is reproducible and CI-pinned.
The lane is deliberately named ``cold_start_grounding`` rather than
``fluency``:
- It measures **routing** (intent → grounding source), not
sentence quality, morphology, or surface diversity.
- The cold-start qualifier reflects the fresh-``ChatRuntime()``-
per-case design. Re-using a runtime across cases would
contaminate the vault from earlier turns and was the exact bug
observed during the probe before the per-case-runtime fix.
Files:
evals/cold_start_grounding/contract.md
Lane contract: what is measured, scoring rubric, pass thresholds
(intent ≥ 0.95 / grounding ≥ 0.95 / subject ≥ 0.90), and the
rationale for the deliberate non-fallback on CAUSE/VERIFICATION
without teaching chains.
evals/cold_start_grounding/public/v1/cases.jsonl
44 cases across 16 categories. Each case carries id, prompt,
category, expected_intent, expected_grounding_source, and an
optional expected_subject. Categories cover every intent
pattern fixed in b52e04a (Define, What-does-X-mean, infinitive,
How-does-X-work, What-causes-X) plus OOV controls and CAUSE
cases with/without teaching chains.
evals/cold_start_grounding/dev/cases.jsonl
5 representative cases for fast local iteration.
evals/cold_start_grounding/runner.py
Framework-compliant ``run_lane(cases, config=None) -> LaneReport``.
Constructs a fresh ChatRuntime() inside ``_run_case`` (cold-start
invariant). Emits intent_accuracy, grounding_accuracy,
subject_accuracy, full grounding distributions, and a per-
category breakdown for regression attribution.
tests/test_cold_start_grounding_lane.py
16 contract tests covering: case-set integrity, valid enum
values, unique ids, lane discovery, pass thresholds, expected-
vs-actual distribution match (drift detection), the architectural
invariants on oov_control and cause_no_teaching_chain cases, the
cold-start invariant (static check that the runner constructs
ChatRuntime() inside the per-case helper, not at module scope),
and result JSON-serialization round-trip.
Baseline metrics (this commit, all v1 public cases):
intent_accuracy: 1.0000 (44/44)
grounding_accuracy: 1.0000 (44/44)
subject_accuracy: 1.0000 (44/44)
grounding distribution (actual == expected exactly):
pack: 37
oov: 4
teaching: 1
none: 2 (deliberate — CAUSE without teaching chain)
Why "none" cases are *expected* to ground as none:
CAUSE / VERIFICATION on a pack-resident lemma WITHOUT an active
teaching chain stays grounding_source='none' on purpose. Falling
through to pack_grounded_surface here would mask the discovery-
candidate signal the teaching pipeline uses to identify chains
worth authoring. The contract test in
TestArchitecturalInvariants::test_cause_no_chain_cases_route_to_none
pins this doctrine.
Verification: 16/16 lane tests green; full lane run via
``core eval cold_start_grounding`` reports 100% on every metric.
Subsequent steps in the agreed sequence (NOT in this commit):
2. Hygiene: runtime API wrappers (achat/arespond/respond) + the
stale CAUSE/VERIFICATION docstring in
tests/test_intent_classification_extensions.py.
3. Harden gloss resolver in feat/pack-glosses-wip
(lexicon-residency check, dual checksum, cache clearing,
malformed-JSONL skip tests).
4. Wire gloss-backed pack_grounded_surface().
5. Author starter glosses with checksum discipline.
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