Defect Taxonomy — QUACKO V2

Every failure gets exactly one class. The class decides who fixes what — and what the failure gallery shows.

Classes

Class	Definition	Example	Fix owner
SUT-error	The web service misbehaves: wrong status code, schema violation, 5xx, crash, timeout handling	`POST /api/ocr` with a valid image returns 500; response missing `boxes`	app code
Model-error	The service is correct but Tesseract violates a hard gate: metamorphic relation beyond its locked tolerance, invariant broken, or CER regressed > 10% vs the committed baseline	M1 rotation field-CER 0.23 > 0.20; REG clean CER 0.25 > baseline 0.195 + 10%	engine/preprocessing decision (logged); baseline moves only via the re-baseline procedure (Quality Gates)
Env-delta	Same code + data, different environment (OS / Tesseract version / pipeline): REG red with provenance mismatch, no code change since the baseline commit	CI apt Tesseract 5.3.x vs baseline 5.5.0, clean CER drift on several receipts	re-baseline from CI artifacts under a logged order (Quality Gates §re-baseline procedure) — environment correction, not a burying event
Data-error	Ground truth vs image mismatch: the label itself is wrong for the real image	GT address line differs from what is visibly on the receipt	label correction with recorded reason (never "fix" the test)
Test-flake	Non-deterministic environment failure, not reproducible on rerun: port in use, transient network, browser crash	second run of the identical test passes	environment/CI config

Reproduce on the same machine + same commit (if it doesn't reproduce → suspect Test-flake; rerun twice before classifying).
Is the HTTP layer correct? (status, schema, headers) → if not: SUT-error.
Is the GT correct? Compare GT fields against the actual image content → if the label is wrong: Data-error (fix label, record reason in this doc's log below).
Otherwise it is a real model miss → Model-error; the failure gallery entry (input | degraded | GT | pred | defect class) is the artifact of record.