S03.2 — Persist and reload the baseline artifact with parity

Migration identity#

• Canonical identifier: S03.2 (GitHub issue type: subtask).
• Legacy identifier: C03.2 (retained as old_identifier).
• Parent epic: E03.
• Milestone: M1 — IntentGuard Weekend MVP.

Objective#

Save the fitted baseline and required provenance as a versioned local artifact and verify reload prediction parity.

Rationale#

Evaluation must compare a fixed baseline rather than refit or silently change it.

Parent identifier#

E03.

Source task#

T-003.

Traceability#

Primary ownership is task-local under U03; supports FR-002, NFR-008, and AC-002.

Prerequisites#

C03.1 fitted pipeline and stable artifact schema.

Likely files#

src/intentguard/artifacts.py, src/intentguard/baseline.py, tests/unit/test_artifacts.py, artifacts/README.md.

Implementation boundary#

Baseline serialization and immutable metadata only; transformer artifact behavior stays in U04.

MUST scope#

Pipeline, label map, configuration, dataset fingerprint, dependency versions, checksums, and reload parity.

Explicit non-goals#

Remote registry, mutable latest pointer as evidence, MLflow, or model serving.

Acceptance criteria#

The artifact has a unique ID, refuses incomplete metadata, reloads without fitting, and matches reference labels/probabilities within declared tolerance.

Validation commands#

uv run pytest tests/unit/test_artifacts.py tests/unit/test_baseline.py -q.

Expected evidence#

Artifact manifest/checksums and reference prediction parity output.

Fallback and status consequence#

In-memory-only baseline is Partial and cannot support strict comparison evidence.

Stop condition#

Stop for reload divergence, mutable completed artifact, missing provenance, or unsafe serialization assumptions.

Definition of ready#

C03.1 is stable and the local artifact schema is reviewed.

Definition of done#

A completed immutable baseline artifact passes reload parity.

Labels#

type:subtask, priority:MUST, area:baseline

Estimate#

0.75 hour.