fix(accuracy): stabilize phase 4 evidence fingerprint

backend/tests/test_accuracy_phase4_evaluation.py

@@ -35,6 +35,7 @@ from run_accuracy_phase4_benchmark import (  # noqa: E402
     active_model_availability_gate,
     build_release_gate_report,
     canonical_golden_baseline,
+    readiness_snapshot,
     firewall_contract_checks,
     product_baseline_manifest_gate,
     product_gate_evidence,
@@ -1181,12 +1182,76 @@ def test_one_workflow_is_byte_reproducible_complete_and_fail_closed(
     )
     assert input_manifest["product_baseline"]["validation_status"] == "not_evaluable"
     assert input_manifest["product_baseline"]["artifacts"] == []
+    assert "docs/accuracy-program/status.json" not in {
+        item["path"] for item in input_manifest["inputs"]
+    }
+    assert input_manifest["readiness_snapshot"]["source_paths"][
+        "accuracy_status_projection"
+    ]["selected_json_pointers"] == ["/runtime/active_model"]
     assert benchmark_manifest["product_baseline"] == input_manifest["product_baseline"]
     assert (
         benchmark_manifest["product_gate_evidence_sha256"]
         == first["product_gate_evidence_sha256"]
     )
-    assert first["evidence_run_id"].startswith("p4-2.0.0-")
+    assert first["evidence_run_id"].startswith("p4-2.0.1-")
+
+
+def test_readiness_snapshot_ignores_phase4_bookkeeping_but_binds_active_model(
+    tmp_path: Path,
+) -> None:
+    status_path = tmp_path / "docs/accuracy-program/status.json"
+    scan_path = tmp_path / "artifacts/evidence/accuracy/P3/full-scan-manifest.json"
+    leakage_path = tmp_path / "artifacts/evidence/accuracy/P3/leakage-report.json"
+    status_path.parent.mkdir(parents=True)
+    scan_path.parent.mkdir(parents=True)
+    status = {
+        "generated_at": "2026-08-02T00:00:00+02:00",
+        "documents": ["old.md"],
+        "phase5": {"status": "not_ready"},
+        "verification": {"phase4_evaluation": {"status": "pending"}},
+        "phase4": {"status": "ready"},
+        "runtime": {
+            "active_model": {
+                "model_id": "model-a",
+                "path": "/models/a.pt",
+                "sha256": "a" * 64,
+            }
+        },
+    }
+    status_path.write_text(json.dumps(status), encoding="utf-8")
+    scan_path.write_text(
+        json.dumps({"scan_id": "scan-a", "content_hash": "b" * 64}),
+        encoding="utf-8",
+    )
+    leakage_path.write_text(json.dumps({"status": "attention"}), encoding="utf-8")
+
+    original = readiness_snapshot(tmp_path)
+    status["phase4"] = {"status": "in_progress", "evidence_run_id": "run-a"}
+    status["generated_at"] = "2026-08-02T05:00:00+02:00"
+    status["documents"] = ["old.md", "new.md"]
+    status["phase5"] = {"status": "blocked"}
+    status["verification"] = {"phase4_evaluation": {"status": "local_pass"}}
+    status_path.write_text(json.dumps(status), encoding="utf-8")
+    bookkeeping_update = readiness_snapshot(tmp_path)
+
+    assert bookkeeping_update == original
+    assert "accuracy_status" not in original["source_paths"]
+    assert original["source_paths"]["accuracy_status_projection"][
+        "selected_json_pointers"
+    ] == ["/runtime/active_model"]
+
+    status["runtime"]["active_model"]["sha256"] = "c" * 64
+    status_path.write_text(json.dumps(status), encoding="utf-8")
+    assert readiness_snapshot(tmp_path) != original
+
+    assert original["source_paths"]["accuracy_status_projection"][
+        "sha256"
+    ] == canonical_hash(
+        {
+            "schema_version": 1,
+            "runtime": {"active_model": original["active_model"]},
+        }
+    )
 
 
 def test_immutable_workflow_refuses_to_replace_changed_evidence(tmp_path: Path) -> None: