Add a framework mechanism for prepared modules and validators to contribute checkpoint identity fingerprints

internal/modules/dnd/extract/spells/extractor.go

@@ -43,6 +43,7 @@ func referenceSlots() []contracts.ReferenceSlot {
 }
 
 var _ contracts.Extractor[dnd.SpellList] = (*Extractor)(nil)
+var _ pipeline.CheckpointFingerprintProvider = (*Extractor)(nil)
 
 type Options struct{}
 
@@ -109,6 +110,13 @@ func (e *Extractor) ManifestMetadata() map[string]any {
 	return metadata
 }
 
+func (e *Extractor) CheckpointFingerprints() []pipeline.CheckpointFingerprint {
+	if e == nil {
+		return nil
+	}
+	return []pipeline.CheckpointFingerprint{{Name: "effective_catalog", Value: e.effectiveCatalog.Digest()}}
+}
+
 func (e *Extractor) Extract(ctx context.Context, req contracts.TypedExtractionRequest) (contracts.TypedExtractionResult[dnd.SpellList], error) {
 	if e == nil {
 		return contracts.TypedExtractionResult[dnd.SpellList]{}, extractorErrorf("extractor must not be nil")

internal/modules/dnd/extract/spells/extractor_test.go

@@ -117,6 +117,10 @@ func TestExtractPromptUsesCanonicalOverlayNamesWithoutAliasesOrMetadata(t *testi
 	if got, ok := metadata["catalog_overlay_ids"].([]string); !ok || !reflect.DeepEqual(got, []string{"campaign.example"}) {
 		t.Fatalf("catalog overlay metadata = %#v", metadata["catalog_overlay_ids"])
 	}
+	fingerprints := newExtractor(t, &fakeSpellsLLMClient{}, overlaySpellCatalogReference()).CheckpointFingerprints()
+	if len(fingerprints) != 1 || fingerprints[0].Name != "effective_catalog" || fingerprints[0].Value != metadata["catalog_digest"] {
+		t.Fatalf("checkpoint fingerprints = %#v, want manifest catalog digest %#v", fingerprints, metadata["catalog_digest"])
+	}
 	encoded, err := json.Marshal(metadata)
 	if err != nil {
 		t.Fatal(err)