Add D&D scene description validation

internal/modules/dnd/validate/scenedescriptions/invariants/validator.go

@@ -0,0 +1,119 @@
+// Package invariants validates normalized D&D scene description artifacts.
+package invariants
+
+import (
+	"context"
+	"fmt"
+	"sort"
+
+	"gitea.maximumdirect.net/eric/notarius/internal/core/source"
+	"gitea.maximumdirect.net/eric/notarius/internal/framework/contracts"
+	"gitea.maximumdirect.net/eric/notarius/internal/framework/pipeline"
+	"gitea.maximumdirect.net/eric/notarius/internal/modules/dnd"
+	"gitea.maximumdirect.net/eric/notarius/internal/modules/dnd/shared/diagnostics"
+	"gitea.maximumdirect.net/eric/notarius/internal/modules/dnd/validate/scenedescriptions/shape"
+)
+
+const (
+	Key        = "normalize/dnd/scene-descriptions/invariants"
+	ReasonCode = "invalid_scene_description_normalization"
+	policy     = "dnd.scene_descriptions.validator.invariants.v1"
+)
+
+type Options struct{}
+type Validator struct{}
+
+var _ contracts.TypedValidator[dnd.SceneDescriptionList] = (*Validator)(nil)
+var _ pipeline.CheckpointFingerprintProvider = (*Validator)(nil)
+
+func New(Options) *Validator      { return &Validator{} }
+func (v *Validator) Name() string { return Key }
+func (v *Validator) ExecutionClass() contracts.ExecutionClass {
+	return contracts.ExecutionClassDeterministic
+}
+func (v *Validator) CheckpointFingerprints() []pipeline.CheckpointFingerprint {
+	return []pipeline.CheckpointFingerprint{{Name: "policy", Value: policy}}
+}
+
+func (v *Validator) Validate(_ context.Context, req contracts.TypedValidationRequest[dnd.SceneDescriptionList]) (contracts.ValidationResult, error) {
+	if shape.Validate(req.Value) != nil || !sourceRefsValid(req.Source, req.Value) {
+		return contracts.ValidationResult{Approved: true}, nil
+	}
+	issues := issuesFor(req.Source, req.Value)
+	if len(issues) == 0 {
+		return contracts.ValidationResult{Approved: true}, nil
+	}
+	return contracts.ValidationResult{
+		Approved: false, ReasonCode: ReasonCode,
+		Message: diagnostics.Aggregate("invalid scene description normalization", issues),
+	}, nil
+}
+
+func sourceRefsValid(doc *source.SourceDocument, value dnd.SceneDescriptionList) bool {
+	for _, scene := range value.Scenes {
+		if source.ValidateRef(doc, scene.SourceRef) != nil {
+			return false
+		}
+	}
+	return true
+}
+
+func issuesFor(doc *source.SourceDocument, value dnd.SceneDescriptionList) []string {
+	issues := make([]string, 0)
+	if !sort.SliceIsSorted(value.Scenes, func(left, right int) bool {
+		leftStart, _ := source.UnitIndex(doc, value.Scenes[left].SourceRef.StartUnitID)
+		rightStart, _ := source.UnitIndex(doc, value.Scenes[right].SourceRef.StartUnitID)
+		if leftStart != rightStart {
+			return leftStart < rightStart
+		}
+		return value.Scenes[left].ID < value.Scenes[right].ID
+	}) {
+		issues = append(issues, "scenes are not in canonical source order")
+	}
+
+	byID := make(map[string]int, len(value.Scenes))
+	byRange := make(map[source.SourceRef]int, len(value.Scenes))
+	for index, scene := range value.Scenes {
+		if index > 0 && value.Scenes[index-1] == scene {
+			issues = append(issues, fmt.Sprintf("scenes[%d] duplicates scenes[%d]", index, index-1))
+		}
+		if previous, ok := byID[scene.ID]; ok && value.Scenes[previous] != scene {
+			issues = append(issues, fmt.Sprintf("scenes[%d] conflicts with scenes[%d] for scene ID", index, previous))
+		} else if !ok {
+			byID[scene.ID] = index
+		}
+		if previous, ok := byRange[scene.SourceRef]; ok && !sameModelContent(value.Scenes[previous], scene) {
+			issues = append(issues, fmt.Sprintf("scenes[%d] conflicts with scenes[%d] for source range", index, previous))
+		} else if !ok {
+			byRange[scene.SourceRef] = index
+		}
+	}
+	return issues
+}
+
+func sameModelContent(left, right dnd.SceneDescription) bool {
+	return left.Kind == right.Kind && left.Title == right.Title && left.Summary == right.Summary
+}
+
+func Spec() pipeline.ValidatorSpec {
+	return pipeline.ValidatorSpec{Key: Key, ExecutionClass: contracts.ExecutionClassDeterministic}
+}
+
+func Register(registry *pipeline.ValidatorRegistry) error {
+	return pipeline.RegisterTypedValidatorBuilder(registry, dnd.SceneDescriptionListKind, Spec(), validateOptions, func(request pipeline.BuildRequest) (contracts.TypedValidator[dnd.SceneDescriptionList], error) {
+		options, err := DecodeOptions(request.Options)
+		if err != nil {
+			return nil, err
+		}
+		return New(options), nil
+	})
+}
+
+func DecodeOptions(options map[string]any) (Options, error) {
+	if err := pipeline.RejectUnknownOptions(options); err != nil {
+		return Options{}, err
+	}
+	return Options{}, nil
+}
+
+func validateOptions(options map[string]any) error { _, err := DecodeOptions(options); return err }

internal/modules/dnd/validate/scenedescriptions/invariants/validator_test.go

@@ -0,0 +1,69 @@
+package invariants
+
+import (
+	"context"
+	"reflect"
+	"testing"
+
+	"gitea.maximumdirect.net/eric/notarius/internal/core/source"
+	"gitea.maximumdirect.net/eric/notarius/internal/framework/contracts"
+	"gitea.maximumdirect.net/eric/notarius/internal/framework/pipeline"
+	"gitea.maximumdirect.net/eric/notarius/internal/modules/dnd"
+)
+
+func TestValidatorEnforcesOrderDuplicatesAndConflicts(t *testing.T) {
+	doc := document()
+	first := scene("first", 1, dnd.SceneKindNarrative, "Arrival", "The party arrives.")
+	second := scene("second", 2, dnd.SceneKindCombat, "Ambush", "Bandits attack.")
+	validator := New(Options{})
+	for _, test := range []struct {
+		name     string
+		value    dnd.SceneDescriptionList
+		approved bool
+	}{
+		{name: "normalized", value: dnd.SceneDescriptionList{Scenes: []dnd.SceneDescription{first, second}}, approved: true},
+		{name: "out of order", value: dnd.SceneDescriptionList{Scenes: []dnd.SceneDescription{second, first}}},
+		{name: "exact duplicate", value: dnd.SceneDescriptionList{Scenes: []dnd.SceneDescription{first, first}}},
+		{name: "same ID conflict", value: dnd.SceneDescriptionList{Scenes: []dnd.SceneDescription{first, scene("first", 2, dnd.SceneKindCombat, "Ambush", "Bandits attack.")}}},
+		{name: "same range conflict", value: dnd.SceneDescriptionList{Scenes: []dnd.SceneDescription{first, scene("other", 1, dnd.SceneKindMeta, "Rules", "The table checks rules.")}}},
+		{name: "same range same content different ID", value: dnd.SceneDescriptionList{Scenes: []dnd.SceneDescription{scene("a", 1, dnd.SceneKindNarrative, "Arrival", "The party arrives."), scene("b", 1, dnd.SceneKindNarrative, "Arrival", "The party arrives.")}}, approved: true},
+	} {
+		t.Run(test.name, func(t *testing.T) {
+			result, err := validator.Validate(context.Background(), contracts.TypedValidationRequest[dnd.SceneDescriptionList]{Source: doc, Value: test.value})
+			if err != nil || result.Approved != test.approved {
+				t.Fatalf("Validate() = %#v, %v; want approved=%t", result, err, test.approved)
+			}
+		})
+	}
+}
+
+func TestValidatorDefersOwnedFailuresAndRegistersPolicy(t *testing.T) {
+	doc := document()
+	result, err := New(Options{}).Validate(context.Background(), contracts.TypedValidationRequest[dnd.SceneDescriptionList]{Source: doc, Value: dnd.SceneDescriptionList{}})
+	if err != nil || !result.Approved {
+		t.Fatalf("Validate() = %#v, %v; want shape deferral", result, err)
+	}
+	invalidRef := dnd.SceneDescriptionList{Scenes: []dnd.SceneDescription{scene("one", 9, dnd.SceneKindNarrative, "Arrival", "The party arrives.")}}
+	result, err = New(Options{}).Validate(context.Background(), contracts.TypedValidationRequest[dnd.SceneDescriptionList]{Source: doc, Value: invalidRef})
+	if err != nil || !result.Approved {
+		t.Fatalf("Validate() = %#v, %v; want source-reference deferral", result, err)
+	}
+	registry := pipeline.NewValidatorRegistry()
+	if err := Register(registry); err != nil {
+		t.Fatal(err)
+	}
+	if _, ok := registry.Spec(Key); !ok {
+		t.Fatalf("registry missing %q", Key)
+	}
+	if got, want := New(Options{}).CheckpointFingerprints(), []pipeline.CheckpointFingerprint{{Name: "policy", Value: policy}}; !reflect.DeepEqual(got, want) {
+		t.Fatalf("fingerprints = %#v, want %#v", got, want)
+	}
+}
+
+func document() *source.SourceDocument {
+	return &source.SourceDocument{ID: "session", Units: []source.SourceUnit{{ID: 1, Text: "The party arrives."}, {ID: 2, Text: "Bandits attack."}}}
+}
+
+func scene(id string, unit int, kind dnd.SceneKind, title, summary string) dnd.SceneDescription {
+	return dnd.SceneDescription{ID: id, SourceRef: source.SourceRef{SourceID: "session", StartUnitID: unit, EndUnitID: unit}, Kind: kind, Title: title, Summary: summary}
+}

internal/modules/dnd/validate/scenedescriptions/shape/validator.go

@@ -0,0 +1,112 @@
+// Package shape validates required D&D scene description fields.
+package shape
+
+import (
+	"context"
+	"fmt"
+	"strings"
+
+	"gitea.maximumdirect.net/eric/notarius/internal/framework/contracts"
+	"gitea.maximumdirect.net/eric/notarius/internal/framework/pipeline"
+	"gitea.maximumdirect.net/eric/notarius/internal/modules/dnd"
+	"gitea.maximumdirect.net/eric/notarius/internal/modules/dnd/shared/diagnostics"
+)
+
+const (
+	Key        = "extract/dnd/scene-descriptions/shape"
+	ReasonCode = "invalid_scene_description_shape"
+	policy     = "dnd.scene_descriptions.validator.shape.v1"
+)
+
+type Options struct{}
+type Validator struct{}
+
+var _ contracts.TypedValidator[dnd.SceneDescriptionList] = (*Validator)(nil)
+var _ pipeline.CheckpointFingerprintProvider = (*Validator)(nil)
+
+func New(Options) *Validator      { return &Validator{} }
+func (v *Validator) Name() string { return Key }
+func (v *Validator) ExecutionClass() contracts.ExecutionClass {
+	return contracts.ExecutionClassDeterministic
+}
+func (v *Validator) CheckpointFingerprints() []pipeline.CheckpointFingerprint {
+	return []pipeline.CheckpointFingerprint{{Name: "policy", Value: policy}}
+}
+
+func (v *Validator) Validate(_ context.Context, req contracts.TypedValidationRequest[dnd.SceneDescriptionList]) (contracts.ValidationResult, error) {
+	if err := ValidateForStage(req.Value, req.Stage); err != nil {
+		return contracts.ValidationResult{Approved: false, ReasonCode: ReasonCode, Message: err.Error()}, nil
+	}
+	return contracts.ValidationResult{Approved: true}, nil
+}
+
+func Validate(value dnd.SceneDescriptionList) error { return validate(value, false) }
+
+func ValidateForStage(value dnd.SceneDescriptionList, stage string) error {
+	return validate(value, stage == string(pipeline.StageExtract))
+}
+
+func validate(value dnd.SceneDescriptionList, exactlyOne bool) error {
+	issues := make([]string, 0)
+	if value.Scenes == nil {
+		issues = append(issues, "scenes must be present")
+	} else if len(value.Scenes) == 0 {
+		issues = append(issues, "scenes must not be empty")
+	} else if exactlyOne && len(value.Scenes) != 1 {
+		issues = append(issues, "extraction must contain exactly one scene")
+	}
+	for index, scene := range value.Scenes {
+		prefix := fmt.Sprintf("scenes[%d]", index)
+		if strings.TrimSpace(scene.ID) == "" || scene.ID != strings.TrimSpace(scene.ID) {
+			issues = append(issues, prefix+".id must be non-empty and trimmed")
+		}
+		if !ValidKind(scene.Kind) {
+			issues = append(issues, prefix+".kind is unsupported: "+diagnostics.Quote(string(scene.Kind)))
+		}
+		if strings.TrimSpace(scene.Title) == "" || scene.Title != strings.TrimSpace(scene.Title) {
+			issues = append(issues, prefix+".title must be non-empty and trimmed")
+		}
+		if strings.TrimSpace(scene.Summary) == "" || scene.Summary != strings.TrimSpace(scene.Summary) {
+			issues = append(issues, prefix+".summary must be non-empty and trimmed")
+		}
+		if strings.TrimSpace(scene.SourceRef.SourceID) == "" || scene.SourceRef.SourceID != strings.TrimSpace(scene.SourceRef.SourceID) || scene.SourceRef.StartUnitID <= 0 || scene.SourceRef.EndUnitID <= 0 {
+			issues = append(issues, prefix+".source_ref must have a trimmed source ID and positive unit IDs")
+		}
+	}
+	if len(issues) == 0 {
+		return nil
+	}
+	return fmt.Errorf("%s", diagnostics.Aggregate("invalid scene description shape", issues))
+}
+
+func ValidKind(value dnd.SceneKind) bool {
+	switch value {
+	case dnd.SceneKindCombat, dnd.SceneKindNarrative, dnd.SceneKindRecap, dnd.SceneKindMeta:
+		return true
+	default:
+		return false
+	}
+}
+
+func Spec() pipeline.ValidatorSpec {
+	return pipeline.ValidatorSpec{Key: Key, ExecutionClass: contracts.ExecutionClassDeterministic}
+}
+
+func Register(registry *pipeline.ValidatorRegistry) error {
+	return pipeline.RegisterTypedValidatorBuilder(registry, dnd.SceneDescriptionListKind, Spec(), validateOptions, func(request pipeline.BuildRequest) (contracts.TypedValidator[dnd.SceneDescriptionList], error) {
+		options, err := DecodeOptions(request.Options)
+		if err != nil {
+			return nil, err
+		}
+		return New(options), nil
+	})
+}
+
+func DecodeOptions(options map[string]any) (Options, error) {
+	if err := pipeline.RejectUnknownOptions(options); err != nil {
+		return Options{}, err
+	}
+	return Options{}, nil
+}
+
+func validateOptions(options map[string]any) error { _, err := DecodeOptions(options); return err }

internal/modules/dnd/validate/scenedescriptions/shape/validator_test.go

@@ -0,0 +1,65 @@
+package shape
+
+import (
+	"context"
+	"reflect"
+	"testing"
+
+	"gitea.maximumdirect.net/eric/notarius/internal/core/source"
+	"gitea.maximumdirect.net/eric/notarius/internal/framework/contracts"
+	"gitea.maximumdirect.net/eric/notarius/internal/framework/pipeline"
+	"gitea.maximumdirect.net/eric/notarius/internal/modules/dnd"
+)
+
+func TestValidatorRequiresSceneShapeAndExactlyOneExtractionRecord(t *testing.T) {
+	valid := list(scene("one", dnd.SceneKindNarrative, "Arrival", "The party arrives.", 1, 1))
+	validator := New(Options{})
+	for _, test := range []struct {
+		name     string
+		value    dnd.SceneDescriptionList
+		stage    string
+		approved bool
+	}{
+		{name: "valid normalization", value: valid, approved: true},
+		{name: "valid extraction", value: valid, stage: string(pipeline.StageExtract), approved: true},
+		{name: "multiple extraction records", value: list(valid.Scenes[0], scene("two", dnd.SceneKindMeta, "Rules", "The table checks rules.", 2, 2)), stage: string(pipeline.StageExtract)},
+		{name: "nil list", value: dnd.SceneDescriptionList{}},
+		{name: "empty list", value: dnd.SceneDescriptionList{Scenes: []dnd.SceneDescription{}}},
+		{name: "blank ID", value: list(scene(" ", dnd.SceneKindNarrative, "Arrival", "The party arrives.", 1, 1))},
+		{name: "unsupported kind", value: list(scene("one", "other", "Arrival", "The party arrives.", 1, 1))},
+		{name: "untrimmed prose", value: list(scene("one", dnd.SceneKindNarrative, " Arrival ", "The party arrives.", 1, 1))},
+		{name: "empty source reference", value: dnd.SceneDescriptionList{Scenes: []dnd.SceneDescription{{ID: "one", Kind: dnd.SceneKindNarrative, Title: "Arrival", Summary: "The party arrives."}}}},
+	} {
+		t.Run(test.name, func(t *testing.T) {
+			result, err := validator.Validate(context.Background(), contracts.TypedValidationRequest[dnd.SceneDescriptionList]{Stage: test.stage, Value: test.value})
+			if err != nil || result.Approved != test.approved {
+				t.Fatalf("Validate() = %#v, %v; want approved=%t", result, err, test.approved)
+			}
+		})
+	}
+}
+
+func TestValidatorContractAndRegistration(t *testing.T) {
+	registry := pipeline.NewValidatorRegistry()
+	if err := Register(registry); err != nil {
+		t.Fatalf("Register() error = %v", err)
+	}
+	if _, ok := registry.Spec(Key); !ok {
+		t.Fatalf("registry has no spec for %q", Key)
+	}
+	if _, err := DecodeOptions(map[string]any{"unexpected": true}); err == nil {
+		t.Fatal("DecodeOptions() accepted unknown options")
+	}
+	validator := New(Options{})
+	if got, want := validator.CheckpointFingerprints(), []pipeline.CheckpointFingerprint{{Name: "policy", Value: policy}}; !reflect.DeepEqual(got, want) {
+		t.Fatalf("fingerprints = %#v, want %#v", got, want)
+	}
+}
+
+func list(scenes ...dnd.SceneDescription) dnd.SceneDescriptionList {
+	return dnd.SceneDescriptionList{Scenes: scenes}
+}
+
+func scene(id string, kind dnd.SceneKind, title, summary string, start, end int) dnd.SceneDescription {
+	return dnd.SceneDescription{ID: id, Kind: kind, Title: title, Summary: summary, SourceRef: source.SourceRef{SourceID: "session", StartUnitID: start, EndUnitID: end}}
+}

internal/modules/dnd/validate/scenedescriptions/source_refs/validator.go

@@ -0,0 +1,90 @@
+// Package sourcerefs validates D&D scene-description source identity.
+package sourcerefs
+
+import (
+	"context"
+	"fmt"
+
+	"gitea.maximumdirect.net/eric/notarius/internal/core/source"
+	"gitea.maximumdirect.net/eric/notarius/internal/framework/contracts"
+	"gitea.maximumdirect.net/eric/notarius/internal/framework/pipeline"
+	"gitea.maximumdirect.net/eric/notarius/internal/modules/dnd"
+	"gitea.maximumdirect.net/eric/notarius/internal/modules/dnd/shared/diagnostics"
+	"gitea.maximumdirect.net/eric/notarius/internal/modules/dnd/validate/scenedescriptions/shape"
+)
+
+const (
+	Key        = "extract/dnd/scene-descriptions/source_refs"
+	ReasonCode = "invalid_scene_description_source_refs"
+	policy     = "dnd.scene_descriptions.validator.source_refs.v1"
+)
+
+type Options struct{}
+type Validator struct{}
+
+var _ contracts.TypedValidator[dnd.SceneDescriptionList] = (*Validator)(nil)
+var _ pipeline.CheckpointFingerprintProvider = (*Validator)(nil)
+
+func New(Options) *Validator      { return &Validator{} }
+func (v *Validator) Name() string { return Key }
+func (v *Validator) ExecutionClass() contracts.ExecutionClass {
+	return contracts.ExecutionClassDeterministic
+}
+func (v *Validator) CheckpointFingerprints() []pipeline.CheckpointFingerprint {
+	return []pipeline.CheckpointFingerprint{{Name: "policy", Value: policy}}
+}
+
+func (v *Validator) Validate(_ context.Context, req contracts.TypedValidationRequest[dnd.SceneDescriptionList]) (contracts.ValidationResult, error) {
+	if shape.ValidateForStage(req.Value, req.Stage) != nil {
+		return contracts.ValidationResult{Approved: true}, nil
+	}
+	issues := make([]string, 0)
+	if req.Stage == string(pipeline.StageExtract) && req.Chunk == nil {
+		issues = append(issues, "current extraction chunk must not be nil")
+	}
+	for index, scene := range req.Value.Scenes {
+		prefix := fmt.Sprintf("scenes[%d]", index)
+		if err := source.ValidateRef(req.Source, scene.SourceRef); err != nil {
+			issues = append(issues, prefix+".source_ref: "+diagnostics.Truncate(err.Error()))
+			continue
+		}
+		if req.Stage == string(pipeline.StageExtract) && req.Chunk != nil {
+			if scene.ID != req.Chunk.ID {
+				issues = append(issues, prefix+".id must equal the current extraction chunk ID")
+			}
+			if scene.SourceRef != req.Chunk.Ref {
+				issues = append(issues, prefix+".source_ref must equal the current extraction chunk range")
+			}
+		}
+	}
+	if len(issues) == 0 {
+		return contracts.ValidationResult{Approved: true}, nil
+	}
+	return contracts.ValidationResult{
+		Approved: false, ReasonCode: ReasonCode,
+		Message: diagnostics.Aggregate("invalid scene description source references", issues),
+	}, nil
+}
+
+func Spec() pipeline.ValidatorSpec {
+	return pipeline.ValidatorSpec{Key: Key, ExecutionClass: contracts.ExecutionClassDeterministic}
+}
+
+func Register(registry *pipeline.ValidatorRegistry) error {
+	return pipeline.RegisterTypedValidatorBuilder(registry, dnd.SceneDescriptionListKind, Spec(), validateOptions, func(request pipeline.BuildRequest) (contracts.TypedValidator[dnd.SceneDescriptionList], error) {
+		options, err := DecodeOptions(request.Options)
+		if err != nil {
+			return nil, err
+		}
+		return New(options), nil
+	})
+}
+
+func DecodeOptions(options map[string]any) (Options, error) {
+	if err := pipeline.RejectUnknownOptions(options); err != nil {
+		return Options{}, err
+	}
+	return Options{}, nil
+}
+
+func validateOptions(options map[string]any) error { _, err := DecodeOptions(options); return err }

internal/modules/dnd/validate/scenedescriptions/source_refs/validator_test.go

@@ -0,0 +1,59 @@
+package sourcerefs
+
+import (
+	"context"
+	"reflect"
+	"testing"
+
+	"gitea.maximumdirect.net/eric/notarius/internal/core/source"
+	"gitea.maximumdirect.net/eric/notarius/internal/framework/contracts"
+	"gitea.maximumdirect.net/eric/notarius/internal/framework/pipeline"
+	"gitea.maximumdirect.net/eric/notarius/internal/modules/dnd"
+)
+
+func TestValidatorRequiresExactExtractionChunkIdentity(t *testing.T) {
+	doc := document()
+	chunk := &source.Chunk{ID: "chunk-1", SourceID: doc.ID, Ref: source.SourceRef{SourceID: doc.ID, StartUnitID: 1, EndUnitID: 2}}
+	valid := dnd.SceneDescriptionList{Scenes: []dnd.SceneDescription{{ID: chunk.ID, SourceRef: chunk.Ref, Kind: dnd.SceneKindNarrative, Title: "Arrival", Summary: "The party arrives."}}}
+	validator := New(Options{})
+	for _, test := range []struct {
+		name     string
+		request  contracts.TypedValidationRequest[dnd.SceneDescriptionList]
+		approved bool
+	}{
+		{name: "exact extraction identity", request: contracts.TypedValidationRequest[dnd.SceneDescriptionList]{Stage: string(pipeline.StageExtract), Source: doc, Chunk: chunk, Value: valid}, approved: true},
+		{name: "wrong ID", request: contracts.TypedValidationRequest[dnd.SceneDescriptionList]{Stage: string(pipeline.StageExtract), Source: doc, Chunk: chunk, Value: dnd.SceneDescriptionList{Scenes: []dnd.SceneDescription{{ID: "other", SourceRef: chunk.Ref, Kind: dnd.SceneKindNarrative, Title: "Arrival", Summary: "The party arrives."}}}}},
+		{name: "contained but unequal range", request: contracts.TypedValidationRequest[dnd.SceneDescriptionList]{Stage: string(pipeline.StageExtract), Source: doc, Chunk: chunk, Value: dnd.SceneDescriptionList{Scenes: []dnd.SceneDescription{{ID: chunk.ID, SourceRef: source.SourceRef{SourceID: doc.ID, StartUnitID: 1, EndUnitID: 1}, Kind: dnd.SceneKindNarrative, Title: "Arrival", Summary: "The party arrives."}}}}},
+		{name: "missing chunk", request: contracts.TypedValidationRequest[dnd.SceneDescriptionList]{Stage: string(pipeline.StageExtract), Source: doc, Value: valid}},
+		{name: "normalization needs no chunk", request: contracts.TypedValidationRequest[dnd.SceneDescriptionList]{Stage: string(pipeline.StageNormalize), Source: doc, Value: valid}, approved: true},
+		{name: "invalid current source", request: contracts.TypedValidationRequest[dnd.SceneDescriptionList]{Source: doc, Value: dnd.SceneDescriptionList{Scenes: []dnd.SceneDescription{{ID: "chunk", SourceRef: source.SourceRef{SourceID: doc.ID, StartUnitID: 7, EndUnitID: 7}, Kind: dnd.SceneKindNarrative, Title: "Arrival", Summary: "The party arrives."}}}}},
+	} {
+		t.Run(test.name, func(t *testing.T) {
+			result, err := validator.Validate(context.Background(), test.request)
+			if err != nil || result.Approved != test.approved {
+				t.Fatalf("Validate() = %#v, %v; want approved=%t", result, err, test.approved)
+			}
+		})
+	}
+}
+
+func TestValidatorDefersMalformedShapeAndRegistersPolicy(t *testing.T) {
+	result, err := New(Options{}).Validate(context.Background(), contracts.TypedValidationRequest[dnd.SceneDescriptionList]{Value: dnd.SceneDescriptionList{}})
+	if err != nil || !result.Approved {
+		t.Fatalf("Validate() = %#v, %v; want malformed shape deferred", result, err)
+	}
+	registry := pipeline.NewValidatorRegistry()
+	if err := Register(registry); err != nil {
+		t.Fatal(err)
+	}
+	if _, ok := registry.Spec(Key); !ok {
+		t.Fatalf("registry missing %q", Key)
+	}
+	if got, want := New(Options{}).CheckpointFingerprints(), []pipeline.CheckpointFingerprint{{Name: "policy", Value: policy}}; !reflect.DeepEqual(got, want) {
+		t.Fatalf("fingerprints = %#v, want %#v", got, want)
+	}
+}
+
+func document() *source.SourceDocument {
+	return &source.SourceDocument{ID: "session", Units: []source.SourceUnit{{ID: 1, Text: "The party arrives."}, {ID: 2, Text: "They investigate."}}}
+}

internal/modules/dnd/validate/scenedescriptions/source_relatedness/validator.go

@@ -0,0 +1,139 @@
+// Package sourcerelatedness warns when scene prose has no lexical grounding.
+package sourcerelatedness
+
+import (
+	"context"
+	"fmt"
+	"unicode/utf8"
+
+	"gitea.maximumdirect.net/eric/notarius/internal/core/source"
+	"gitea.maximumdirect.net/eric/notarius/internal/framework/contracts"
+	"gitea.maximumdirect.net/eric/notarius/internal/framework/pipeline"
+	"gitea.maximumdirect.net/eric/notarius/internal/modules/dnd"
+	"gitea.maximumdirect.net/eric/notarius/internal/modules/dnd/shared"
+	"gitea.maximumdirect.net/eric/notarius/internal/modules/dnd/shared/diagnostics"
+	"gitea.maximumdirect.net/eric/notarius/internal/modules/dnd/validate/scenedescriptions/shape"
+)
+
+const (
+	Key               = "extract/dnd/scene-descriptions/source_relatedness"
+	WarningReasonCode = "scene_description_not_near_source"
+	OmittedReasonCode = "scene_description_relatedness_warnings_omitted"
+	policy            = "dnd.scene_descriptions.validator.source_relatedness.v1"
+)
+
+var stopwords = map[string]struct{}{
+	"a": {}, "an": {}, "and": {}, "are": {}, "as": {}, "at": {}, "be": {}, "but": {}, "by": {}, "for": {}, "from": {},
+	"had": {}, "has": {}, "have": {}, "he": {}, "her": {}, "him": {}, "his": {}, "in": {}, "into": {}, "is": {}, "it": {}, "its": {},
+	"of": {}, "on": {}, "or": {}, "she": {}, "that": {}, "the": {}, "their": {}, "them": {}, "they": {}, "this": {}, "to": {},
+	"was": {}, "were": {}, "with": {},
+}
+
+type Options struct{}
+type Validator struct{}
+
+var _ contracts.TypedValidator[dnd.SceneDescriptionList] = (*Validator)(nil)
+var _ pipeline.CheckpointFingerprintProvider = (*Validator)(nil)
+
+func New(Options) *Validator      { return &Validator{} }
+func (v *Validator) Name() string { return Key }
+func (v *Validator) ExecutionClass() contracts.ExecutionClass {
+	return contracts.ExecutionClassDeterministic
+}
+func (v *Validator) CheckpointFingerprints() []pipeline.CheckpointFingerprint {
+	return []pipeline.CheckpointFingerprint{{Name: "policy", Value: policy}}
+}
+
+func (v *Validator) Validate(_ context.Context, req contracts.TypedValidationRequest[dnd.SceneDescriptionList]) (contracts.ValidationResult, error) {
+	if shape.Validate(req.Value) != nil || !sourceRefsValid(req.Source, req.Value) {
+		return contracts.ValidationResult{Approved: true}, nil
+	}
+	warnings := make([]contracts.Warning, 0)
+	for index, scene := range req.Value.Scenes {
+		citedText, err := shared.CitedText(req.Source, []source.SourceRef{scene.SourceRef})
+		if err != nil {
+			return contracts.ValidationResult{Approved: true}, nil
+		}
+		citedTokens := tokenSet(citedText)
+		if !hasGroundedToken(citedTokens, scene.Title) {
+			warnings = append(warnings, warning(index, "title"))
+		}
+		if !hasGroundedToken(citedTokens, scene.Summary) {
+			warnings = append(warnings, warning(index, "summary"))
+		}
+	}
+	return contracts.ValidationResult{
+		Approved: true,
+		Warnings: diagnostics.LimitWarnings(warnings, "scenes", OmittedReasonCode),
+	}, nil
+}
+
+func sourceRefsValid(doc *source.SourceDocument, value dnd.SceneDescriptionList) bool {
+	for _, scene := range value.Scenes {
+		if source.ValidateRef(doc, scene.SourceRef) != nil {
+			return false
+		}
+	}
+	return true
+}
+
+func tokenSet(value string) map[string]struct{} {
+	tokens := make(map[string]struct{})
+	for _, token := range shared.NormalizedTokens(value) {
+		if significant(token) {
+			tokens[token] = struct{}{}
+		}
+	}
+	return tokens
+}
+
+func hasGroundedToken(cited map[string]struct{}, value string) bool {
+	for _, token := range shared.NormalizedTokens(value) {
+		if !significant(token) {
+			continue
+		}
+		if _, ok := cited[token]; ok {
+			return true
+		}
+	}
+	return false
+}
+
+func significant(token string) bool {
+	if utf8.RuneCountInString(token) < 3 {
+		return false
+	}
+	_, ignored := stopwords[token]
+	return !ignored
+}
+
+func warning(index int, field string) contracts.Warning {
+	return contracts.Warning{
+		Scope:      fmt.Sprintf("scenes[%d].%s", index, field),
+		ReasonCode: WarningReasonCode,
+		Message:    "scene description " + field + " has no significant token in cited source text",
+	}
+}
+
+func Spec() pipeline.ValidatorSpec {
+	return pipeline.ValidatorSpec{Key: Key, ExecutionClass: contracts.ExecutionClassDeterministic}
+}
+
+func Register(registry *pipeline.ValidatorRegistry) error {
+	return pipeline.RegisterTypedValidatorBuilder(registry, dnd.SceneDescriptionListKind, Spec(), validateOptions, func(request pipeline.BuildRequest) (contracts.TypedValidator[dnd.SceneDescriptionList], error) {
+		options, err := DecodeOptions(request.Options)
+		if err != nil {
+			return nil, err
+		}
+		return New(options), nil
+	})
+}
+
+func DecodeOptions(options map[string]any) (Options, error) {
+	if err := pipeline.RejectUnknownOptions(options); err != nil {
+		return Options{}, err
+	}
+	return Options{}, nil
+}
+
+func validateOptions(options map[string]any) error { _, err := DecodeOptions(options); return err }

internal/modules/dnd/validate/scenedescriptions/source_relatedness/validator_test.go

@@ -0,0 +1,78 @@
+package sourcerelatedness
+
+import (
+	"context"
+	"reflect"
+	"strings"
+	"testing"
+
+	"gitea.maximumdirect.net/eric/notarius/internal/core/source"
+	"gitea.maximumdirect.net/eric/notarius/internal/framework/contracts"
+	"gitea.maximumdirect.net/eric/notarius/internal/framework/pipeline"
+	"gitea.maximumdirect.net/eric/notarius/internal/modules/dnd"
+)
+
+func TestValidatorWarnsIndependentlyForUngroundedTitleAndSummary(t *testing.T) {
+	doc := document()
+	value := dnd.SceneDescriptionList{Scenes: []dnd.SceneDescription{
+		scene("one", "Watchtower arrival", "The group enters the ruined watchtower."),
+		scene("two", "Moonlit council", "Whispers linger."),
+		scene("three", "The and to", "An or the"),
+	}}
+	result, err := New(Options{}).Validate(context.Background(), contracts.TypedValidationRequest[dnd.SceneDescriptionList]{Source: doc, Value: value})
+	if err != nil || !result.Approved {
+		t.Fatalf("Validate() = %#v, %v", result, err)
+	}
+	wantScopes := []string{"scenes[1].title", "scenes[1].summary", "scenes[2].title", "scenes[2].summary"}
+	if len(result.Warnings) != len(wantScopes) {
+		t.Fatalf("warnings = %#v, want %d", result.Warnings, len(wantScopes))
+	}
+	for index, scope := range wantScopes {
+		item := result.Warnings[index]
+		if item.Scope != scope || item.ReasonCode != WarningReasonCode {
+			t.Fatalf("warning[%d] = %#v, want scope %q", index, item, scope)
+		}
+		if len(item.Message) > 4096 || strings.Contains(item.Message, doc.Units[0].Text) {
+			t.Fatalf("warning[%d] is not safely bounded: %#v", index, item)
+		}
+	}
+}
+
+func TestValidatorUsesTranscriptOnlyAndDefersInvalidInputs(t *testing.T) {
+	doc := document()
+	value := dnd.SceneDescriptionList{Scenes: []dnd.SceneDescription{scene("one", "Greencloak", "Greencloak arrives.")}}
+	result, err := New(Options{}).Validate(context.Background(), contracts.TypedValidationRequest[dnd.SceneDescriptionList]{
+		Source: doc, Value: value,
+		References: contracts.ReferenceSet{Slots: map[string]contracts.ResolvedReferenceSlot{
+			"glossary": {Items: []contracts.ReferenceItem{{Content: []byte("Greencloak: title")}}},
+		}},
+	})
+	if err != nil || len(result.Warnings) != 2 {
+		t.Fatalf("Validate() = %#v, %v; want transcript-only warnings", result, err)
+	}
+	malformed, err := New(Options{}).Validate(context.Background(), contracts.TypedValidationRequest[dnd.SceneDescriptionList]{Source: doc, Value: dnd.SceneDescriptionList{}})
+	if err != nil || !malformed.Approved || len(malformed.Warnings) != 0 {
+		t.Fatalf("malformed Validate() = %#v, %v; want deferral", malformed, err)
+	}
+}
+
+func TestValidatorRegistrationAndPolicyFingerprint(t *testing.T) {
+	registry := pipeline.NewValidatorRegistry()
+	if err := Register(registry); err != nil {
+		t.Fatal(err)
+	}
+	if _, ok := registry.Spec(Key); !ok {
+		t.Fatalf("registry missing %q", Key)
+	}
+	if got, want := New(Options{}).CheckpointFingerprints(), []pipeline.CheckpointFingerprint{{Name: "policy", Value: policy}}; !reflect.DeepEqual(got, want) {
+		t.Fatalf("fingerprints = %#v, want %#v", got, want)
+	}
+}
+
+func document() *source.SourceDocument {
+	return &source.SourceDocument{ID: "session", Units: []source.SourceUnit{{ID: 1, Text: "The group enters the ruined watchtower."}}}
+}
+
+func scene(id, title, summary string) dnd.SceneDescription {
+	return dnd.SceneDescription{ID: id, SourceRef: source.SourceRef{SourceID: "session", StartUnitID: 1, EndUnitID: 1}, Kind: dnd.SceneKindNarrative, Title: title, Summary: summary}
+}