Verify D&D scene chunker run output

AGENTS.md

@@ -1,3 +1,6 @@
-Please carefully review the documents in `docs/policy` before making any changes to this repository.
+Please review `docs/internal/overview.md` for initial orientation in this repository.
- - `architecture.md` provides the canonical high-level architecture policy for this repository.
+
- - `documentation.md` provides the canonical documentation policy for this repository.
+Additionally, please carefully review the relevant documents in `docs/policy` before making any changes to this repository.
+ - `development.md` defines the contributor workflow for this application.
+ - `architecture.md` provides the canonical high-level architecture policy for this repository, and should be reviewed before writing or changing any code.
+ - `documentation.md` provides the canonical documentation policy for this repository, and should be reviewed before writing or changing any documentation.

docs/cli.md

@@ -117,7 +117,7 @@ go run ./cmd/notarius pipelines list \
 The production CLI currently registers these module keys:
 
 - input: `seriatim`
-- chunk: `generic`
+- chunk: `generic`, `dnd/scenes`
 - extract: `dnd/spells`
 - merge: `appendorder`
 - normalize: `noop`

docs/config.md

@@ -167,6 +167,7 @@ one configured profile.
 | --- | --- | --- |
 | input | `seriatim` | Reads Seriatim transcript JSON. |
 | chunk | `generic` | Splits source units into ordered chunks. |
+| chunk | `dnd/scenes` | Uses an LLM to split transcript source units into D&D scenes. |
 | extract | `dnd/spells` | Extracts `dnd.spell_cast` artifacts. |
 | merge | `appendorder` | Keeps candidates in append order. |
 | normalize | `noop` | Passes merged artifacts through unchanged. |
@@ -178,6 +179,9 @@ The `generic` chunker accepts:
 - `overlap_units`: non-negative integer, default `0`, and must be less than
   `max_units`.
 
+The `dnd/scenes` chunker requires transcript source capabilities, calls the
+configured structured LLM provider, and does not accept module options.
+
 ## Diagnostics
 
 `diagnostics` fields:

docs/internal/modules.md

@@ -20,6 +20,11 @@ A production module package should provide:
 Module specs should describe capabilities accurately. Resolution uses specs to
 reject incompatible pipelines before execution.
 
+Chunk modules receive the structured LLM client through `contracts.ChunkRequest`
+when they need model-backed chunking. The pipeline runner validates generic
+chunk result invariants before extraction; module-owned policies may be stricter
+but must stay within the module package.
+
 ## `seriatim` Input
 
 Package: `internal/modules/input/seriatim`
@@ -54,6 +59,37 @@ Provides:
 
 - `chunks`
 
+## `dnd/scenes` Chunker
+
+Package: `internal/modules/chunk/dnd/scenes`
+
+The `dnd/scenes` chunker uses the structured LLM client to divide transcript
+source units into coherent D&D scenes. It renders embedded prompts, loads the
+embedded structured response schema, validates model-authored source-unit
+boundaries, and converts each scene into a deterministic source chunk.
+
+Requires:
+
+- `source.transcript`
+
+Provides:
+
+- `chunks`
+- `chunks.scenes`
+
+Options: none. Non-empty options are rejected.
+
+The chunker enforces full source-unit coverage from the first source unit to the
+last, exact source-unit IDs, sequential contiguous scenes, and no overlap. It
+assigns chunk IDs such as `scene-000001` and stores scene metadata including
+title, primary mode, participants, summary, boundary note, confidence, boundary
+unit IDs, and unit count. Boundary caveats become warnings with reason code
+`scene_boundary_caveat`.
+
+Malformed model output fails explicitly rather than falling back to another
+chunker. The chunker exposes prompt and response-schema provenance through its
+metadata provider without raw prompts, raw schemas, source text, or secrets.
+
 ## `dnd/spells` Extractor
 
 Package: `internal/modules/extract/dnd/spells`

docs/internal/pipeline.md

@@ -73,8 +73,34 @@ The runner:
 2. builds the input adapter and parses the raw input into a source document;
 3. validates the source document;
 4. builds the chunker and produces source chunks;
-5. runs each selected artifact lane in sorted resolved order;
+5. validates source chunks against framework invariants;
-6. builds the output encoder and validates logical output file names.
+6. runs each selected artifact lane in sorted resolved order;
+7. builds the output encoder and validates logical output file names.
+
+## Chunk Results
+
+Chunkers implement `contracts.Chunker` and receive a `contracts.ChunkRequest`
+with the validated source document, the structured LLM client, the configured
+LLM profile, module options, and run metadata. Deterministic and LLM-backed
+chunkers use the same contract; provider construction stays outside chunk
+modules.
+
+After `Chunk` returns, the runner appends chunker warnings before returning any
+chunker error. When chunking succeeds, the runner validates generic chunk
+invariants before running extractors:
+
+- chunk IDs must be non-empty and unique in the chunk result;
+- each chunk `SourceID` must match the source document ID;
+- each chunk `Index` must match its zero-based returned order;
+- each chunk must contain at least one source unit;
+- a chunk must not repeat a source unit;
+- every chunk source unit must exist in the source document;
+- source units inside each chunk must appear in source-document order.
+
+The framework does not require complete source-unit coverage and does not reject
+overlap between different chunks. Stricter policies, such as full coverage or
+non-overlap, belong to individual chunk modules when they are part of that
+module's contract.
 
 Within an artifact lane, the runner:
 

docs/roadmap/chunk.md

@@ -0,0 +1,104 @@
+# Chunk Module Roadmap
+
+Current Notarius behavior is documented in the canonical README, CLI,
+configuration, operations, internal, and integration docs. This roadmap records
+future chunk-module behavior only.
+
+## Goal
+
+Chunk modules should be a clear module-author boundary, and LLM-backed chunking
+should be a first-class capability.
+
+The immediate target is a D&D-specific scene chunker that divides transcript
+source units into coherent scenes before extraction. The broader target is that
+any chunk module can be implemented as a black box when it satisfies the
+framework chunk contract.
+
+## Target Chunk Contract
+
+The framework chunk contract should support deterministic and LLM-backed
+chunkers through the same module interface.
+
+Chunkers should receive runtime dependencies from the runner, including the
+structured LLM client when a chunker needs model calls. Chunkers should not
+construct provider clients internally.
+
+The framework should validate these result invariants for every chunk module:
+
+- chunk IDs are non-empty and unique within a run;
+- each chunk references the input source document ID;
+- chunk indexes are deterministic and sequential in returned order;
+- each chunk contains at least one source unit;
+- each chunk source unit comes from the source document;
+- source units within each chunk appear in source-document order.
+
+The framework should not require complete source-unit coverage and should not
+forbid overlap between chunks. Individual chunk modules may enforce stricter
+policies, such as full coverage or non-overlap, when those policies are part of
+the module's own contract.
+
+Chunk metadata should remain flexible and module-owned. Framework code should
+preserve chunk metadata and pass it to downstream modules, but it should not
+adopt transcript-specific or D&D-specific metadata fields.
+
+## D&D Scene Chunker Target
+
+The D&D scene chunker should live under
+`internal/modules/chunk/dnd/scenes` and use the module key `dnd/scenes`.
+
+It should require transcript source capabilities and provide the generic
+`chunks` capability plus a scene-specific chunk capability. D&D scene-boundary
+prompt logic, response-schema interpretation, and stricter scene policies belong
+inside the module.
+
+The module should use the framework structured LLM client for scene-boundary
+detection. The model response should describe source-unit boundaries and useful
+scene metadata; the Go module should validate the response and convert it into
+`contracts.SourceChunk` values.
+
+For `dnd/scenes`, the module-owned policy should be:
+
+- cover the full source document from first source unit to last source unit;
+- return sequential, contiguous, non-overlapping scenes;
+- use exact source-unit IDs for boundaries;
+- fail with actionable errors for malformed model output rather than silently
+  falling back to a generic chunker.
+
+Scene chunk IDs and indexes should be assigned by the module, not trusted from
+model output. Useful scene information should be stored in chunk metadata, such
+as title, primary mode, participants, summary, boundary note, and boundary
+confidence. Overall boundary caveats should be surfaced as chunker warnings.
+
+## Draft Asset Target
+
+Initial D&D scene chunker prompt and schema drafts exist under
+`internal/modules/chunk/dnd/scenes/assets`. They should be revised before the
+module is implemented.
+
+The response schema should be versioned and named consistently with existing
+module-owned response schemas, such as `dnd_scenes.v1.json`, with a schema key,
+schema ID, schema version, and OpenAI-compatible response schema name.
+
+Boundary fields should use source-unit ID strings, not integer segment IDs.
+The schema should focus on boundary and metadata decisions rather than final
+framework chunk fields. Prompt terminology and schema terminology should match
+exactly, including primary mode enum values and boundary field names.
+
+The user prompt should be a Go template that includes source document ID,
+chunking scope, ordered source units, and selected metadata such as speaker and
+timestamps when available. It may contain D&D-specific scene guidance, but it
+should not imply that the framework itself is transcript-specific.
+
+## Documentation Target
+
+Current-behavior docs should be updated only after the corresponding behavior is
+implemented.
+
+Internal module-author documentation should eventually define the chunk module
+API, including `Chunker`, `ChunkRequest`, `ChunkResult`, `SourceChunk`,
+validation invariants, warning semantics, LLM-backed chunker expectations,
+module specs, capability guidance, and option parsing expectations.
+
+When `dnd/scenes` becomes production behavior, configuration, CLI, internal
+module, and troubleshooting docs should describe the implemented module and its
+failure modes.

docs/roadmap/implementation.md

@@ -0,0 +1,312 @@
+# Chunk Module Implementation Plan
+
+This plan implements the accepted target state in
+[Chunk Module Roadmap](chunk.md). It is written for an LLM coding agent that
+will implement each stage in order.
+
+Before beginning any stage, review:
+
+- `docs/policy/architecture.md`
+- `docs/policy/development.md`
+- `docs/policy/documentation.md`
+- `docs/roadmap/chunk.md`
+
+Do not move planned behavior into non-roadmap docs until the corresponding code
+is implemented. Do not revert unrelated user changes.
+
+## Stage 1: Framework Chunk Contract
+
+Goal: make LLM-backed chunking first-class and enforce generic chunk result
+invariants without adding any D&D-specific framework behavior.
+
+Code changes:
+
+- Add `LLMClient contracts.StructuredLLMClient` to `contracts.ChunkRequest` in
+  `internal/framework/contracts/contracts.go`.
+- Update `internal/framework/pipeline/runner.go` so the runner passes
+  `input.LLMClient` to the chunker in `contracts.ChunkRequest`.
+- Add framework-level chunk result validation after `chunker.Chunk` returns and
+  before lanes execute.
+- Keep validation source-generic. The validator should reject:
+  - empty chunk ID;
+  - duplicate chunk ID;
+  - chunk `SourceID` that does not match the source document ID;
+  - chunk `Index` that does not match returned order;
+  - empty chunk units;
+  - repeated source unit inside one chunk;
+  - source unit not found in the source document;
+  - chunk units that do not appear in source-document order.
+- The validator must not require complete coverage and must not reject overlap
+  between different chunks.
+- Preserve existing warning behavior: append chunker warnings before returning
+  chunk errors, as the runner does today.
+
+Documentation changes:
+
+- Update implemented internal docs under `docs/internal/` to define the chunk
+  module API and validation invariants once the code exists.
+- Keep examples and user docs unchanged in this stage unless an existing doc
+  becomes inaccurate.
+
+Tests:
+
+- Update contract tests for the new `ChunkRequest.LLMClient` field where useful.
+- Add focused pipeline runner tests for each invalid chunk result case listed
+  above.
+- Add runner tests proving partial coverage and overlapping chunks remain
+  accepted.
+- Run:
+
+```sh
+go test ./internal/framework/contracts ./internal/framework/pipeline
+```
+
+Stage completion criteria:
+
+- Existing generic chunking still works.
+- A fake chunker can receive the structured LLM client through `ChunkRequest`.
+- Framework tests prove the accepted generic chunk invariants.
+
+## Stage 2: D&D Scene Assets And Module Skeleton
+
+Goal: revise the draft D&D scene prompt and schema into module-owned assets and
+add load/render plumbing without registering production behavior.
+
+Asset decisions:
+
+- Rename `internal/modules/chunk/dnd/scenes/assets/schemas/scene_map.schema.json`
+  to `internal/modules/chunk/dnd/scenes/assets/schemas/dnd_scenes.v1.json`.
+- Use these schema constants unless a code-local naming conflict requires a
+  mechanical adjustment:
+  - prompt ID: `dnd.scenes`
+  - response schema key: `dnd_scenes`
+  - response schema ID: `notarius.dnd.scenes`
+  - response schema version: `v1`
+  - response schema name: `notarius_dnd_scenes_v1`
+- Use this structured response shape:
+
+```json
+{
+  "scenes": [
+    {
+      "start_unit_id": "seg-001",
+      "end_unit_id": "seg-010",
+      "short_title": "Ambush at the gate",
+      "primary_mode": "Combat",
+      "main_participants": ["Aria", "Bandit mage"],
+      "summary": "The party fights the bandit mage at the gate.",
+      "boundary_note": "The scene begins when combat starts and ends when the immediate threat is resolved.",
+      "boundary_confidence": "High"
+    }
+  ],
+  "boundary_caveats": []
+}
+```
+
+- Required top-level fields: `scenes`, `boundary_caveats`.
+- Required scene fields: `start_unit_id`, `end_unit_id`, `short_title`,
+  `primary_mode`, `main_participants`, `summary`, `boundary_note`,
+  `boundary_confidence`.
+- Boundary fields are source-unit ID strings, not integers.
+- `primary_mode` enum: `Recap`, `Discussion`, `Combat`, `Narrative`.
+- `boundary_confidence` enum: `High`, `Medium`, `Low`.
+- Keep `additionalProperties: false` throughout the schema.
+- Do not include model-authored final chunk IDs or chunk indexes in the schema.
+  The Go module assigns deterministic chunk IDs and indexes.
+
+Prompt decisions:
+
+- Keep D&D-specific scene guidance in the D&D scene module.
+- Make the user prompt a Go template similar to the spell extractor prompt.
+- Include source document ID and ordered source units.
+- Include selected source-unit metadata when present: `speaker`, `start`, and
+  `end`.
+- Align prompt terms exactly with schema field names and enum values.
+- Keep `dnd/scenes` module policy explicit in the prompt: full coverage,
+  sequential scenes, no gaps, no overlap, exact source-unit IDs.
+
+Code changes:
+
+- Add `assets.go` with an `embed.FS` for prompts and schemas.
+- Add `schema.go` with the constants and a `loadResponseSchema` function using
+  `llm.LoadResponseSchema`, following the pattern in
+  `internal/modules/extract/dnd/spells/schema.go`.
+- Add prompt rendering code using `framework/prompt.Bundle`, following the
+  pattern in `internal/modules/extract/dnd/spells/prompt.go`.
+- Add internal response structs for the schema shape.
+- Do not register the module in `internal/cli/catalog.go` in this stage.
+
+Tests:
+
+- Add tests that the schema loads, is valid JSON, has the expected metadata, and
+  rejects the old integer-boundary assumption through Go-side type expectations.
+- Add prompt rendering tests that source unit IDs and selected metadata appear
+  in the rendered user prompt.
+- Run:
+
+```sh
+go test ./internal/modules/chunk/dnd/scenes
+```
+
+Stage completion criteria:
+
+- The scene schema and prompts are loadable embedded assets.
+- The prompt/schema terminology is internally consistent.
+- No production catalog behavior changes yet.
+
+## Stage 3: D&D Scene Chunker Implementation
+
+Goal: implement `dnd/scenes` as a contract-compliant chunk module with strict
+module-owned validation.
+
+Module decisions:
+
+- Package path: `internal/modules/chunk/dnd/scenes`.
+- Package name: `scenes`.
+- Module key: `dnd/scenes`.
+- `ModuleSpec`:
+  - `Stage`: `pipeline.StageChunk`
+  - `Requires`: `source.transcript`
+  - `Provides`: `chunks`, `chunks.scenes`
+- Constructor: `New() *Chunker`.
+- Registration function: `Register(registry *pipeline.ChunkerRegistry) error`.
+- No module options initially. Reject non-empty options with an actionable
+  module-prefixed error unless a clear option is implemented in the same stage.
+
+Chunking behavior:
+
+- Validate `context.Context`, source document, non-empty source units, and
+  non-nil `LLMClient`.
+- Render the scene prompt over the full source document.
+- Call `LLMClient.CompleteStructured` with:
+  - `StageName`: `dnd/scenes`
+  - response schema name and schema JSON from the module schema loader.
+- Validate the decoded response before producing chunks:
+  - `scenes` must be present and non-empty;
+  - every boundary ID must exist in the source document;
+  - each scene start must be at or before its end;
+  - the first scene starts at the first source unit;
+  - the final scene ends at the final source unit;
+  - scenes are contiguous in source order;
+  - scenes do not overlap;
+  - required metadata fields are non-empty after trimming;
+  - `main_participants` entries are trimmed and empty entries rejected.
+- Assign deterministic chunk fields:
+  - `ID`: `scene-000001`, `scene-000002`, and so on;
+  - `SourceID`: source document ID;
+  - `Index`: zero-based returned order;
+  - `Units`: defensive copies of the source units in the scene range.
+- Store per-scene metadata on each chunk:
+  - `scene_title`
+  - `primary_mode`
+  - `main_participants`
+  - `summary`
+  - `boundary_note`
+  - `boundary_confidence`
+  - `start_unit_id`
+  - `end_unit_id`
+  - `unit_count`
+- Convert each `boundary_caveats` entry into a `contracts.Warning` with:
+  - `Scope`: `dnd/scenes`
+  - `ReasonCode`: `scene_boundary_caveat`
+  - `Message`: the caveat text.
+- Fail explicitly for malformed model output. Do not fall back to `generic`.
+- Implement `contracts.ManifestMetadataProvider` and include prompt and
+  response-schema provenance without raw prompts, raw schemas, source text, or
+  secrets.
+
+Tests:
+
+- Registration and `ModuleSpec`.
+- Successful chunking from a fake LLM response.
+- Prompt request uses the expected schema name and schema JSON.
+- Caveats become warnings.
+- Defensive copy behavior for source units and metadata.
+- Errors for nil context, nil source, invalid source, nil LLM client, empty
+  model scenes, unknown boundary ID, out-of-order boundaries, gaps, overlap,
+  incomplete coverage, empty metadata fields, and non-empty unsupported options.
+- Manifest metadata contains prompt/schema provenance.
+- Run:
+
+```sh
+go test ./internal/modules/chunk/dnd/scenes
+go test ./internal/framework/pipeline
+```
+
+Stage completion criteria:
+
+- `dnd/scenes` works in focused tests with fake LLM clients.
+- It is still not production-registered unless Stage 4 is completed.
+
+## Stage 4: Production Registration And Implemented Docs
+
+Goal: make `dnd/scenes` available in production configuration and document only
+the behavior that now exists.
+
+Code changes:
+
+- Register `dnd/scenes` in `internal/cli/catalog.go`.
+- Add or update catalog/default module tests so the production catalog exposes
+  the new chunk module.
+- Add CLI/config validation tests proving a pipeline can select
+  `chunk: dnd/scenes`.
+- Do not change the existing maintained example config unless the related CLI
+  fixture tests are updated to keep it loadable and useful.
+
+Documentation changes:
+
+- Update `docs/config.md` implemented production module tables and chunk module
+  notes.
+- Update `docs/cli.md` implemented production module list.
+- Update `docs/internal/modules.md` with `dnd/scenes` behavior, capabilities,
+  metadata, and failure policy.
+- Update or add internal chunk-module documentation if Stage 1 did not already
+  create a clear API reference.
+- Update `docs/troubleshooting.md` for common scene chunker failures:
+  malformed model output, invalid boundaries, incomplete coverage, and provider
+  failures during chunking.
+- Keep roadmap docs for any deferred options or future prompt tuning.
+
+Tests:
+
+```sh
+go test ./internal/cli
+go test ./internal/core/config
+go test ./internal/framework/pipeline
+go test ./internal/modules/chunk/dnd/scenes
+```
+
+Stage completion criteria:
+
+- Config resolution can bind `dnd/scenes`.
+- User and internal docs describe the implemented module accurately.
+- Existing examples and CLI docs remain truthful.
+
+## Stage 5: Full Verification
+
+Goal: verify the complete feature across contracts, production wiring, docs, and
+the command entry point.
+
+Run:
+
+```sh
+go test ./...
+go vet ./...
+go build ./cmd/notarius
+```
+
+Inspect diagnostics-sensitive output manually in tests or fixtures where
+relevant:
+
+- no raw prompts, source text, provider payloads, API keys, or secrets in
+  manifest metadata;
+- errors name the module and operation;
+- warnings are preserved in `RunOutput.Warnings`;
+- run manifests record the `dnd/scenes` chunker when selected.
+
+Stage completion criteria:
+
+- Full validation commands pass.
+- The feature is documented as implemented only where code supports it.
+- `docs/roadmap/chunk.md` retains target-state context and does not duplicate
+  current-behavior reference material.

docs/troubleshooting.md

@@ -177,6 +177,31 @@ Fix:
 
 Provider error messages are redacted for configured API key values.
 
+## Scene Chunking Failure
+
+Symptoms include:
+
+- `dnd scenes chunker`
+- `malformed structured output`
+- `start_unit_id`
+- `end_unit_id`
+- `gap`
+- `overlap`
+- `final scene`
+- `complete structured output`
+
+Fix:
+
+- Validate the pipeline configuration and confirm the input module provides a
+  transcript source when using `chunk: dnd/scenes`.
+- Confirm the LLM profile has a working OpenAI-compatible `base_url`, `model`,
+  and credentials.
+- Inspect retained diagnostics for the run error and resolved pipeline.
+- If the error names malformed structured output, retry with a model that
+  follows structured response schemas reliably.
+- Scene boundaries must use exact source-unit IDs, cover the full source
+  document, be contiguous, and not overlap.
+
 ## Output Write Failure
 
 Symptoms include:

internal/cli/catalog.go

@@ -10,6 +10,7 @@ import (
 	"gitea.maximumdirect.net/eric/notarius/internal/framework/contracts"
 	"gitea.maximumdirect.net/eric/notarius/internal/framework/llm"
 	"gitea.maximumdirect.net/eric/notarius/internal/framework/pipeline"
+	"gitea.maximumdirect.net/eric/notarius/internal/modules/chunk/dnd/scenes"
 	"gitea.maximumdirect.net/eric/notarius/internal/modules/chunk/generic"
 	"gitea.maximumdirect.net/eric/notarius/internal/modules/extract/dnd/spells"
 	"gitea.maximumdirect.net/eric/notarius/internal/modules/input/seriatim"
@@ -34,6 +35,9 @@ func productionRegistries() (pipeline.Registries, error) {
 	if err := generic.Register(registries.Chunkers); err != nil {
 		return pipeline.Registries{}, fmt.Errorf("register generic chunker: %w", err)
 	}
+	if err := scenes.Register(registries.Chunkers); err != nil {
+		return pipeline.Registries{}, fmt.Errorf("register dnd scenes chunker: %w", err)
+	}
 	if err := spells.Register(registries.Extractors); err != nil {
 		return pipeline.Registries{}, fmt.Errorf("register dnd spells extractor: %w", err)
 	}

internal/cli/run_test.go

@@ -16,6 +16,7 @@ import (
 	"gitea.maximumdirect.net/eric/notarius/internal/core/diagnostics"
 	"gitea.maximumdirect.net/eric/notarius/internal/framework/contracts"
 	"gitea.maximumdirect.net/eric/notarius/internal/framework/pipeline"
+	"gitea.maximumdirect.net/eric/notarius/internal/modules/chunk/dnd/scenes"
 	"gitea.maximumdirect.net/eric/notarius/internal/modules/chunk/generic"
 	"gitea.maximumdirect.net/eric/notarius/internal/modules/extract/dnd/spells"
 	"gitea.maximumdirect.net/eric/notarius/internal/modules/input/seriatim"
@@ -136,6 +137,11 @@ func TestProductionCatalogIncludesDefaultModules(t *testing.T) {
 			got:  func() (pipeline.ModuleSpec, bool) { return catalog.Chunkers.Spec(generic.Key) },
 			want: generic.ModuleSpec(),
 		},
+		{
+			name: "dnd scenes chunker",
+			got:  func() (pipeline.ModuleSpec, bool) { return catalog.Chunkers.Spec(scenes.Key) },
+			want: scenes.ModuleSpec(),
+		},
 		{
 			name: "dnd spells extractor",
 			got:  func() (pipeline.ModuleSpec, bool) { return catalog.Extractors.Spec(spells.Key) },
@@ -186,6 +192,21 @@ func TestRunConfigValidateUsesProductionCatalogByDefault(t *testing.T) {
 	}
 }
 
+func TestRunConfigValidateAcceptsDNDScenesChunker(t *testing.T) {
+	configPath := writeTestConfig(t, mvpConfigYAMLWithChunk("dnd-session", scenes.Key, "dnd/spells"))
+	var stdout bytes.Buffer
+	var stderr bytes.Buffer
+
+	code := RunWithOptions([]string{"config", "validate", "--config", configPath, "--pipeline", "dnd-session"}, &stdout, &stderr, Options{})
+
+	if code != 0 {
+		t.Fatalf("RunWithOptions() code = %d, stderr=%q", code, stderr.String())
+	}
+	if !strings.Contains(stdout.String(), "is valid for pipeline") {
+		t.Fatalf("stdout = %q, want validation success", stdout.String())
+	}
+}
+
 func TestRunConfigValidateUnknownProductionModuleIncludesContext(t *testing.T) {
 	configPath := writeTestConfig(t, mvpConfigYAML("dnd-session", "missing/extract"))
 	var stdout bytes.Buffer
@@ -1041,6 +1062,50 @@ func TestExampleFixtureRunWritesExpectedJSON(t *testing.T) {
 	}
 }
 
+func TestExampleFixtureRunWithDNDScenesRecordsChunkerAndWarnings(t *testing.T) {
+	configPath := writeTestConfig(t, mvpConfigYAMLWithChunk("dnd-session", scenes.Key, "dnd/spells"))
+	inputPath := fixturePath(t, "examples/seriatim-minimal-transcript.json")
+	outputDir := t.TempDir()
+	diagnosticsDir := t.TempDir()
+	client := newSceneRunLLMClient("Scene boundary was ambiguous.")
+	var stdout bytes.Buffer
+	var stderr bytes.Buffer
+
+	code := RunWithOptions([]string{"run", "dnd-session", "--config", configPath, "--input", inputPath, "--output-dir", outputDir, "--diagnostics-dir", diagnosticsDir}, &stdout, &stderr, Options{
+		LLMClientFactory: fakeLLMFactory(client, nil),
+	})
+
+	if code != 0 {
+		t.Fatalf("RunWithOptions() code = %d, stderr=%q", code, stderr.String())
+	}
+	if client.calls != 2 {
+		t.Fatalf("LLM calls = %d, want chunking and extraction calls", client.calls)
+	}
+	if !strings.Contains(stderr.String(), "1 warning") {
+		t.Fatalf("stderr = %q, want warning count", stderr.String())
+	}
+
+	runOutputDir := onlyChildDir(t, outputDir)
+	manifestBytes := readFile(t, filepath.Join(runOutputDir, "manifest.json"))
+	var manifest artifacts.RunManifest
+	if err := json.Unmarshal(manifestBytes, &manifest); err != nil {
+		t.Fatalf("unmarshal manifest: %v", err)
+	}
+	if manifest.Chunker != scenes.Key {
+		t.Fatalf("manifest chunker = %q, want %q", manifest.Chunker, scenes.Key)
+	}
+	for _, forbidden := range []string{"Source document ID:", "Aria casts Cure Wounds.", "spell_casts", "Scene boundary was ambiguous."} {
+		if strings.Contains(string(manifestBytes), forbidden) {
+			t.Fatalf("manifest leaked %q: %s", forbidden, manifestBytes)
+		}
+	}
+
+	warnings := string(readFile(t, filepath.Join(runOutputDir, "warnings.json")))
+	if !strings.Contains(warnings, "scene_boundary_caveat") || !strings.Contains(warnings, "Scene boundary was ambiguous.") {
+		t.Fatalf("warnings output = %s, want scene boundary caveat", warnings)
+	}
+}
+
 func TestExampleFixtureRunOnlySpells(t *testing.T) {
 	configPath := fixturePath(t, "examples/dnd-spells.config.yml")
 	inputPath := fixturePath(t, "examples/seriatim-minimal-transcript.json")
@@ -1220,6 +1285,18 @@ pipelines:
 `
 }
 
+func mvpConfigYAMLWithChunk(pipelineID string, chunker string, extractor string) string {
+	return `version: 1
+pipelines:
+  ` + pipelineID + `:
+    input: seriatim
+    chunk: ` + chunker + `
+    artifacts:
+      spells:
+        extract: ` + extractor + `
+`
+}
+
 func mvpConfigYAMLForLanes(pipelineID string, laneIDs ...string) string {
 	var b strings.Builder
 	b.WriteString("version: 1\n")
@@ -1287,6 +1364,7 @@ type fakeRunLLMClient struct {
 	calls            int
 	err              error
 	payload          map[string]any
+	sceneCaveat      string
 }
 
 func newFakeRunLLMClient(invalidSourceRef bool) *fakeRunLLMClient {
@@ -1301,11 +1379,43 @@ func newMalformedRunLLMClient() *fakeRunLLMClient {
 	return &fakeRunLLMClient{payload: map[string]any{}}
 }
 
+func newSceneRunLLMClient(caveat string) *fakeRunLLMClient {
+	return &fakeRunLLMClient{sceneCaveat: caveat}
+}
+
 func (client *fakeRunLLMClient) CompleteStructured(ctx context.Context, req contracts.StructuredCompletionRequest, out any) (contracts.StructuredCompletionResponse, error) {
 	client.calls++
 	if client.err != nil {
 		return contracts.StructuredCompletionResponse{}, client.err
 	}
+	if req.StageName == scenes.Key && client.payload == nil {
+		payload := map[string]any{
+			"scenes": []map[string]any{
+				{
+					"start_unit_id":       "seg-001",
+					"end_unit_id":         "seg-002",
+					"short_title":         "Opening spell",
+					"primary_mode":        "Narrative",
+					"main_participants":   []string{"Aria"},
+					"summary":             "Aria casts a spell.",
+					"boundary_note":       "The provided source units form one scene.",
+					"boundary_confidence": "High",
+				},
+			},
+			"boundary_caveats": []string{},
+		}
+		if client.sceneCaveat != "" {
+			payload["boundary_caveats"] = []string{client.sceneCaveat}
+		}
+		encoded, err := json.Marshal(payload)
+		if err != nil {
+			return contracts.StructuredCompletionResponse{}, err
+		}
+		if err := json.Unmarshal(encoded, out); err != nil {
+			return contracts.StructuredCompletionResponse{}, err
+		}
+		return contracts.StructuredCompletionResponse{Content: encoded}, nil
+	}
 	startUnitID := "seg-001"
 	if client.invalidSourceRef {
 		startUnitID = "missing-segment"

internal/core/config/effective_config_test.go

@@ -98,6 +98,43 @@ func TestResolveSurfacesMissingCapabilityThroughCatalog(t *testing.T) {
 	}
 }
 
+func TestResolveCanBindSceneChunkerFromCatalog(t *testing.T) {
+	cfg := validConfig()
+	profile := cfg.Pipelines["example"]
+	profile.Chunk = pipeline.Binding("dnd/scenes")
+	lane := profile.Artifacts["events"]
+	profile.Artifacts = map[string]pipeline.ArtifactLaneProfile{"events": lane}
+	cfg.Pipelines["example"] = profile
+
+	catalog := fakeCatalog(t,
+		pipeline.ModuleSpec{
+			Key:      "fake/input",
+			Stage:    pipeline.StageInput,
+			Provides: []string{"source.transcript"},
+		},
+		pipeline.ModuleSpec{
+			Key:      "fake/extract",
+			Stage:    pipeline.StageExtract,
+			Requires: []string{"chunks", "source.transcript"},
+			Provides: []string{"artifact"},
+		},
+	)
+	mustRegisterChunker(t, catalog.Chunkers, pipeline.ModuleSpec{
+		Key:      "dnd/scenes",
+		Stage:    pipeline.StageChunk,
+		Requires: []string{"source.transcript"},
+		Provides: []string{"chunks", "chunks.scenes"},
+	})
+
+	effective, err := cfg.Resolve(ResolveInput{PipelineID: "example", Catalog: catalog})
+	if err != nil {
+		t.Fatalf("Resolve() error = %v, want nil", err)
+	}
+	if got := effective.ResolvedPipeline.Chunk.Module; got != "dnd/scenes" {
+		t.Fatalf("Chunk.Module = %q, want dnd/scenes", got)
+	}
+}
+
 func TestResolveDigestChangesWhenEffectiveConfigChanges(t *testing.T) {
 	cfg := validConfig()
 	first, err := cfg.Resolve(ResolveInput{PipelineID: "example", Catalog: fakeCatalog(t)})

internal/framework/contracts/composition_test.go

@@ -17,6 +17,7 @@ var _ contracts.Extractor = compositionExtractor{}
 var _ contracts.Merger = compositionMerger{}
 var _ contracts.Normalizer = compositionNormalizer{}
 var _ contracts.Validator = compositionValidator{}
+var _ contracts.StructuredLLMClient = compositionLLMClient{}
 var _ contracts.OutputEncoder = compositionOutputEncoder{}
 
 func TestContractsComposeAcrossPackages(t *testing.T) {
@@ -38,8 +39,9 @@ func TestContractsComposeAcrossPackages(t *testing.T) {
 	}
 
 	chunking, err := chunker.Chunk(ctx, contracts.ChunkRequest{
-		Source:   doc,
+		Source:    doc,
-		Metadata: map[string]any{"max_units": 2},
+		LLMClient: compositionLLMClient{},
+		Metadata:  map[string]any{"max_units": 2},
 	})
 	if err != nil {
 		t.Fatalf("Chunk() error = %v, want nil", err)
@@ -164,6 +166,9 @@ func (chunker compositionChunker) Chunk(ctx context.Context, req contracts.Chunk
 	if req.Source == nil {
 		return contracts.ChunkResult{}, errors.New("source document is required")
 	}
+	if req.LLMClient == nil {
+		return contracts.ChunkResult{}, errors.New("structured llm client is required")
+	}
 
 	return contracts.ChunkResult{
 		Chunks: []contracts.SourceChunk{
@@ -178,6 +183,12 @@ func (chunker compositionChunker) Chunk(ctx context.Context, req contracts.Chunk
 	}, nil
 }
 
+type compositionLLMClient struct{}
+
+func (client compositionLLMClient) CompleteStructured(ctx context.Context, req contracts.StructuredCompletionRequest, out any) (contracts.StructuredCompletionResponse, error) {
+	return contracts.StructuredCompletionResponse{}, nil
+}
+
 type compositionExtractor struct{}
 
 func (extractor compositionExtractor) Key() string {

internal/framework/contracts/contracts.go

@@ -58,6 +58,7 @@ type SourceChunk struct {
 
 type ChunkRequest struct {
 	Source     *source.SourceDocument `json:"-"`
+	LLMClient  StructuredLLMClient    `json:"-"`
 	LLMProfile string                 `json:"llm_profile,omitempty"`
 	Options    map[string]any         `json:"options,omitempty"`
 	Metadata   map[string]any         `json:"metadata,omitempty"`

internal/framework/contracts/contracts_test.go

@@ -117,6 +117,27 @@ func TestFakeChunkerReturnsSourceChunks(t *testing.T) {
 	}
 }
 
+func TestFakeChunkerReceivesLLMClient(t *testing.T) {
+	doc := &source.SourceDocument{
+		ID:     "source-1",
+		Kind:   "document",
+		Format: "text/plain",
+		Digest: "sha256:abc123",
+		Units: []source.SourceUnit{
+			{ID: "u1", Kind: "section", Text: "Source text."},
+		},
+	}
+	client := fakeLLMClient{}
+	chunker := &recordingChunker{key: "llm-chunker"}
+
+	if _, err := chunker.Chunk(context.Background(), ChunkRequest{Source: doc, LLMClient: client}); err != nil {
+		t.Fatalf("Chunk() error = %v, want nil", err)
+	}
+	if chunker.request.LLMClient == nil {
+		t.Fatal("ChunkRequest.LLMClient = nil, want structured LLM client")
+	}
+}
+
 func TestFakeExtractorReceivesChunkAndAmbientContext(t *testing.T) {
 	extractor := fakeExtractor{
 		key:           "generic-extractor",
@@ -305,6 +326,20 @@ func (chunker fakeChunker) Chunk(ctx context.Context, req ChunkRequest) (ChunkRe
 	}, nil
 }
 
+type recordingChunker struct {
+	key     string
+	request ChunkRequest
+}
+
+func (chunker *recordingChunker) Key() string {
+	return chunker.key
+}
+
+func (chunker *recordingChunker) Chunk(ctx context.Context, req ChunkRequest) (ChunkResult, error) {
+	chunker.request = req
+	return fakeChunker{key: chunker.key}.Chunk(ctx, req)
+}
+
 type fakeExtractor struct {
 	key           string
 	artifactType  string

internal/framework/pipeline/chunk_validation.go

@@ -0,0 +1,60 @@
+package pipeline
+
+import (
+	"fmt"
+	"strings"
+
+	"gitea.maximumdirect.net/eric/notarius/internal/core/source"
+	"gitea.maximumdirect.net/eric/notarius/internal/framework/contracts"
+)
+
+func validateChunkResult(doc *source.SourceDocument, chunks []contracts.SourceChunk) error {
+	sourceUnitIndexes := make(map[string]int, len(doc.Units))
+	for index, unit := range doc.Units {
+		sourceUnitIndexes[unit.ID] = index
+	}
+
+	seenChunkIDs := make(map[string]struct{}, len(chunks))
+	for chunkIndex, chunk := range chunks {
+		if strings.TrimSpace(chunk.ID) == "" {
+			return fmt.Errorf("chunk[%d].id must not be empty", chunkIndex)
+		}
+		if _, ok := seenChunkIDs[chunk.ID]; ok {
+			return fmt.Errorf("chunk id %q is duplicated", chunk.ID)
+		}
+		seenChunkIDs[chunk.ID] = struct{}{}
+
+		if chunk.SourceID != doc.ID {
+			return fmt.Errorf("chunk %q source_id %q does not match source document id %q", chunk.ID, chunk.SourceID, doc.ID)
+		}
+		if chunk.Index != chunkIndex {
+			return fmt.Errorf("chunk %q index %d does not match returned order %d", chunk.ID, chunk.Index, chunkIndex)
+		}
+		if len(chunk.Units) == 0 {
+			return fmt.Errorf("chunk %q units must not be empty", chunk.ID)
+		}
+
+		seenUnitIDs := make(map[string]struct{}, len(chunk.Units))
+		previousSourceIndex := -1
+		for unitIndex, unit := range chunk.Units {
+			if strings.TrimSpace(unit.ID) == "" {
+				return fmt.Errorf("chunk %q unit[%d].id must not be empty", chunk.ID, unitIndex)
+			}
+			if _, ok := seenUnitIDs[unit.ID]; ok {
+				return fmt.Errorf("chunk %q repeats source unit %q", chunk.ID, unit.ID)
+			}
+			seenUnitIDs[unit.ID] = struct{}{}
+
+			sourceIndex, ok := sourceUnitIndexes[unit.ID]
+			if !ok {
+				return fmt.Errorf("chunk %q source unit %q was not found in source document %q", chunk.ID, unit.ID, doc.ID)
+			}
+			if sourceIndex <= previousSourceIndex {
+				return fmt.Errorf("chunk %q source units must appear in source document order", chunk.ID)
+			}
+			previousSourceIndex = sourceIndex
+		}
+	}
+
+	return nil
+}

internal/framework/pipeline/runner.go

@@ -91,6 +91,7 @@ func (r *Runner) Run(ctx context.Context, input RunInput) (RunOutput, error) {
 	}
 	chunkResult, err := chunker.Chunk(ctx, contracts.ChunkRequest{
 		Source:     doc,
+		LLMClient:  input.LLMClient,
 		LLMProfile: input.Pipeline.Chunk.LLMProfile,
 		Options:    cloneOptions(input.Pipeline.Chunk.Options),
 		Metadata:   input.Metadata,
@@ -102,6 +103,9 @@ func (r *Runner) Run(ctx context.Context, input RunInput) (RunOutput, error) {
 	if len(chunkResult.Chunks) == 0 {
 		return failOutput(output), fmt.Errorf("chunker %q returned no chunks", chunker.Key())
 	}
+	if err := validateChunkResult(doc, chunkResult.Chunks); err != nil {
+		return failOutput(output), fmt.Errorf("validate chunks from chunker %q: %w", chunker.Key(), err)
+	}
 
 	nextCandidateIndex := 0
 	for _, lane := range input.Pipeline.ArtifactLanes {

internal/framework/pipeline/runner_test.go

@@ -256,6 +256,91 @@ func TestRunRejectsChunkerBuildChunkAndEmptyChunkErrors(t *testing.T) {
 	}
 }
 
+func TestRunRejectsInvalidChunks(t *testing.T) {
+	tests := []struct {
+		name   string
+		chunks []contracts.SourceChunk
+		want   string
+	}{
+		{
+			name:   "empty chunk id",
+			chunks: []contracts.SourceChunk{{ID: "", SourceID: "source-1", Index: 0, Units: []source.SourceUnit{unitWithID("u1")}}},
+			want:   "id must not be empty",
+		},
+		{
+			name: "duplicate chunk id",
+			chunks: []contracts.SourceChunk{
+				{ID: "chunk-0", SourceID: "source-1", Index: 0, Units: []source.SourceUnit{unitWithID("u1")}},
+				{ID: "chunk-0", SourceID: "source-1", Index: 1, Units: []source.SourceUnit{unitWithID("u2")}},
+			},
+			want: "duplicated",
+		},
+		{
+			name:   "wrong source id",
+			chunks: []contracts.SourceChunk{{ID: "chunk-0", SourceID: "other-source", Index: 0, Units: []source.SourceUnit{unitWithID("u1")}}},
+			want:   "source_id",
+		},
+		{
+			name:   "wrong index",
+			chunks: []contracts.SourceChunk{{ID: "chunk-0", SourceID: "source-1", Index: 1, Units: []source.SourceUnit{unitWithID("u1")}}},
+			want:   "index",
+		},
+		{
+			name:   "empty units",
+			chunks: []contracts.SourceChunk{{ID: "chunk-0", SourceID: "source-1", Index: 0}},
+			want:   "units must not be empty",
+		},
+		{
+			name:   "repeated unit inside chunk",
+			chunks: []contracts.SourceChunk{{ID: "chunk-0", SourceID: "source-1", Index: 0, Units: []source.SourceUnit{unitWithID("u1"), unitWithID("u1")}}},
+			want:   "repeats source unit",
+		},
+		{
+			name:   "unknown unit",
+			chunks: []contracts.SourceChunk{{ID: "chunk-0", SourceID: "source-1", Index: 0, Units: []source.SourceUnit{unitWithID("u9")}}},
+			want:   "was not found",
+		},
+		{
+			name:   "units out of source order",
+			chunks: []contracts.SourceChunk{{ID: "chunk-0", SourceID: "source-1", Index: 0, Units: []source.SourceUnit{unitWithID("u2"), unitWithID("u1")}}},
+			want:   "source document order",
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			modules := defaultRunnerModules()
+			modules.chunker.chunks = test.chunks
+
+			output, err := New(newRunnerRegistries(t, modules)).Run(context.Background(), RunInput{Pipeline: resolvedPipeline()})
+
+			assertRunError(t, err, test.want)
+			if output.Manifest.ValidationStatus != "failed" {
+				t.Fatalf("ValidationStatus = %q, want failed", output.Manifest.ValidationStatus)
+			}
+			if len(modules.extractors["extract-alpha"].requests) != 0 {
+				t.Fatalf("extractor calls = %d, want none after invalid chunks", len(modules.extractors["extract-alpha"].requests))
+			}
+		})
+	}
+}
+
+func TestRunAllowsPartialCoverageAndOverlappingChunks(t *testing.T) {
+	modules := defaultRunnerModules()
+	modules.chunker.chunks = []contracts.SourceChunk{
+		{ID: "chunk-0", SourceID: "source-1", Index: 0, Units: []source.SourceUnit{unitWithID("u1"), unitWithID("u2")}},
+		{ID: "chunk-1", SourceID: "source-1", Index: 1, Units: []source.SourceUnit{unitWithID("u2")}},
+	}
+
+	output, err := New(newRunnerRegistries(t, modules)).Run(context.Background(), RunInput{Pipeline: resolvedPipeline()})
+	if err != nil {
+		t.Fatalf("Run() error = %v, want nil", err)
+	}
+	if len(output.Approved) != 2 {
+		t.Fatalf("len(Approved) = %d, want one candidate per accepted chunk", len(output.Approved))
+	}
+}
+
 func TestRunExecutesChunksAndPassesChunkAndLLMClient(t *testing.T) {
 	modules := defaultRunnerModules()
 	llmClient := fakeLLMClient{}
@@ -273,6 +358,9 @@ func TestRunExecutesChunksAndPassesChunkAndLLMClient(t *testing.T) {
 	if !reflect.DeepEqual(extractor.seenChunkIDs, []string{"chunk-0", "chunk-1"}) {
 		t.Fatalf("seen chunks = %#v, want both chunks", extractor.seenChunkIDs)
 	}
+	if len(modules.chunker.requests) != 1 || modules.chunker.requests[0].LLMClient == nil {
+		t.Fatalf("chunker LLM client = %#v, want client on chunk request", modules.chunker.requests)
+	}
 	if len(extractor.seenLLMClients) != 2 || extractor.seenLLMClients[0] == nil || extractor.seenLLMClients[1] == nil {
 		t.Fatalf("seen LLM clients = %#v, want client for each chunk", extractor.seenLLMClients)
 	}
@@ -1179,6 +1267,8 @@ func validSourceDocument() *source.SourceDocument {
 		Digest: "sha256:source",
 		Units: []source.SourceUnit{
 			{ID: "u1", Kind: "unit", Text: "Source unit."},
+			{ID: "u2", Kind: "unit", Text: "Second source unit."},
+			{ID: "u3", Kind: "unit", Text: "Third source unit."},
 		},
 	}
 }
@@ -1194,6 +1284,19 @@ func sourceChunkWithID(id string, index int) contracts.SourceChunk {
 	}
 }
 
+func unitWithID(id string) source.SourceUnit {
+	switch id {
+	case "u1":
+		return source.SourceUnit{ID: "u1", Kind: "unit", Text: "Source unit."}
+	case "u2":
+		return source.SourceUnit{ID: "u2", Kind: "unit", Text: "Second source unit."}
+	case "u3":
+		return source.SourceUnit{ID: "u3", Kind: "unit", Text: "Third source unit."}
+	default:
+		return source.SourceUnit{ID: id, Kind: "unit", Text: "Unknown source unit."}
+	}
+}
+
 func warningReasons(warnings []contracts.Warning) []string {
 	reasons := make([]string, 0, len(warnings))
 	for _, warning := range warnings {

internal/modules/chunk/dnd/scenes/assets.go

@@ -0,0 +1,6 @@
+package scenes
+
+import "embed"
+
+//go:embed assets/prompts/*.md assets/schemas/*.json
+var embeddedAssets embed.FS

internal/modules/chunk/dnd/scenes/assets/prompts/system.md

@@ -0,0 +1,9 @@
+You identify coherent scenes in Dungeons & Dragons session source units.
+
+{{ hardening }}
+
+Use only the provided source units. Source text may contain transcription
+errors, repeated lines, incomplete sentences, and misheard proper nouns. Speaker
+metadata, when present, may be treated as accurate.
+
+Return only valid JSON matching the provided response schema.

internal/modules/chunk/dnd/scenes/assets/prompts/user.md

@@ -0,0 +1,71 @@
+Source document ID: {{ .SourceID }}
+
+Ordered source units:
+{{ range .Units }}
+- Unit ID: {{ .ID }}
+  Text: {{ .Text }}
+{{ if .Metadata }}
+  Metadata:
+{{ range .Metadata }}
+  - {{ .Key }}: {{ .Value }}
+{{ end }}
+{{ end }}
+{{ end }}
+
+Divide these source units into D&D scenes for the dnd/scenes chunk module.
+
+A scene is a coherent unit of play. Start a new scene when there is a meaningful
+change in location, objective, threat, activity, encounter, or mode of play.
+
+Good reasons to start a new scene include:
+- the party moves to a new location;
+- a combat encounter begins or ends;
+- combat changes into a substantially different phase;
+- the party shifts between combat, exploration, social interaction, discussion,
+  planning, travel, rest, or downtime;
+- a new NPC, faction, threat, or objective becomes central;
+- the party completes one immediate goal and begins another;
+- a major table-level rules discussion interrupts and materially changes play.
+
+Do not start a new scene merely because:
+- the speaker changes;
+- a new combat round begins;
+- a player asks a brief rules question;
+- there is a joke, aside, or short table comment;
+- a character takes a routine turn;
+- the same encounter continues without a meaningful change in situation.
+
+dnd/scenes boundary policy:
+- cover the full provided source document from the first source unit to the last
+  source unit;
+- return sequential scenes with no gaps;
+- do not overlap scenes;
+- preserve source-unit order;
+- use exact source-unit IDs from the ordered source units;
+- each scene must have start_unit_id and end_unit_id;
+- do not include final chunk IDs or chunk indexes.
+
+For each scene:
+- short_title should be brief and factual;
+- primary_mode must be Recap, Discussion, Combat, or Narrative;
+- main_participants should include only principal characters, NPCs, factions, or
+  groups involved;
+- summary should be factual and compact, usually one to three sentences;
+- boundary_note should explain why the scene begins at start_unit_id and ends at
+  end_unit_id;
+- boundary_confidence must be High, Medium, or Low.
+
+Primary mode guidance:
+- Use Recap for opening recap, initiative setup, session framing, or immediate
+  continuation from prior events.
+- Use Discussion when the party is primarily discussing options or choosing a
+  course of action.
+- Use Combat when active combat or combat-resolution mechanics dominate.
+- Use Narrative for all other non-combat gameplay, including exploration, social
+  interactions, shopping, preparation, travel, rest, and downtime.
+
+In boundary_caveats, list overall caveats about scene divisions. Include scenes
+that could reasonably be split differently, combat phases that were kept
+together, gradual transitions, or places where map context would have helped.
+
+Return exactly one JSON object and no explanatory text.

internal/modules/chunk/dnd/scenes/assets/schemas/dnd_scenes.v1.json

@@ -0,0 +1,83 @@
+{
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "$id": "notarius.dnd.scenes",
+  "type": "object",
+  "additionalProperties": false,
+  "required": [
+    "scenes",
+    "boundary_caveats"
+  ],
+  "properties": {
+    "scenes": {
+      "type": "array",
+      "minItems": 1,
+      "items": {
+        "type": "object",
+        "additionalProperties": false,
+        "required": [
+          "start_unit_id",
+          "end_unit_id",
+          "short_title",
+          "primary_mode",
+          "main_participants",
+          "summary",
+          "boundary_note",
+          "boundary_confidence"
+        ],
+        "properties": {
+          "start_unit_id": {
+            "type": "string",
+            "minLength": 1
+          },
+          "end_unit_id": {
+            "type": "string",
+            "minLength": 1
+          },
+          "short_title": {
+            "type": "string",
+            "minLength": 1
+          },
+          "primary_mode": {
+            "type": "string",
+            "enum": [
+              "Recap",
+              "Discussion",
+              "Combat",
+              "Narrative"
+            ]
+          },
+          "main_participants": {
+            "type": "array",
+            "minItems": 1,
+            "items": {
+              "type": "string",
+              "minLength": 1
+            }
+          },
+          "summary": {
+            "type": "string",
+            "minLength": 1
+          },
+          "boundary_note": {
+            "type": "string",
+            "minLength": 1
+          },
+          "boundary_confidence": {
+            "type": "string",
+            "enum": [
+              "High",
+              "Medium",
+              "Low"
+            ]
+          }
+        }
+      }
+    },
+    "boundary_caveats": {
+      "type": "array",
+      "items": {
+        "type": "string"
+      }
+    }
+  }
+}

internal/modules/chunk/dnd/scenes/chunker.go

@@ -0,0 +1,303 @@
+package scenes
+
+import (
+	"context"
+	"fmt"
+	"strings"
+
+	"gitea.maximumdirect.net/eric/notarius/internal/core/source"
+	"gitea.maximumdirect.net/eric/notarius/internal/framework/contracts"
+	"gitea.maximumdirect.net/eric/notarius/internal/framework/pipeline"
+)
+
+const Key = "dnd/scenes"
+
+var requiredCapabilities = []string{
+	"source.transcript",
+}
+
+var providedCapabilities = []string{
+	"chunks",
+	"chunks.scenes",
+}
+
+var _ contracts.Chunker = (*Chunker)(nil)
+var _ contracts.ManifestMetadataProvider = (*Chunker)(nil)
+
+type Chunker struct{}
+
+func New() *Chunker {
+	return &Chunker{}
+}
+
+func (c *Chunker) Key() string {
+	return Key
+}
+
+func (c *Chunker) ManifestMetadata() map[string]any {
+	promptMetadata := scenesPromptBundle.Metadata()
+	metadata := map[string]any{
+		"prompt_id":            PromptID,
+		"prompt_version":       promptMetadata.PromptVersion,
+		"prompt_sha256":        promptMetadata.SHA256,
+		"response_schema_key":  string(ResponseSchemaKey),
+		"response_schema_id":   ResponseSchemaID,
+		"response_schema_name": ResponseSchemaName,
+	}
+	if schema, err := loadResponseSchema(); err == nil {
+		metadata["response_schema_version"] = schema.Version
+		metadata["response_schema_sha256"] = schema.SHA256
+	}
+	return metadata
+}
+
+func (c *Chunker) Chunk(ctx context.Context, req contracts.ChunkRequest) (contracts.ChunkResult, error) {
+	if c == nil {
+		return contracts.ChunkResult{}, chunkerErrorf("chunker must not be nil")
+	}
+	if ctx == nil {
+		return contracts.ChunkResult{}, chunkerErrorf("context must not be nil")
+	}
+	if err := ctx.Err(); err != nil {
+		return contracts.ChunkResult{}, chunkerErrorf("context error before chunking: %w", err)
+	}
+	if req.Source == nil {
+		return contracts.ChunkResult{}, chunkerErrorf("source must not be nil")
+	}
+	if len(req.Source.Units) == 0 {
+		return contracts.ChunkResult{}, chunkerErrorf("source units must not be empty")
+	}
+	if err := source.ValidateDocument(req.Source); err != nil {
+		return contracts.ChunkResult{}, chunkerErrorf("validate source document: %w", err)
+	}
+	if req.LLMClient == nil {
+		return contracts.ChunkResult{}, chunkerErrorf("LLM client must not be nil")
+	}
+	if len(req.Options) > 0 {
+		return contracts.ChunkResult{}, chunkerErrorf("options are not supported")
+	}
+
+	system, user, _, err := renderPrompt(req)
+	if err != nil {
+		return contracts.ChunkResult{}, chunkerErrorf("render prompt: %w", err)
+	}
+	schema, err := loadResponseSchema()
+	if err != nil {
+		return contracts.ChunkResult{}, chunkerErrorf("load response schema %q: %w", ResponseSchemaKey, err)
+	}
+
+	var response chunkResponse
+	if _, err := req.LLMClient.CompleteStructured(ctx, contracts.StructuredCompletionRequest{
+		StageName: Key,
+		Messages: []contracts.LLMMessage{
+			{Role: "system", Content: system},
+			{Role: "user", Content: user},
+		},
+		ResponseSchemaName: schema.Name,
+		ResponseSchema:     schema.JSONSchema,
+	}, &response); err != nil {
+		return contracts.ChunkResult{}, chunkerErrorf("complete structured output: %w", err)
+	}
+
+	chunks, err := chunksFromResponse(req.Source, response)
+	if err != nil {
+		return contracts.ChunkResult{}, chunkerErrorf("malformed structured output: %w", err)
+	}
+	return contracts.ChunkResult{
+		Chunks:   chunks,
+		Warnings: warningsFromCaveats(response.BoundaryCaveats),
+	}, nil
+}
+
+func ModuleSpec() pipeline.ModuleSpec {
+	return pipeline.ModuleSpec{
+		Key:      Key,
+		Stage:    pipeline.StageChunk,
+		Requires: append([]string(nil), requiredCapabilities...),
+		Provides: append([]string(nil), providedCapabilities...),
+	}
+}
+
+func Register(registry *pipeline.ChunkerRegistry) error {
+	return registry.RegisterWithSpec(ModuleSpec(), func() (contracts.Chunker, error) {
+		return New(), nil
+	})
+}
+
+func chunksFromResponse(doc *source.SourceDocument, response chunkResponse) ([]contracts.SourceChunk, error) {
+	if response.Scenes == nil {
+		return nil, fmt.Errorf("scenes must be present")
+	}
+	if len(response.Scenes) == 0 {
+		return nil, fmt.Errorf("scenes must not be empty")
+	}
+
+	unitIndexes := make(map[string]int, len(doc.Units))
+	for i, unit := range doc.Units {
+		unitIndexes[unit.ID] = i
+	}
+
+	chunks := make([]contracts.SourceChunk, 0, len(response.Scenes))
+	previousEnd := -1
+	for i, scene := range response.Scenes {
+		normalized, err := normalizeScene(i, scene)
+		if err != nil {
+			return nil, err
+		}
+
+		startIndex, ok := unitIndexes[normalized.StartUnitID]
+		if !ok {
+			return nil, fmt.Errorf("scene[%d] start_unit_id %q was not found", i, normalized.StartUnitID)
+		}
+		endIndex, ok := unitIndexes[normalized.EndUnitID]
+		if !ok {
+			return nil, fmt.Errorf("scene[%d] end_unit_id %q was not found", i, normalized.EndUnitID)
+		}
+		if startIndex > endIndex {
+			return nil, fmt.Errorf("scene[%d] start_unit_id %q appears after end_unit_id %q", i, normalized.StartUnitID, normalized.EndUnitID)
+		}
+
+		if i == 0 && startIndex != 0 {
+			return nil, fmt.Errorf("first scene must start at first source unit %q", doc.Units[0].ID)
+		}
+		if i > 0 {
+			if startIndex <= previousEnd {
+				return nil, fmt.Errorf("scene[%d] overlaps previous scene", i)
+			}
+			if startIndex > previousEnd+1 {
+				return nil, fmt.Errorf("scene[%d] leaves a gap after previous scene", i)
+			}
+		}
+		previousEnd = endIndex
+
+		units := cloneUnits(doc.Units[startIndex : endIndex+1])
+		chunks = append(chunks, contracts.SourceChunk{
+			ID:       fmt.Sprintf("scene-%06d", i+1),
+			SourceID: doc.ID,
+			Index:    i,
+			Units:    units,
+			Metadata: map[string]any{
+				"scene_title":         normalized.ShortTitle,
+				"primary_mode":        normalized.PrimaryMode,
+				"main_participants":   append([]string(nil), normalized.MainParticipants...),
+				"summary":             normalized.Summary,
+				"boundary_note":       normalized.BoundaryNote,
+				"boundary_confidence": normalized.BoundaryConfidence,
+				"start_unit_id":       normalized.StartUnitID,
+				"end_unit_id":         normalized.EndUnitID,
+				"unit_count":          len(units),
+			},
+		})
+	}
+
+	if previousEnd != len(doc.Units)-1 {
+		return nil, fmt.Errorf("final scene must end at final source unit %q", doc.Units[len(doc.Units)-1].ID)
+	}
+	return chunks, nil
+}
+
+func normalizeScene(index int, scene sceneResponse) (sceneResponse, error) {
+	out := sceneResponse{
+		StartUnitID:        strings.TrimSpace(scene.StartUnitID),
+		EndUnitID:          strings.TrimSpace(scene.EndUnitID),
+		ShortTitle:         strings.TrimSpace(scene.ShortTitle),
+		PrimaryMode:        strings.TrimSpace(scene.PrimaryMode),
+		Summary:            strings.TrimSpace(scene.Summary),
+		BoundaryNote:       strings.TrimSpace(scene.BoundaryNote),
+		BoundaryConfidence: strings.TrimSpace(scene.BoundaryConfidence),
+	}
+
+	required := map[string]string{
+		"start_unit_id":       out.StartUnitID,
+		"end_unit_id":         out.EndUnitID,
+		"short_title":         out.ShortTitle,
+		"primary_mode":        out.PrimaryMode,
+		"summary":             out.Summary,
+		"boundary_note":       out.BoundaryNote,
+		"boundary_confidence": out.BoundaryConfidence,
+	}
+	for field, value := range required {
+		if value == "" {
+			return sceneResponse{}, fmt.Errorf("scene[%d] %s must not be empty", index, field)
+		}
+	}
+	if !validPrimaryMode(out.PrimaryMode) {
+		return sceneResponse{}, fmt.Errorf("scene[%d] primary_mode %q is not supported", index, out.PrimaryMode)
+	}
+	if !validBoundaryConfidence(out.BoundaryConfidence) {
+		return sceneResponse{}, fmt.Errorf("scene[%d] boundary_confidence %q is not supported", index, out.BoundaryConfidence)
+	}
+	if len(scene.MainParticipants) == 0 {
+		return sceneResponse{}, fmt.Errorf("scene[%d] main_participants must not be empty", index)
+	}
+	out.MainParticipants = make([]string, 0, len(scene.MainParticipants))
+	for participantIndex, participant := range scene.MainParticipants {
+		trimmed := strings.TrimSpace(participant)
+		if trimmed == "" {
+			return sceneResponse{}, fmt.Errorf("scene[%d] main_participants[%d] must not be empty", index, participantIndex)
+		}
+		out.MainParticipants = append(out.MainParticipants, trimmed)
+	}
+	return out, nil
+}
+
+func validPrimaryMode(value string) bool {
+	switch value {
+	case "Recap", "Discussion", "Combat", "Narrative":
+		return true
+	default:
+		return false
+	}
+}
+
+func validBoundaryConfidence(value string) bool {
+	switch value {
+	case "High", "Medium", "Low":
+		return true
+	default:
+		return false
+	}
+}
+
+func warningsFromCaveats(caveats []string) []contracts.Warning {
+	if len(caveats) == 0 {
+		return nil
+	}
+	warnings := make([]contracts.Warning, 0, len(caveats))
+	for _, caveat := range caveats {
+		warnings = append(warnings, contracts.Warning{
+			Scope:      Key,
+			ReasonCode: "scene_boundary_caveat",
+			Message:    caveat,
+		})
+	}
+	return warnings
+}
+
+func cloneUnits(units []source.SourceUnit) []source.SourceUnit {
+	out := make([]source.SourceUnit, 0, len(units))
+	for _, unit := range units {
+		out = append(out, source.SourceUnit{
+			ID:       unit.ID,
+			Kind:     unit.Kind,
+			Text:     unit.Text,
+			Metadata: cloneMetadata(unit.Metadata),
+		})
+	}
+	return out
+}
+
+func cloneMetadata(metadata map[string]any) map[string]any {
+	if len(metadata) == 0 {
+		return nil
+	}
+	out := make(map[string]any, len(metadata))
+	for key, value := range metadata {
+		out[key] = value
+	}
+	return out
+}
+
+func chunkerErrorf(format string, args ...any) error {
+	return fmt.Errorf("dnd scenes chunker: "+format, args...)
+}

internal/modules/chunk/dnd/scenes/chunker_test.go

@@ -0,0 +1,465 @@
+package scenes
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"errors"
+	"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"
+)
+
+func TestNewModuleSpecAndRegister(t *testing.T) {
+	chunker := New()
+	if chunker == nil {
+		t.Fatal("New() = nil, want chunker")
+	}
+	if chunker.Key() != Key {
+		t.Fatalf("Key() = %q, want %q", chunker.Key(), Key)
+	}
+
+	want := pipeline.ModuleSpec{
+		Key:      Key,
+		Stage:    pipeline.StageChunk,
+		Requires: []string{"source.transcript"},
+		Provides: []string{"chunks", "chunks.scenes"},
+	}
+	if got := ModuleSpec(); !reflect.DeepEqual(got, want) {
+		t.Fatalf("ModuleSpec() = %#v, want %#v", got, want)
+	}
+	got := ModuleSpec()
+	got.Requires[0] = "changed"
+	got.Provides[0] = "changed"
+	if again := ModuleSpec(); !reflect.DeepEqual(again, want) {
+		t.Fatalf("ModuleSpec() after caller mutation = %#v, want %#v", again, want)
+	}
+
+	registry := pipeline.NewChunkerRegistry()
+	if err := Register(registry); err != nil {
+		t.Fatalf("Register() error = %v, want nil", err)
+	}
+	registered, ok := registry.Spec(Key)
+	if !ok {
+		t.Fatalf("Spec(%q) ok = false, want true", Key)
+	}
+	if !reflect.DeepEqual(registered, want) {
+		t.Fatalf("registered spec = %#v, want %#v", registered, want)
+	}
+	built, err := registry.Build(Key)
+	if err != nil {
+		t.Fatalf("Build(%q) error = %v, want nil", Key, err)
+	}
+	if built.Key() != Key {
+		t.Fatalf("built Key() = %q, want %q", built.Key(), Key)
+	}
+}
+
+func TestRegisterNilRegistryReturnsError(t *testing.T) {
+	err := Register(nil)
+	if err == nil {
+		t.Fatal("Register(nil) error = nil, want error")
+	}
+	if !strings.Contains(err.Error(), "chunker registry") {
+		t.Fatalf("Register(nil) error = %q, want registry context", err.Error())
+	}
+}
+
+func TestChunkReturnsSceneChunksFromStructuredOutput(t *testing.T) {
+	client := &fakeScenesLLMClient{
+		response: chunkResponse{
+			Scenes: []sceneResponse{
+				{
+					StartUnitID:        "seg-001",
+					EndUnitID:          "seg-002",
+					ShortTitle:         " Goblin parley ",
+					PrimaryMode:        "Discussion",
+					MainParticipants:   []string{" Aria ", "Goblin scout"},
+					Summary:            " The party negotiates with a scout. ",
+					BoundaryNote:       " The scene covers the discussion before fighting starts. ",
+					BoundaryConfidence: "High",
+				},
+				{
+					StartUnitID:        "seg-003",
+					EndUnitID:          "seg-004",
+					ShortTitle:         "Ambush at the gate",
+					PrimaryMode:        "Combat",
+					MainParticipants:   []string{"Aria", "Goblin ambushers"},
+					Summary:            "The goblins attack at the gate.",
+					BoundaryNote:       "Combat begins and resolves the immediate threat.",
+					BoundaryConfidence: "Medium",
+				},
+			},
+			BoundaryCaveats: []string{"The transition into combat is gradual."},
+		},
+	}
+
+	result, err := New().Chunk(context.Background(), chunkRequestWithClient(client))
+	if err != nil {
+		t.Fatalf("Chunk() error = %v, want nil", err)
+	}
+
+	if len(client.requests) != 1 {
+		t.Fatalf("LLM calls = %d, want 1", len(client.requests))
+	}
+	req := client.requests[0]
+	if req.StageName != Key {
+		t.Fatalf("StageName = %q, want %q", req.StageName, Key)
+	}
+	schema, err := loadResponseSchema()
+	if err != nil {
+		t.Fatalf("loadResponseSchema() error = %v, want nil", err)
+	}
+	if req.ResponseSchemaName != schema.Name {
+		t.Fatalf("ResponseSchemaName = %q, want %q", req.ResponseSchemaName, schema.Name)
+	}
+	if !bytes.Equal(req.ResponseSchema, schema.JSONSchema) {
+		t.Fatal("ResponseSchema does not match D&D scenes schema")
+	}
+	if len(req.Messages) != 2 || req.Messages[0].Role != "system" || req.Messages[1].Role != "user" {
+		t.Fatalf("Messages = %#v, want system then user", req.Messages)
+	}
+	for _, want := range []string{"session-alpha", "seg-001", "seg-004", "start_unit_id", "boundary_confidence"} {
+		if !strings.Contains(req.Messages[1].Content, want) {
+			t.Fatalf("user message = %q, want substring %q", req.Messages[1].Content, want)
+		}
+	}
+
+	if got := chunkIDs(result.Chunks); !reflect.DeepEqual(got, []string{"scene-000001", "scene-000002"}) {
+		t.Fatalf("chunk IDs = %#v, want deterministic scene IDs", got)
+	}
+	gotUnits := [][]string{unitIDs(result.Chunks[0].Units), unitIDs(result.Chunks[1].Units)}
+	wantUnits := [][]string{{"seg-001", "seg-002"}, {"seg-003", "seg-004"}}
+	if !reflect.DeepEqual(gotUnits, wantUnits) {
+		t.Fatalf("chunk units = %#v, want %#v", gotUnits, wantUnits)
+	}
+	first := result.Chunks[0]
+	if first.SourceID != "session-alpha" || first.Index != 0 {
+		t.Fatalf("first chunk = %#v, want source and index fields", first)
+	}
+	if first.Metadata["scene_title"] != "Goblin parley" ||
+		first.Metadata["primary_mode"] != "Discussion" ||
+		first.Metadata["summary"] != "The party negotiates with a scout." ||
+		first.Metadata["boundary_note"] != "The scene covers the discussion before fighting starts." ||
+		first.Metadata["boundary_confidence"] != "High" ||
+		first.Metadata["start_unit_id"] != "seg-001" ||
+		first.Metadata["end_unit_id"] != "seg-002" ||
+		first.Metadata["unit_count"] != 2 {
+		t.Fatalf("first metadata = %#v, want scene metadata", first.Metadata)
+	}
+	if got, ok := first.Metadata["main_participants"].([]string); !ok || !reflect.DeepEqual(got, []string{"Aria", "Goblin scout"}) {
+		t.Fatalf("main_participants = %#v, want trimmed participant slice", first.Metadata["main_participants"])
+	}
+	if got := result.Warnings; len(got) != 1 ||
+		got[0].Scope != Key ||
+		got[0].ReasonCode != "scene_boundary_caveat" ||
+		got[0].Message != "The transition into combat is gradual." {
+		t.Fatalf("Warnings = %#v, want boundary caveat warning", got)
+	}
+}
+
+func TestChunkDefensivelyCopiesSourceUnitsAndMetadata(t *testing.T) {
+	doc := sceneSourceDocument()
+	client := &fakeScenesLLMClient{response: validSceneResponse()}
+
+	result, err := New().Chunk(context.Background(), contracts.ChunkRequest{
+		Source:    doc,
+		LLMClient: client,
+	})
+	if err != nil {
+		t.Fatalf("Chunk() error = %v, want nil", err)
+	}
+
+	doc.Units[0].ID = "mutated"
+	doc.Units[0].Metadata["speaker"] = "mutated"
+	client.response.Scenes[0].MainParticipants[0] = "mutated"
+
+	if result.Chunks[0].Units[0].ID != "seg-001" {
+		t.Fatalf("chunk unit ID changed after source mutation: %#v", result.Chunks[0].Units[0])
+	}
+	if result.Chunks[0].Units[0].Metadata["speaker"] != "Alice" {
+		t.Fatalf("chunk unit metadata changed after source mutation: %#v", result.Chunks[0].Units[0].Metadata)
+	}
+	participants, ok := result.Chunks[0].Metadata["main_participants"].([]string)
+	if !ok || participants[0] != "Aria" {
+		t.Fatalf("participants = %#v, want defensive copy", result.Chunks[0].Metadata["main_participants"])
+	}
+}
+
+func TestChunkerManifestMetadataIncludesPromptAndSchemaProvenance(t *testing.T) {
+	metadata := New().ManifestMetadata()
+
+	tests := map[string]string{
+		"prompt_id":               PromptID,
+		"prompt_version":          ResponseSchemaVersion,
+		"response_schema_key":     string(ResponseSchemaKey),
+		"response_schema_id":      ResponseSchemaID,
+		"response_schema_name":    ResponseSchemaName,
+		"response_schema_version": ResponseSchemaVersion,
+	}
+	for key, want := range tests {
+		if metadata[key] != want {
+			t.Fatalf("metadata[%q] = %#v, want %q", key, metadata[key], want)
+		}
+	}
+	for _, key := range []string{"prompt_sha256", "response_schema_sha256"} {
+		value, ok := metadata[key].(string)
+		if !ok || !strings.HasPrefix(value, "sha256:") {
+			t.Fatalf("metadata[%q] = %#v, want sha256 value", key, metadata[key])
+		}
+	}
+	for _, forbidden := range []string{"prompt", "schema", "source", "text"} {
+		if _, ok := metadata[forbidden]; ok {
+			t.Fatalf("metadata includes raw %q field: %#v", forbidden, metadata)
+		}
+	}
+}
+
+func TestChunkRejectsInvalidRequests(t *testing.T) {
+	validClient := &fakeScenesLLMClient{response: validSceneResponse()}
+	validReq := chunkRequestWithClient(validClient)
+	canceledCtx, cancel := context.WithCancel(context.Background())
+	cancel()
+	invalidDoc := sceneSourceDocument()
+	invalidDoc.Units[0].ID = ""
+	emptyDoc := sceneSourceDocument()
+	emptyDoc.Units = nil
+
+	tests := []struct {
+		name    string
+		chunker *Chunker
+		ctx     context.Context
+		req     contracts.ChunkRequest
+		want    string
+	}{
+		{name: "nil chunker", chunker: nil, ctx: context.Background(), req: validReq, want: "chunker"},
+		{name: "nil context", chunker: New(), ctx: nil, req: validReq, want: "context"},
+		{name: "canceled context", chunker: New(), ctx: canceledCtx, req: validReq, want: "context"},
+		{name: "nil source", chunker: New(), ctx: context.Background(), req: contracts.ChunkRequest{LLMClient: validClient}, want: "source"},
+		{name: "empty source units", chunker: New(), ctx: context.Background(), req: contracts.ChunkRequest{Source: emptyDoc, LLMClient: validClient}, want: "units"},
+		{name: "invalid source", chunker: New(), ctx: context.Background(), req: contracts.ChunkRequest{Source: invalidDoc, LLMClient: validClient}, want: "validate source document"},
+		{name: "nil LLM client", chunker: New(), ctx: context.Background(), req: contracts.ChunkRequest{Source: sceneSourceDocument()}, want: "LLM client"},
+		{name: "unsupported options", chunker: New(), ctx: context.Background(), req: requestWithOptions(validReq), want: "options"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			_, err := tt.chunker.Chunk(tt.ctx, tt.req)
+			if err == nil {
+				t.Fatal("Chunk() error = nil, want error")
+			}
+			if !strings.Contains(err.Error(), "dnd scenes") || !strings.Contains(err.Error(), tt.want) {
+				t.Fatalf("Chunk() error = %q, want module context and %q", err.Error(), tt.want)
+			}
+		})
+	}
+}
+
+func TestChunkRejectsMalformedStructuredOutput(t *testing.T) {
+	tests := []struct {
+		name     string
+		response chunkResponse
+		want     string
+	}{
+		{name: "missing scenes", response: chunkResponse{}, want: "scenes"},
+		{name: "empty scenes", response: chunkResponse{Scenes: []sceneResponse{}}, want: "scenes"},
+		{
+			name: "unknown boundary id",
+			response: replaceScenes(validSceneResponse(), []sceneResponse{
+				scene("seg-001", "seg-999"),
+			}),
+			want: "was not found",
+		},
+		{
+			name: "out of order boundaries",
+			response: replaceScenes(validSceneResponse(), []sceneResponse{
+				scene("seg-003", "seg-002"),
+			}),
+			want: "appears after",
+		},
+		{
+			name: "gap",
+			response: replaceScenes(validSceneResponse(), []sceneResponse{
+				scene("seg-001", "seg-001"),
+				scene("seg-003", "seg-004"),
+			}),
+			want: "gap",
+		},
+		{
+			name: "overlap",
+			response: replaceScenes(validSceneResponse(), []sceneResponse{
+				scene("seg-001", "seg-002"),
+				scene("seg-002", "seg-004"),
+			}),
+			want: "overlap",
+		},
+		{
+			name: "incomplete coverage",
+			response: replaceScenes(validSceneResponse(), []sceneResponse{
+				scene("seg-001", "seg-003"),
+			}),
+			want: "final scene",
+		},
+		{
+			name: "empty metadata field",
+			response: replaceScenes(validSceneResponse(), []sceneResponse{
+				{
+					StartUnitID:        "seg-001",
+					EndUnitID:          "seg-004",
+					ShortTitle:         " ",
+					PrimaryMode:        "Narrative",
+					MainParticipants:   []string{"Aria"},
+					Summary:            "Summary.",
+					BoundaryNote:       "Note.",
+					BoundaryConfidence: "High",
+				},
+			}),
+			want: "short_title",
+		},
+		{
+			name: "empty participant",
+			response: replaceScenes(validSceneResponse(), []sceneResponse{
+				{
+					StartUnitID:        "seg-001",
+					EndUnitID:          "seg-004",
+					ShortTitle:         "Title",
+					PrimaryMode:        "Narrative",
+					MainParticipants:   []string{"Aria", " "},
+					Summary:            "Summary.",
+					BoundaryNote:       "Note.",
+					BoundaryConfidence: "High",
+				},
+			}),
+			want: "main_participants",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			client := &fakeScenesLLMClient{response: tt.response}
+			_, err := New().Chunk(context.Background(), chunkRequestWithClient(client))
+			if err == nil {
+				t.Fatal("Chunk() error = nil, want error")
+			}
+			if !strings.Contains(err.Error(), "dnd scenes") || !strings.Contains(err.Error(), tt.want) {
+				t.Fatalf("Chunk() error = %q, want module context and %q", err.Error(), tt.want)
+			}
+		})
+	}
+}
+
+func TestChunkWrapsLLMClientError(t *testing.T) {
+	client := &fakeScenesLLMClient{err: errors.New("provider unavailable")}
+
+	_, err := New().Chunk(context.Background(), chunkRequestWithClient(client))
+	if err == nil {
+		t.Fatal("Chunk() error = nil, want LLM error")
+	}
+	if !strings.Contains(err.Error(), "dnd scenes") || !strings.Contains(err.Error(), "provider unavailable") {
+		t.Fatalf("Chunk() error = %q, want wrapped LLM context", err.Error())
+	}
+}
+
+func chunkRequestWithClient(client contracts.StructuredLLMClient) contracts.ChunkRequest {
+	return contracts.ChunkRequest{
+		Source:    sceneSourceDocument(),
+		LLMClient: client,
+	}
+}
+
+func requestWithOptions(req contracts.ChunkRequest) contracts.ChunkRequest {
+	req.Options = map[string]any{"max_units": 2}
+	return req
+}
+
+func sceneSourceDocument() *source.SourceDocument {
+	return &source.SourceDocument{
+		ID:     "session-alpha",
+		Kind:   "transcript",
+		Format: "application/vnd.seriatim.minimal+json",
+		Digest: "sha256:source",
+		Units: []source.SourceUnit{
+			{ID: "seg-001", Kind: "transcript_segment", Text: "Aria asks whether the goblin will parley.", Metadata: map[string]any{"speaker": "Alice"}},
+			{ID: "seg-002", Kind: "transcript_segment", Text: "The goblin scout describes the gate guards."},
+			{ID: "seg-003", Kind: "transcript_segment", Text: "The guards rush out with blades drawn."},
+			{ID: "seg-004", Kind: "transcript_segment", Text: "The party defeats the ambushers."},
+		},
+	}
+}
+
+func validSceneResponse() chunkResponse {
+	return chunkResponse{
+		Scenes: []sceneResponse{
+			scene("seg-001", "seg-004"),
+		},
+		BoundaryCaveats: []string{},
+	}
+}
+
+func replaceScenes(response chunkResponse, scenes []sceneResponse) chunkResponse {
+	response.Scenes = scenes
+	return response
+}
+
+func scene(startUnitID string, endUnitID string) sceneResponse {
+	return sceneResponse{
+		StartUnitID:        startUnitID,
+		EndUnitID:          endUnitID,
+		ShortTitle:         "Scene title",
+		PrimaryMode:        "Narrative",
+		MainParticipants:   []string{"Aria"},
+		Summary:            "A compact summary.",
+		BoundaryNote:       "The source units form one coherent scene.",
+		BoundaryConfidence: "High",
+	}
+}
+
+func chunkIDs(chunks []contracts.SourceChunk) []string {
+	ids := make([]string, 0, len(chunks))
+	for _, chunk := range chunks {
+		ids = append(ids, chunk.ID)
+	}
+	return ids
+}
+
+func unitIDs(units []source.SourceUnit) []string {
+	ids := make([]string, 0, len(units))
+	for _, unit := range units {
+		ids = append(ids, unit.ID)
+	}
+	return ids
+}
+
+type fakeScenesLLMClient struct {
+	response chunkResponse
+	err      error
+	requests []contracts.StructuredCompletionRequest
+}
+
+func (client *fakeScenesLLMClient) CompleteStructured(ctx context.Context, req contracts.StructuredCompletionRequest, out any) (contracts.StructuredCompletionResponse, error) {
+	client.requests = append(client.requests, contracts.StructuredCompletionRequest{
+		StageName:          req.StageName,
+		Messages:           append([]contracts.LLMMessage(nil), req.Messages...),
+		Model:              req.Model,
+		ResponseSchemaName: req.ResponseSchemaName,
+		ResponseSchema:     append(json.RawMessage(nil), req.ResponseSchema...),
+	})
+	if client.err != nil {
+		return contracts.StructuredCompletionResponse{}, client.err
+	}
+
+	target, ok := out.(*chunkResponse)
+	if !ok {
+		return contracts.StructuredCompletionResponse{}, errors.New("unexpected output target")
+	}
+	*target = client.response
+	content, err := json.Marshal(client.response)
+	if err != nil {
+		return contracts.StructuredCompletionResponse{}, err
+	}
+	return contracts.StructuredCompletionResponse{Content: content}, nil
+}

internal/modules/chunk/dnd/scenes/model.go

@@ -0,0 +1,17 @@
+package scenes
+
+type chunkResponse struct {
+	Scenes          []sceneResponse `json:"scenes"`
+	BoundaryCaveats []string        `json:"boundary_caveats"`
+}
+
+type sceneResponse struct {
+	StartUnitID        string   `json:"start_unit_id"`
+	EndUnitID          string   `json:"end_unit_id"`
+	ShortTitle         string   `json:"short_title"`
+	PrimaryMode        string   `json:"primary_mode"`
+	MainParticipants   []string `json:"main_participants"`
+	Summary            string   `json:"summary"`
+	BoundaryNote       string   `json:"boundary_note"`
+	BoundaryConfidence string   `json:"boundary_confidence"`
+}

internal/modules/chunk/dnd/scenes/prompt.go

@@ -0,0 +1,97 @@
+package scenes
+
+import (
+	"fmt"
+	"strings"
+
+	"gitea.maximumdirect.net/eric/notarius/internal/core/source"
+	"gitea.maximumdirect.net/eric/notarius/internal/framework/contracts"
+	"gitea.maximumdirect.net/eric/notarius/internal/framework/prompt"
+)
+
+type promptData struct {
+	SourceID string
+	Units    []promptUnit
+}
+
+type promptUnit struct {
+	ID       string
+	Text     string
+	Metadata []promptMetadata
+}
+
+type promptMetadata struct {
+	Key   string
+	Value string
+}
+
+var scenesPromptBundle = mustLoadPromptBundle()
+
+func mustLoadPromptBundle() *prompt.Bundle {
+	bundle, err := prompt.LoadBundle(embeddedAssets, prompt.Definition{
+		PromptID:     PromptID,
+		Version:      ResponseSchemaVersion,
+		EmbeddedPath: "assets/prompts",
+		SystemPath:   "assets/prompts/system.md",
+		UserPath:     "assets/prompts/user.md",
+	})
+	if err != nil {
+		panic(err)
+	}
+	return bundle
+}
+
+func buildPromptData(req contracts.ChunkRequest) (promptData, error) {
+	if req.Source == nil {
+		return promptData{}, fmt.Errorf("dnd scenes prompt: source must not be nil")
+	}
+
+	data := promptData{
+		SourceID: req.Source.ID,
+		Units:    make([]promptUnit, 0, len(req.Source.Units)),
+	}
+	for _, unit := range req.Source.Units {
+		data.Units = append(data.Units, promptUnit{
+			ID:       unit.ID,
+			Text:     unit.Text,
+			Metadata: selectedMetadata(unit),
+		})
+	}
+	return data, nil
+}
+
+func renderPrompt(req contracts.ChunkRequest) (system string, user string, metadata prompt.Metadata, err error) {
+	data, err := buildPromptData(req)
+	if err != nil {
+		return "", "", prompt.Metadata{}, err
+	}
+	system, user, metadata, err = scenesPromptBundle.RenderUserSystem(data)
+	if err != nil {
+		return "", "", prompt.Metadata{}, fmt.Errorf("dnd scenes prompt: %w", err)
+	}
+	return system, user, metadata, nil
+}
+
+func selectedMetadata(unit source.SourceUnit) []promptMetadata {
+	if len(unit.Metadata) == 0 {
+		return nil
+	}
+
+	keys := []string{"speaker", "start", "end"}
+	metadata := make([]promptMetadata, 0, len(keys))
+	for _, key := range keys {
+		value, ok := unit.Metadata[key]
+		if !ok {
+			continue
+		}
+		rendered := strings.TrimSpace(fmt.Sprint(value))
+		if rendered == "" {
+			continue
+		}
+		metadata = append(metadata, promptMetadata{
+			Key:   key,
+			Value: rendered,
+		})
+	}
+	return metadata
+}

internal/modules/chunk/dnd/scenes/prompt_test.go

@@ -0,0 +1,155 @@
+package scenes
+
+import (
+	"encoding/json"
+	"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/prompt"
+)
+
+func TestBuildPromptDataFromSourceDocument(t *testing.T) {
+	req := promptChunkRequest()
+
+	data, err := buildPromptData(req)
+	if err != nil {
+		t.Fatalf("buildPromptData() error = %v, want nil", err)
+	}
+
+	if data.SourceID != "session-alpha" {
+		t.Fatalf("SourceID = %q, want session-alpha", data.SourceID)
+	}
+	if len(data.Units) != 2 {
+		t.Fatalf("len(Units) = %d, want 2", len(data.Units))
+	}
+	first := data.Units[0]
+	if first.ID != "seg-001" || first.Text != "Aria and Bram discuss whether to enter the ruins." {
+		t.Fatalf("first unit = %#v, want source unit data", first)
+	}
+	wantMetadata := []promptMetadata{
+		{Key: "speaker", Value: "Alice"},
+		{Key: "start", Value: "1.25"},
+		{Key: "end", Value: "3.5"},
+	}
+	if !reflect.DeepEqual(first.Metadata, wantMetadata) {
+		t.Fatalf("first.Metadata = %#v, want %#v", first.Metadata, wantMetadata)
+	}
+	if len(data.Units[1].Metadata) != 0 {
+		t.Fatalf("second.Metadata = %#v, want no selected metadata", data.Units[1].Metadata)
+	}
+}
+
+func TestBuildPromptDataDoesNotMutateRequest(t *testing.T) {
+	req := promptChunkRequest()
+	beforeSource := mustJSON(t, req.Source)
+	beforeRequest := mustJSON(t, req)
+
+	if _, err := buildPromptData(req); err != nil {
+		t.Fatalf("buildPromptData() error = %v, want nil", err)
+	}
+	afterSource := mustJSON(t, req.Source)
+	afterRequest := mustJSON(t, req)
+	if beforeSource != afterSource || beforeRequest != afterRequest {
+		t.Fatalf(
+			"request mutated:\nsource before: %s\nsource after:  %s\nrequest before: %s\nrequest after:  %s",
+			beforeSource,
+			afterSource,
+			beforeRequest,
+			afterRequest,
+		)
+	}
+}
+
+func TestRenderPromptIncludesSourceUnitsAndMetadata(t *testing.T) {
+	system, user, metadata, err := renderPrompt(promptChunkRequest())
+	if err != nil {
+		t.Fatalf("renderPrompt() error = %v, want nil", err)
+	}
+
+	if !strings.Contains(system, prompt.HardeningText()) {
+		t.Fatalf("system prompt = %q, want hardening text", system)
+	}
+	for _, want := range []string{
+		"session-alpha",
+		"seg-001",
+		"seg-002",
+		"Aria and Bram discuss whether to enter the ruins.",
+		"The goblins rush out and initiative begins.",
+		"speaker: Alice",
+		"start: 1.25",
+		"end: 3.5",
+		"start_unit_id",
+		"end_unit_id",
+		"primary_mode",
+		"boundary_confidence",
+		"Recap, Discussion, Combat, or Narrative",
+		"High, Medium, or Low",
+		"no gaps",
+		"do not overlap",
+	} {
+		if !strings.Contains(user, want) {
+			t.Fatalf("user prompt = %q, want substring %q", user, want)
+		}
+	}
+	if metadata.PromptID != PromptID {
+		t.Fatalf("metadata.PromptID = %q, want %q", metadata.PromptID, PromptID)
+	}
+	if metadata.PromptVersion != ResponseSchemaVersion {
+		t.Fatalf("metadata.PromptVersion = %q, want %q", metadata.PromptVersion, ResponseSchemaVersion)
+	}
+	if metadata.EmbeddedPath != "assets/prompts" {
+		t.Fatalf("metadata.EmbeddedPath = %q, want assets/prompts", metadata.EmbeddedPath)
+	}
+}
+
+func TestBuildPromptDataRejectsMissingSourceContext(t *testing.T) {
+	if _, err := buildPromptData(contracts.ChunkRequest{}); err == nil || !strings.Contains(err.Error(), "source") {
+		t.Fatalf("buildPromptData() error = %v, want source error", err)
+	}
+}
+
+func promptChunkRequest() contracts.ChunkRequest {
+	return contracts.ChunkRequest{
+		Source: promptSourceDocument(),
+	}
+}
+
+func promptSourceDocument() *source.SourceDocument {
+	return &source.SourceDocument{
+		ID:     "session-alpha",
+		Kind:   "transcript",
+		Format: "application/vnd.seriatim.minimal+json",
+		Digest: "sha256:test",
+		Units: []source.SourceUnit{
+			{
+				ID:   "seg-001",
+				Kind: "transcript_segment",
+				Text: "Aria and Bram discuss whether to enter the ruins.",
+				Metadata: map[string]any{
+					"speaker": "Alice",
+					"start":   json.Number("1.25"),
+					"end":     json.Number("3.5"),
+					"ignored": "not rendered",
+				},
+			},
+			{
+				ID:       "seg-002",
+				Kind:     "transcript_segment",
+				Text:     "The goblins rush out and initiative begins.",
+				Metadata: map[string]any{"ignored": "not rendered"},
+			},
+		},
+	}
+}
+
+func mustJSON(t *testing.T, value any) string {
+	t.Helper()
+	encoded, err := json.Marshal(value)
+	if err != nil {
+		t.Fatalf("Marshal() error = %v, want nil", err)
+	}
+	return string(encoded)
+}

internal/modules/chunk/dnd/scenes/schema.go

@@ -0,0 +1,21 @@
+package scenes
+
+import "gitea.maximumdirect.net/eric/notarius/internal/framework/llm"
+
+const (
+	PromptID              = "dnd.scenes"
+	ResponseSchemaKey     = llm.ResponseSchemaKey("dnd_scenes")
+	ResponseSchemaID      = "notarius.dnd.scenes"
+	ResponseSchemaVersion = "v1"
+	ResponseSchemaName    = "notarius_dnd_scenes_v1"
+)
+
+func loadResponseSchema() (llm.ResponseSchema, error) {
+	return llm.LoadResponseSchema(embeddedAssets, llm.ResponseSchemaDefinition{
+		Key:       ResponseSchemaKey,
+		ID:        ResponseSchemaID,
+		Version:   ResponseSchemaVersion,
+		Name:      ResponseSchemaName,
+		AssetPath: "assets/schemas/dnd_scenes.v1.json",
+	})
+}

internal/modules/chunk/dnd/scenes/schema_test.go

@@ -0,0 +1,138 @@
+package scenes
+
+import (
+	"encoding/json"
+	"strings"
+	"testing"
+)
+
+func TestLoadResponseSchemaForScenes(t *testing.T) {
+	schema, err := loadResponseSchema()
+	if err != nil {
+		t.Fatalf("loadResponseSchema() error = %v, want nil", err)
+	}
+	if schema.Key != ResponseSchemaKey {
+		t.Fatalf("schema.Key = %q, want %q", schema.Key, ResponseSchemaKey)
+	}
+	if schema.ID != ResponseSchemaID {
+		t.Fatalf("schema.ID = %q, want %q", schema.ID, ResponseSchemaID)
+	}
+	if schema.Version != ResponseSchemaVersion {
+		t.Fatalf("schema.Version = %q, want %q", schema.Version, ResponseSchemaVersion)
+	}
+	if schema.Name != ResponseSchemaName {
+		t.Fatalf("schema.Name = %q, want %q", schema.Name, ResponseSchemaName)
+	}
+	if !strings.HasPrefix(schema.SHA256, "sha256:") {
+		t.Fatalf("schema.SHA256 = %q, want sha256 prefix", schema.SHA256)
+	}
+	if !json.Valid(schema.JSONSchema) {
+		t.Fatalf("schema.JSONSchema is invalid JSON: %s", schema.JSONSchema)
+	}
+}
+
+func TestResponseSchemaShapeUsesSourceUnitBoundaries(t *testing.T) {
+	schema, err := loadResponseSchema()
+	if err != nil {
+		t.Fatalf("loadResponseSchema() error = %v, want nil", err)
+	}
+
+	var decoded map[string]any
+	if err := json.Unmarshal(schema.JSONSchema, &decoded); err != nil {
+		t.Fatalf("Unmarshal() error = %v, want nil", err)
+	}
+	if decoded["$id"] != ResponseSchemaID {
+		t.Fatalf("$id = %#v, want %q", decoded["$id"], ResponseSchemaID)
+	}
+	if decoded["additionalProperties"] != false {
+		t.Fatalf("additionalProperties = %#v, want false", decoded["additionalProperties"])
+	}
+
+	properties := decoded["properties"].(map[string]any)
+	if _, ok := properties["artifact_type"]; ok {
+		t.Fatal("schema includes artifact_type, want only scene response fields")
+	}
+	if _, ok := properties["session_scope"]; ok {
+		t.Fatal("schema includes session_scope, want no session wrapper")
+	}
+
+	sceneProperties := properties["scenes"].(map[string]any)["items"].(map[string]any)["properties"].(map[string]any)
+	for _, field := range []string{"scene_id", "start_segment_id", "end_segment_id"} {
+		if _, ok := sceneProperties[field]; ok {
+			t.Fatalf("scene schema includes old field %q", field)
+		}
+	}
+	for _, field := range []string{"start_unit_id", "end_unit_id"} {
+		property := sceneProperties[field].(map[string]any)
+		if property["type"] != "string" {
+			t.Fatalf("%s type = %#v, want string", field, property["type"])
+		}
+	}
+
+	modeEnum := sceneProperties["primary_mode"].(map[string]any)["enum"].([]any)
+	if !sameStrings(modeEnum, []string{"Recap", "Discussion", "Combat", "Narrative"}) {
+		t.Fatalf("primary_mode enum = %#v, want Recap/Discussion/Combat/Narrative", modeEnum)
+	}
+	confidenceEnum := sceneProperties["boundary_confidence"].(map[string]any)["enum"].([]any)
+	if !sameStrings(confidenceEnum, []string{"High", "Medium", "Low"}) {
+		t.Fatalf("boundary_confidence enum = %#v, want High/Medium/Low", confidenceEnum)
+	}
+}
+
+func TestResponseStructRejectsIntegerBoundaries(t *testing.T) {
+	raw := []byte(`{
+		"scenes": [
+			{
+				"start_unit_id": 1,
+				"end_unit_id": 3,
+				"short_title": "Ambush",
+				"primary_mode": "Combat",
+				"main_participants": ["Aria"],
+				"summary": "The party fights.",
+				"boundary_note": "Combat starts and resolves.",
+				"boundary_confidence": "High"
+			}
+		],
+		"boundary_caveats": []
+	}`)
+
+	var response chunkResponse
+	err := json.Unmarshal(raw, &response)
+	if err == nil {
+		t.Fatalf("Unmarshal() error = nil, want integer boundary type error: %#v", response)
+	}
+	if !strings.Contains(err.Error(), "string") {
+		t.Fatalf("Unmarshal() error = %v, want string type error", err)
+	}
+}
+
+func TestResponseSchemaJSONIsMutationSafe(t *testing.T) {
+	first, err := loadResponseSchema()
+	if err != nil {
+		t.Fatalf("loadResponseSchema() error = %v, want nil", err)
+	}
+	first.JSONSchema[0] = '['
+
+	second, err := loadResponseSchema()
+	if err != nil {
+		t.Fatalf("loadResponseSchema() error = %v, want nil", err)
+	}
+	if !json.Valid(second.JSONSchema) {
+		t.Fatalf("schema JSON was mutated: %s", second.JSONSchema)
+	}
+	if len(second.JSONSchema) > 0 && second.JSONSchema[0] == '[' {
+		t.Fatalf("schema JSON did not use defensive copy")
+	}
+}
+
+func sameStrings(got []any, want []string) bool {
+	if len(got) != len(want) {
+		return false
+	}
+	for i := range want {
+		if got[i] != want[i] {
+			return false
+		}
+	}
+	return true
+}