Carry accepted chunk maps through the runner

internal/framework/contracts/artifact.go

@@ -69,6 +69,16 @@ func CloneSerializedArtifact(artifact SerializedArtifact) SerializedArtifact {
 	return artifact
 }
 
+// CloneSerializedArtifactPointer returns an independently owned artifact when
+// one is present.
+func CloneSerializedArtifactPointer(artifact *SerializedArtifact) *SerializedArtifact {
+	if artifact == nil {
+		return nil
+	}
+	cloned := CloneSerializedArtifact(*artifact)
+	return &cloned
+}
+
 func CloneSerializedOutput(output SerializedOutput) SerializedOutput {
 	output.Artifact = CloneSerializedArtifact(output.Artifact)
 	return output

internal/framework/contracts/contracts.go

@@ -291,6 +291,7 @@ type OutputRequest struct {
 	Warnings         []Warning             `json:"warnings,omitempty"`
 	LLMProfile       string                `json:"llm_profile,omitempty"`
 	Metadata         map[string]any        `json:"metadata,omitempty"`
+	ChunkMap         *SerializedArtifact   `json:"chunk_map,omitempty"`
 }
 
 type OutputFile struct {

internal/framework/contracts/contracts_test.go

@@ -26,6 +26,25 @@ func TestCloneReferenceSlotsEmptyInputReturnsNil(t *testing.T) {
 	}
 }
 
+func TestCloneSerializedArtifactPointerOwnsArtifactData(t *testing.T) {
+	original := &SerializedArtifact{
+		Kind:     "test/artifact",
+		Schema:   ArtifactSchema{ID: "test.schema", JSONSchema: []byte(`{"type":"object"}`)},
+		Content:  []byte(`{"items":[]}`),
+		Metadata: map[string]any{"count": 1},
+	}
+	cloned := CloneSerializedArtifactPointer(original)
+	original.Schema.JSONSchema[0] = '['
+	original.Content[0] = '['
+	original.Metadata["count"] = 2
+	if cloned == nil || string(cloned.Schema.JSONSchema) != `{"type":"object"}` || string(cloned.Content) != `{"items":[]}` || cloned.Metadata["count"] != 1 {
+		t.Fatalf("CloneSerializedArtifactPointer() = %#v, want independent artifact data", cloned)
+	}
+	if CloneSerializedArtifactPointer(nil) != nil {
+		t.Fatal("CloneSerializedArtifactPointer(nil) must return nil")
+	}
+}
+
 func TestCloneReferenceSlotsPreservesFields(t *testing.T) {
 	slots := []ReferenceSlot{
 		{