diff --git a/internal/project/project.go b/internal/project/project.go
index 6f719f8..a206182 100644
--- a/internal/project/project.go
+++ b/internal/project/project.go
@@ -365,6 +365,7 @@ type AutogenConsumerConfig struct {
 	HeadVisualeffects HeadVisualeffectsConfig `json:"accessory_visualeffects" yaml:"accessory_visualeffects"`
 	Manifest          AutogenManifestConfig   `json:"manifest" yaml:"manifest"`
 	LocalOverrideRoot string                  `json:"local_override_root,omitempty" yaml:"local_override_root,omitempty"`
+	ManifestFile      string                  `json:"manifest_file,omitempty" yaml:"manifest_file,omitempty"`
 }
 
 type HeadVisualeffectsConfig struct {
diff --git a/internal/topdata/autogen.go b/internal/topdata/autogen.go
index 5cdde09..0a8e6f3 100644
--- a/internal/topdata/autogen.go
+++ b/internal/topdata/autogen.go
@@ -225,6 +225,9 @@ func autogenConsumerTargetsDataset(dataset nativeCollectedDataset, consumer proj
 }
 
 func resolveAutogenConsumerManifest(p *project.Project, consumer project.AutogenConsumerConfig, progress func(string)) (*autogenManifest, error) {
+	if manifestFile := strings.TrimSpace(consumer.ManifestFile); manifestFile != "" {
+		return readAutogenConsumerManifestFile(p, consumer, manifestFile, progress)
+	}
 	overrideRoot, err := resolveAutogenLocalOverrideRoot(p, consumer)
 	if err != nil {
 		return nil, err
@@ -242,6 +245,37 @@ func resolveAutogenConsumerManifest(p *project.Project, consumer project.Autogen
 	return resolveReleasedAutogenManifest(p, consumer, progress)
 }
 
+// readAutogenConsumerManifestFile reads a pre-resolved autogenManifest JSON from
+// a local file (relative paths resolve against the project root). A missing file
+// is an ignorable-optional condition — it returns errAutogenManifestUnavailable
+// so an optional consumer fails open and preserves its pinned lock IDs. A present
+// but malformed file, or an id that disagrees with the consumer's producer, is a
+// hard error.
+func readAutogenConsumerManifestFile(p *project.Project, consumer project.AutogenConsumerConfig, manifestFile string, progress func(string)) (*autogenManifest, error) {
+	path := manifestFile
+	if !filepath.IsAbs(path) {
+		path = filepath.Join(p.Root, path)
+	}
+	raw, err := os.ReadFile(path)
+	if err != nil {
+		if os.IsNotExist(err) {
+			return nil, unavailableAutogenManifest(fmt.Errorf("manifest file %s not found", path))
+		}
+		return nil, fmt.Errorf("read autogen manifest file %s: %w", path, err)
+	}
+	var manifest autogenManifest
+	if err := json.Unmarshal(raw, &manifest); err != nil {
+		return nil, fmt.Errorf("parse autogen manifest file %s: %w", path, err)
+	}
+	if manifest.ID != "" && manifest.ID != consumer.Producer {
+		return nil, fmt.Errorf("autogen manifest file %s declared id %q, expected %q", path, manifest.ID, consumer.Producer)
+	}
+	if progress != nil {
+		progress(fmt.Sprintf("Reading local autogen manifest for %s from %s...", consumer.ID, path))
+	}
+	return &manifest, nil
+}
+
 func resolveAutogenLocalOverrideRoot(p *project.Project, consumer project.AutogenConsumerConfig) (string, error) {
 	root := strings.TrimSpace(consumer.LocalOverrideRoot)
 	if root != "" {
diff --git a/internal/topdata/autogen_manifest_file_test.go b/internal/topdata/autogen_manifest_file_test.go
new file mode 100644
index 0000000..b581ec3
--- /dev/null
+++ b/internal/topdata/autogen_manifest_file_test.go
@@ -0,0 +1,103 @@
+package topdata
+
+import (
+	"path/filepath"
+	"testing"
+
+	"git.westgate.pw/ShadowsOverWestgate/sow-tools/internal/project"
+)
+
+// The manifest_file branch reads a local autogenManifest JSON, augments the
+// visualeffects dataset from its entries, and assigns lock IDs — no network.
+func TestApplyAutogenConsumersReadsManifestFile(t *testing.T) {
+	root := testProjectRoot(t)
+	manifestPath := filepath.Join(root, ".cache", "sow-accessory-vfx-manifest.json")
+	mkdirAll(t, filepath.Join(root, ".cache"))
+	writeFile(t, manifestPath, `{
+  "id": "accessory_visualeffects",
+  "repo": "ShadowsOverWestgate/sow-assets-manifest",
+  "ref": "v1.2.3",
+  "generated_at": "2026-06-21T00:00:00Z",
+  "entries": [
+    {"source": "head_accessories/hat/hfx_bandana.mdl", "model_stem": "hfx_bandana", "group": "head_accessories", "subgroup": "hat"}
+  ]
+}`+"\n")
+
+	p := testProject(root)
+	p.Config.Autogen.Consumers = []project.AutogenConsumerConfig{
+		{
+			ID:           "accessory_visualeffects",
+			Producer:     "accessory_visualeffects",
+			Dataset:      "visualeffects",
+			Mode:         "accessory_visualeffects",
+			Optional:     true,
+			ManifestFile: ".cache/sow-accessory-vfx-manifest.json",
+		},
+	}
+
+	collected := []nativeCollectedDataset{
+		{
+			Dataset: nativeDataset{Name: "visualeffects", Kind: nativeDatasetBase},
+			Columns: []string{"Label", "Type_FD", "OrientWithGround", "Imp_HeadCon_Node", "OrientWithObject"},
+			Rows:    nil,
+			LockData: map[string]int{
+				"visualeffects:existing": 17,
+			},
+		},
+	}
+
+	got, err := applyAutogenConsumers(p, collected, nil)
+	if err != nil {
+		t.Fatalf("applyAutogenConsumers failed: %v", err)
+	}
+	if len(got) != 1 || len(got[0].Rows) != 1 {
+		t.Fatalf("expected one autogenerated row, got %#v", got)
+	}
+	row := got[0].Rows[0]
+	if row["key"] != "visualeffects:head_accessories/hat/bandana" || row["Imp_HeadCon_Node"] != "hfx_bandana" {
+		t.Fatalf("unexpected generated row: %#v", row)
+	}
+	if _, ok := got[0].LockData["visualeffects:head_accessories/hat/bandana"]; !ok {
+		t.Fatalf("expected lock id for generated accessory, got %#v", got[0].LockData)
+	}
+	// Authored key untouched.
+	if got[0].LockData["visualeffects:existing"] != 17 {
+		t.Fatalf("expected authored lock id retained at 17, got %#v", got[0].LockData)
+	}
+}
+
+// A missing manifest_file is an ignorable-optional condition: the optional
+// consumer fails open (no rows) and preserves existing lock IDs.
+func TestApplyAutogenConsumersMissingManifestFileFailsOpen(t *testing.T) {
+	root := testProjectRoot(t)
+	lockPath := filepath.Join(root, "visualeffects-lock.json")
+	writeFile(t, lockPath, `{"visualeffects:head_accessories/hat/bandana":10101}`+"\n")
+
+	p := testProject(root)
+	p.Config.Autogen.Consumers = []project.AutogenConsumerConfig{
+		{
+			ID:           "accessory_visualeffects",
+			Producer:     "accessory_visualeffects",
+			Dataset:      "visualeffects",
+			Mode:         "accessory_visualeffects",
+			Optional:     true,
+			ManifestFile: ".cache/does-not-exist.json",
+		},
+	}
+	collected := []nativeCollectedDataset{
+		{
+			Dataset:  nativeDataset{Name: "visualeffects", Kind: nativeDatasetBase, LockPath: lockPath},
+			Columns:  []string{"Label"},
+			Rows:     nil,
+			LockData: map[string]int{},
+		},
+	}
+
+	got, err := applyAutogenConsumers(p, collected, nil)
+	if err != nil {
+		t.Fatalf("expected fail-open, got error: %v", err)
+	}
+	if id, ok := got[0].LockData["visualeffects:head_accessories/hat/bandana"]; !ok || id != 10101 {
+		t.Fatalf("expected preserved lock id 10101, got %v (present=%v)", id, ok)
+	}
+}