diff --git a/packages/workflow-register/__tests__/build-descriptor.test.ts b/packages/workflow-register/__tests__/build-descriptor.test.ts
new file mode 100644
index 0000000..d5056fd
--- /dev/null
+++ b/packages/workflow-register/__tests__/build-descriptor.test.ts
@@ -0,0 +1,53 @@
+import { describe, expect, test } from "bun:test";
+import {
+  END,
+  START,
+  type ModeratorTable,
+  type WorkflowDefinition,
+} from "@uncaged/workflow-protocol";
+import * as z from "zod/v4";
+import { buildDescriptor } from "../src/bundle/build-descriptor.js";
+
+const phaseSchema = z.object({
+  hash: z.string().meta({ "x-cas-ref": true }),
+  title: z.string(),
+});
+
+type TestMeta = {
+  planner: { phases: Array<{ hash: string; title: string }>; label: string };
+};
+
+const testTable: ModeratorTable<TestMeta> = {
+  [START]: [{ condition: "FALLBACK", role: "planner" }],
+  planner: [{ condition: "FALLBACK", role: END }],
+};
+
+describe("buildDescriptor", () => {
+  test("preserves x-cas-ref in role JSON Schema", () => {
+    const def: WorkflowDefinition<TestMeta> = {
+      description: "test workflow",
+      roles: {
+        planner: {
+          description: "plans work",
+          systemPrompt: "plan",
+          schema: z.object({
+            phases: z.array(phaseSchema),
+            label: z.string(),
+          }),
+        },
+      },
+      table: testTable,
+    };
+
+    const descriptor = buildDescriptor(def);
+    const props = (descriptor.roles.planner.schema as { properties: Record<string, unknown> })
+      .properties;
+    const phaseProps = (
+      (props.phases as { items: { properties: Record<string, unknown> } }).items
+    ).properties;
+
+    expect((phaseProps.hash as Record<string, unknown>)["x-cas-ref"]).toBe(true);
+    expect((phaseProps.title as Record<string, unknown>)["x-cas-ref"]).toBeUndefined();
+    expect((props.label as Record<string, unknown>)["x-cas-ref"]).toBeUndefined();
+  });
+});
diff --git a/packages/workflow-register/package.json b/packages/workflow-register/package.json
index 39976f8..dea6e94 100644
--- a/packages/workflow-register/package.json
+++ b/packages/workflow-register/package.json
@@ -29,6 +29,9 @@
     "zod": "^4.0.0",
     "typescript": "^5.8.3"
   },
+  "scripts": {
+    "test": "bun test"
+  },
   "publishConfig": {
     "access": "public"
   }
diff --git a/packages/workflow-runtime/__tests__/collect-cas-refs.test.ts b/packages/workflow-runtime/__tests__/collect-cas-refs.test.ts
index dbdfc2b..f315bf5 100644
--- a/packages/workflow-runtime/__tests__/collect-cas-refs.test.ts
+++ b/packages/workflow-runtime/__tests__/collect-cas-refs.test.ts
@@ -3,7 +3,7 @@ import * as z from "zod/v4";
 import { collectCasRefs } from "../src/collect-cas-refs.js";
 
 const phaseSchema = z.object({
-  hash: z.string().meta({ casRef: true }),
+  hash: z.string().meta({ 'x-cas-ref': true }),
   title: z.string(),
 });
 
@@ -19,9 +19,9 @@ const plannerMetaSchema = z.discriminatedUnion("status", [
 ]);
 
 describe("collectCasRefs", () => {
-  test("1. flat field with casRef annotation", () => {
+  test("1. flat field with x-cas-ref annotation", () => {
     const schema = z.object({
-      completedPhase: z.string().meta({ casRef: true }),
+      completedPhase: z.string().meta({ 'x-cas-ref': true }),
     });
     expect(collectCasRefs(schema, { completedPhase: "BHAAAAAAAAAAA" })).toEqual(["BHAAAAAAAAAAA"]);
   });
@@ -29,7 +29,7 @@ describe("collectCasRefs", () => {
   test("2. plain string without annotation is ignored", () => {
     const schema = z.object({
       summary: z.string(),
-      completedPhase: z.string().meta({ casRef: true }),
+      completedPhase: z.string().meta({ 'x-cas-ref': true }),
     });
     expect(
       collectCasRefs(schema, {
@@ -76,8 +76,8 @@ describe("collectCasRefs", () => {
 
   test("5. null and undefined annotated fields are skipped", () => {
     const schema = z.object({
-      ref: z.string().meta({ casRef: true }).nullable(),
-      optionalRef: z.string().meta({ casRef: true }).optional(),
+      ref: z.string().meta({ 'x-cas-ref': true }).nullable(),
+      optionalRef: z.string().meta({ 'x-cas-ref': true }).optional(),
     });
     expect(collectCasRefs(schema, { ref: null, optionalRef: undefined })).toEqual([]);
     expect(collectCasRefs(schema, { ref: "BH55555555555", optionalRef: undefined })).toEqual([
@@ -89,7 +89,7 @@ describe("collectCasRefs", () => {
     const schema = z.object({
       label: z.string(),
       phase: z.object({
-        hash: z.string().meta({ casRef: true }),
+        hash: z.string().meta({ 'x-cas-ref': true }),
         title: z.string(),
       }),
       tags: z.array(z.string()),
diff --git a/packages/workflow-runtime/src/collect-cas-refs.ts b/packages/workflow-runtime/src/collect-cas-refs.ts
index 59e7e14..27c2b8a 100644
--- a/packages/workflow-runtime/src/collect-cas-refs.ts
+++ b/packages/workflow-runtime/src/collect-cas-refs.ts
@@ -6,7 +6,7 @@ type DefPipeIn = { in: ZodSchema };
 
 function hasCasRef(schema: ZodSchema): boolean {
   const meta = z.globalRegistry.get(schema);
-  return meta !== undefined && meta.casRef === true;
+  return meta !== undefined && meta["x-cas-ref"] === true;
 }
 
 function walkOptional(schema: z.ZodOptional<ZodSchema>, data: unknown): string[] {
@@ -116,7 +116,7 @@ function walkCasRefs(schema: ZodSchema, data: unknown): string[] {
   }
 }
 
-/** Collect CAS content hashes from meta using `casRef` annotations on the Zod schema. */
+/** Collect CAS content hashes from meta using `x-cas-ref` annotations on the Zod schema. */
 export function collectCasRefs(schema: ZodSchema, data: unknown): string[] {
   return walkCasRefs(schema, data);
 }