diff --git a/packages/workflow-runtime/src/bundle/index.ts b/packages/workflow-runtime/src/bundle/index.ts
index 6a2f60d..fde4867 100644
--- a/packages/workflow-runtime/src/bundle/index.ts
+++ b/packages/workflow-runtime/src/bundle/index.ts
@@ -1,2 +1 @@
 export type { WorkflowDescriptor, WorkflowRoleDescriptor, WorkflowRoleSchema } from "./types.js";
-export { validateWorkflowDescriptor } from "./workflow-descriptor.js";
diff --git a/packages/workflow-runtime/src/bundle/workflow-descriptor.ts b/packages/workflow-runtime/src/bundle/workflow-descriptor.ts
deleted file mode 100644
index e21851b..0000000
--- a/packages/workflow-runtime/src/bundle/workflow-descriptor.ts
+++ /dev/null
@@ -1,40 +0,0 @@
-import { err, ok, type Result } from "../util/index.js";
-
-import type { WorkflowDescriptor, WorkflowRoleDescriptor, WorkflowRoleSchema } from "./types.js";
-
-export function validateWorkflowDescriptor(value: unknown): Result<WorkflowDescriptor, string> {
-  if (value === null || typeof value !== "object" || Array.isArray(value)) {
-    return err("descriptor must be a non-array object");
-  }
-  const root = value as Record<string, unknown>;
-  const description = root.description;
-  if (typeof description !== "string") {
-    return err("descriptor.description must be a string");
-  }
-  const rolesRaw = root.roles;
-  if (rolesRaw === null || typeof rolesRaw !== "object" || Array.isArray(rolesRaw)) {
-    return err("descriptor.roles must be a non-array object");
-  }
-
-  const roles: Record<string, WorkflowRoleDescriptor> = {};
-  for (const [roleName, specUnknown] of Object.entries(rolesRaw)) {
-    if (specUnknown === null || typeof specUnknown !== "object" || Array.isArray(specUnknown)) {
-      return err(`descriptor.roles.${roleName} must be a non-array object`);
-    }
-    const spec = specUnknown as Record<string, unknown>;
-    const roleDesc = spec.description;
-    if (typeof roleDesc !== "string") {
-      return err(`descriptor.roles.${roleName}.description must be a string`);
-    }
-    const schema = spec.schema;
-    if (schema === null || typeof schema !== "object" || Array.isArray(schema)) {
-      return err(`descriptor.roles.${roleName}.schema must be a non-array object`);
-    }
-    roles[roleName] = {
-      description: roleDesc,
-      schema: schema as WorkflowRoleSchema,
-    };
-  }
-
-  return ok({ description, roles });
-}
diff --git a/packages/workflow-runtime/src/index.ts b/packages/workflow-runtime/src/index.ts
index 2416179..317c61b 100644
--- a/packages/workflow-runtime/src/index.ts
+++ b/packages/workflow-runtime/src/index.ts
@@ -3,7 +3,6 @@ export type {
   WorkflowRoleDescriptor,
   WorkflowRoleSchema,
 } from "./bundle/types.js";
-export { validateWorkflowDescriptor } from "./bundle/workflow-descriptor.js";
 export type { CasStore } from "./cas/index.js";
 export { createWorkflow } from "./engine/index.js";
 export type { ExtractFn } from "./extract/index.js";
diff --git a/packages/workflow/src/bundle/workflow-descriptor.ts b/packages/workflow/src/bundle/workflow-descriptor.ts
index fb586fa..e21851b 100644
--- a/packages/workflow/src/bundle/workflow-descriptor.ts
+++ b/packages/workflow/src/bundle/workflow-descriptor.ts
@@ -1 +1,40 @@
-export { validateWorkflowDescriptor } from "@uncaged/workflow-runtime";
+import { err, ok, type Result } from "../util/index.js";
+
+import type { WorkflowDescriptor, WorkflowRoleDescriptor, WorkflowRoleSchema } from "./types.js";
+
+export function validateWorkflowDescriptor(value: unknown): Result<WorkflowDescriptor, string> {
+  if (value === null || typeof value !== "object" || Array.isArray(value)) {
+    return err("descriptor must be a non-array object");
+  }
+  const root = value as Record<string, unknown>;
+  const description = root.description;
+  if (typeof description !== "string") {
+    return err("descriptor.description must be a string");
+  }
+  const rolesRaw = root.roles;
+  if (rolesRaw === null || typeof rolesRaw !== "object" || Array.isArray(rolesRaw)) {
+    return err("descriptor.roles must be a non-array object");
+  }
+
+  const roles: Record<string, WorkflowRoleDescriptor> = {};
+  for (const [roleName, specUnknown] of Object.entries(rolesRaw)) {
+    if (specUnknown === null || typeof specUnknown !== "object" || Array.isArray(specUnknown)) {
+      return err(`descriptor.roles.${roleName} must be a non-array object`);
+    }
+    const spec = specUnknown as Record<string, unknown>;
+    const roleDesc = spec.description;
+    if (typeof roleDesc !== "string") {
+      return err(`descriptor.roles.${roleName}.description must be a string`);
+    }
+    const schema = spec.schema;
+    if (schema === null || typeof schema !== "object" || Array.isArray(schema)) {
+      return err(`descriptor.roles.${roleName}.schema must be a non-array object`);
+    }
+    roles[roleName] = {
+      description: roleDesc,
+      schema: schema as WorkflowRoleSchema,
+    };
+  }
+
+  return ok({ description, roles });
+}