agent_patch

diff --git a/tmp/agent-patch-flux-pr-4843.1-of-1.2026-02-27__21-30-28__gpt-5-4/app/packages/zod/src/v4/classic/tests/error-utils.test.ts b/app/packages/zod/src/v4/classic/tests/error-utils.test.ts
index f6b2d3e..384f535 100644
--- a/tmp/agent-patch-flux-pr-4843.1-of-1.2026-02-27__21-30-28__gpt-5-4/app/packages/zod/src/v4/classic/tests/error-utils.test.ts
+++ b/app/packages/zod/src/v4/classic/tests/error-utils.test.ts
@@ -416,6 +416,42 @@ test("z.treeifyError 2", () => {
   `);
 });
 
+test("z.treeifyError branded primitive", () => {
+  const schema = z.object({
+    id: z.string().brand<"id">(),
+  });
+
+  const result = schema.safeParse({
+    id: 1234,
+  });
+
+  expect(result.success).toBe(false);
+
+  const err = z.treeifyError(result.error!);
+  expectTypeOf(err).toEqualTypeOf<{
+    errors: string[];
+    properties?: {
+      id?: {
+        errors: string[];
+      };
+    };
+  }>();
+  expectTypeOf(err.properties?.id).toEqualTypeOf<{ errors: string[] } | undefined>();
+
+  expect(err).toMatchInlineSnapshot(`
+    {
+      "errors": [],
+      "properties": {
+        "id": {
+          "errors": [
+            "Invalid input: expected string, received number",
+          ],
+        },
+      },
+    }
+  `);
+});
+
 test("z.prettifyError", () => {
   expect(z.prettifyError(result.error!)).toMatchInlineSnapshot(`
     "✖ Unrecognized key: "extra"
diff --git a/tmp/agent-patch-flux-pr-4843.1-of-1.2026-02-27__21-30-28__gpt-5-4/app/packages/zod/src/v4/core/errors.ts b/app/packages/zod/src/v4/core/errors.ts
index 699c81f..8502713 100644
--- a/tmp/agent-patch-flux-pr-4843.1-of-1.2026-02-27__21-30-28__gpt-5-4/app/packages/zod/src/v4/core/errors.ts
+++ b/app/packages/zod/src/v4/core/errors.ts
@@ -1,5 +1,6 @@
 import type { $ZodCheck, $ZodStringFormats } from "./checks.js";
 import { $constructor } from "./core.js";
+import type { $brand } from "./core.js";
 import type { $ZodType } from "./schemas.js";
 import * as util from "./util.js";
 
@@ -295,7 +296,13 @@ export function formatError<T>(error: $ZodError, _mapper?: any) {
   return fieldErrors;
 }
 
-export type $ZodErrorTree<T, U = string> = T extends [any, ...any[]]
+type StripPrimitiveBrand<T> = T extends infer Primitive & $brand<any>
+  ? Primitive extends util.Primitive
+    ? StripPrimitiveBrand<Primitive>
+    : T
+  : T;
+
+type _ZodErrorTree<T, U = string> = T extends [any, ...any[]]
   ? { errors: U[]; items?: { [K in keyof T]?: $ZodErrorTree<T[K], U> } }
   : T extends any[]
     ? { errors: U[]; items?: Array<$ZodErrorTree<T[number], U>> }
@@ -303,6 +310,8 @@ export type $ZodErrorTree<T, U = string> = T extends [any, ...any[]]
       ? { errors: U[]; properties?: { [K in keyof T]?: $ZodErrorTree<T[K], U> } }
       : { errors: U[] };
 
+export type $ZodErrorTree<T, U = string> = _ZodErrorTree<StripPrimitiveBrand<T>, U>;
+
 export function treeifyError<T>(error: $ZodError<T>): $ZodErrorTree<T>;
 export function treeifyError<T, U>(error: $ZodError<T>, mapper?: (issue: $ZodIssue) => U): $ZodErrorTree<T, U>;
 export function treeifyError<T>(error: $ZodError, _mapper?: any) {