diff --git a/packages/shared/src/git.test.ts b/packages/shared/src/git.test.ts
index 80578e262f9..96539f0aae2 100644
--- a/packages/shared/src/git.test.ts
+++ b/packages/shared/src/git.test.ts
@@ -71,6 +71,29 @@ describe("isTemporaryWorktreeBranch", () => {
     expect(isTemporaryWorktreeBranch(`${WORKTREE_BRANCH_PREFIX}/DEADBEEF`)).toBe(true);
   });
 
+  it("normalizes a UUID-shaped random callback to the canonical 8-hex form", () => {
+    expect(buildTemporaryWorktreeBranchName(() => "f4ae4e0e-f971-4d48-b4f2-9cf0aa54ab12")).toBe(
+      `${WORKTREE_BRANCH_PREFIX}/f4ae4e0e`,
+    );
+  });
+
+  it("matches legacy UUID-shaped temporary worktree refs from older mobile builds", () => {
+    expect(
+      isTemporaryWorktreeBranch(`${WORKTREE_BRANCH_PREFIX}/f4ae4e0e-f971-4d48-b4f2-9cf0aa54ab12`),
+    ).toBe(true);
+  });
+
+  it("rejects UUID-shaped refs that are not RFC 4122 v4", () => {
+    // version nibble is not 4
+    expect(
+      isTemporaryWorktreeBranch(`${WORKTREE_BRANCH_PREFIX}/f4ae4e0e-f971-1d48-b4f2-9cf0aa54ab12`),
+    ).toBe(false);
+    // variant nibble is not [89ab]
+    expect(
+      isTemporaryWorktreeBranch(`${WORKTREE_BRANCH_PREFIX}/f4ae4e0e-f971-4d48-c4f2-9cf0aa54ab12`),
+    ).toBe(false);
+  });
+
   it("rejects non-temporary refName names", () => {
     expect(isTemporaryWorktreeBranch(`${WORKTREE_BRANCH_PREFIX}/feature/demo`)).toBe(false);
     expect(isTemporaryWorktreeBranch("main")).toBe(false);
diff --git a/packages/shared/src/git.ts b/packages/shared/src/git.ts
index ae50b148835..71fe2e806cf 100644
--- a/packages/shared/src/git.ts
+++ b/packages/shared/src/git.ts
@@ -11,7 +11,13 @@ import * as Result from "effect/Result";
 import { detectSourceControlProviderFromRemoteUrl } from "./sourceControl.ts";
 
 export const WORKTREE_BRANCH_PREFIX = "t3code";
-const TEMP_WORKTREE_BRANCH_PATTERN = new RegExp(`^${WORKTREE_BRANCH_PREFIX}\\/[0-9a-f]{8}$`);
+// Canonical form is `t3code/<8 hex>`. Older mobile builds generated `t3code/<uuid>`
+// via Crypto.randomUUID() (always RFC 4122 v4), so the matcher also accepts exactly
+// that shape — version nibble `4`, variant nibble `[89ab]` — to keep those threads
+// eligible for branch regeneration without loosening beyond what was ever generated.
+const TEMP_WORKTREE_BRANCH_PATTERN = new RegExp(
+  `^${WORKTREE_BRANCH_PREFIX}\\/(?:[0-9a-f]{8}|[0-9a-f]{8}-[0-9a-f]{4}-4[0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12})$`,
+);
 
 /**
  * Sanitize an arbitrary string into a valid, lowercase git refName fragment.
@@ -89,7 +95,12 @@ export function deriveLocalBranchNameFromRemoteRef(branchName: string): string {
 export function buildTemporaryWorktreeBranchName(
   randomHex: (byteLength: number) => string,
 ): string {
-  const token = randomHex(4).toLowerCase();
+  // Normalize to exactly 8 lowercase hex chars so a UUID-shaped callback
+  // still produces the canonical temporary branch form.
+  const token = randomHex(4)
+    .toLowerCase()
+    .replace(/[^0-9a-f]/g, "")
+    .slice(0, 8);
   return `${WORKTREE_BRANCH_PREFIX}/${token}`;
 }