diff --git a/packages/opencode/test/fixture/fixture.ts b/packages/opencode/test/fixture/fixture.ts
index 0b83bb316..3a3e4c0b8 100644
--- a/packages/opencode/test/fixture/fixture.ts
+++ b/packages/opencode/test/fixture/fixture.ts
@@ -10,7 +10,10 @@ type TmpDirOptions<T> = {
 export async function tmpdir<T>(options?: TmpDirOptions<T>) {
   const dirpath = path.join(os.tmpdir(), "opencode-test-" + Math.random().toString(36).slice(2))
   await $`mkdir -p ${dirpath}`.quiet()
-  if (options?.git) await $`git init`.cwd(dirpath).quiet()
+  if (options?.git) {
+    await $`git init`.cwd(dirpath).quiet()
+    await $`git commit --allow-empty -m "root commit ${dirpath}"`.cwd(dirpath).quiet()
+  }
   const extra = await options?.init?.(dirpath)
   const result = {
     [Symbol.asyncDispose]: async () => {