diff --git a/src/main/git/command-runner/git-admission-output-parity.test.ts b/src/main/git/command-runner/git-admission-output-parity.test.ts
new file mode 100644
index 00000000000..c75519cfc7c
--- /dev/null
+++ b/src/main/git/command-runner/git-admission-output-parity.test.ts
@@ -0,0 +1,60 @@
+// Runs on every platform: parity against real git is the Windows-relevant half of
+// the admission evidence, so it must not share the storm harness's POSIX gate.
+import { execFileSync } from 'node:child_process'
+import { mkdtemp, readFile, rm, writeFile } from 'node:fs/promises'
+import { tmpdir } from 'node:os'
+import path from 'node:path'
+import { afterEach, expect, it } from 'vitest'
+import { gitExecFileAsync, gitExecFileAsyncBuffer } from './git-exec-file'
+import { _resetGitAdmissionForTests } from './git-subprocess-admission'
+
+const tempRoots: string[] = []
+const originalAdmissionDisabled = process.env.ORCA_GIT_ADMISSION_DISABLED
+
+afterEach(async () => {
+  if (originalAdmissionDisabled === undefined) {
+    delete process.env.ORCA_GIT_ADMISSION_DISABLED
+  } else {
+    process.env.ORCA_GIT_ADMISSION_DISABLED = originalAdmissionDisabled
+  }
+  _resetGitAdmissionForTests()
+  await Promise.all(tempRoots.splice(0).map((root) => rm(root, { recursive: true, force: true })))
+})
+
+function setAdmissionDisabled(disabled: boolean): void {
+  if (disabled) {
+    process.env.ORCA_GIT_ADMISSION_DISABLED = '1'
+  } else {
+    delete process.env.ORCA_GIT_ADMISSION_DISABLED
+  }
+}
+
+it('keeps real git output byte-identical with admission on and bypassed', async () => {
+  const root = await mkdtemp(path.join(tmpdir(), 'orca-git-output-parity-'))
+  tempRoots.push(root)
+  execFileSync('git', ['init', '-q'], { cwd: root })
+  execFileSync('git', ['config', 'user.email', 'test@example.com'], { cwd: root })
+  execFileSync('git', ['config', 'user.name', 'Orca Test'], { cwd: root })
+  await writeFile(path.join(root, 'tracked.txt'), 'line one\nline two\n')
+  await writeFile(path.join(root, 'blob.bin'), Buffer.from([0, 1, 2, 3, 255]))
+  execFileSync('git', ['add', '.'], { cwd: root })
+  execFileSync('git', ['commit', '-q', '-m', 'fixture'], { cwd: root })
+  await writeFile(path.join(root, 'tracked.txt'), 'line one\nchanged\n')
+
+  const runBattery = async (disabled: boolean): Promise<(string | Buffer)[]> => {
+    setAdmissionDisabled(disabled)
+    return [
+      (await gitExecFileAsync(['status', '--porcelain=v2'], { cwd: root })).stdout,
+      (await gitExecFileAsync(['diff', '--numstat'], { cwd: root })).stdout,
+      (await gitExecFileAsync(['branch', '-a'], { cwd: root })).stdout,
+      (await gitExecFileAsync(['rev-parse', 'HEAD'], { cwd: root })).stdout,
+      (await gitExecFileAsyncBuffer(['show', 'HEAD:blob.bin'], { cwd: root })).stdout
+    ]
+  }
+
+  const enabled = await runBattery(false)
+  const bypassed = await runBattery(true)
+  expect(bypassed).toEqual(enabled)
+  expect(await readFile(path.join(root, 'blob.bin'))).toEqual(enabled.at(-1))
+  console.info('GIT_ADMISSION_OUTPUT_PARITY=byte-identical')
+})
diff --git a/src/main/git/command-runner/git-admission-storm-measurement.test.ts b/src/main/git/command-runner/git-admission-storm-measurement.test.ts
index 5191be576cb..2fb3e896b20 100644
--- a/src/main/git/command-runner/git-admission-storm-measurement.test.ts
+++ b/src/main/git/command-runner/git-admission-storm-measurement.test.ts
@@ -2,12 +2,11 @@
  * POSIX-only measurement: a PATH-injected git fixture exercises the real spawn path.
  * Timing distributions are reported for field comparison; CI assertions stay structural.
  */
-import { execFileSync } from 'node:child_process'
-import { chmod, mkdtemp, mkdir, readFile, readdir, rm, writeFile } from 'node:fs/promises'
+import { chmod, mkdtemp, mkdir, readdir, rm, writeFile } from 'node:fs/promises'
 import { tmpdir } from 'node:os'
 import path from 'node:path'
 import { afterEach, describe, expect, it } from 'vitest'
-import { gitExecFileAsync, gitExecFileAsyncBuffer } from './git-exec-file'
+import { gitExecFileAsync } from './git-exec-file'
 import {
   GIT_ADMISSION_AGING_MS,
   GitAdmissionScheduler,
@@ -246,33 +245,6 @@ describe.skipIf(process.platform === 'win32')('git admission storm measurement',
     assertAdmissionLedger(enabled)
   })
 
-  it('keeps real git output byte-identical with admission on and bypassed', async () => {
-    const root = await mkdtemp(path.join(tmpdir(), 'orca-git-output-parity-'))
-    tempRoots.push(root)
-    execFileSync('git', ['init', '-q'], { cwd: root })
-    execFileSync('git', ['config', 'user.email', 'test@example.com'], { cwd: root })
-    execFileSync('git', ['config', 'user.name', 'Orca Test'], { cwd: root })
-    await writeFile(path.join(root, 'tracked.txt'), 'line one\nline two\n')
-    await writeFile(path.join(root, 'blob.bin'), Buffer.from([0, 1, 2, 3, 255]))
-    execFileSync('git', ['add', '.'], { cwd: root })
-    execFileSync('git', ['commit', '-q', '-m', 'fixture'], { cwd: root })
-    await writeFile(path.join(root, 'tracked.txt'), 'line one\nchanged\n')
-
-    const runBattery = async (disabled: boolean): Promise<(string | Buffer)[]> => {
-      setAdmissionMode(disabled ? 'disabled' : 'enabled')
-      return [
-        (await gitExecFileAsync(['status', '--porcelain=v2'], { cwd: root })).stdout,
-        (await gitExecFileAsync(['diff', '--numstat'], { cwd: root })).stdout,
-        (await gitExecFileAsync(['branch', '-a'], { cwd: root })).stdout,
-        (await gitExecFileAsync(['rev-parse', 'HEAD'], { cwd: root })).stdout,
-        (await gitExecFileAsyncBuffer(['show', 'HEAD:blob.bin'], { cwd: root })).stdout
-      ]
-    }
-
-    const enabled = await runBattery(false)
-    const bypassed = await runBattery(true)
-    expect(bypassed).toEqual(enabled)
-    expect(await readFile(path.join(root, 'blob.bin'))).toEqual(enabled.at(-1))
-    console.info('GIT_ADMISSION_OUTPUT_PARITY=byte-identical')
-  })
+  // Output parity lives in git-admission-output-parity.test.ts: it needs real git,
+  // not the PATH stub, so it runs on win32 too and cannot share this file's gate.
 })