diff --git a/src/main/skills/skill-placement-copy-drift.test.ts b/src/main/skills/skill-placement-copy-drift.test.ts
new file mode 100644
index 00000000000..367c280e8a2
--- /dev/null
+++ b/src/main/skills/skill-placement-copy-drift.test.ts
@@ -0,0 +1,93 @@
+import { mkdir, mkdtemp, readFile, rm, writeFile } from 'node:fs/promises'
+import { tmpdir } from 'node:os'
+import { join } from 'node:path'
+import { afterEach, describe, expect, it } from 'vitest'
+import type { SkillInstallReceiptV1 } from './skill-install-provenance'
+import { nativeSkillInstallFilesystem } from './skill-install-filesystem'
+import { reconcileSkillProviderPlacement } from './skill-placement-reconciliation'
+import { isRemovableSkillPlacement } from './skill-removable-placement'
+
+const roots: string[] = []
+
+async function fixture() {
+  const root = await mkdtemp(join(tmpdir(), 'orca-skill-copy-drift-'))
+  roots.push(root)
+  const canonicalPath = join(root, 'canonical', 'private-skill')
+  const providerRoot = join(root, 'provider')
+  const placementPath = join(providerRoot, 'private-skill')
+  await Promise.all([
+    mkdir(canonicalPath, { recursive: true }),
+    mkdir(placementPath, { recursive: true })
+  ])
+  await Promise.all([
+    writeFile(join(canonicalPath, 'SKILL.md'), 'old skill'),
+    writeFile(join(placementPath, 'SKILL.md'), 'old skill')
+  ])
+  const packageDigest = (await nativeSkillInstallFilesystem.observeSkill(canonicalPath))
+    .observedDigest
+  const receipt: SkillInstallReceiptV1 = {
+    schemaVersion: 1,
+    packageId: 'package_1',
+    versionId: 'version_1',
+    packageDigest,
+    archiveSha256: 'a'.repeat(64),
+    scope: 'global',
+    destinationIdentity: 'global:test',
+    canonicalPath,
+    placements: [
+      {
+        provider: 'claude',
+        path: placementPath,
+        topology: 'independent-copy',
+        status: 'installed'
+      }
+    ],
+    installedAt: '2026-08-11T00:00:00.000Z',
+    hostIdentity: 'test'
+  }
+  return { canonicalPath, providerRoot, placementPath, receipt }
+}
+
+afterEach(async () => {
+  await Promise.all(roots.splice(0).map((root) => rm(root, { recursive: true, force: true })))
+})
+
+describe('independent skill placement copy drift', () => {
+  it('preserves a locally modified copy during update reconciliation', async () => {
+    const value = await fixture()
+    await writeFile(join(value.canonicalPath, 'SKILL.md'), 'new cloud version')
+    await writeFile(join(value.placementPath, 'local.md'), 'local change')
+    const packageDigest = (await nativeSkillInstallFilesystem.observeSkill(value.canonicalPath))
+      .observedDigest
+
+    const result = await reconcileSkillProviderPlacement({
+      canonicalPath: value.canonicalPath,
+      skillName: 'private-skill',
+      destination: { provider: 'claude', rootPath: value.providerRoot, readsCanonicalRoot: false },
+      previousReceipt: value.receipt,
+      packageDigest
+    })
+
+    expect(result).toMatchObject({
+      topology: 'independent-copy',
+      status: 'skipped',
+      errorCategory: 'skill-placement-modified-copy'
+    })
+    expect(await readFile(join(value.placementPath, 'local.md'), 'utf8')).toBe('local change')
+  })
+
+  it('refuses to remove a locally modified copy', async () => {
+    const value = await fixture()
+    await writeFile(join(value.placementPath, 'local.md'), 'local change')
+
+    await expect(
+      isRemovableSkillPlacement({
+        placement: value.receipt.placements[0]!,
+        receipt: value.receipt,
+        allowedProviderRoots: [value.providerRoot],
+        filesystem: nativeSkillInstallFilesystem
+      })
+    ).resolves.toBe(false)
+    expect(await readFile(join(value.placementPath, 'local.md'), 'utf8')).toBe('local change')
+  })
+})