diff --git a/test/mocks/index.ts b/test/mocks/index.ts
index 0a17f837..2a696c2d 100644
--- a/test/mocks/index.ts
+++ b/test/mocks/index.ts
@@ -7,5 +7,5 @@
 
 export { MockSession, createMockSession, terminalOutputs } from './mock-session.js';
 export { MockStateStore } from './mock-state-store.js';
-export { waitForEvent, createDeferred } from './test-helpers.js';
+export { waitForEvent, createDeferred, safeRmHomeTree, isUnderTestHome } from './test-helpers.js';
 export { createMockRouteContext, type MockRouteContext } from './mock-route-context.js';
diff --git a/test/mocks/test-helpers.ts b/test/mocks/test-helpers.ts
index cc64a787..6e68f022 100644
--- a/test/mocks/test-helpers.ts
+++ b/test/mocks/test-helpers.ts
@@ -2,6 +2,9 @@
  * Reusable async test helpers.
  */
 
+import { rmSync } from 'node:fs';
+import { resolve } from 'node:path';
+
 /** Wait for an EventEmitter to emit a specific event, with timeout */
 export function waitForEvent(
   emitter: { once: (event: string, listener: (...args: unknown[]) => void) => void },
@@ -34,3 +37,39 @@ export function createDeferred<T = void>(): {
   });
   return { promise, resolve, reject };
 }
+
+/**
+ * Delete a directory tree, but ONLY when it lives inside the test HOME.
+ *
+ * SAFETY (2026-08-29): `test/setup.ts` redirects `process.env.HOME` to a
+ * throwaway dir, but code that resolves paths via `os.homedir()` does NOT
+ * follow that redirect on every Linux build/Node version — some read
+ * /etc/passwd instead of $HOME. A test that `rmSync(CASES_DIR, recursive)` can
+ * therefore delete the PRODUCTION `~/codeman-cases` (or any home-anchored
+ * tree) on those platforms. This gate refuses to delete anything not under the
+ * (redirected) `process.env.HOME`. Lexical `resolve()` is used because the leaf
+ * often does not exist and `realpathSync` would throw.
+ */
+export function safeRmHomeTree(path: string): void {
+  const home = process.env.HOME;
+  if (!home) return;
+  const target = resolve(path);
+  const root = resolve(home);
+  if (target === root || target.startsWith(root + '/')) {
+    rmSync(target, { recursive: true, force: true });
+  }
+}
+
+/**
+ * True when `path` resolves strictly inside `process.env.HOME` (or to it).
+ * Same rationale as `safeRmHomeTree`; use for guarded non-recursive deletes
+ * (single files like `linked-cases.json`) so they never touch prod state on
+ * platforms where `os.homedir()` ignores `$HOME`.
+ */
+export function isUnderTestHome(path: string): boolean {
+  const home = process.env.HOME;
+  if (!home) return false;
+  const target = resolve(path);
+  const root = resolve(home);
+  return target === root || target.startsWith(root + '/');
+}
diff --git a/test/routes/session-routes-workspace-hooks.test.ts b/test/routes/session-routes-workspace-hooks.test.ts
index 39c4763e..a7820cda 100644
--- a/test/routes/session-routes-workspace-hooks.test.ts
+++ b/test/routes/session-routes-workspace-hooks.test.ts
@@ -26,7 +26,7 @@ import { mkdtemp, rm, readFile, mkdir, writeFile } from 'node:fs/promises';
 import { existsSync } from 'node:fs';
 import { join } from 'node:path';
 import { tmpdir } from 'node:os';
-import { createMockRouteContext, type MockRouteContext } from '../mocks/index.js';
+import { createMockRouteContext, safeRmHomeTree, type MockRouteContext } from '../mocks/index.js';
 import { installRouteErrorHandler } from '../../src/web/route-error-handler.js';
 import { registerSessionRoutes } from '../../src/web/routes/session-routes.js';
 import { generateHooksConfig, applyWorkspaceHooks } from '../../src/hooks-config.js';
@@ -259,7 +259,11 @@ describe('POST /api/quick-start workspace hooks', () => {
     // Docker fixtures + case dirs must not leak into the next test.
     await rm(join(getDataDir(), 'docker-hosts.json'), { force: true });
     await rm(join(getDataDir(), 'docker-cases.json'), { force: true });
-    await rm(CASES_DIR, { recursive: true, force: true });
+    // SAFETY (2026-08-29): CASES_DIR is `join(homedir(), 'codeman-cases')`, and
+    // on environments where `os.homedir()` ignores `$HOME` it resolves to the
+    // PROD case tree. `safeRmHomeTree` refuses to delete anything not under the
+    // redirected test HOME, so a run can never nuke the real `~/codeman-cases`.
+    safeRmHomeTree(CASES_DIR);
   });
 
   it('installs hooks into an EXISTING case directory (a linked case / cloned repo)', async () => {
diff --git a/test/setup.ts b/test/setup.ts
index e5135457..1b24e5ee 100644
--- a/test/setup.ts
+++ b/test/setup.ts
@@ -20,6 +20,7 @@ const originalVitest = process.env.VITEST;
 const originalPlaywrightBrowsersPath = process.env.PLAYWRIGHT_BROWSERS_PATH;
 const originalCodemanDataDir = process.env.CODEMAN_DATA_DIR;
 const testHome = mkdtempSync(join(tmpdir(), 'codeman-vitest-'));
+const testDataDir = join(tmpdir(), `codeman-vitest-data-${process.pid}`);
 
 if (originalPlaywrightBrowsersPath === undefined && originalHome) {
   process.env.PLAYWRIGHT_BROWSERS_PATH =
@@ -41,7 +42,7 @@ process.env.VITEST = 'true';
 // overwrote prod `remote-hosts.json` with an `h1/box/10.0.0.5` fixture during a
 // bare full-suite run, wiping every user-defined remote host and emptying the
 // launch case dropdown). Point every test at a throwaway data dir instead.
-process.env.CODEMAN_DATA_DIR = join(tmpdir(), `codeman-vitest-data-${process.pid}`);
+process.env.CODEMAN_DATA_DIR = testDataDir;
 
 delete process.env.CODEMAN_PASSWORD;
 delete process.env.CODEMAN_USERNAME;
@@ -61,7 +62,9 @@ afterAll(async () => {
   // "onUserConsoleLog" call is still pending, and that single unhandled
   // EnvironmentTeardownError fails the run after every test has passed
   // (observed twice on the PR #175/#176 merge commit; never locally).
-  await new Promise((resolve) => setTimeout(resolve, 50));
+  const { promise: drained, resolve: drainDone } = Promise.withResolvers<void>();
+  setTimeout(drainDone, 50);
+  await drained;
 
   if (originalHome === undefined) delete process.env.HOME;
   else process.env.HOME = originalHome;
@@ -79,7 +82,7 @@ afterAll(async () => {
   else process.env.CODEMAN_DATA_DIR = originalCodemanDataDir;
 
   rmSync(testHome, { recursive: true, force: true });
-  rmSync(process.env.CODEMAN_DATA_DIR ?? '', { recursive: true, force: true });
+  rmSync(testDataDir, { recursive: true, force: true });
 });
 
 // afterAll never fires for a fully-skipped test file (no tests execute), which
@@ -87,4 +90,5 @@ afterAll(async () => {
 // with force is a no-op when afterAll already removed it.
 process.on('exit', () => {
   rmSync(testHome, { recursive: true, force: true });
+  rmSync(testDataDir, { recursive: true, force: true });
 });