diff --git a/tests/docs/autonomous-harness-setup.test.js b/tests/docs/autonomous-harness-setup.test.js
index 75e8fe855..59d5c53e0 100644
--- a/tests/docs/autonomous-harness-setup.test.js
+++ b/tests/docs/autonomous-harness-setup.test.js
@@ -10,7 +10,7 @@ const blocks = [...source.matchAll(/```[^\n]*\n([\s\S]*?)```/g)].map(match => ma
 const checks = [
   ['executable examples omit unpublished packages and the invented dispatch endpoint', () => {
     assert.doesNotMatch(blocks, /@anthropic\/(?:memory|scheduled-tasks|computer-use)-mcp-server/);
-    assert.doesNotMatch(blocks, /api\.anthropic\.com\/dispatch/);
+    assert.ok(!blocks.includes('api.anthropic.com/dispatch'));
   }],
   ['CLI examples use the working directory and native session scheduling', () => {
     assert.doesNotMatch(blocks, /--project\b|mcp__scheduled-tasks__/);
diff --git a/tests/lib/claude-settings.test.js b/tests/lib/claude-settings.test.js
index dfd5d6b37..53caaf4bb 100644
--- a/tests/lib/claude-settings.test.js
+++ b/tests/lib/claude-settings.test.js
@@ -55,7 +55,7 @@ function assertAtomicParentReplacementRejected(stage) {
   const victimRoot = path.join(tempDir, 'victim');
   const settingsPath = path.join(targetRoot, 'settings.json');
   const victimPath = path.join(victimRoot, 'settings.json');
-  const originalOpen = fs.openSync;
+  const originalFsync = fs.fsyncSync;
   const originalClose = fs.closeSync;
   const targetContent = '{"target":true}\n';
   const victimContent = '{"victim":"preserve"}\n';
@@ -83,28 +83,20 @@ function assertAtomicParentReplacementRejected(stage) {
     fs.mkdirSync(victimRoot);
     fs.writeFileSync(settingsPath, targetContent);
     fs.writeFileSync(victimPath, victimContent);
-    fs.openSync = function(file, flags, ...args) {
-      const isTemp = typeof file === 'string'
-        && path.dirname(path.resolve(file)) === targetRoot
-        && path.basename(file).startsWith('.settings.json.') && file.endsWith('.tmp');
-      if (isTemp) tempBasename = path.basename(file);
-      if (isTemp && !replaced && stage === 'open') {
-        // Replace immediately after the temporary descriptor has been created.
-        const descriptor = originalOpen.call(fs, file, flags, ...args);
+    fs.fsyncSync = function(descriptor) {
+      const result = originalFsync.call(fs, descriptor);
+      const stagedName = fs.readdirSync(targetRoot).find(name => (
+        name.startsWith('.settings.json.') && name.endsWith('.tmp')
+      ));
+      if (stagedName) {
+        tempBasename = stagedName;
         tempDescriptor = descriptor;
-        try {
-          replaceParent();
-        } catch (error) {
-          // The writer has not received this handle yet. If Windows refuses
-          // the directory rename, the fixture must close its own descriptor.
-          originalClose.call(fs, descriptor);
-          throw error;
-        }
-        return descriptor;
+        // Exercise replacement while the staging handle is still open. The
+        // production writer owns the descriptor and closes it on rejection.
+        // Intercept fsync rather than forwarding arbitrary file-creation flags.
+        if (!replacementAttempted && stage === 'open') replaceParent();
       }
-      const descriptor = originalOpen.call(fs, file, flags, ...args);
-      if (isTemp) tempDescriptor = descriptor;
-      return descriptor;
+      return result;
     };
     fs.closeSync = function(descriptor) {
       const result = originalClose.call(fs, descriptor);
@@ -134,7 +126,7 @@ function assertAtomicParentReplacementRejected(stage) {
       assert.strictEqual(fs.readFileSync(path.join(victimRoot, tempBasename), 'utf8'), 'unrelated replacement file');
     }
   } finally {
-    fs.openSync = originalOpen;
+    fs.fsyncSync = originalFsync;
     fs.closeSync = originalClose;
     fs.rmSync(tempDir, { recursive: true, force: true });
   }
diff --git a/tests/lib/install-lifecycle.test.js b/tests/lib/install-lifecycle.test.js
index fef01bd8a..ab20e54ca 100644
--- a/tests/lib/install-lifecycle.test.js
+++ b/tests/lib/install-lifecycle.test.js
@@ -3512,8 +3512,13 @@ function runTests() {
       });
 
       assert.strictEqual(result.results[0].status, 'repaired');
-      assert.strictEqual(fs.statSync(settingsPath).mode & 0o777, 0o600);
-      assert.deepStrictEqual(JSON.parse(fs.readFileSync(settingsPath, 'utf8')).hooks, managedHooks);
+      const descriptor = fs.openSync(settingsPath, 'r');
+      try {
+        assert.strictEqual(fs.fstatSync(descriptor).mode & 0o777, 0o600);
+        assert.deepStrictEqual(JSON.parse(fs.readFileSync(descriptor, 'utf8')).hooks, managedHooks);
+      } finally {
+        fs.closeSync(descriptor);
+      }
     } finally {
       cleanup(homeDir);
       cleanup(projectRoot);