diff --git a/browse/src/server.ts b/browse/src/server.ts
index 4c9103edc..b247c5084 100644
--- a/browse/src/server.ts
+++ b/browse/src/server.ts
@@ -243,6 +243,14 @@ export interface ServerConfig {
    * reference is the PID record + the file paths.
    */
   ownsTerminalAgent?: boolean;
+  /**
+   * Process-exit seam. shutdown() calls this at the very end of its async
+   * teardown; defaults to process.exit. In-process test runs inject a
+   * recording stub here — the fire-and-forget shutdown path otherwise races
+   * per-test process.exit stubs, and a straggler real exit(0) truncates the
+   * whole bun test run with a green exit code and no failure tally.
+   */
+  exitFn?: (code?: number) => void;
 }
 
 /**
@@ -1494,6 +1502,9 @@ export function buildFetchHandler(cfg: ServerConfig): ServerHandle {
   // to gstack-owns. Matches the "default-true preserves CLI bit-for-bit"
   // premise even under malformed cfg.
   const ownsTerminalAgent = cfg.ownsTerminalAgent === false ? false : true;
+  // Exit seam: production defaults to process.exit; tests inject a stub so
+  // in-process shutdowns can never terminate the test runner itself.
+  const exitFn = cfg.exitFn ?? ((code?: number) => process.exit(code));
 
   // ─── Terminal-Agent Watchdog (v1.44+) ─────────────────────────────
   //
@@ -1619,7 +1630,7 @@ export function buildFetchHandler(cfg: ServerConfig): ServerHandle {
 
     cleanSingletonLocks(resolveChromiumProfile());
     safeUnlinkQuiet(config.stateFile);
-    process.exit(exitCode);
+    exitFn(exitCode);
   }
 
   // Named lifecycle helper (matches closeTunnel style). Logs failures so
diff --git a/browse/test/batch.test.ts b/browse/test/batch.test.ts
index 3d904a1a9..0a52e1eaf 100644
--- a/browse/test/batch.test.ts
+++ b/browse/test/batch.test.ts
@@ -42,9 +42,16 @@ beforeAll(async () => {
   // The test needs to start a server. Let's use the existing server infrastructure.
 });
 
-afterAll(() => {
+afterAll(async () => {
   try { testServer.server.stop(); } catch {}
-  setTimeout(() => process.exit(0), 500);
+  // Close the real browser (capped at 5s — close can hang) instead of a
+  // delayed process.exit(0): that timer fired ~500ms into the NEXT test
+  // file in a full-suite run and killed the whole bun process with a green
+  // exit code and no tally, silently truncating the run.
+  await Promise.race([
+    bm.close().catch(() => {}),
+    new Promise<void>(r => setTimeout(r, 5000)),
+  ]);
 });
 
 // We need a running browse server for HTTP tests.
diff --git a/browse/test/commands.test.ts b/browse/test/commands.test.ts
index 9382cb27e..48f0f6424 100644
--- a/browse/test/commands.test.ts
+++ b/browse/test/commands.test.ts
@@ -94,11 +94,18 @@ beforeAll(async () => {
   await bm.launch();
 });
 
-afterAll(() => {
+afterAll(async () => {
   // Force kill browser instead of graceful close (avoids hang)
   try { testServer.server.stop(); } catch {}
   // bm.close() can hang — just let process exit handle it
-  setTimeout(() => process.exit(0), 500);
+  // Close the real browser (capped at 5s — close can hang) instead of a
+  // delayed process.exit(0): that timer fired ~500ms into the NEXT test
+  // file in a full-suite run and killed the whole bun process with a green
+  // exit code and no tally, silently truncating the run.
+  await Promise.race([
+    bm.close().catch(() => {}),
+    new Promise<void>(r => setTimeout(r, 5000)),
+  ]);
 });
 
 // ─── Navigation ─────────────────────────────────────────────────
diff --git a/browse/test/compare-board.test.ts b/browse/test/compare-board.test.ts
index 0a453a43a..36c09f706 100644
--- a/browse/test/compare-board.test.ts
+++ b/browse/test/compare-board.test.ts
@@ -69,10 +69,17 @@ beforeAll(async () => {
   await handleWriteCommand('goto', [boardUrl], bm);
 });
 
-afterAll(() => {
+afterAll(async () => {
   try { server.stop(); } catch {}
   fs.rmSync(tmpDir, { recursive: true, force: true });
-  setTimeout(() => process.exit(0), 500);
+  // Close the real browser (capped at 5s — close can hang) instead of a
+  // delayed process.exit(0): that timer fired ~500ms into the NEXT test
+  // file in a full-suite run and killed the whole bun process with a green
+  // exit code and no tally, silently truncating the run.
+  await Promise.race([
+    bm.close().catch(() => {}),
+    new Promise<void>(r => setTimeout(r, 5000)),
+  ]);
 });
 
 // ─── DOM Structure ──────────────────────────────────────────────
diff --git a/browse/test/content-security.test.ts b/browse/test/content-security.test.ts
index 8c760460d..01710c108 100644
--- a/browse/test/content-security.test.ts
+++ b/browse/test/content-security.test.ts
@@ -422,9 +422,16 @@ describe('Hidden element stripping', () => {
     await bm.launch();
   });
 
-  afterAll(() => {
+  afterAll(async () => {
     try { testServer.server.stop(); } catch {}
-    setTimeout(() => process.exit(0), 500);
+    // Close the real browser (capped at 5s — close can hang) instead of a
+    // delayed process.exit(0): that timer fired ~500ms into the NEXT test
+    // file in a full-suite run and killed the whole bun process with a green
+    // exit code and no tally, silently truncating the run.
+    await Promise.race([
+      bm.close().catch(() => {}),
+      new Promise<void>(r => setTimeout(r, 5000)),
+    ]);
   });
 
   test('detects CSS-hidden elements on injection-hidden page', async () => {
diff --git a/browse/test/handoff.test.ts b/browse/test/handoff.test.ts
index e6754637f..ab4eaf74d 100644
--- a/browse/test/handoff.test.ts
+++ b/browse/test/handoff.test.ts
@@ -26,9 +26,16 @@ beforeAll(async () => {
   await bm.launch();
 });
 
-afterAll(() => {
+afterAll(async () => {
   try { testServer.server.stop(); } catch {}
-  setTimeout(() => process.exit(0), 500);
+  // Close the real browser (capped at 5s — close can hang) instead of a
+  // delayed process.exit(0): that timer fired ~500ms into the NEXT test
+  // file in a full-suite run and killed the whole bun process with a green
+  // exit code and no tally, silently truncating the run.
+  await Promise.race([
+    bm.close().catch(() => {}),
+    new Promise<void>(r => setTimeout(r, 5000)),
+  ]);
 });
 
 // ─── Unit Tests: Failure Tracking (no browser needed) ────────────
diff --git a/browse/test/security-live-playwright.test.ts b/browse/test/security-live-playwright.test.ts
index c75a115d3..07855f843 100644
--- a/browse/test/security-live-playwright.test.ts
+++ b/browse/test/security-live-playwright.test.ts
@@ -56,9 +56,16 @@ describe('defense-in-depth — live Playwright fixture', () => {
     await bm.launch();
   });
 
-  afterAll(() => {
+  afterAll(async () => {
     try { testServer.server.stop(); } catch {}
-    setTimeout(() => process.exit(0), 500);
+    // Close the real browser (capped at 5s — close can hang) instead of a
+    // delayed process.exit(0): that timer fired ~500ms into the NEXT test
+    // file in a full-suite run and killed the whole bun process with a green
+    // exit code and no tally, silently truncating the run.
+    await Promise.race([
+      bm.close().catch(() => {}),
+      new Promise<void>(r => setTimeout(r, 5000)),
+    ]);
   });
 
   test('L2 — content-security.ts hidden-element stripper detects the .sneaky div', async () => {
diff --git a/browse/test/server-factory.test.ts b/browse/test/server-factory.test.ts
index 0cfc73126..cd2d9fc18 100644
--- a/browse/test/server-factory.test.ts
+++ b/browse/test/server-factory.test.ts
@@ -1,4 +1,4 @@
-import { describe, test, expect, beforeEach, mock } from 'bun:test';
+import { describe, test, expect, beforeAll, beforeEach, afterAll, mock } from 'bun:test';
 import {
   resolveConfigFromEnv,
   buildFetchHandler,
@@ -445,92 +445,68 @@ describe('idle timer + onDisconnect dual-instance fix', () => {
   });
 
   test('CRITICAL — REGRESSION: headed embedder does not auto-shutdown at idle', () => {
-    const exitMock = mock((_code?: number) => { throw new Error('process.exit called'); });
-    const originalExit = process.exit;
-    (process as any).exit = exitMock;
-    try {
-      const mockBM = makeMockBrowserManager('headed');
-      buildFetchHandler(makeMinimalConfig({ browserManager: mockBM as any }));
-      // Drive lastActivity past the idle threshold via the test seam instead
-      // of mutating Date.now — the leaked module-level setInterval would
-      // see fake-time and could fire shutdown if the timing aligned.
-      __testInternals__.setLastActivity(Date.now() - (31 * 60 * 1000));
-      __testInternals__.idleCheckTick();
-      expect(exitMock).not.toHaveBeenCalled();
-    } finally {
-      (process as any).exit = originalExit;
-    }
+    const exitSpy = mock((_code?: number) => {});
+    const mockBM = makeMockBrowserManager('headed');
+    buildFetchHandler(makeMinimalConfig({ browserManager: mockBM as any, exitFn: exitSpy }));
+    // Drive lastActivity past the idle threshold via the test seam instead
+    // of mutating Date.now — the leaked module-level setInterval would
+    // see fake-time and could fire shutdown if the timing aligned.
+    __testInternals__.setLastActivity(Date.now() - (31 * 60 * 1000));
+    __testInternals__.idleCheckTick();
+    expect(exitSpy).not.toHaveBeenCalled();
   });
 
   test('headless still auto-shuts down at idle (paired defensive)', async () => {
-    // Non-throwing mock: idleCheckTick fires shutdown as a fire-and-forget
-    // async call. Throwing from process.exit becomes an unhandled rejection
-    // that the test runner catches. Recording the call is enough.
-    const exitMock = mock((_code?: number) => {});
-    const originalExit = process.exit;
-    (process as any).exit = exitMock;
-    try {
-      const mockBM = makeMockBrowserManager('launched');
-      buildFetchHandler(makeMinimalConfig({ browserManager: mockBM as any }));
-      __testInternals__.setLastActivity(Date.now() - (31 * 60 * 1000));
-      __testInternals__.idleCheckTick();
-      // Poll until the fire-and-forget shutdown reaches process.exit. A fixed
-      // microtask drain can lose the race on slower hosts — and then the REAL
-      // process.exit(0) fires after the finally restores it, killing the whole
-      // bun test run mid-suite with a green exit code and no failure tally.
-      for (let i = 0; i < 500 && exitMock.mock.calls.length === 0; i++) {
-        await new Promise<void>(r => setTimeout(r, 10));
-      }
-      expect(exitMock).toHaveBeenCalled();
-    } finally {
-      // Reset activity so the module-level 60s idle interval (which outlives
-      // this file) cannot re-fire shutdown with the real process.exit later
-      // in the suite.
-      __testInternals__.setLastActivity(Date.now());
-      (process as any).exit = originalExit;
+    // Shutdown is fire-and-forget async and hard-calling process.exit from it
+    // is what this seam exists to avoid: a per-test process.exit stub can be
+    // restored while a straggler shutdown is still in flight, and the real
+    // exit(0) then kills the whole bun run mid-suite with a green exit code.
+    // The injected exitFn spy makes the assertion race-free and harmless.
+    const exitSpy = mock((_code?: number) => {});
+    const mockBM = makeMockBrowserManager('launched');
+    buildFetchHandler(makeMinimalConfig({ browserManager: mockBM as any, exitFn: exitSpy }));
+    __testInternals__.setLastActivity(Date.now() - (31 * 60 * 1000));
+    __testInternals__.idleCheckTick();
+    // Poll until the async shutdown reaches the exit seam.
+    for (let i = 0; i < 500 && exitSpy.mock.calls.length === 0; i++) {
+      await new Promise<void>(r => setTimeout(r, 10));
     }
+    expect(exitSpy).toHaveBeenCalled();
+    // Reset activity so the module-level 60s idle interval cannot re-fire
+    // shutdown later in the suite.
+    __testInternals__.setLastActivity(Date.now());
   });
 
   test('buildFetchHandler chains cfgBrowserManager.onDisconnect, preserving caller-set handler', async () => {
     const mockBM = makeMockBrowserManager('headed');
     const callerCb = mock(async (_code?: number) => {});
     mockBM.onDisconnect = callerCb;
-    buildFetchHandler(makeMinimalConfig({ browserManager: mockBM as any }));
+    const exitSpy = mock((_code?: number) => {});
+    buildFetchHandler(makeMinimalConfig({ browserManager: mockBM as any, exitFn: exitSpy }));
     // gstack should have wrapped the caller-installed handler instead of
     // clobbering it (Codex finding: BrowserManager.onDisconnect is a public
     // field; gbrowser may set it before calling buildFetchHandler).
     expect(typeof mockBM.onDisconnect).toBe('function');
     expect(mockBM.onDisconnect).not.toBe(callerCb);
     // Verify the chain: invoking the wrapped handler runs the caller
-    // callback AND reaches activeShutdown (which calls process.exit at the
-    // very end of its async path). Stubbing process.exit to throw aborts
-    // the chain before isShuttingDown can leak into later tests.
-    const exitMock = mock((_code?: number) => { throw new Error('process.exit called'); });
-    const originalExit = process.exit;
-    (process as any).exit = exitMock;
-    try {
-      await expect((mockBM.onDisconnect as any)(0)).rejects.toThrow('process.exit called');
-      expect(callerCb).toHaveBeenCalledWith(0);
-      expect(exitMock).toHaveBeenCalledWith(0);
-    } finally {
-      (process as any).exit = originalExit;
+    // callback AND reaches activeShutdown, whose teardown ends at the
+    // injected exit seam instead of the real process.exit.
+    await (mockBM.onDisconnect as any)(0);
+    for (let i = 0; i < 500 && exitSpy.mock.calls.length === 0; i++) {
+      await new Promise<void>(r => setTimeout(r, 10));
     }
+    expect(callerCb).toHaveBeenCalledWith(0);
+    expect(exitSpy).toHaveBeenCalledWith(0);
   });
 
   test('tunnelActive blocks idle-shutdown even in headless mode', () => {
-    const exitMock = mock((_code?: number) => { throw new Error('process.exit called'); });
-    const originalExit = process.exit;
-    (process as any).exit = exitMock;
-    try {
-      const mockBM = makeMockBrowserManager('launched');
-      buildFetchHandler(makeMinimalConfig({ browserManager: mockBM as any }));
-      __testInternals__.setTunnelActive(true);
-      __testInternals__.setLastActivity(Date.now() - (31 * 60 * 1000));
-      __testInternals__.idleCheckTick();
-      expect(exitMock).not.toHaveBeenCalled();
-    } finally {
-      (process as any).exit = originalExit;
-    }
+    const exitSpy = mock((_code?: number) => {});
+    const mockBM = makeMockBrowserManager('launched');
+    buildFetchHandler(makeMinimalConfig({ browserManager: mockBM as any, exitFn: exitSpy }));
+    __testInternals__.setTunnelActive(true);
+    __testInternals__.setLastActivity(Date.now() - (31 * 60 * 1000));
+    __testInternals__.idleCheckTick();
+    expect(exitSpy).not.toHaveBeenCalled();
   });
 
   test('lifecycle handlers (idleCheckTick + parent watchdog + SIGTERM) read activeBrowserManager, not module-level browserManager', () => {
diff --git a/browse/test/snapshot.test.ts b/browse/test/snapshot.test.ts
index 17b26c3d4..e08b340a6 100644
--- a/browse/test/snapshot.test.ts
+++ b/browse/test/snapshot.test.ts
@@ -31,9 +31,13 @@ beforeAll(async () => {
   await bm.launch();
 });
 
-afterAll(() => {
+afterAll(async () => {
   try { testServer.server.stop(); } catch {}
-  setTimeout(() => process.exit(0), 500);
+  // Close the real browser instead of scheduling a delayed process.exit(0):
+  // in a full-suite run that timer fired ~500ms into the NEXT test file and
+  // killed the entire bun process with a green exit code and no tally —
+  // silently truncating the run and hiding every failure after this file.
+  await bm.close().catch(() => {});
 });
 
 // ─── Snapshot Output ────────────────────────────────────────────
diff --git a/design/test/feedback-roundtrip.test.ts b/design/test/feedback-roundtrip.test.ts
index e8d63db23..be952dbc2 100644
--- a/design/test/feedback-roundtrip.test.ts
+++ b/design/test/feedback-roundtrip.test.ts
@@ -121,10 +121,15 @@ beforeAll(async () => {
   await bm.launch();
 });
 
-afterAll(() => {
+afterAll(async () => {
   try { server.stop(); } catch {}
   fs.rmSync(tmpDir, { recursive: true, force: true });
-  setTimeout(() => process.exit(0), 500);
+  // Close the browser (capped) instead of a delayed process.exit(0): that
+  // timer killed the whole bun process mid-suite with a green exit code.
+  await Promise.race([
+    bm.close().catch(() => {}),
+    new Promise(r => setTimeout(r, 5000)),
+  ]);
 });
 
 // ─── The critical test: browser click → file on disk ─────────────