From 9d1e4d78054829e843105ae96704f79c9efa9d4e Mon Sep 17 00:00:00 2001
From: Yunfei He <i.heyunfei@gmail.com>
Date: Sat, 30 May 2026 19:57:52 +0800
Subject: [PATCH] feat(runtime)!: replace useExit() with Ink-aligned
 useAppContext() (#69)
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Ink's `useApp()` returns `{ exit, waitUntilRenderFlush }`. vue-tui previously
exposed only `exit()` via `useExit()` and kept `waitUntilRenderFlush` on the
`TuiApp` handle alone. Align the public surface with Ink: add `useAppContext()`
returning the same pair, and remove `useExit()`.

- thread `waitUntilRenderFlush` into the injected `AppContext` via a hoisted
  impl shared by the `TuiApp` handle and the composable, so both resolve
  identically
- add `useAppContext()`; delete `useExit()`; migrate all call sites, PTY
  fixtures, examples, READMEs and the public-API surface test
- port Ink's two "useApp waitUntilRenderFlush" tests; Ink's third relies on
  React concurrent mode (N/A in Vue)
- rewrite the ink-divergences entry: this is now a *naming* divergence
  (`useAppContext` vs `useApp`, mirroring `createApp` vs `render`), not a
  surface one — and fix the prior wrong claim that Ink's `useApp` returns
  stdin/stdout/stderr

The name is qualified (`useAppContext`, not `useApp`) so it doesn't read as the
Vue application instance (`createApp`/`app.mount`) — the same Vue-native naming
choice vue-tui already makes with `createApp()` vs Ink's `render()`.

BREAKING CHANGE: `useExit()` is removed. Replace `const exit = useExit()` with
`const { exit } = useAppContext()`.

Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>
---
 .agents/docs/ink-divergences.md               | 15 +--
 README.md                                     | 12 +--
 examples/coding-agent/src/App.vue             |  4 +-
 examples/flappy-bird/src/App.vue              |  4 +-
 .../accessibility/screen-reader.test.tsx      |  1 +
 .../lifecycle/error-handling.test.tsx         |  8 +-
 .../integration/lifecycle/exit.test.tsx       | 49 +++++-----
 .../integration/lifecycle/wait-flush.test.tsx | 95 +++++++++++++++++--
 ...exit-on-exit-with-error-value-property.tsx |  4 +-
 .../pty/fixtures/exit-on-exit-with-error.tsx  |  4 +-
 .../pty/fixtures/exit-on-exit-with-result.tsx |  4 +-
 .../exit-on-exit-with-value-object.tsx        |  4 +-
 .../integration/pty/fixtures/exit-on-exit.tsx |  4 +-
 .../fixtures/exit-raw-on-exit-with-error.tsx  |  4 +-
 .../pty/fixtures/exit-raw-on-exit.tsx         |  4 +-
 .../pty/fixtures/exit-with-static.tsx         |  4 +-
 .../fixtures/fullscreen-no-extra-newline.tsx  |  4 +-
 .../pty/fixtures/issue-442-full-height.tsx    |  4 +-
 .../fixtures/issue-450-fixture-helpers.tsx    |  6 +-
 .../use-animation-interactive-false-exit.tsx  |  4 +-
 .../use-animation-non-interactive-exit.tsx    |  4 +-
 .../pty/fixtures/use-input-ctrl-c.tsx         |  4 +-
 .../fixtures/use-input-discrete-priority.tsx  |  4 +-
 .../pty/fixtures/use-input-kitty.tsx          |  4 +-
 .../pty/fixtures/use-input-many.tsx           |  4 +-
 .../pty/fixtures/use-input-multiple.tsx       |  4 +-
 .../integration/pty/fixtures/use-input.tsx    |  4 +-
 .../integration/pty/fixtures/use-paste.tsx    |  6 +-
 .../integration/pty/fixtures/use-stdout.tsx   |  4 +-
 .../integration/public-api.test.ts            |  2 +-
 .../integration/render-to-string.test.tsx     |  6 +-
 packages/runtime/README.md                    |  2 +-
 .../runtime/src/composables/useAppContext.ts  | 27 ++++++
 packages/runtime/src/composables/useExit.ts   | 14 ---
 packages/runtime/src/context.ts               |  1 +
 packages/runtime/src/index.ts                 |  2 +-
 packages/runtime/src/render-to-string.ts      |  5 +-
 packages/runtime/src/render.ts                | 13 ++-
 38 files changed, 226 insertions(+), 122 deletions(-)
 create mode 100644 packages/runtime/src/composables/useAppContext.ts
 delete mode 100644 packages/runtime/src/composables/useExit.ts

diff --git a/.agents/docs/ink-divergences.md b/.agents/docs/ink-divergences.md
index fb01f5c..d7a9042 100644
--- a/.agents/docs/ink-divergences.md
+++ b/.agents/docs/ink-divergences.md
@@ -31,14 +31,15 @@ deliberate. Divergences fall into a few kinds:
 - **Why:** mirrors Vue's own `createApp` mental model — a Vue developer expects an app
   object they mount, not a one-shot render call.
 
-### App composable — `useExit()` instead of `useApp()`
+### App composable — `useAppContext()` instead of `useApp()`
 
-- **Ink:** `useApp()` returns the full AppContext (`exit`, `waitUntilRenderFlush`,
-  stdin/stdout/stderr, …).
-- **vue-tui:** `useExit()` returns only the `exit` function; the rest is reached through
-  dedicated composables (`useStdin`, `useStdout`, `useStderr`, …).
-- **Why:** intentionally minimal, single-purpose composables. `waitUntilRenderFlush` is
-  deliberately **not** exposed.
+- **Ink:** `useApp()` returns `{ exit, waitUntilRenderFlush }` — stdin/stdout/stderr are
+  separate hooks (`useStdin`/`useStdout`/`useStderr`), not part of it.
+- **vue-tui:** `useAppContext()` returns the same `{ exit, waitUntilRenderFlush }`, with
+  streams on those same peer composables.
+- **Why:** only the name differs — `useApp` reads as "the Vue application instance"
+  (`createApp`, `app.mount`), so vue-tui qualifies it as `useAppContext`. The shape is
+  identical to Ink; a naming divergence, not a surface one.
 
 ### Named type / prop re-exports
 
diff --git a/README.md b/README.md
index cbcf545..b727872 100644
--- a/README.md
+++ b/README.md
@@ -83,11 +83,11 @@ useInput((input) => {
 
 ## Packages
 
-| Package                                                              | Description                                                                                                                                                                                |
-| -------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
-| [`@vue-tui/runtime`](https://www.npmjs.com/package/@vue-tui/runtime) | The core framework — Vue 3 renderer for the terminal with components (`Box`, `Text`, `Static`, etc.), composables (`useInput`, `useFocus`, `useExit`, etc.), and yoga-based flexbox layout |
-| [`@vue-tui/cli`](https://www.npmjs.com/package/@vue-tui/cli)         | Development tool — `vue-tui dev` starts your app with Vite-powered HMR                                                                                                                     |
-| [`@vue-tui/testing`](https://www.npmjs.com/package/@vue-tui/testing) | Test harness — render in an isolated fake terminal, simulate input, assert output frame by frame                                                                                           |
+| Package                                                              | Description                                                                                                                                                                                      |
+| -------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
+| [`@vue-tui/runtime`](https://www.npmjs.com/package/@vue-tui/runtime) | The core framework — Vue 3 renderer for the terminal with components (`Box`, `Text`, `Static`, etc.), composables (`useInput`, `useFocus`, `useAppContext`, etc.), and yoga-based flexbox layout |
+| [`@vue-tui/cli`](https://www.npmjs.com/package/@vue-tui/cli)         | Development tool — `vue-tui dev` starts your app with Vite-powered HMR                                                                                                                           |
+| [`@vue-tui/testing`](https://www.npmjs.com/package/@vue-tui/testing) | Test harness — render in an isolated fake terminal, simulate input, assert output frame by frame                                                                                                 |
 
 ## Examples
 
@@ -116,7 +116,7 @@ useInput((input) => {
 | `useInput(handler, opts?)` | Handle keyboard input — receives `(input, key)` with modifier and arrow key detection |
 | `useFocus(opts?)`          | Component-level focus — returns `{ isFocused, focus }`                                |
 | `useFocusManager()`        | App-level focus control — `focusNext()`, `focusPrevious()`, `focus(id)`               |
-| `useExit()`                | Programmatic app exit — returns `exit(error?)`                                        |
+| `useAppContext()`          | App context — `{ exit(error?), waitUntilRenderFlush() }`                              |
 | `useTerminalSize()`        | Reactive terminal dimensions — `{ columns, rows }`                                    |
 | `useStdin()`               | Access stdin stream and raw mode control                                              |
 | `useStdout()`              | Write directly to stdout                                                              |
diff --git a/examples/coding-agent/src/App.vue b/examples/coding-agent/src/App.vue
index ad6d98c..b4a7c76 100644
--- a/examples/coding-agent/src/App.vue
+++ b/examples/coding-agent/src/App.vue
@@ -1,6 +1,6 @@
 <script setup lang="ts">
 import { shallowRef } from "vue";
-import { Box, Text, Static, useInput, useExit } from "@vue-tui/runtime";
+import { Box, Text, Static, useInput, useAppContext } from "@vue-tui/runtime";
 import { runAgentLoop, type Message, type ToolCall } from "./agent";
 import MessageList from "./components/MessageList.vue";
 
@@ -14,7 +14,7 @@ const pendingCommand = shallowRef("");
 const messages: Message[] = [];
 
 let approvalResolve: ((approved: boolean) => void) | null = null;
-const exit = useExit();
+const { exit } = useAppContext();
 
 const autoApprove = process.argv.includes("--yolo");
 
diff --git a/examples/flappy-bird/src/App.vue b/examples/flappy-bird/src/App.vue
index d4f8b51..d68c63a 100644
--- a/examples/flappy-bird/src/App.vue
+++ b/examples/flappy-bird/src/App.vue
@@ -1,7 +1,7 @@
 <script setup lang="ts">
 import { computed, onScopeDispose, reactive } from "vue";
 import chalk from "chalk";
-import { Box, Text, useExit, useInput } from "@vue-tui/runtime";
+import { Box, Text, useAppContext, useInput } from "@vue-tui/runtime";
 
 // --- world dimensions ----------------------------------------------------
 
@@ -130,7 +130,7 @@ function renderFrame(w: World): string[] {
 
 // --- component -----------------------------------------------------------
 
-const exit = useExit();
+const { exit } = useAppContext();
 const world = reactive<World>(makeWorld(0));
 
 function flap(): void {
diff --git a/packages/runtime-tests/integration/accessibility/screen-reader.test.tsx b/packages/runtime-tests/integration/accessibility/screen-reader.test.tsx
index 0a2ca9e..65251ad 100644
--- a/packages/runtime-tests/integration/accessibility/screen-reader.test.tsx
+++ b/packages/runtime-tests/integration/accessibility/screen-reader.test.tsx
@@ -30,6 +30,7 @@ const DIRECTION_LTR = 0;
 function createTestAppContext(): AppContext {
   return {
     exit: () => {},
+    waitUntilRenderFlush: async () => {},
     stdout: process.stdout,
     stderr: process.stderr,
     stdin: process.stdin,
diff --git a/packages/runtime-tests/integration/lifecycle/error-handling.test.tsx b/packages/runtime-tests/integration/lifecycle/error-handling.test.tsx
index 73023c4..d717c19 100644
--- a/packages/runtime-tests/integration/lifecycle/error-handling.test.tsx
+++ b/packages/runtime-tests/integration/lifecycle/error-handling.test.tsx
@@ -1,7 +1,7 @@
 import { defineComponent, nextTick, shallowRef } from "vue";
 import { expect, test } from "vite-plus/test";
 import { render } from "@vue-tui/testing";
-import { Box, Text, useExit } from "@vue-tui/runtime";
+import { Box, Text, useAppContext } from "@vue-tui/runtime";
 
 test("setup() throw rejects render()", async () => {
   const Boom = defineComponent(() => {
@@ -32,20 +32,20 @@ test("render-time throw does not prevent unmount", async () => {
   expect(() => unmount()).not.toThrow();
 });
 
-test("useExit() called with error rejects waitUntilExit", async () => {
+test("useAppContext() called with error rejects waitUntilExit", async () => {
   // Mirrors Ink's "exit on exit() with error" fixture test, adapted for
   // render-based testing. Verifies exit(err) rejects the promise cleanly.
   // Also covered by exit.test.tsx "exit(error) rejects waitUntilExit with the error".
   let exitFn!: (err?: Error) => void;
 
   const App = defineComponent(() => {
-    exitFn = useExit();
+    exitFn = useAppContext().exit;
     return () => <Text>running</Text>;
   });
 
   const { waitUntilExit } = await render(App);
 
-  const err = new Error("errored via useExit");
+  const err = new Error("errored via useAppContext");
   exitFn(err);
 
   await expect(waitUntilExit()).rejects.toBe(err);
diff --git a/packages/runtime-tests/integration/lifecycle/exit.test.tsx b/packages/runtime-tests/integration/lifecycle/exit.test.tsx
index 499aa75..a80876c 100644
--- a/packages/runtime-tests/integration/lifecycle/exit.test.tsx
+++ b/packages/runtime-tests/integration/lifecycle/exit.test.tsx
@@ -2,15 +2,15 @@ import { Writable } from "node:stream";
 import { defineComponent, onMounted, onScopeDispose } from "vue";
 import { expect, test } from "vite-plus/test";
 import { render } from "@vue-tui/testing";
-import { createApp, Text, useExit } from "@vue-tui/runtime";
+import { createApp, Text, useAppContext } from "@vue-tui/runtime";
 import { makeFakeWritable, makeFakeStdin, isWriteBarrierChunk } from "./test-streams.ts";
 
-test("useExit() triggers teardown and waitUntilExit resolves", async () => {
+test("useAppContext() triggers teardown and waitUntilExit resolves", async () => {
   let exitFn!: () => void;
   let disposed = false;
 
   const App = defineComponent(() => {
-    const exit = useExit();
+    const { exit } = useAppContext();
     exitFn = exit;
     onScopeDispose(() => {
       disposed = true;
@@ -30,7 +30,7 @@ test("exit(error) rejects waitUntilExit with the error", async () => {
   let exitFn!: (err: Error) => void;
 
   const App = defineComponent(() => {
-    const exit = useExit();
+    const { exit } = useAppContext();
     exitFn = exit;
     return () => <Text>x</Text>;
   });
@@ -56,7 +56,7 @@ test("unmount() after exit() is idempotent", async () => {
   let exitFn!: () => void;
 
   const App = defineComponent(() => {
-    const exit = useExit();
+    const { exit } = useAppContext();
     exitFn = exit;
     return () => <Text>x</Text>;
   });
@@ -74,7 +74,7 @@ test("exit() called multiple times is idempotent", async () => {
   let exitFn!: () => void;
 
   const App = defineComponent(() => {
-    exitFn = useExit();
+    exitFn = useAppContext().exit;
     return () => <Text>x</Text>;
   });
 
@@ -89,7 +89,7 @@ test("waitUntilExit() resolves with result value passed to exit()", async () =>
   let exitFn!: (errorOrResult?: unknown) => void;
 
   const App = defineComponent(() => {
-    exitFn = useExit();
+    exitFn = useAppContext().exit;
     return () => <Text>hello from vue-tui</Text>;
   });
 
@@ -105,7 +105,7 @@ test("waitUntilExit() resolves with object result value", async () => {
   let exitFn!: (errorOrResult?: unknown) => void;
 
   const App = defineComponent(() => {
-    exitFn = useExit();
+    exitFn = useAppContext().exit;
     return () => <Text>hello</Text>;
   });
 
@@ -119,7 +119,7 @@ test("waitUntilExit() resolves with undefined when exit() called with no args",
   let exitFn!: (errorOrResult?: unknown) => void;
 
   const App = defineComponent(() => {
-    exitFn = useExit();
+    exitFn = useAppContext().exit;
     return () => <Text>hello</Text>;
   });
 
@@ -135,7 +135,7 @@ test("onScopeDispose fires when exit(error) is called", async () => {
   let disposed = false;
 
   const App = defineComponent(() => {
-    exitFn = useExit();
+    exitFn = useAppContext().exit;
     onScopeDispose(() => {
       disposed = true;
     });
@@ -156,7 +156,7 @@ test("exit(error) followed by exit(value) still rejects", async () => {
   let exitFn!: (errorOrResult?: unknown) => void;
 
   const App = defineComponent(() => {
-    exitFn = useExit();
+    exitFn = useAppContext().exit;
     return () => <Text>hello</Text>;
   });
 
@@ -175,7 +175,7 @@ test("exit(value) resolves with the FIRST value when called rapidly twice", asyn
   let exitFn!: (errorOrResult?: unknown) => void;
 
   const App = defineComponent(() => {
-    exitFn = useExit();
+    exitFn = useAppContext().exit;
     return () => <Text>hello</Text>;
   });
 
@@ -194,7 +194,7 @@ test("exit(err1) then exit(err2) rejects with the FIRST error", async () => {
   let exitFn!: (errorOrResult?: unknown) => void;
 
   const App = defineComponent(() => {
-    exitFn = useExit();
+    exitFn = useAppContext().exit;
     return () => <Text>hello</Text>;
   });
 
@@ -215,7 +215,7 @@ test("exit(value) then exit(error) resolves with the FIRST value", async () => {
   let exitFn!: (errorOrResult?: unknown) => void;
 
   const App = defineComponent(() => {
-    exitFn = useExit();
+    exitFn = useAppContext().exit;
     return () => <Text>hello</Text>;
   });
 
@@ -229,8 +229,9 @@ test("exit(value) then exit(error) resolves with the FIRST value", async () => {
 
 test("exit('late') after app.unmount() is a no-op (unmount value wins)", async () => {
   // isUnmounting parity (Ink parity G33): app.unmount() runs teardown()+
-  // resolveExit() without setting exitInitiated. A retained useExit() called
-  // AFTER unmount has started teardown must be a complete no-op — it must not
+  // resolveExit() without setting exitInitiated. A retained exit() (from
+  // useAppContext()) called AFTER unmount has started teardown must be a
+  // complete no-op — it must not
   // overwrite the resolved exit value. waitUntilExit resolves the original
   // unmount value (undefined), NOT 'late'. Without the teardownStarted guard in
   // exit(), the late exit captures 'late' into pendingExitResult and 'late'
@@ -238,7 +239,7 @@ test("exit('late') after app.unmount() is a no-op (unmount value wins)", async (
   let exitFn!: (errorOrResult?: unknown) => void;
 
   const App = defineComponent(() => {
-    exitFn = useExit();
+    exitFn = useAppContext().exit;
     return () => <Text>hello</Text>;
   });
 
@@ -251,8 +252,8 @@ test("exit('late') after app.unmount() is a no-op (unmount value wins)", async (
 });
 
 test("retained exit() re-entered DURING unmount teardown writes is a no-op", async () => {
-  // isUnmounting parity (Ink parity G33), faithful reentrancy: a useExit()
-  // captured during setup is invoked re-entrantly from inside the stdout write
+  // isUnmounting parity (Ink parity G33), faithful reentrancy: an exit() (from
+  // useAppContext()) captured during setup is invoked re-entrantly from inside the stdout write
   // that unmount()'s final commit performs. teardownStarted is already true at
   // that point, so exit("reentrant") is a complete no-op and the original
   // unmount value (undefined) wins. Without the teardownStarted guard the
@@ -278,7 +279,7 @@ test("retained exit() re-entered DURING unmount teardown writes is a no-op", asy
   stdout.isTTY = true;
 
   const App = defineComponent(() => {
-    const exit = useExit();
+    const { exit } = useAppContext();
     onMounted(() => {
       exitFn = exit;
     });
@@ -306,7 +307,7 @@ test("single exit('x') resolves with 'x' (control)", async () => {
   let exitFn!: (errorOrResult?: unknown) => void;
 
   const App = defineComponent(() => {
-    exitFn = useExit();
+    exitFn = useAppContext().exit;
     return () => <Text>hello</Text>;
   });
 
@@ -340,7 +341,7 @@ test("waitUntilExit resolves FIRST exit value when duplicate exits happen during
   stdout.columns = 100;
 
   const App = defineComponent(() => {
-    const exit = useExit();
+    const { exit } = useAppContext();
     onMounted(() => {
       exit("first");
       setTimeout(() => exit("second"), 0);
@@ -388,7 +389,7 @@ test("waitUntilExit resolves FIRST exit value when exit is re-entered during unm
   stdout.isTTY = true;
 
   const App = defineComponent(() => {
-    const exit = useExit();
+    const { exit } = useAppContext();
     onMounted(() => {
       exitFn = exit;
       shouldReenterExit = true;
@@ -437,7 +438,7 @@ test("exit with cross-realm Error resolves after stdout write callback", async (
   const foreignError = vm.runInNewContext("new Error('boom')") as Error;
 
   const App = defineComponent(() => {
-    const exit = useExit();
+    const { exit } = useAppContext();
     onMounted(() => {
       setTimeout(() => exit(foreignError), 0);
     });
diff --git a/packages/runtime-tests/integration/lifecycle/wait-flush.test.tsx b/packages/runtime-tests/integration/lifecycle/wait-flush.test.tsx
index 4c3a94b..ef6f621 100644
--- a/packages/runtime-tests/integration/lifecycle/wait-flush.test.tsx
+++ b/packages/runtime-tests/integration/lifecycle/wait-flush.test.tsx
@@ -1,7 +1,7 @@
 import { defineComponent, nextTick, onMounted, shallowRef } from "vue";
 import { expect, test } from "vite-plus/test";
 import { render } from "@vue-tui/testing";
-import { createApp, Text, useExit } from "@vue-tui/runtime";
+import { createApp, Text, useAppContext } from "@vue-tui/runtime";
 import stripAnsi from "strip-ansi";
 import {
   makeFakeWritable,
@@ -229,7 +229,7 @@ test("waitUntilRenderFlush waits for unmount write callback", async () => {
 test("waitUntilRenderFlush resolves after exit with error", async () => {
   let exitFn!: (err: Error) => void;
   const App = defineComponent(() => {
-    const exit = useExit();
+    const { exit } = useAppContext();
     onMounted(() => {
       exitFn = exit as (err: Error) => void;
     });
@@ -248,12 +248,91 @@ test("waitUntilRenderFlush resolves after exit with error", async () => {
   await app.waitUntilRenderFlush();
 });
 
-// useApp-level waitUntilRenderFlush tests:
-// These test that waitUntilRenderFlush works when called from inside a component.
-// In vue-tui, waitUntilRenderFlush is on the app instance, not a composable,
-// so these are tested via the app.waitUntilRenderFlush() API above.
-// The 2 "useApp waitUntilRenderFlush" tests from Ink are covered by the
-// existing tests since vue-tui exposes the same API on the app object.
+// useAppContext-level waitUntilRenderFlush tests (Ink parity, ported from Ink
+// render.tsx "useApp waitUntilRenderFlush …"): waitUntilRenderFlush is reachable
+// from INSIDE a component via useAppContext() — Ink's useApp() returns the same
+// { exit, waitUntilRenderFlush } pair. Ink's third "queued in same effect tick"
+// test relies on React `concurrent: true` (concurrent mode is N/A in Vue — see
+// .agents/docs/ink-divergences.md), so only the first two are ported.
+
+test("useAppContext waitUntilRenderFlush resolves after the first frame write callback", async () => {
+  let didInitialWriteCallbackFire = false;
+  let didFlushResolve = false;
+
+  const stdout = createDelayedWriteCallbackStdout({
+    shouldDelay: (chunk) => !isWriteBarrierChunk(chunk),
+    onDelayElapsed: () => {
+      didInitialWriteCallbackFire = true;
+    },
+  });
+
+  const App = defineComponent(() => {
+    const { exit, waitUntilRenderFlush } = useAppContext();
+    onMounted(() => {
+      void (async () => {
+        await waitUntilRenderFlush();
+        didFlushResolve = true;
+        exit();
+      })();
+    });
+    return () => <Text>Hello</Text>;
+  });
+
+  const app = createApp(App);
+  const stderr = makeFakeWritable();
+  const { stream: stdin } = makeFakeStdin();
+  app.mount({ stdout, stdin, stderr, exitOnCtrlC: false });
+
+  await app.waitUntilExit();
+  expect(didInitialWriteCallbackFire).toBe(true);
+  expect(didFlushResolve).toBe(true);
+});
+
+test("useAppContext waitUntilRenderFlush waits for state update frame flush", async () => {
+  let didWorldWriteCallbackFire = false;
+  let didFlushResolve = false;
+
+  const stdout = createDelayedWriteCallbackStdout({
+    shouldDelay: (chunk) =>
+      !isWriteBarrierChunk(chunk) &&
+      stripAnsi(typeof chunk === "string" ? chunk : new TextDecoder().decode(chunk)).includes(
+        "World",
+      ),
+    onDelayElapsed: () => {
+      didWorldWriteCallbackFire = true;
+    },
+  });
+
+  const text = shallowRef("Hello");
+  const App = defineComponent(() => {
+    const { exit, waitUntilRenderFlush } = useAppContext();
+    onMounted(() => {
+      void (async () => {
+        // Settle the initial "Hello" frame first (not delayed by the harness,
+        // which only delays the "World" chunk) so the subsequent "World" write
+        // is unambiguously a second, state-update frame — mirroring the stable
+        // app-level "waits for rerender write callback" test above.
+        await waitUntilRenderFlush();
+        text.value = "World";
+        await nextTick();
+        await nextTick();
+        await waitUntilRenderFlush();
+        didFlushResolve = true;
+        exit();
+      })();
+    });
+    return () => <Text>{text.value}</Text>;
+  });
+
+  const app = createApp(App);
+  const stderr = makeFakeWritable();
+  const { stream: stdin } = makeFakeStdin();
+  app.mount({ stdout, stdin, stderr, exitOnCtrlC: false });
+
+  await app.waitUntilExit();
+  expect(didWorldWriteCallbackFire).toBe(true);
+  expect(didFlushResolve).toBe(true);
+});
 
 // --- clear() API test ---
 
diff --git a/packages/runtime-tests/integration/pty/fixtures/exit-on-exit-with-error-value-property.tsx b/packages/runtime-tests/integration/pty/fixtures/exit-on-exit-with-error-value-property.tsx
index 2d47834..6ebf455 100644
--- a/packages/runtime-tests/integration/pty/fixtures/exit-on-exit-with-error-value-property.tsx
+++ b/packages/runtime-tests/integration/pty/fixtures/exit-on-exit-with-error-value-property.tsx
@@ -1,8 +1,8 @@
-import { createApp, Text, useExit } from "@vue-tui/runtime";
+import { createApp, Text, useAppContext } from "@vue-tui/runtime";
 import { defineComponent, onMounted } from "vue";
 
 const App = defineComponent(() => {
-  const exit = useExit();
+  const { exit } = useAppContext();
 
   onMounted(() => {
     setTimeout(() => {
diff --git a/packages/runtime-tests/integration/pty/fixtures/exit-on-exit-with-error.tsx b/packages/runtime-tests/integration/pty/fixtures/exit-on-exit-with-error.tsx
index 09ce889..3b3f479 100644
--- a/packages/runtime-tests/integration/pty/fixtures/exit-on-exit-with-error.tsx
+++ b/packages/runtime-tests/integration/pty/fixtures/exit-on-exit-with-error.tsx
@@ -1,9 +1,9 @@
-import { createApp, Text, useExit } from "@vue-tui/runtime";
+import { createApp, Text, useAppContext } from "@vue-tui/runtime";
 import { defineComponent, onMounted, onScopeDispose, shallowRef } from "vue";
 
 const App = defineComponent(() => {
   const counter = shallowRef(0);
-  const exit = useExit();
+  const { exit } = useAppContext();
 
   onMounted(() => {
     setTimeout(() => {
diff --git a/packages/runtime-tests/integration/pty/fixtures/exit-on-exit-with-result.tsx b/packages/runtime-tests/integration/pty/fixtures/exit-on-exit-with-result.tsx
index f2861ae..9f00b56 100644
--- a/packages/runtime-tests/integration/pty/fixtures/exit-on-exit-with-result.tsx
+++ b/packages/runtime-tests/integration/pty/fixtures/exit-on-exit-with-result.tsx
@@ -1,8 +1,8 @@
-import { createApp, Text, useExit } from "@vue-tui/runtime";
+import { createApp, Text, useAppContext } from "@vue-tui/runtime";
 import { defineComponent, onMounted } from "vue";
 
 const App = defineComponent(() => {
-  const exit = useExit();
+  const { exit } = useAppContext();
 
   onMounted(() => {
     setTimeout(() => {
diff --git a/packages/runtime-tests/integration/pty/fixtures/exit-on-exit-with-value-object.tsx b/packages/runtime-tests/integration/pty/fixtures/exit-on-exit-with-value-object.tsx
index 0f1ef80..842669d 100644
--- a/packages/runtime-tests/integration/pty/fixtures/exit-on-exit-with-value-object.tsx
+++ b/packages/runtime-tests/integration/pty/fixtures/exit-on-exit-with-value-object.tsx
@@ -1,8 +1,8 @@
-import { createApp, Text, useExit } from "@vue-tui/runtime";
+import { createApp, Text, useAppContext } from "@vue-tui/runtime";
 import { defineComponent, onMounted } from "vue";
 
 const App = defineComponent(() => {
-  const exit = useExit();
+  const { exit } = useAppContext();
 
   onMounted(() => {
     setTimeout(() => {
diff --git a/packages/runtime-tests/integration/pty/fixtures/exit-on-exit.tsx b/packages/runtime-tests/integration/pty/fixtures/exit-on-exit.tsx
index ab85cce..d2d6a62 100644
--- a/packages/runtime-tests/integration/pty/fixtures/exit-on-exit.tsx
+++ b/packages/runtime-tests/integration/pty/fixtures/exit-on-exit.tsx
@@ -1,9 +1,9 @@
-import { createApp, Text, useExit } from "@vue-tui/runtime";
+import { createApp, Text, useAppContext } from "@vue-tui/runtime";
 import { defineComponent, onMounted, onScopeDispose, shallowRef } from "vue";
 
 const App = defineComponent(() => {
   const counter = shallowRef(0);
-  const exit = useExit();
+  const { exit } = useAppContext();
 
   onMounted(() => {
     setTimeout(exit, 500);
diff --git a/packages/runtime-tests/integration/pty/fixtures/exit-raw-on-exit-with-error.tsx b/packages/runtime-tests/integration/pty/fixtures/exit-raw-on-exit-with-error.tsx
index b295433..5af67d7 100644
--- a/packages/runtime-tests/integration/pty/fixtures/exit-raw-on-exit-with-error.tsx
+++ b/packages/runtime-tests/integration/pty/fixtures/exit-raw-on-exit-with-error.tsx
@@ -1,8 +1,8 @@
-import { createApp, Text, useExit, useStdin } from "@vue-tui/runtime";
+import { createApp, Text, useAppContext, useStdin } from "@vue-tui/runtime";
 import { defineComponent, onMounted } from "vue";
 
 const App = defineComponent(() => {
-  const exit = useExit();
+  const { exit } = useAppContext();
   const { setRawMode } = useStdin();
 
   onMounted(() => {
diff --git a/packages/runtime-tests/integration/pty/fixtures/exit-raw-on-exit.tsx b/packages/runtime-tests/integration/pty/fixtures/exit-raw-on-exit.tsx
index fb668ab..391c722 100644
--- a/packages/runtime-tests/integration/pty/fixtures/exit-raw-on-exit.tsx
+++ b/packages/runtime-tests/integration/pty/fixtures/exit-raw-on-exit.tsx
@@ -1,8 +1,8 @@
-import { createApp, Text, useExit, useStdin } from "@vue-tui/runtime";
+import { createApp, Text, useAppContext, useStdin } from "@vue-tui/runtime";
 import { defineComponent, onMounted } from "vue";
 
 const App = defineComponent(() => {
-  const exit = useExit();
+  const { exit } = useAppContext();
   const { setRawMode } = useStdin();
 
   onMounted(() => {
diff --git a/packages/runtime-tests/integration/pty/fixtures/exit-with-static.tsx b/packages/runtime-tests/integration/pty/fixtures/exit-with-static.tsx
index 8c637dc..1e8198a 100644
--- a/packages/runtime-tests/integration/pty/fixtures/exit-with-static.tsx
+++ b/packages/runtime-tests/integration/pty/fixtures/exit-with-static.tsx
@@ -1,8 +1,8 @@
-import { createApp, Static, Text, useExit } from "@vue-tui/runtime";
+import { createApp, Static, Text, useAppContext } from "@vue-tui/runtime";
 import { defineComponent, onMounted } from "vue";
 
 const App = defineComponent(() => {
-  const exit = useExit();
+  const { exit } = useAppContext();
 
   onMounted(() => {
     exit(new Error("errored"));
diff --git a/packages/runtime-tests/integration/pty/fixtures/fullscreen-no-extra-newline.tsx b/packages/runtime-tests/integration/pty/fixtures/fullscreen-no-extra-newline.tsx
index a2bfc21..fed89b3 100644
--- a/packages/runtime-tests/integration/pty/fixtures/fullscreen-no-extra-newline.tsx
+++ b/packages/runtime-tests/integration/pty/fixtures/fullscreen-no-extra-newline.tsx
@@ -1,9 +1,9 @@
 import process from "node:process";
-import { Box, Text, createApp, useExit } from "@vue-tui/runtime";
+import { Box, Text, createApp, useAppContext } from "@vue-tui/runtime";
 import { defineComponent, h, onMounted, onScopeDispose } from "vue";
 
 const Fullscreen = defineComponent(() => {
-  const exit = useExit();
+  const { exit } = useAppContext();
 
   onMounted(() => {
     const timer = setTimeout(() => {
diff --git a/packages/runtime-tests/integration/pty/fixtures/issue-442-full-height.tsx b/packages/runtime-tests/integration/pty/fixtures/issue-442-full-height.tsx
index 107143e..072c4d6 100644
--- a/packages/runtime-tests/integration/pty/fixtures/issue-442-full-height.tsx
+++ b/packages/runtime-tests/integration/pty/fixtures/issue-442-full-height.tsx
@@ -1,9 +1,9 @@
 import process from "node:process";
-import { Box, Text, createApp, useExit } from "@vue-tui/runtime";
+import { Box, Text, createApp, useAppContext } from "@vue-tui/runtime";
 import { defineComponent, h, onMounted, onScopeDispose } from "vue";
 
 const App = defineComponent(() => {
-  const exit = useExit();
+  const { exit } = useAppContext();
 
   onMounted(() => {
     const timer = setTimeout(() => {
diff --git a/packages/runtime-tests/integration/pty/fixtures/issue-450-fixture-helpers.tsx b/packages/runtime-tests/integration/pty/fixtures/issue-450-fixture-helpers.tsx
index fd15879..fe59628 100644
--- a/packages/runtime-tests/integration/pty/fixtures/issue-450-fixture-helpers.tsx
+++ b/packages/runtime-tests/integration/pty/fixtures/issue-450-fixture-helpers.tsx
@@ -1,5 +1,5 @@
 import process from "node:process";
-import { Box, Static, Text, createApp, useExit } from "@vue-tui/runtime";
+import { Box, Static, Text, createApp, useAppContext } from "@vue-tui/runtime";
 import { Fragment, defineComponent, h, onMounted, onScopeDispose, shallowRef, watch } from "vue";
 
 type RerenderFixtureOptions = {
@@ -18,7 +18,7 @@ const Issue450RerenderFixtureComponent = defineComponent(
     heightForFrame: (rows: number, frameCount: number) => number;
     rows: number;
   }) => {
-    const exit = useExit();
+    const { exit } = useAppContext();
     const frameCount = shallowRef(0);
     let timer: ReturnType<typeof setTimeout> | undefined;
 
@@ -102,7 +102,7 @@ type InitialFixtureOptions = {
 
 const Issue450InitialFixtureComponent = defineComponent(
   (props: { renderedMarker: string; lineCount: number; linePrefix: string }) => {
-    const exit = useExit();
+    const { exit } = useAppContext();
 
     onMounted(() => {
       const timer = setTimeout(() => {
diff --git a/packages/runtime-tests/integration/pty/fixtures/use-animation-interactive-false-exit.tsx b/packages/runtime-tests/integration/pty/fixtures/use-animation-interactive-false-exit.tsx
index f7a8fe8..854f553 100644
--- a/packages/runtime-tests/integration/pty/fixtures/use-animation-interactive-false-exit.tsx
+++ b/packages/runtime-tests/integration/pty/fixtures/use-animation-interactive-false-exit.tsx
@@ -1,9 +1,9 @@
-import { Text, createApp, useAnimation, useExit } from "@vue-tui/runtime";
+import { Text, createApp, useAnimation, useAppContext } from "@vue-tui/runtime";
 import { defineComponent, h, watch } from "vue";
 
 const Spinner = defineComponent(() => {
   const { frame } = useAnimation({ interval: 8 });
-  const exit = useExit();
+  const { exit } = useAppContext();
 
   watch(frame, (value) => {
     if (value >= 3) {
diff --git a/packages/runtime-tests/integration/pty/fixtures/use-animation-non-interactive-exit.tsx b/packages/runtime-tests/integration/pty/fixtures/use-animation-non-interactive-exit.tsx
index f4e7795..897bd98 100644
--- a/packages/runtime-tests/integration/pty/fixtures/use-animation-non-interactive-exit.tsx
+++ b/packages/runtime-tests/integration/pty/fixtures/use-animation-non-interactive-exit.tsx
@@ -1,9 +1,9 @@
-import { Text, createApp, useAnimation, useExit } from "@vue-tui/runtime";
+import { Text, createApp, useAnimation, useAppContext } from "@vue-tui/runtime";
 import { defineComponent, h, watch } from "vue";
 
 const Spinner = defineComponent(() => {
   const { frame } = useAnimation({ interval: 8 });
-  const exit = useExit();
+  const { exit } = useAppContext();
 
   watch(frame, (value) => {
     if (value >= 3) {
diff --git a/packages/runtime-tests/integration/pty/fixtures/use-input-ctrl-c.tsx b/packages/runtime-tests/integration/pty/fixtures/use-input-ctrl-c.tsx
index e624e8f..b9e9a49 100644
--- a/packages/runtime-tests/integration/pty/fixtures/use-input-ctrl-c.tsx
+++ b/packages/runtime-tests/integration/pty/fixtures/use-input-ctrl-c.tsx
@@ -1,9 +1,9 @@
 import process from "node:process";
-import { createApp, useInput, useExit } from "@vue-tui/runtime";
+import { createApp, useInput, useAppContext } from "@vue-tui/runtime";
 import { defineComponent, onMounted } from "vue";
 
 const UserInput = defineComponent(() => {
-  const exit = useExit();
+  const { exit } = useAppContext();
 
   useInput((input, key) => {
     if (input === "c" && key.ctrl) {
diff --git a/packages/runtime-tests/integration/pty/fixtures/use-input-discrete-priority.tsx b/packages/runtime-tests/integration/pty/fixtures/use-input-discrete-priority.tsx
index 502b265..8e249c4 100644
--- a/packages/runtime-tests/integration/pty/fixtures/use-input-discrete-priority.tsx
+++ b/packages/runtime-tests/integration/pty/fixtures/use-input-discrete-priority.tsx
@@ -1,5 +1,5 @@
 import process from "node:process";
-import { createApp, Box, Text, useInput, useExit } from "@vue-tui/runtime";
+import { createApp, Box, Text, useInput, useAppContext } from "@vue-tui/runtime";
 import { computed, defineComponent, h, onMounted, shallowRef, watch } from "vue";
 
 /**
@@ -11,7 +11,7 @@ import { computed, defineComponent, h, onMounted, shallowRef, watch } from "vue"
  * processed before the deferred state catches up.
  */
 const App = defineComponent(() => {
-  const exit = useExit();
+  const { exit } = useAppContext();
   const query = shallowRef("abcde");
   const deferredQuery = shallowRef("abcde");
   let done = false;
diff --git a/packages/runtime-tests/integration/pty/fixtures/use-input-kitty.tsx b/packages/runtime-tests/integration/pty/fixtures/use-input-kitty.tsx
index 8cb2af2..3cfa15e 100644
--- a/packages/runtime-tests/integration/pty/fixtures/use-input-kitty.tsx
+++ b/packages/runtime-tests/integration/pty/fixtures/use-input-kitty.tsx
@@ -1,5 +1,5 @@
 import process from "node:process";
-import { createApp, useInput, useExit } from "@vue-tui/runtime";
+import { createApp, useInput, useAppContext } from "@vue-tui/runtime";
 import { defineComponent, onMounted } from "vue";
 
 const KittyInput = defineComponent({
@@ -7,7 +7,7 @@ const KittyInput = defineComponent({
     test: { type: String, default: undefined },
   },
   setup(props) {
-    const exit = useExit();
+    const { exit } = useAppContext();
 
     onMounted(() => {
       process.stdout.write("__READY__");
diff --git a/packages/runtime-tests/integration/pty/fixtures/use-input-many.tsx b/packages/runtime-tests/integration/pty/fixtures/use-input-many.tsx
index 2985475..c04581d 100644
--- a/packages/runtime-tests/integration/pty/fixtures/use-input-many.tsx
+++ b/packages/runtime-tests/integration/pty/fixtures/use-input-many.tsx
@@ -1,5 +1,5 @@
 import process from "node:process";
-import { createApp, Text, useInput, useExit } from "@vue-tui/runtime";
+import { createApp, Text, useInput, useAppContext } from "@vue-tui/runtime";
 import { defineComponent, h, onMounted } from "vue";
 
 // Detect MaxListenersExceededWarning
@@ -15,7 +15,7 @@ const InputHandler = defineComponent(() => {
 });
 
 const App = defineComponent(() => {
-  const exit = useExit();
+  const { exit } = useAppContext();
 
   onMounted(() => {
     setTimeout(exit, 100);
diff --git a/packages/runtime-tests/integration/pty/fixtures/use-input-multiple.tsx b/packages/runtime-tests/integration/pty/fixtures/use-input-multiple.tsx
index dd4d6cf..a9f106a 100644
--- a/packages/runtime-tests/integration/pty/fixtures/use-input-multiple.tsx
+++ b/packages/runtime-tests/integration/pty/fixtures/use-input-multiple.tsx
@@ -1,9 +1,9 @@
 import process from "node:process";
-import { createApp, Text, useInput, useExit } from "@vue-tui/runtime";
+import { createApp, Text, useInput, useAppContext } from "@vue-tui/runtime";
 import { defineComponent, h, onMounted, shallowRef } from "vue";
 
 const App = defineComponent(() => {
-  const exit = useExit();
+  const { exit } = useAppContext();
   const input = shallowRef("");
 
   const handleInput = (char: string) => {
diff --git a/packages/runtime-tests/integration/pty/fixtures/use-input.tsx b/packages/runtime-tests/integration/pty/fixtures/use-input.tsx
index eb4f119..761afc1 100644
--- a/packages/runtime-tests/integration/pty/fixtures/use-input.tsx
+++ b/packages/runtime-tests/integration/pty/fixtures/use-input.tsx
@@ -1,5 +1,5 @@
 import process from "node:process";
-import { createApp, useInput, useExit } from "@vue-tui/runtime";
+import { createApp, useInput, useAppContext } from "@vue-tui/runtime";
 import { defineComponent, onMounted } from "vue";
 
 const UserInput = defineComponent({
@@ -7,7 +7,7 @@ const UserInput = defineComponent({
     test: { type: String, default: undefined },
   },
   setup(props) {
-    const exit = useExit();
+    const { exit } = useAppContext();
     let rapidDownArrowCount = 0;
     let rapidTimeout: ReturnType<typeof setTimeout> | undefined;
 
diff --git a/packages/runtime-tests/integration/pty/fixtures/use-paste.tsx b/packages/runtime-tests/integration/pty/fixtures/use-paste.tsx
index bef9123..18f3ed5 100644
--- a/packages/runtime-tests/integration/pty/fixtures/use-paste.tsx
+++ b/packages/runtime-tests/integration/pty/fixtures/use-paste.tsx
@@ -1,5 +1,5 @@
 import process from "node:process";
-import { createApp, useExit, useInput, usePaste } from "@vue-tui/runtime";
+import { createApp, useAppContext, useInput, usePaste } from "@vue-tui/runtime";
 import { defineComponent, onMounted } from "vue";
 
 const PasteDemo = defineComponent({
@@ -7,7 +7,7 @@ const PasteDemo = defineComponent({
     test: { type: String, default: undefined },
   },
   setup(props) {
-    const exit = useExit();
+    const { exit } = useAppContext();
 
     usePaste((text) => {
       if (props.test === "basic" && text === "hello world") {
@@ -41,7 +41,7 @@ const PasteDemo = defineComponent({
 });
 
 const MultipleHooksDemo = defineComponent(() => {
-  const exit = useExit();
+  const { exit } = useAppContext();
   let receivedCount = 0;
 
   const onPaste = (text: string) => {
diff --git a/packages/runtime-tests/integration/pty/fixtures/use-stdout.tsx b/packages/runtime-tests/integration/pty/fixtures/use-stdout.tsx
index e446c9e..83cf939 100644
--- a/packages/runtime-tests/integration/pty/fixtures/use-stdout.tsx
+++ b/packages/runtime-tests/integration/pty/fixtures/use-stdout.tsx
@@ -1,9 +1,9 @@
-import { createApp, Text, useStdout, useExit } from "@vue-tui/runtime";
+import { createApp, Text, useStdout, useAppContext } from "@vue-tui/runtime";
 import { defineComponent, h, onMounted } from "vue";
 
 const WriteToStdout = defineComponent(() => {
   const { write } = useStdout();
-  const exit = useExit();
+  const { exit } = useAppContext();
 
   onMounted(() => {
     write("Hello from vue-tui to stdout\n");
diff --git a/packages/runtime-tests/integration/public-api.test.ts b/packages/runtime-tests/integration/public-api.test.ts
index 2435eff..ea66ee7 100644
--- a/packages/runtime-tests/integration/public-api.test.ts
+++ b/packages/runtime-tests/integration/public-api.test.ts
@@ -13,7 +13,7 @@ test("public API exposes documented members", () => {
     "Static",
     "Transform",
     // Composables
-    "useExit",
+    "useAppContext",
     "useInput",
     "useFocus",
     "useFocusManager",
diff --git a/packages/runtime-tests/integration/render-to-string.test.tsx b/packages/runtime-tests/integration/render-to-string.test.tsx
index bea0340..675cbe8 100644
--- a/packages/runtime-tests/integration/render-to-string.test.tsx
+++ b/packages/runtime-tests/integration/render-to-string.test.tsx
@@ -10,7 +10,7 @@ import {
   Static,
   Transform,
   useInput,
-  useExit,
+  useAppContext,
   useFocus,
   useFocusManager,
   useStdin,
@@ -65,9 +65,9 @@ describe("renderToString", () => {
     expect(output).toContain("with input");
   });
 
-  test("useExit does not throw in renderToString", () => {
+  test("useAppContext does not throw in renderToString", () => {
     const App = defineComponent(() => {
-      const exit = useExit();
+      const { exit } = useAppContext();
       // exit is a function but calling it is a no-op
       void exit;
       return () => <Text>with exit</Text>;
diff --git a/packages/runtime/README.md b/packages/runtime/README.md
index 0090648..25a80ef 100644
--- a/packages/runtime/README.md
+++ b/packages/runtime/README.md
@@ -73,7 +73,7 @@ useInput((input) => {
 | `useInput(handler, opts?)` | Keyboard input — `(input, key)` with modifier and arrow key detection |
 | `useFocus(opts?)`          | Component-level focus — returns `{ isFocused, focus }`                |
 | `useFocusManager()`        | App-level focus — `focusNext()`, `focusPrevious()`, `focus(id)`       |
-| `useExit()`                | Programmatic exit — returns `exit(error?)`                            |
+| `useAppContext()`          | App context — `{ exit(error?), waitUntilRenderFlush() }`              |
 | `useTerminalSize()`        | Reactive terminal dimensions — `{ columns, rows }`                    |
 | `useAnimation(opts?)`      | Frame-based animation loop — returns `{ frame, time, delta, reset }`  |
 | `useBoxMetrics(ref)`       | Reactive layout metrics — `{ width, height, left, top, hasMeasured }` |
diff --git a/packages/runtime/src/composables/useAppContext.ts b/packages/runtime/src/composables/useAppContext.ts
new file mode 100644
index 0000000..6bf45b5
--- /dev/null
+++ b/packages/runtime/src/composables/useAppContext.ts
@@ -0,0 +1,27 @@
+import { inject } from "vue";
+import { AppContextKey } from "../context.ts";
+
+/**
+ * Returns the app-level context for a component inside the render tree:
+ *
+ * - `exit(error?)` — end the app. Pass an `Error` to reject `app.waitUntilExit()`
+ *   (and any awaiter); pass any other value to resolve with it as the result;
+ *   call with no args to resolve with `undefined`.
+ * - `waitUntilRenderFlush()` — resolve once the next frame has been committed and
+ *   flushed to the output stream.
+ *
+ * Mirrors Ink's `useApp()` (which returns `{ exit, waitUntilRenderFlush }`). It
+ * is named `useAppContext` rather than `useApp` to avoid colliding with Vue's
+ * own "App" mental model (`createApp`, the Vue application instance) — the same
+ * Vue-native-naming choice vue-tui makes with `createApp()` vs Ink's `render()`.
+ * Streams remain on their dedicated peer composables (`useStdin`, `useStdout`,
+ * `useStderr`), exactly as in Ink.
+ */
+export function useAppContext(): {
+  exit: (errorOrResult?: unknown) => void;
+  waitUntilRenderFlush: () => Promise<void>;
+} {
+  const ctx = inject(AppContextKey);
+  if (!ctx) throw new Error("useAppContext() must be called inside a vue-tui render tree");
+  return { exit: ctx.exit, waitUntilRenderFlush: ctx.waitUntilRenderFlush };
+}
diff --git a/packages/runtime/src/composables/useExit.ts b/packages/runtime/src/composables/useExit.ts
deleted file mode 100644
index a100c1c..0000000
--- a/packages/runtime/src/composables/useExit.ts
+++ /dev/null
@@ -1,14 +0,0 @@
-import { inject } from "vue";
-import { AppContextKey } from "../context.ts";
-
-/**
- * Returns the exit function so a component can end the app from inside the
- * tree. Pass an Error to reject `app.waitUntilExit()` (and any awaiter); pass
- * any other value to resolve with it as the result; call with no args to
- * resolve with undefined.
- */
-export function useExit(): (errorOrResult?: unknown) => void {
-  const ctx = inject(AppContextKey);
-  if (!ctx) throw new Error("useExit() must be called inside a vue-tui render tree");
-  return ctx.exit;
-}
diff --git a/packages/runtime/src/context.ts b/packages/runtime/src/context.ts
index 9d1f3d8..10645b8 100644
--- a/packages/runtime/src/context.ts
+++ b/packages/runtime/src/context.ts
@@ -9,6 +9,7 @@ export interface CursorPosition {
 
 export interface AppContext {
   exit: (errorOrResult?: unknown) => void;
+  waitUntilRenderFlush: () => Promise<void>;
   stdout: NodeJS.WriteStream;
   stderr: NodeJS.WriteStream;
   stdin: NodeJS.ReadStream;
diff --git a/packages/runtime/src/index.ts b/packages/runtime/src/index.ts
index b042681..5bf4bcf 100644
--- a/packages/runtime/src/index.ts
+++ b/packages/runtime/src/index.ts
@@ -14,7 +14,7 @@ export { Spacer } from "./components/Spacer.ts";
 export { Static, type StaticProps } from "./components/Static.ts";
 export { Transform, type TransformProps } from "./components/Transform.ts";
 
-export { useExit } from "./composables/useExit.ts";
+export { useAppContext } from "./composables/useAppContext.ts";
 export { useInput, type Key, type UseInputOptions } from "./composables/useInput.ts";
 export { usePaste, type UsePasteOptions } from "./composables/usePaste.ts";
 export { useFocus, type UseFocusOptions } from "./composables/useFocus.ts";
diff --git a/packages/runtime/src/render-to-string.ts b/packages/runtime/src/render-to-string.ts
index ee4ef78..e9fe457 100644
--- a/packages/runtime/src/render-to-string.ts
+++ b/packages/runtime/src/render-to-string.ts
@@ -46,7 +46,7 @@ export interface RenderToStringOptions {
  * starting a persistent terminal application.
  *
  * Terminal-specific composables (`useInput`, `useStdin`, `useStdout`,
- * `useStderr`, `useExit`, `useFocus`, `useFocusManager`) return default
+ * `useStderr`, `useAppContext`, `useFocus`, `useFocusManager`) return default
  * no-op values since there is no terminal session. They will not throw, but
  * they will not function as in a live terminal.
  *
@@ -168,6 +168,9 @@ export function renderToString(component: Component, options?: RenderToStringOpt
 function createNoOpAppContext(isScreenReaderEnabled = false): AppContext {
   return {
     exit: () => {},
+    // No terminal session: nothing to flush, resolve immediately (mirrors Ink's
+    // default AppContext `async waitUntilRenderFlush() {}`).
+    waitUntilRenderFlush: async () => {},
     stdout: process.stdout,
     stderr: process.stderr,
     stdin: process.stdin,
diff --git a/packages/runtime/src/render.ts b/packages/runtime/src/render.ts
index 664539b..c32d2a6 100644
--- a/packages/runtime/src/render.ts
+++ b/packages/runtime/src/render.ts
@@ -545,7 +545,7 @@ export function createApp(root: Component, rootProps?: RootProps | null): TuiApp
         //
         // teardownStarted mirrors Ink's `isUnmounting` half of that guard:
         // app.unmount() runs teardown()+resolveExit() WITHOUT setting
-        // exitInitiated, so a retained useExit() called re-entrantly DURING
+        // exitInitiated, so a retained exit() (from useAppContext()) called re-entrantly DURING
         // unmount teardown (or any exit() after unmount) would otherwise pass
         // the exitInitiated check, overwrite pendingExitResult/pendingExitError
         // and queue a microtask — letting that late value win over the unmount.
@@ -570,6 +570,7 @@ export function createApp(root: Component, rootProps?: RootProps | null): TuiApp
           resolveExit();
         });
       },
+      waitUntilRenderFlush,
       stdout,
       stderr,
       stdin,
@@ -959,7 +960,7 @@ export function createApp(root: Component, rootProps?: RootProps | null): TuiApp
     // Auto-cleanup on process exit (process.exit, event-loop drain, uncaught
     // exception — anything that fires Node's 'exit' event). teardown() is
     // sync and idempotent, safe to call from this hook. If the user already
-    // called unmount() / useExit(), this is a no-op.
+    // called unmount() / exit() (via useAppContext()), this is a no-op.
     const exitListener = () => teardown();
     process.on("exit", exitListener);
     mountedExitListener = exitListener;
@@ -1030,7 +1031,10 @@ export function createApp(root: Component, rootProps?: RootProps | null): TuiApp
     return exitPromise;
   };
 
-  app.waitUntilRenderFlush = async function waitUntilRenderFlush(): Promise<void> {
+  // Hoisted so the injected appContext (built inside mount()) can expose the
+  // SAME implementation via useAppContext().waitUntilRenderFlush — both the
+  // TuiApp handle and the in-tree composable resolve identically.
+  async function waitUntilRenderFlush(): Promise<void> {
     // Flush any pending OR scheduled render. Gating on hasPending() alone
     // misses the window after schedule() queues a commit but before the
     // post-flush callback sets hasPendingFlag, letting this resolve early.
@@ -1051,7 +1055,8 @@ export function createApp(root: Component, rootProps?: RootProps | null): TuiApp
         setImmediate(resolve);
       }
     });
-  };
+  }
+  app.waitUntilRenderFlush = waitUntilRenderFlush;
 
   app.clear = function clear(): void {
     mountedClear?.();