diff --git a/.claude/settings.json b/.claude/settings.json
index 71e7387..ffd5940 100644
--- a/.claude/settings.json
+++ b/.claude/settings.json
@@ -1,6 +1,18 @@
 {
   "$schema": "https://json.schemastore.org/claude-code-settings.json",
   "hooks": {
+    "SessionStart": [
+      {
+        "hooks": [
+          {
+            "type": "command",
+            "command": "bun ./prune-worktrees.ts",
+            "timeout": 30,
+            "statusMessage": "Pruning stale agent worktrees"
+          }
+        ]
+      }
+    ],
     "PreToolUse": [
       {
         "matcher": "Bash",
diff --git a/prune-worktrees.ts b/prune-worktrees.ts
new file mode 100644
index 0000000..84669d9
--- /dev/null
+++ b/prune-worktrees.ts
@@ -0,0 +1,95 @@
+#!/usr/bin/env bun
+/**
+ * Removes agent worktrees under `.claude/worktrees/` that have nothing left in
+ * them, and runs on `SessionStart` (see `.claude/settings.json`).
+ *
+ * Claude Code creates one of these per `isolation: "worktree"` subagent and is
+ * meant to clean it up when the copy comes back unchanged. One survived and sat
+ * at 276MB — 195MB of it a second `node_modules`, 74MB a second `site/` — for a
+ * branch that had already been merged. Nothing points at these directories
+ * (`.gitignore:42` keeps them out of the repo entirely), so the only thing that
+ * would ever notice is `du`.
+ *
+ * The bar for removing one is deliberately high, because the alternative is
+ * deleting work that only exists there:
+ *
+ *   - the working tree is clean, tracked *and* untracked (`--porcelain` with
+ *     `-unormal`, so a stray file someone dropped in counts as work), and
+ *   - the branch it is on has no commits the default branch lacks.
+ *
+ * Anything else is left alone and reported, which is the case worth seeing: a
+ * worktree with real work in it is not clutter, it is something you forgot.
+ *
+ * `git worktree prune` is not this. It only forgets administrative files whose
+ * directory has already been deleted by hand — the 276MB directory is exactly
+ * the case it walks past.
+ */
+
+import { $ } from "bun";
+
+const WORKTREE_ROOT = ".claude/worktrees";
+
+type Worktree = { path: string; branch: string | null };
+
+/** `git worktree list --porcelain` as records; the first is always the main checkout. */
+async function listWorktrees(): Promise<Worktree[]> {
+  const out = await $`git worktree list --porcelain`.text();
+  const worktrees: Worktree[] = [];
+  for (const block of out.trim().split("\n\n")) {
+    const path = block.match(/^worktree (.+)$/m)?.[1];
+    if (!path) continue;
+    const ref = block.match(/^branch (.+)$/m)?.[1] ?? null;
+    worktrees.push({ path, branch: ref?.replace(/^refs\/heads\//, "") ?? null });
+  }
+  return worktrees;
+}
+
+async function defaultBranch(): Promise<string> {
+  for (const candidate of ["main", "master"]) {
+    if (await $`git show-ref --verify --quiet refs/heads/${candidate}`.nothrow().then((r) => r.exitCode === 0)) {
+      return candidate;
+    }
+  }
+  return "HEAD";
+}
+
+async function isClean(path: string): Promise<boolean> {
+  const status = await $`git -C ${path} status --porcelain -unormal`.nothrow().text();
+  return status.trim() === "";
+}
+
+/** True when `branch` holds no commit that `base` does not already have. */
+async function isMerged(branch: string, base: string): Promise<boolean> {
+  const ahead = await $`git rev-list --count ${base}..${branch}`.nothrow().text();
+  return ahead.trim() === "0";
+}
+
+const base = await defaultBranch();
+const [, ...agentWorktrees] = await listWorktrees();
+const kept: string[] = [];
+
+for (const { path, branch } of agentWorktrees) {
+  if (!path.includes(WORKTREE_ROOT)) continue;
+
+  const reason = !(await isClean(path))
+    ? "uncommitted changes"
+    : branch && !(await isMerged(branch, base))
+      ? `commits not in ${base}`
+      : null;
+
+  if (reason) {
+    kept.push(`${path} (${reason})`);
+    continue;
+  }
+
+  const removed = await $`git worktree remove ${path}`.nothrow();
+  if (removed.exitCode !== 0) {
+    kept.push(`${path} (git declined to remove it)`);
+    continue;
+  }
+  console.log(`pruned stale agent worktree: ${path}`);
+}
+
+if (kept.length > 0) {
+  console.log(`agent worktrees left in place:\n  ${kept.join("\n  ")}`);
+}
diff --git a/site/public/terminal.png b/site/public/terminal.png
index 88655a1..cdf79a5 100644
Binary files a/site/public/terminal.png and b/site/public/terminal.png differ
diff --git a/tui/src/app.overlay.test.tsx b/tui/src/app.overlay.test.tsx
index 818d11c..04b05a1 100644
--- a/tui/src/app.overlay.test.tsx
+++ b/tui/src/app.overlay.test.tsx
@@ -105,6 +105,21 @@ function mount() {
   return { stdout, stdin, unmount: () => instance.unmount() };
 }
 
+/**
+ * Wait for the frame to contain what the test is about, rather than for a fixed
+ * duration. The 1000-item transcript took 83–117ms to draw against the old 120ms
+ * sleep, so a loaded CI runner read a half-drawn frame and went red.
+ */
+async function waitForFrame(app: { stdout: Capture }, needle: string): Promise<void> {
+  const deadline = Date.now() + 10_000;
+  while (Date.now() < deadline) {
+    if (app.stdout.text().includes(needle)) return;
+    await new Promise((resolve) => setTimeout(resolve, 10));
+  }
+  throw new Error(`no ${JSON.stringify(needle)} in the frame after 10s`);
+}
+
+/** Only for asserting something did *not* happen, where there is no frame to wait for. */
 const settle = () => new Promise((resolve) => setTimeout(resolve, 120));
 const TRANSCRIPT = "explain the readme";
 
@@ -118,7 +133,7 @@ describe("dialogs float over the app", () => {
   test("keeps the transcript on screen behind the model picker", async () => {
     const app = mount();
     store.openModelPicker();
-    await settle();
+    await waitForFrame(app, "Select model");
 
     // Before, the dialog replaced the main content and the screen went black.
     expect(app.stdout.text()).toContain(TRANSCRIPT);
@@ -133,7 +148,7 @@ describe("dialogs float over the app", () => {
       command: "bun test",
       toolName: "run_tests",
     });
-    await settle();
+    await waitForFrame(app, "Run tests");
 
     expect(app.stdout.text()).toContain(TRANSCRIPT);
     expect(app.stdout.text()).toContain("Run tests");
@@ -146,7 +161,7 @@ describe("dialogs float over the app", () => {
   test("keeps the transcript on screen behind a question", async () => {
     const app = mount();
     const answer = store.setPendingQuestion({ id: "q-1", questions: ["Which database?"] });
-    await settle();
+    await waitForFrame(app, "Which database?");
 
     expect(app.stdout.text()).toContain(TRANSCRIPT);
     expect(app.stdout.text()).toContain("Which database?");
@@ -159,7 +174,7 @@ describe("dialogs float over the app", () => {
   test("draws the background faded and the panel lit", async () => {
     const app = mount();
     store.openModelPicker();
-    await settle();
+    await waitForFrame(app, "Select model");
 
     const emitted = app.stdout.foregrounds();
     // Both palettes on screen at once is the whole point: dimmed behind, lit in
@@ -171,7 +186,7 @@ describe("dialogs float over the app", () => {
 
   test("uses only the lit palette when no dialog is open", async () => {
     const app = mount();
-    await settle();
+    await waitForFrame(app, TRANSCRIPT);
 
     const emitted = app.stdout.foregrounds();
     expect(emitted).toContain(colors.textBase);
@@ -228,7 +243,9 @@ describe("a chord never answers the diff", () => {
   test("Ctrl+A leaves the edit pending instead of applying it", async () => {
     const app = mount();
     leaveUnanswered("ctrl-a");
-    await settle();
+    // The diff has to be on screen before the key is pressed, or there is no
+    // mounted handler to ignore it and the assertion below passes for no reason.
+    await waitForFrame(app, "notes.txt");
 
     app.stdin.press(CTRL_A);
     await settle();
@@ -241,7 +258,7 @@ describe("a chord never answers the diff", () => {
   test("Ctrl+R leaves the edit pending instead of rejecting it", async () => {
     const app = mount();
     leaveUnanswered("ctrl-r");
-    await settle();
+    await waitForFrame(app, "notes.txt");
 
     app.stdin.press(CTRL_R);
     await settle();
@@ -254,7 +271,7 @@ describe("a chord never answers the diff", () => {
   test("Enter still applies the edit", async () => {
     const app = mount();
     const decision = store.setPendingEdit(pendingEdit("enter"));
-    await settle();
+    await waitForFrame(app, "notes.txt");
 
     app.stdin.press(ENTER);
 
@@ -266,7 +283,7 @@ describe("a chord never answers the diff", () => {
   test("Esc still rejects the edit", async () => {
     const app = mount();
     const decision = store.setPendingEdit(pendingEdit("esc"));
-    await settle();
+    await waitForFrame(app, "notes.txt");
 
     app.stdin.press(ESC);
 
@@ -310,7 +327,8 @@ describe("the diff owns the screen while it is being judged", () => {
 
       const app = mount();
       const decision = store.setPendingEdit(longEdit());
-      await settle();
+      // The 1000-item case is the one that overran a fixed sleep on CI.
+      await waitForFrame(app, "added line 0");
 
       const frame = app.stdout.text();
       expect(frame).toContain("runtime/loop.ts");