test(providers): reproduce plugin migration, steering, and chunk failures

* fix(server): keep overlapping directory searches within their scan budget

Construct child paths and branch iterators as the round-robin walk consumes them. Eager sibling expansion retained hundreds of thousands of unvisited children per search and exhausted the heap when requests overlapped.

* test(server): stop directory-search children before fixture cleanup

---------

Co-authored-by: paseo-bot[bot] <266920839+paseo-bot[bot]@users.noreply.github.com>

nix/npm-deps.hash

@@ -1 +1 @@
-sha256-1WmrHvE68Lzyil4On7xtsPMQTODXZ3Jb3/juUg3nHi4=
+sha256-O8sNh6oXFIddUljYiC6RbVZF5/7a7A7W9UWrOd0tIV4=

packages/app/e2e/browser/chat-find.spec.ts

@@ -5,6 +5,7 @@ import {
   seedMockAgentWorkspace,
   type MockAgentWorkspace,
 } from "../support/helpers/mock-agent";
+import { waitForTimelineGeometryToSettle } from "../support/helpers/timeline-pagination";
 import { installDaemonWebSocketGate } from "../support/helpers/daemon-websocket-gate";
 import {
   expectReconnectingToastGone,
@@ -19,6 +20,10 @@ import {
 } from "../support/helpers/composer";
 
 import { openCommandCenter, closeCommandCenter } from "../support/helpers/command-center";
+import {
+  expectPromptsDrawnByPlugin,
+  withPromptTimelinePlugin,
+} from "../support/helpers/plugin-timeline";
 
 const MAC_USER_AGENT =
   "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/130.0.0.0 Safari/537.36";
@@ -120,6 +125,49 @@ async function closeFind(page: Page) {
     .toEqual([]);
 }
 
+async function expectChatKeyboardScroll(page: Page, key: "PageUp" | "PageDown") {
+  // The scrolling surface has no accessible name; use its existing test id.
+  const viewport = page.getByTestId("agent-chat-scroll");
+  await waitForTimelineGeometryToSettle(page);
+  const before = await viewport.evaluate((element) => element.scrollTop);
+  await page.keyboard.press(key);
+  const direction = key === "PageUp" ? -1 : 1;
+  await expect
+    .poll(
+      async () => direction * ((await viewport.evaluate((element) => element.scrollTop)) - before),
+    )
+    .toBeGreaterThan(100);
+}
+
+test("keeps keyboard scrolling the chat after closing Find", async ({ page }, testInfo) => {
+  const agent = await seedMockAgentWorkspace({
+    repoPrefix: "chat-find-scroll-focus-",
+    title: "Chat Find keyboard scrolling",
+    initialPrompt: "Render the response",
+    featureValues: { mockAssistantResponse: TALL_RESPONSE },
+  });
+  try {
+    await agent.client.waitForFinish(agent.agentId, 15_000);
+    await openAgentRoute(page, agent);
+    await expect(page.getByTestId("assistant-message").first()).toBeVisible();
+    await searchChat(page, "Closing paragraph");
+    await expectHighlight(page, "Closing paragraph");
+    await waitForTimelineGeometryToSettle(page);
+    await closeFind(page);
+    await expectChatKeyboardScroll(page, "PageUp");
+    await page.screenshot({ path: testInfo.outputPath("chat-after-find-page-up.png") });
+    await expectChatKeyboardScroll(page, "PageDown");
+    await searchChat(page, "Closing paragraph");
+    await expectHighlight(page, "Closing paragraph");
+    await waitForTimelineGeometryToSettle(page);
+    await page.getByRole("button", { name: "Close Find", exact: true }).click();
+    await expect(query(page)).toHaveCount(0);
+    await expectChatKeyboardScroll(page, "PageUp");
+  } finally {
+    await agent.cleanup();
+  }
+});
+
 test("loads older history through prompt navigation and finds repeated rendered Markdown", async ({
   page,
 }, testInfo) => {
@@ -174,7 +222,7 @@ async function highlightedMessage(page: Page) {
     const range = entry && Array.from(entry[1])[0];
     if (!(range instanceof Range)) return null;
     const message = range.startContainer.parentElement?.closest<HTMLElement>(
-      '[data-testid="user-message"], [data-testid="assistant-message"]',
+      '[data-testid="user-message"], [data-testid="plugin-prompt"], [data-testid="assistant-message"]',
     );
     return message?.dataset.testid ?? null;
   });
@@ -219,6 +267,34 @@ test("counts and steps through every match in the chat, not just the selected me
   }
 });
 
+test("finds text in a prompt a timeline plugin draws", async ({ page }, testInfo) => {
+  testInfo.setTimeout(120_000);
+  const agent = await seedMockAgentWorkspace({
+    repoPrefix: "chat-find-plugin-prompt-",
+    title: "Chat Find plugin prompt",
+    initialPrompt: ACROSS_PROMPT,
+    featureValues: { mockAssistantResponse: ACROSS_RESPONSE },
+  });
+  try {
+    await agent.client.waitForFinish(agent.agentId, 15_000);
+    await withPromptTimelinePlugin(async () => {
+      await openAgentRoute(page, agent);
+      await expectPromptsDrawnByPlugin(page);
+      await openChatFind(page);
+      await query(page).fill("scope-needle");
+      await expect(status(page)).toHaveText("1 of 3");
+      await expectHighlight(page, "scope-needle");
+      await expectHighlightedMessage(page, "plugin-prompt");
+      await page.screenshot({ path: testInfo.outputPath("chat-find-plugin-prompt.png") });
+      await expectNextMatch(page, "2 of 3", "scope-needle");
+      await expectHighlightedMessage(page, "assistant-message");
+      await closeFind(page);
+    });
+  } finally {
+    await agent.cleanup();
+  }
+});
+
 test("rejects invisible source matches and ignores a late reply after closing", async ({
   page,
 }) => {

packages/app/src/agent-stream/chat-find/index.web.tsx

@@ -118,8 +118,8 @@ export function ChatFind({
   }, [active, isInteractive, model]);
   const close = useCallback(() => {
     model.close();
-    root.current?.focus({ preventScroll: true });
-  }, [model]);
+    viewportRef.current?.focus?.();
+  }, [model, viewportRef]);
   let status = "";
   if (state.phase === "searching") status = t("paneFind.searching");
   else if (state.phase === "loading") status = t("paneFind.loading");

packages/app/src/agent-stream/chat-find/ranges.browser.test.ts

@@ -76,3 +76,49 @@ it("keeps semantic Markdown paragraphs separate while finding inline matches", (
   ]);
   expect(findRenderedMatches(row, ".another")).toEqual([]);
 });
+
+function pluginRow(html: string) {
+  const row = document.createElement("div");
+  row.dataset.pluginRow = "true";
+  row.dataset.messageId = "message-1";
+  row.innerHTML = html;
+  document.body.append(row);
+  return row;
+}
+
+it("searches a plugin row that sets no text marker, bounding matches by view", () => {
+  const row = pluginRow(
+    "<div><div>Prompt</div><div>find <span>this</span> needle</div><div>needle</div><button>needle</button></div>",
+  );
+  expect(findRenderedMatches(row, "needle").map((range) => range.toString())).toEqual([
+    "needle",
+    "needle",
+  ]);
+  expect(findRenderedMatches(row, "Promptfind")).toEqual([]);
+  expect(findRenderedMatches(row, "find this needle")).toHaveLength(1);
+  expect(findMessageMatches(row.parentElement, "message-1", "needle")).toHaveLength(2);
+});
+
+it("leaves rows without the plugin marker limited to marked message text", () => {
+  const row = document.createElement("div");
+  row.innerHTML = "<div>needle</div>";
+  document.body.append(row);
+  expect(findRenderedMatches(row, "needle")).toEqual([]);
+});
+
+it("counts only drawn text in a plugin row, including an opened popover", () => {
+  const row = pluginRow(
+    '<div><span>visible needle</span><div hidden>hidden needle</div><div style="display:none">display needle</div><span style="visibility:hidden">visibility needle</span><span style="opacity:0">transparent needle</span><div popover="manual">popover needle</div></div>',
+  );
+  expect(findRenderedMatches(row, "needle").map((range) => range.toString())).toEqual(["needle"]);
+  row.querySelector<HTMLElement>("[popover]")!.showPopover();
+  expect(findRenderedMatches(row, "needle")).toHaveLength(2);
+});
+
+it("keeps text around nested plugin blocks in separate occurrences", () => {
+  const row = pluginRow("<div>alpha <div>details</div>beta</div><div>gamma <div></div>delta</div>");
+  expect(findRenderedMatches(row, "alpha beta")).toEqual([]);
+  expect(findRenderedMatches(row, "gamma delta")).toEqual([]);
+  expect(findRenderedMatches(row, "details").map((range) => range.toString())).toEqual(["details"]);
+  expect(findRenderedMatches(row, "beta").map((range) => range.toString())).toEqual(["beta"]);
+});

packages/app/src/agent-stream/chat-find/ranges.web.ts

@@ -21,28 +21,55 @@ export function findMessageMatches(
   return findMessageRows(root, messageId).flatMap((row) => findRenderedMatches(row, query));
 }
 
+function renderedTextGroups(row: HTMLElement): Text[][] {
+  const groups: Text[][] = [];
+  // A plugin renderer owns the DOM of the message it replaced and sets no markers, so the
+  // whole row is searched and each div (a React Native View or Text) bounds a match.
+  const pluginRow = row.dataset.pluginRow === "true";
+  const blocks = pluginRow ? `${BLOCKS},div` : BLOCKS;
+  const contents = pluginRow
+    ? [row]
+    : row.querySelectorAll<HTMLElement>('[data-message-text="true"]');
+  for (const content of contents) {
+    let group: { block: Element; texts: Text[] } | undefined;
+    const walker = document.createTreeWalker(
+      content,
+      NodeFilter.SHOW_ELEMENT | NodeFilter.SHOW_TEXT,
+    );
+    let node: Node | null;
+    while ((node = walker.nextNode())) {
+      if (node instanceof Element) {
+        // Even an empty nested block separates the text before and after it.
+        if (node.matches(blocks)) group = undefined;
+        continue;
+      }
+      if (!(node instanceof Text) || node.parentElement?.closest(IGNORED)) continue;
+      if (
+        pluginRow &&
+        !node.parentElement?.checkVisibility({ opacityProperty: true, visibilityProperty: true })
+      )
+        continue;
+      const block = node.parentElement?.closest(blocks) ?? content;
+      if (group?.block !== block) {
+        group = { block, texts: [] };
+        groups.push(group.texts);
+      }
+      group.texts.push(node);
+    }
+  }
+  return groups;
+}
+
 /** Local offsets belong to the DOM that supplied the text, never to a host parser. */
 export function findRenderedMatches(row: HTMLElement, query: string): Range[] {
   if (!query.trim()) return [];
-  const groups = new Map<Element, Text[]>();
-  for (const content of row.querySelectorAll<HTMLElement>('[data-message-text="true"]')) {
-    const walker = document.createTreeWalker(content, NodeFilter.SHOW_TEXT);
-    let node: Node | null;
-    while ((node = walker.nextNode())) {
-      if (!(node instanceof Text) || node.parentElement?.closest(IGNORED)) continue;
-      const block = node.parentElement?.closest(BLOCKS) ?? content;
-      const texts = groups.get(block) ?? [];
-      texts.push(node);
-      groups.set(block, texts);
-    }
-  }
   const pattern = query
     .trim()
     .split(/\s+/)
     .map((part) => part.replace(/[.*+?^${}()|[\]\\]/g, "\\$&"))
     .join("\\s+");
   const ranges: Range[] = [];
-  for (const texts of groups.values()) {
+  for (const texts of renderedTextGroups(row)) {
     const points = texts.map((node) => ({ node, start: 0, end: 0 }));
     let text = "";
     for (const point of points) {

packages/app/src/agent-stream/strategy-web.tsx

@@ -1162,6 +1162,7 @@ function WebStreamViewport(props: StreamRenderInput & { isMobileBreakpoint: bool
 
   useEffect(() => {
     const handle: StreamViewportHandle = {
+      focus: () => scrollContainerRef.current?.focus({ preventScroll: true }),
       scrollToBottom: () => {
         setFollowOutput(true);
         cancelPendingStickToBottom();
@@ -1250,6 +1251,7 @@ function WebStreamViewport(props: StreamRenderInput & { isMobileBreakpoint: bool
         key={item.id}
         data-history-row-id={item.id}
         data-message-id={getStreamItemMessageId(item)}
+        data-plugin-row={item.kind === "plugin" ? "true" : undefined}
         style={streamRowStyle}
       >
         <StreamRowContent
@@ -1267,6 +1269,7 @@ function WebStreamViewport(props: StreamRenderInput & { isMobileBreakpoint: bool
         key={item.id}
         data-history-row-id={item.id}
         data-message-id={getStreamItemMessageId(item)}
+        data-plugin-row={item.kind === "plugin" ? "true" : undefined}
         style={streamRowStyle}
       >
         <StreamRowContent
@@ -1329,6 +1332,7 @@ function WebStreamViewport(props: StreamRenderInput & { isMobileBreakpoint: bool
                     data-index={virtualRow.index}
                     data-history-row-id={item.id}
                     data-message-id={getStreamItemMessageId(item)}
+                    data-plugin-row={item.kind === "plugin" ? "true" : undefined}
                     ref={measureVirtualizedRowElement}
                     style={renderVirtualRowStyle(virtualRow.start)}
                   >

packages/app/src/agent-stream/strategy.ts

@@ -51,6 +51,8 @@ export interface ScrollToMessageOccurrence {
 }
 
 export interface StreamViewportHandle {
+  /** Give keyboard navigation back to the scrolling surface on web. */
+  focus?: () => void;
   scrollToBottom: (reason?: BottomAnchorLocalRequest["reason"]) => void;
   prepareForViewportChange: () => void;
   scrollToMessage?: (messageId: string, occurrence?: ScrollToMessageOccurrence) => void;

packages/app/src/terminal/native-renderer/terminal-selection.test.ts

@@ -41,6 +41,93 @@ function rowWithText(
 }
 
 describe("native terminal selection", () => {
+  it.each([
+    { startCol: 1, endCol: 8, expected: "한글 문장" },
+    { startCol: 3, endCol: 8, expected: "글 문장" },
+    { startCol: 1, endCol: 1, expected: "한" },
+    { startCol: 0, endCol: 0, expected: "한" },
+    { startCol: 0, endCol: 1, expected: "한" },
+    { startCol: 4, endCol: 6, expected: " 문" },
+  ])(
+    "copies complete wide characters for selected columns $startCol through $endCol",
+    async ({ startCol, endCol, expected }) => {
+      const terminal = createNativeHeadlessTerminal({ rows: 3, cols: 30 });
+      const copied: string[] = [];
+      try {
+        await terminal.write("한글 문장");
+        const bounds = terminal.getBufferBounds();
+        const selection = createTerminalSelectionModel();
+        selection.begin({
+          coordinate: { row: bounds.cursorRow, col: endCol },
+          bounds,
+        });
+        selection.update({
+          coordinate: { row: bounds.cursorRow, col: startCol },
+          bounds,
+        });
+
+        await copyTerminalSelection({
+          terminal,
+          selection: selection.getSnapshot().range,
+          clipboard: {
+            writeText: async (text) => {
+              copied.push(text);
+            },
+          },
+        });
+
+        expect(copied).toEqual([expected]);
+      } finally {
+        terminal.dispose();
+      }
+    },
+  );
+
+  it("copies Korean output without adding spaces for continuation cells", async () => {
+    const terminal = createNativeHeadlessTerminal({ rows: 3, cols: 30 });
+    const copied: string[] = [];
+    try {
+      await terminal.write("한글 문장");
+      const bounds = terminal.getBufferBounds();
+      await copyTerminalSelection({
+        terminal,
+        selection: {
+          start: { row: bounds.cursorRow, col: 0 },
+          end: { row: bounds.cursorRow, col: bounds.cursorCol - 1 },
+          coordinateEpoch: bounds.coordinateEpoch,
+        },
+        clipboard: {
+          writeText: async (text) => {
+            copied.push(text);
+          },
+        },
+      });
+      expect(copied).toEqual(["한글 문장"]);
+    } finally {
+      terminal.dispose();
+    }
+  });
+
+  it("copies Korean text and real spaces without wide-character continuation spaces", async () => {
+    const terminal = createNativeHeadlessTerminal({ rows: 3, cols: 30 });
+    try {
+      await terminal.write("한글 문장 | 성공");
+      const bounds = terminal.getBufferBounds();
+      expect(
+        extractTerminalSelectedText({
+          terminal,
+          selection: {
+            start: { row: bounds.cursorRow, col: 0 },
+            end: { row: bounds.cursorRow, col: bounds.cursorCol - 1 },
+            coordinateEpoch: bounds.coordinateEpoch,
+          },
+        }),
+      ).toBe("한글 문장 | 성공");
+    } finally {
+      terminal.dispose();
+    }
+  });
+
   it("expands a long-press coordinate to the whole terminal word", async () => {
     const terminal = createNativeHeadlessTerminal({ rows: 4, cols: 32, scrollbackLines: 20 });
     await terminal.write("before PASEO_TARGET after\r\n");

packages/app/src/terminal/native-renderer/terminal-selection.ts

@@ -324,10 +324,17 @@ export function extractTerminalSelectedText(input: TerminalSelectedTextInput): s
     const cells = window.rows[offset] ?? [];
     const startsOnThisRow = row === selection.start.row;
     const endsOnThisRow = row === selection.end.row;
-    const startCol = startsOnThisRow ? selection.start.col : 0;
+    let startCol = Math.max(0, startsOnThisRow ? selection.start.col : 0);
+    // Selecting either half highlights the whole wide character, so copy its leading cell too.
+    if (startCol > 0 && cells[startCol]?.width === 0) {
+      startCol -= 1;
+    }
     const endCol = endsOnThisRow ? selection.end.col : cells.length - 1;
-    const selectedCells = cells.slice(Math.max(0, startCol), Math.max(0, endCol) + 1);
-    const line = selectedCells.map((cell) => cell.char || " ").join("");
+    const selectedCells = cells.slice(startCol, Math.max(0, endCol) + 1);
+    const line = selectedCells
+      .filter((cell) => cell.width !== 0)
+      .map((cell) => cell.char)
+      .join("");
     if (offset > 0 && window.wrappedRows[offset] !== true) {
       text += "\n";
     }

packages/app/src/timeline/replica.test.ts

@@ -77,6 +77,90 @@ function applySynced(agentId: string, seq: number): void {
 afterEach(() => useSessionStore.getState().clearSession(SERVER_ID));
 
 describe("viewed timeline persistence", () => {
+  it("keeps one complete reply when live chunks arrive before a cached chat catches up", async () => {
+    useSessionStore.getState().initializeSession(SERVER_ID, null);
+    const partial = "Paragraph 1. Paragraph 2.";
+    const complete = `${partial} Paragraph 3. END`;
+    const owner = createOwner({
+      readTimeline: async () => ({
+        agentId: AGENT_ID,
+        items: [{ ...item("reply-1", partial, 4), messageId: "reply-1" }],
+        range: { epoch: "epoch-1", startSeq: 1, endSeq: 4 },
+        hasOlder: false,
+      }),
+      commitTimeline: () => undefined,
+    });
+    try {
+      owner.replaceVisibleAgentIds("test", [AGENT_ID]);
+      await expect
+        .poll(
+          () =>
+            selectAgentTimelineState(useSessionStore.getState().sessions[SERVER_ID], AGENT_ID)
+              .status,
+        )
+        .toBe("painted");
+      owner.enqueueStreamEvent(AGENT_ID, {
+        event: {
+          type: "timeline",
+          provider: "codex",
+          item: { type: "assistant_message", text: " Paragraph 3.", messageId: "reply-1" },
+        } as AgentStreamEventPayload,
+        seq: 5,
+        epoch: "epoch-1",
+        timestamp: new Date("2026-08-26T10:00:01.000Z"),
+      });
+      owner.flushStreamAgent(AGENT_ID);
+      owner.applyTimelineResponse({
+        requestId: "resume",
+        agentId: AGENT_ID,
+        agent: null,
+        direction: "after",
+        projection: "projected",
+        reset: false,
+        epoch: "epoch-1",
+        window: { minSeq: 1, maxSeq: 6, nextSeq: 7 },
+        startCursor: { epoch: "epoch-1", seq: 5 },
+        endCursor: { epoch: "epoch-1", seq: 6 },
+        entries: [
+          {
+            provider: "codex",
+            item: { type: "assistant_message", text: complete, messageId: "reply-1" },
+            timestamp: "2026-08-26T10:00:02.000Z",
+            seqStart: 2,
+            seqEnd: 6,
+            sourceSeqRanges: [{ startSeq: 2, endSeq: 6 }],
+            collapsed: ["assistant_merge"],
+          },
+        ],
+        error: null,
+        hasNewer: false,
+        hasOlder: false,
+        staleCursor: false,
+        gap: false,
+      });
+      const replyTexts = () => {
+        const session = useSessionStore.getState().sessions[SERVER_ID];
+        return [
+          ...(session?.agentStreamTail.get(AGENT_ID) ?? []),
+          ...(session?.agentStreamHead.get(AGENT_ID) ?? []),
+        ]
+          .filter((entry) => entry.kind === "assistant_message")
+          .map((entry) => entry.text);
+      };
+      expect.soft(replyTexts()).toEqual([complete]);
+      owner.enqueueStreamEvent(AGENT_ID, {
+        event: { type: "turn_completed", provider: "codex" } as AgentStreamEventPayload,
+        seq: 7,
+        epoch: "epoch-1",
+        timestamp: new Date("2026-08-26T10:00:03.000Z"),
+      });
+      owner.flushStreamAgent(AGENT_ID);
+      expect.soft(replyTexts()).toEqual([complete]);
+    } finally {
+      owner.dispose();
+    }
+  });
+
   it("shares an in-flight cache preparation with the viewed owner", async () => {
     useSessionStore.getState().initializeSession(SERVER_ID, null);
     let release!: (value: CachedTimeline) => void;

packages/app/src/timeline/session-stream-reducers.ts

@@ -811,7 +811,7 @@ function reconcileOverlappingProjectedAssistant(params: {
   };
 
   const headMatch = findMatch(params.head);
-  const tailMatch = headMatch ? null : findMatch(params.tail);
+  const tailMatch = findMatch(params.tail);
   const match = headMatch ?? tailMatch;
   if (!match) {
     return { tail: params.tail, head: params.head, reconciled: false };
@@ -833,8 +833,20 @@ function reconcileOverlappingProjectedAssistant(params: {
   };
 
   if (headMatch) {
+    const tailCursor = tailMatch?.current.timelineCursor;
+    const replacesCachedPrefix =
+      tailMatch !== null &&
+      tailCursor?.epoch === params.epoch &&
+      unit.sourceSeqRanges.some(
+        (range) => range.startSeq <= tailCursor.seq && tailCursor.seq <= range.endSeq,
+      );
     return {
-      tail: params.tail,
+      // Live chunks can arrive before catch-up while their cached prefix is still painted.
+      // The projected reply owns both copies; keeping the prefix would duplicate it and
+      // cause completion to discard the updated head as an already-committed item.
+      tail: replacesCachedPrefix
+        ? [...params.tail.slice(0, tailMatch.index), ...params.tail.slice(tailMatch.index + 1)]
+        : params.tail,
       head: replaceMatch(params.head, headMatch.index),
       reconciled: true,
     };

packages/plugin/src/server/acp.test.ts

@@ -1246,6 +1246,49 @@ describe("runAcpProvider streamed chunks without messageId (#4699)", () => {
     messageId?: string;
   }
 
+  it("keeps reasoning separate from a reply sharing its native message ID", async () => {
+    const harness = connectorHarness({
+      promptUpdates: () => [
+        textChunk("private reasoning", "agent_thought_chunk", "shared-id"),
+        textChunk("public reply", "agent_message_chunk", "shared-id"),
+      ],
+    });
+    const registration = runAcpProvider({
+      id: "chunk-acp",
+      label: "Chunk ACP",
+      connector: harness.connector,
+    });
+    const connection = await registration.connect({
+      versions: [1],
+      capabilities: ["prompt.message"],
+    });
+    const events: ProviderEvent[] = [];
+    connection.onEvent((event) => events.push(event));
+    try {
+      await connection.send(openInput());
+      await waitForEvent(events, (event) => event.type === "session.ready");
+      await connection.send({
+        type: "session.prompt",
+        sessionId: "session-1",
+        prompt: {
+          clientMessageId: "same-id",
+          delivery: "auto",
+          input: { type: "message", content: [{ type: "text", text: "hello" }] },
+        },
+      });
+      await waitForEvent(
+        events,
+        (event) => event.type === "session.turn" && event.state === "completed",
+      );
+      const reply = events.findLast(
+        (event) => event.type === "timeline.item" && event.item.type === "assistant_message",
+      );
+      expect(reply).toMatchObject({ item: { text: "public reply" } });
+    } finally {
+      await connection.close();
+    }
+  });
+
   it("continues one timeline item per turn instead of one per chunk", async () => {
     const chunksByPrompt: Record<string, Chunk[]> = {
       first: [

packages/server/src/server/agent/plugin-provider.test.ts

@@ -287,6 +287,45 @@ function expectNestedChildren(events: AgentStreamEvent[]) {
 }
 
 describe("PluginAgentClientRegistry", () => {
+  test("returns unavailable when steering a provider without prompt.steer capability", async () => {
+    const harness = createProviderHarness();
+    const registry = new PluginAgentClientRegistry(createTestLogger());
+    registry.replace([harness.registration]);
+    const session = await registry.clients()[harness.registration.id]!.createSession({
+      provider: harness.registration.id,
+      cwd: "/tmp",
+    });
+    try {
+      await expect(
+        session.steerActiveTurn!("follow up", { expectedTurnId: "turn-1" }),
+      ).resolves.toEqual({ status: "unavailable" });
+      expect(harness.inputs.filter((input) => input.type === "session.prompt")).toHaveLength(0);
+    } finally {
+      await session.close();
+      registry.replace([]);
+    }
+  });
+
+  test("resumes a native ACP handle after the same provider ID moves to a plugin", async () => {
+    const harness = createProviderHarness();
+    const registry = new PluginAgentClientRegistry(createTestLogger());
+    registry.replace([harness.registration]);
+    try {
+      const session = await registry.clients()[harness.registration.id]!.resumeSession(
+        {
+          provider: harness.registration.id,
+          sessionId: "native-session-id",
+          nativeHandle: "native-session-id",
+          metadata: { provider: "acp", cwd: "/tmp" },
+        },
+        { provider: harness.registration.id, cwd: "/tmp" },
+      );
+      await session.close();
+    } finally {
+      registry.replace([]);
+    }
+  });
+
   test("stores only agent options while the plugin receives merged defaults", async () => {
     const logger = createTestLogger();
     const harness = createProviderHarness();

packages/server/src/utils/directory-suggestions.test.ts

@@ -1,5 +1,5 @@
 import { createHook } from "node:async_hooks";
-import { execFileSync } from "node:child_process";
+import { execFileSync, spawn, type ChildProcess } from "node:child_process";
 import {
   mkdtempSync,
   mkdirSync,
@@ -1066,6 +1066,16 @@ describe("relative typed-entry configuration", () => {
   });
 });
 
+interface SearchProcessExit {
+  code: number | null;
+  signal: string | null;
+}
+
+interface SearchProcess {
+  child: ChildProcess;
+  exited: Promise<SearchProcessExit>;
+}
+
 // Reading a tree is cheap; re-deriving each entry's path state is not. A scan that asks whether
 // every ancestor of every entry is inside the root, or is Git-ignored, costs multiples of the
 // read and is what made large home directories exceed the client request timeout.
@@ -1073,6 +1083,7 @@ describe("home-tree scan cost", () => {
   const DEPTH = 8;
   const CHAINS = 40;
   let scanRoot: string;
+  let searchProcess: SearchProcess | null = null;
 
   beforeEach(() => {
     scanRoot = realpathSync.native(mkdtempSync(path.join(tmpdir(), "directory-scan-cost-")));
@@ -1083,8 +1094,16 @@ describe("home-tree scan cost", () => {
     }
   });
 
-  afterEach(() => {
-    rmSync(scanRoot, { recursive: true, force: true });
+  afterEach(async () => {
+    try {
+      if (searchProcess) {
+        searchProcess.child.kill();
+        await searchProcess.exited;
+      }
+    } finally {
+      searchProcess = null;
+      rmSync(scanRoot, { recursive: true, force: true });
+    }
   });
 
   // Nothing matches, so the scan walks the whole tree instead of stopping at a confident result.
@@ -1102,6 +1121,78 @@ describe("home-tree scan cost", () => {
     return stopPathContainmentMetrics();
   }
 
+  it("finishes overlapping broad-tree searches within a bounded heap", async () => {
+    const broadRoot = path.join(scanRoot, "broad");
+    mkdirSync(broadRoot);
+    for (let branch = 0; branch < 30; branch += 1) {
+      const branchRoot = path.join(broadRoot, `branch-${branch}`);
+      mkdirSync(branchRoot);
+      for (let group = 0; group < 30; group += 1) {
+        const groupRoot = path.join(branchRoot, `group-${group}`);
+        mkdirSync(groupRoot);
+        for (let leaf = 0; leaf < 30; leaf += 1) {
+          mkdirSync(path.join(groupRoot, `leaf-${leaf}`));
+        }
+      }
+    }
+    // A smaller real tree and explicit heap budget keep the million-directory repro cheap in CI.
+    const moduleUrl = new URL("./directory-suggestions.ts", import.meta.url).href;
+    const source = `
+      const { searchDirectoryEntries } = await import(${JSON.stringify(moduleUrl)});
+      const results = await Promise.all(Array.from({ length: 14 }, (_, index) =>
+        searchDirectoryEntries({
+          root: ${JSON.stringify(broadRoot)},
+          query: "z".repeat(index + 1),
+          pathFormat: "absolute",
+          includeFiles: false,
+          includeDirectories: true,
+          pathQueryPolicy: "rooted",
+          rootAliases: ["~"],
+          blankQueryBehavior: "none",
+          confidentResultScanThreshold: 5000,
+          maxEntriesScanned: 2000,
+          limit: 30,
+        })
+      ));
+      process.stdout.write(JSON.stringify(results));
+    `;
+    const child = spawn(
+      process.execPath,
+      [
+        "--max-old-space-size=128",
+        "--conditions=source",
+        "--import",
+        "tsx",
+        "--input-type=module",
+        "--eval",
+        source,
+      ],
+      { stdio: ["ignore", "pipe", "pipe"], timeout: 20_000 },
+    );
+    let stdout = "";
+    let stderr = "";
+    child.stdout.setEncoding("utf8");
+    child.stderr.setEncoding("utf8");
+    child.stdout.on("data", (chunk: string) => {
+      stdout += chunk;
+    });
+    child.stderr.on("data", (chunk: string) => {
+      stderr += chunk;
+    });
+    const exited = new Promise<SearchProcessExit>((resolve, reject) => {
+      child.on("error", reject);
+      child.on("close", (code, signal) => resolve({ code, signal }));
+    });
+    searchProcess = { child, exited };
+    const exit = await exited;
+    expect({ ...exit, outOfMemory: stderr.includes("heap out of memory") }).toEqual({
+      code: 0,
+      signal: null,
+      outOfMemory: false,
+    });
+    expect(JSON.parse(stdout)).toEqual(Array.from({ length: 14 }, () => []));
+  });
+
   it("derives no containment for a tree that cannot leave the root", async () => {
     const checks = await countContainmentChecks(scanWholeTree);
 

packages/server/src/utils/directory-suggestions.ts

@@ -63,6 +63,13 @@ interface WalkStart {
   resolvedPath: string;
 }
 
+interface WalkChildrenOptions {
+  parent: WalkStart;
+  depth: number;
+  input: SearchInput;
+  visited: Set<string>;
+}
+
 interface TraversedEntry extends ChildEntry {
   visiblePath: string;
   depth: number;
@@ -318,17 +325,18 @@ async function searchChildren(input: SearchInput): Promise<RankedEntry[]> {
   const discoveryInput = isInsideExcludedPath(parent, input)
     ? { ...input, excludedDiscoveryPaths: new Set<string>() }
     : input;
-  const entries = await readChildren(parent);
-  return entries.flatMap((entry) => {
+  const ranked: RankedEntry[] = [];
+  for await (const entry of readChildren(parent)) {
     if (!isPathInsideRoot(input.root, entry.resolvedPath) || !shouldDiscover(entry, discoveryInput))
-      return [];
+      continue;
     const candidate: TraversedEntry = {
       ...entry,
       visiblePath: path.join(visibleParent, entry.name),
       depth: 1,
     };
-    return shouldSuggest(candidate, input) ? [rank(candidate, input)] : [];
-  });
+    if (shouldSuggest(candidate, input)) ranked.push(rank(candidate, input));
+  }
+  return ranked;
 }
 
 async function searchTree(
@@ -336,21 +344,8 @@ async function searchTree(
   start: WalkStart = { visiblePath: input.root, resolvedPath: input.root },
 ): Promise<RankedEntry[]> {
   if (!(input.maxEntriesScanned > 0)) return [];
-  const roots = (await readChildren(start.resolvedPath)).filter((entry) =>
-    staysInsideRoot(entry, input.root),
-  );
   const visited = new Set<string>([start.resolvedPath]);
-  const branches = roots.flatMap((entry) =>
-    shouldDiscover(entry, input)
-      ? [
-          walkBranch(
-            { ...entry, visiblePath: path.join(start.visiblePath, entry.name), depth: 1 },
-            input,
-            visited,
-          ),
-        ]
-      : [],
-  );
+  const branches = walkChildren({ parent: start, depth: 1, input, visited });
   const ranked: RankedEntry[] = [];
   let scanned = 0;
   const threshold = input.confidentResultScanThreshold;
@@ -381,38 +376,39 @@ async function* walkBranch(
   )
     return;
   visited.add(entry.resolvedPath);
-  const children = (await readChildren(entry.resolvedPath)).filter((child) =>
-    staysInsideRoot(child, input.root),
-  );
-  const branches = children.flatMap((child) =>
-    shouldDiscover(child, input)
-      ? [
-          walkBranch(
-            {
-              ...child,
-              visiblePath: path.join(entry.visiblePath, child.name),
-              depth: entry.depth + 1,
-            },
-            input,
-            visited,
-          ),
-        ]
-      : [],
-  );
-  yield* roundRobin(branches);
+  yield* roundRobin(walkChildren({ parent: entry, depth: entry.depth + 1, input, visited }));
 }
 
-async function* roundRobin<T>(branches: Array<AsyncGenerator<T>>): AsyncGenerator<T> {
-  let active = branches;
-  while (active.length) {
+// Create a child's path and iterator only when its branch gets a turn. Eagerly constructing every
+// sibling's subtree retained hundreds of thousands of unvisited children beyond the scan budget.
+async function* walkChildren({
+  parent,
+  depth,
+  input,
+  visited,
+}: WalkChildrenOptions): AsyncGenerator<AsyncGenerator<TraversedEntry>> {
+  for await (const child of readChildren(parent.resolvedPath)) {
+    if (!staysInsideRoot(child, input.root) || !shouldDiscover(child, input)) continue;
+    yield walkBranch(
+      { ...child, visiblePath: path.join(parent.visiblePath, child.name), depth },
+      input,
+      visited,
+    );
+  }
+}
+
+async function* roundRobin<T>(branches: AsyncIterable<AsyncGenerator<T>>): AsyncGenerator<T> {
+  let active: AsyncIterable<AsyncGenerator<T>> | Array<AsyncGenerator<T>> = branches;
+  while (true) {
     const nextRound: Array<AsyncGenerator<T>> = [];
-    for (const branch of active) {
+    for await (const branch of active) {
       const next = await branch.next();
       if (!next.done) {
         nextRound.push(branch);
         yield next.value;
       }
     }
+    if (!nextRound.length) return;
     active = nextRound;
   }
 }
@@ -742,9 +738,9 @@ async function resolveDirectory(inputPath: string): Promise<string | null> {
   return info?.isDirectory() ? resolved : null;
 }
 
-async function readChildren(directory: string): Promise<ChildEntry[]> {
+async function* readChildren(directory: string): AsyncGenerator<ChildEntry> {
   const directoryInfo = await stat(directory).catch(() => null);
-  if (!directoryInfo?.isDirectory()) return [];
+  if (!directoryInfo?.isDirectory()) return;
 
   const cached = CAN_VALIDATE_DIRECTORY_CACHE_FROM_METADATA
     ? directoryListCache.get(directory)
@@ -774,9 +770,10 @@ async function readChildren(directory: string): Promise<ChildEntry[]> {
     }
   }
 
-  return (await Promise.all(rawEntries.map((entry) => resolveChild(directory, entry))))
-    .filter((entry): entry is ChildEntry => entry !== null)
-    .sort((left, right) => left.name.localeCompare(right.name));
+  for (const rawEntry of rawEntries) {
+    const entry = await resolveChild(directory, rawEntry);
+    if (entry) yield entry;
+  }
 }
 
 async function loadGitIgnoredPaths(root: string): Promise<Set<string>> {

public-docs/plugins/reference.md

@@ -1318,6 +1318,13 @@ the source row, so updates to one streaming item do not remount its renderer. Us
 `useRevealedText(text, phase)` hook when a renderer should pace streaming text like Paseo's built-in
 assistant rows.
 
+Chat find (Ctrl or Cmd+F) finds and highlights text in replacement rows when the query also
+matches the original message. The host searches the original prompt text or the assistant reply
+with Markdown syntax removed, then the app counts matches in the text your renderer draws.
+Text added only by your renderer is not independently indexed. Matches stay within a rendered
+block, and find skips buttons, icons, and anything with `aria-hidden="true"`. Find only runs on
+the web and desktop apps.
+
 ### Append a timeline row from the daemon
 
 A server handler can add a plugin-owned row to canonical history: