feat(terminal): stream negotiated ANSI replay to clients

Restore configured client history up to host retention without collecting capable replay in the daemon. Preserve single-frame ANSI delivery for older clients and normalize older hosts at the SDK boundary.

packages/app/e2e/browser/terminal-retained-tab-stream.spec.ts

@@ -1,5 +1,6 @@
 import type { Page } from "@playwright/test";
 import { expect, test } from "../support/fixtures";
+import { getTerminalBufferText, waitForTerminalContent } from "../support/helpers/terminal-perf";
 import { TerminalE2EHarness } from "../support/helpers/terminal-dsl";
 
 interface AttachOverlayProbeWindow extends Window {
@@ -59,4 +60,34 @@ test.describe("retained terminal tab streams", () => {
 
     expect(await terminalAttachOverlayWasSeen(page)).toBe(false);
   });
+
+  for (const { count, retainedMarker } of [
+    { count: 400, retainedMarker: "history-0001界🙂" },
+    { count: 3000, retainedMarker: "history-2500界🙂" },
+  ]) {
+    test(`reattach restores retained styled Unicode history from ${count} lines`, async ({
+      page,
+    }) => {
+      await page.addInitScript(() => {
+        const key = "@paseo:app-settings";
+        const settings = JSON.parse(localStorage.getItem(key) ?? "{}");
+        localStorage.setItem(key, JSON.stringify({ ...settings, terminalScrollbackLines: 10000 }));
+      });
+      const terminal = await harness.createTerminal({
+        name: `history-${count}`,
+        command: "/bin/sh",
+        args: [
+          "-lc",
+          `i=1; while [ $i -le ${count} ]; do printf '\\033[31mhistory-%04d界🙂 payload-abcdefghijklmnopqrstuvwxyz0123456789\\033[0m\\n' $i; i=$((i+1)); done; sleep 120`,
+        ],
+      });
+      const last = `history-${String(count).padStart(4, "0")}界🙂`;
+      await harness.openTerminal(page, { terminalId: terminal.id });
+      await waitForTerminalContent(page, (text) => text.includes(last), 10000);
+      expect(await getTerminalBufferText(page)).toContain(retainedMarker);
+      await page.reload();
+      await waitForTerminalContent(page, (text) => text.includes(last), 10000);
+      expect(await getTerminalBufferText(page)).toContain(retainedMarker);
+    });
+  }
 });

packages/app/src/components/terminal-emulator-contract.ts

@@ -19,6 +19,7 @@ import type { TerminalRendererReadyChange } from "../utils/terminal-renderer-rea
 export interface TerminalEmulatorHandle {
   find?: TerminalFindHandle;
   writeOutput: (data: TerminalOutputData) => void;
+  replay: (event: import("@getpaseo/client").TerminalReplayEvent) => void;
   restoreOutput: (data: TerminalOutputData) => void;
   renderSnapshot: (state: TerminalState | null) => void;
   paste: (text: string) => void;

packages/app/src/components/terminal-emulator-native-grid.native.tsx

@@ -361,10 +361,13 @@ function NativeTerminalEmulator({
     (terminal: NativeHeadlessTerminal): NativeTerminalOutputDrain =>
       createNativeTerminalOutputDrain({
         write: async (chunk) => {
+          inputModeTrackerRef.current.feed(chunk);
           await terminal.write(chunk);
           emitInputModeChange();
         },
-        reset: () => {
+        reset: (size) => {
+          inputModeTrackerRef.current.reset();
+          if (size) terminal.resize(size);
           terminal.reset();
           emitInputModeChange();
         },
@@ -477,19 +480,12 @@ function NativeTerminalEmulator({
     ],
   );
 
-  const enqueueOutputText = useCallback(
-    (text: string) => {
-      if (text.length === 0) {
-        return;
-      }
-      const inputModeUpdate = inputModeTrackerRef.current.feed(text);
-      if (inputModeUpdate.changed) {
-        emitInputModeChange();
-      }
-      outputDrainRef.current?.enqueueText(text);
-    },
-    [emitInputModeChange],
-  );
+  const enqueueOutputText = useCallback((text: string) => {
+    if (text.length === 0) {
+      return;
+    }
+    outputDrainRef.current?.enqueueText(text);
+  }, []);
 
   const claimActiveTerminalSize = useCallback(() => {
     activeResizeClaimTokenRef.current += 1;
@@ -512,6 +508,7 @@ function NativeTerminalEmulator({
         const text = outputDecoderRef.current.decode(data, { stream: true });
         enqueueOutputText(text);
       },
+      replay: (event) => outputDrainRef.current?.replay(event),
       restoreOutput: (data: TerminalOutputData) => {
         outputDecoderRef.current.decode();
         resetInputModeTracker();

packages/app/src/components/terminal-emulator.tsx

@@ -40,6 +40,7 @@ import { focusWithRetries } from "../utils/web-focus";
 export interface TerminalEmulatorHandle {
   find?: TerminalFindHandle;
   writeOutput: (data: TerminalOutputData) => void;
+  replay: (event: import("@getpaseo/client").TerminalReplayEvent) => void;
   restoreOutput: (data: TerminalOutputData) => void;
   renderSnapshot: (state: TerminalState | null) => void;
   paste: (text: string) => void;
@@ -253,6 +254,18 @@ export default function TerminalEmulator({
         const data = args[0];
         if (data instanceof Uint8Array) runtimeRef.current?.write({ data });
       },
+      replay: (event) => {
+        if (!event || typeof event !== "object" || Array.isArray(event)) return;
+        if (event.type === "end") runtimeRef.current?.replay({ type: "end" });
+        if (event.type === "data" && event.data instanceof Uint8Array)
+          runtimeRef.current?.replay({ type: "data", data: event.data });
+        if (event.type === "begin")
+          runtimeRef.current?.replay({
+            type: "begin",
+            rows: typeof event.rows === "number" ? event.rows : undefined,
+            cols: typeof event.cols === "number" ? event.cols : undefined,
+          });
+      },
       restoreOutput: (...args) => {
         const data = args[0];
         if (data instanceof Uint8Array) runtimeRef.current?.restoreOutput({ data });
@@ -299,6 +312,7 @@ export default function TerminalEmulator({
       writeOutput: (data: TerminalOutputData) => {
         runtimeRef.current?.write({ data });
       },
+      replay: (event) => runtimeRef.current?.replay(event),
       restoreOutput: (data: TerminalOutputData) => {
         runtimeRef.current?.restoreOutput({ data });
       },

packages/app/src/components/terminal-pane.tsx

@@ -15,7 +15,6 @@ import Animated, { runOnJS, useAnimatedReaction } from "react-native-reanimated"
 import { StyleSheet, useUnistyles } from "react-native-unistyles";
 import { Keyboard as KeyboardIcon, KeyboardOff as KeyboardOffIcon } from "lucide-react-native";
 import type { TerminalKeyInput } from "@getpaseo/protocol/terminal-key-input";
-import type { TerminalState } from "@getpaseo/protocol/messages";
 import {
   DEFAULT_TERMINAL_INPUT_MODE_STATE,
   type TerminalInputModeState,
@@ -60,7 +59,6 @@ import { getDesktopHost } from "@/desktop/host";
 import { routeTerminalDrop } from "@/terminal/drop/terminal-file-drop";
 import { prepareDroppedPathsForTerminal } from "@/terminal/drop/terminal-path";
 import { toErrorMessage } from "@/utils/error-messages";
-import { getWorkspaceTerminalSession } from "@/terminal/runtime/workspace-terminal-session";
 import {
   EMPTY_FOCUS_CLAIM_STATE,
   canRequestFocusClaim,
@@ -88,7 +86,6 @@ import { isNative } from "@/constants/platform";
 import {
   applyTerminalRendererReadyChange,
   resolveTerminalStreamTarget,
-  shouldReplayTerminalSnapshotForRenderer,
   shouldShowTerminalLoadingOverlay,
   type TerminalRendererReadyChange,
 } from "@/utils/terminal-renderer-readiness";
@@ -316,10 +313,6 @@ export function TerminalPane({
   const measuredTerminalSizeRef = useRef<{ rows: number; cols: number } | null>(null);
   const lastSentTerminalSizeRef = useRef<{ rows: number; cols: number } | null>(null);
   const streamControllerRef = useRef<TerminalStreamController | null>(null);
-  const workspaceTerminalSession = useMemo(
-    () => getWorkspaceTerminalSession({ scopeKey }),
-    [scopeKey],
-  );
   const [isAttaching, setIsAttaching] = useState(false);
   const [streamError, setStreamError] = useState<string | null>(null);
   const [rendererReadyStreamKey, setRendererReadyStreamKey] = useState<string | null>(null);
@@ -383,7 +376,6 @@ export function TerminalPane({
   const keyboardRefitTimeoutsRef = useRef<Array<ReturnType<typeof setTimeout>>>([]);
   const lastAutoFocusKeyRef = useRef<string | null>(null);
   const paneFocusResizeClaimRef = useRef(EMPTY_FOCUS_CLAIM_STATE);
-  const initialSnapshot = workspaceTerminalSession.snapshots.get({ terminalId });
 
   useEffect(() => {
     terminalIdRef.current = terminalId;
@@ -441,16 +433,8 @@ export function TerminalPane({
     (change: TerminalRendererReadyChange) => {
       if (!change.isReady && change.streamKey === terminalStreamKey) findRef.current?.reset();
       setRendererReadyStreamKey((current) => applyTerminalRendererReadyChange(current, change));
-      if (!shouldReplayTerminalSnapshotForRenderer({ change, terminalStreamKey })) {
-        return;
-      }
-
-      const snapshot = workspaceTerminalSession.snapshots.get({ terminalId });
-      if (snapshot) {
-        emulatorRef.current?.renderSnapshot(snapshot);
-      }
     },
-    [terminalId, terminalStreamKey, workspaceTerminalSession.snapshots],
+    [terminalStreamKey],
   );
 
   useEffect(() => {
@@ -564,7 +548,6 @@ export function TerminalPane({
   );
 
   const handleStreamExit = useStableEvent((exitedTerminalId: string) => {
-    workspaceTerminalSession.snapshots.clear({ terminalId: exitedTerminalId });
     if (terminalIdRef.current === exitedTerminalId) emulatorRef.current?.clear();
     setModifiers({ ...EMPTY_MODIFIERS });
   });
@@ -604,29 +587,10 @@ export function TerminalPane({
     },
   );
 
-  const handleStreamRestore = useStableEvent(
-    ({ terminalId: restoreTerminalId, data }: { terminalId: string; data: Uint8Array }) => {
-      workspaceTerminalSession.snapshots.clear({ terminalId: restoreTerminalId });
-      if (terminalIdRef.current !== restoreTerminalId) {
-        return;
-      }
-      emulatorRef.current?.restoreOutput(data);
-    },
-  );
-
-  const handleStreamSnapshot = useStableEvent(
-    ({ terminalId: snapshotTerminalId, state }: { terminalId: string; state: TerminalState }) => {
-      workspaceTerminalSession.snapshots.set({ terminalId: snapshotTerminalId, state });
-      if (terminalIdRef.current !== snapshotTerminalId) {
-        return;
-      }
-      emulatorRef.current?.renderSnapshot(state);
-    },
-  );
-
   const getStreamRestoreOptions = useStableEvent(() =>
     resolveTerminalRestoreOptions({
       supportsTerminalRestoreModes,
+      scrollbackLines: settings.terminalScrollbackLines,
       canClaimSize: canRequestFocusClaim({
         isWorkspaceFocused: terminalPresentedRef.current,
         isPaneFocused,
@@ -653,8 +617,9 @@ export function TerminalPane({
       client,
       getPreferredSize: getPreferredStreamSize,
       onOutput: handleStreamOutput,
-      onRestore: handleStreamRestore,
-      onSnapshot: handleStreamSnapshot,
+      onReplay: ({ terminalId: id, replay }) => {
+        if (terminalIdRef.current === id) emulatorRef.current?.replay(replay);
+      },
       onExit: handleStreamExit,
       getRestoreOptions: getStreamRestoreOptions,
       onStatusChange: handleStreamControllerStatus,
@@ -674,8 +639,6 @@ export function TerminalPane({
     getStreamRestoreOptions,
     handleStreamControllerStatus,
     handleStreamOutput,
-    handleStreamRestore,
-    handleStreamSnapshot,
     handleStreamExit,
     isConnected,
   ]);
@@ -1216,7 +1179,6 @@ export function TerminalPane({
             keyboardInset={keyboardInset}
             isKeyboardVisible={isKeyboardVisible}
             swipeGesturesEnabled={swipeGesturesEnabled}
-            initialSnapshot={initialSnapshot}
             onRendererReadyChange={handleRendererReadyChange}
             onSwipeRight={handleSwipeRight}
             onSwipeLeft={handleSwipeLeft}

packages/app/src/screens/workspace/workspace-screen.tsx

@@ -127,7 +127,6 @@ import {
   useWorkspaceSetupStore,
 } from "@/stores/workspace-setup-store";
 import { useWorkspace } from "@/stores/session-store-hooks";
-import { useWorkspaceTerminalSessionRetention } from "@/terminal/hooks/use-workspace-terminal-session-retention";
 import type { CheckoutStatusPayload } from "@/git/use-status-query";
 import { confirmDialog } from "@/utils/confirm-dialog";
 import { useArchiveAgent } from "@/hooks/use-archive-agent";
@@ -881,13 +880,6 @@ function shouldShowWorkspaceScreenHeader(input: {
   return !input.isFocusModeEnabled || input.isMobile;
 }
 
-function buildWorkspaceTerminalScopeKey(serverId: string, workspaceId: string): string | null {
-  if (!serverId || !workspaceId) {
-    return null;
-  }
-  return `${serverId}:${workspaceId}`;
-}
-
 /**
  * A pane the user acted inside owns the tab: it opens there, and an existing tab
  * moves there. No pane means the open has no opinion beyond the focused pane.
@@ -1066,14 +1058,6 @@ function WorkspaceScreenContent({
   const { handleRetryHost, handleManageHost, handleDismissMissingWorkspace } =
     useWorkspaceRouteActions(normalizedServerId);
 
-  const workspaceTerminalScopeKey = useMemo(
-    () => buildWorkspaceTerminalScopeKey(normalizedServerId, normalizedWorkspaceId),
-    [normalizedServerId, normalizedWorkspaceId],
-  );
-  useWorkspaceTerminalSessionRetention({
-    scopeKey: workspaceTerminalScopeKey,
-  });
-
   const client = useHostRuntimeClient(normalizedServerId);
   const isConnected = useHostRuntimeIsConnected(normalizedServerId);
   const supportsProvidersSnapshot = useSessionStore(

packages/app/src/terminal/hooks/use-workspace-terminal-session-retention.ts

@@ -1,18 +0,0 @@
-import { useEffect } from "react";
-import {
-  releaseWorkspaceTerminalSession,
-  retainWorkspaceTerminalSession,
-} from "@/terminal/runtime/workspace-terminal-session";
-
-export function useWorkspaceTerminalSessionRetention(input: { scopeKey: string | null }): void {
-  useEffect(() => {
-    if (!input.scopeKey) {
-      return;
-    }
-
-    retainWorkspaceTerminalSession({ scopeKey: input.scopeKey });
-    return () => {
-      releaseWorkspaceTerminalSession({ scopeKey: input.scopeKey! });
-    };
-  }, [input.scopeKey]);
-}

packages/app/src/terminal/native-renderer/headless-terminal-output-drain.test.ts

@@ -268,3 +268,89 @@ describe("native terminal output drain", () => {
     });
   });
 });
+
+test("replays split Unicode and ANSI with one reset then live output", async () => {
+  const terminal = createNativeHeadlessTerminal({ rows: 4, cols: 40, scrollbackLines: 1000 });
+  let resets = 0;
+  const drain = createNativeTerminalOutputDrain({
+    write: (text) => terminal.write(text),
+    reset: (size) => {
+      resets++;
+      if (size) terminal.resize(size);
+      terminal.reset();
+    },
+    getViewportState: () => terminal.getViewportState(),
+    onPaint: () => {},
+  });
+  try {
+    drain.replay({ type: "begin", rows: 4, cols: 40, retainedHistoryLines: 400 });
+    const bytes = new TextEncoder().encode("\x1b[31m界🙂 replay\x1b[0m\r\n");
+    for (let i = 0; i < bytes.length; i++)
+      drain.replay({ type: "data", data: bytes.subarray(i, i + 1) });
+    drain.replay({ type: "end" });
+    drain.enqueueText("live");
+    await drain.flush();
+    expect(resets).toBe(1);
+    expect(
+      terminal
+        .getBufferWindow({ startRow: 0, rowCount: 4 })
+        .rows.map((row) =>
+          row
+            .filter((cell) => cell.width !== 0)
+            .map((cell) => cell.char)
+            .join(""),
+        )
+        .join("\n"),
+    ).toContain("界🙂 replay");
+    expect(
+      terminal
+        .getBufferWindow({ startRow: 0, rowCount: 4 })
+        .rows.map((row) =>
+          row
+            .filter((cell) => cell.width !== 0)
+            .map((cell) => cell.char)
+            .join(""),
+        )
+        .join("\n"),
+    ).toContain("live");
+  } finally {
+    drain.dispose();
+    terminal.dispose();
+  }
+});
+
+test("an empty replacement replay resets after an in-flight write finishes", async () => {
+  let finish!: () => void;
+  let started!: () => void;
+  const writing = new Promise<void>((resolve) => {
+    started = resolve;
+  });
+  const blocked = new Promise<void>((resolve) => {
+    finish = resolve;
+  });
+  let resets = 0;
+  const drain = createNativeTerminalOutputDrain({
+    write: async () => {
+      started();
+      await blocked;
+    },
+    reset: () => {
+      resets++;
+    },
+    getViewportState: () => null,
+    onPaint: () => {},
+  });
+  try {
+    drain.enqueueText("old terminal");
+    await writing;
+    drain.replay({ type: "begin" });
+    drain.replay({ type: "end" });
+    finish();
+    await drain.flush();
+    expect(resets).toBe(1);
+    expect(drain.getQueuedChars()).toBe(0);
+  } finally {
+    finish();
+    drain.dispose();
+  }
+});

packages/app/src/terminal/native-renderer/headless-terminal-output-drain.ts

@@ -14,6 +14,7 @@ export interface NativeTerminalParseSample {
 }
 
 export interface NativeTerminalOutputDrain {
+  replay(event: import("@getpaseo/client").TerminalReplayEvent): void;
   enqueueText(text: string): void;
   restoreText(text: string): void;
   restoreSnapshot(snapshot: TerminalState): void;
@@ -25,7 +26,7 @@ export interface NativeTerminalOutputDrain {
 
 export interface NativeTerminalOutputDrainOptions {
   write: (chunk: string) => Promise<void>;
-  reset: () => void;
+  reset: (size?: { rows: number; cols: number }) => void;
   getViewportState: () => TerminalViewportState | null;
   onPaint: (state: TerminalViewportState) => void;
   onParse?: (sample: NativeTerminalParseSample) => void;
@@ -75,9 +76,11 @@ export function createNativeTerminalOutputDrain(
   let paintFrame: number | null = null;
   let generation = 0;
   let resetBeforeNextWrite = false;
+  let replaySize: { rows: number; cols: number } | undefined;
+  const replayDecoder = new TextDecoder();
 
   function resolveIdleIfReady(): void {
-    if (drainScheduled || draining || pendingText.length > 0) {
+    if (drainScheduled || draining || pendingText.length > 0 || resetBeforeNextWrite) {
       return;
     }
     while (idleWaiters.length > 0) {
@@ -138,14 +141,16 @@ export function createNativeTerminalOutputDrain(
     let parsedChunks = 0;
 
     try {
+      if (resetBeforeNextWrite) {
+        options.reset(replaySize);
+        replaySize = undefined;
+        resetBeforeNextWrite = false;
+        requestPaint();
+      }
       while (pendingText.length > 0 && parsedChunks < chunksPerTurn) {
         if (disposed || activeGeneration !== generation) {
           return;
         }
-        if (resetBeforeNextWrite) {
-          options.reset();
-          resetBeforeNextWrite = false;
-        }
         const chunk = pendingText.slice(0, chunkChars);
         pendingText = pendingText.slice(chunk.length);
         const parseStart = nativeTerminalPerformanceNow();
@@ -163,7 +168,7 @@ export function createNativeTerminalOutputDrain(
       }
     } finally {
       draining = false;
-      if (!disposed && pendingText.length > 0) {
+      if (!disposed && (pendingText.length > 0 || resetBeforeNextWrite)) {
         scheduleDrain();
       }
       resolveIdleIfReady();
@@ -171,6 +176,17 @@ export function createNativeTerminalOutputDrain(
   }
 
   return {
+    replay(event): void {
+      if (event.type === "begin") {
+        replayDecoder.decode();
+        replaySize = event.rows && event.cols ? { rows: event.rows, cols: event.cols } : undefined;
+        replacePendingText("");
+      } else if (event.type === "data") {
+        this.enqueueText(replayDecoder.decode(event.data, { stream: true }));
+      } else {
+        this.enqueueText(replayDecoder.decode());
+      }
+    },
     enqueueText(text: string): void {
       if (disposed || text.length === 0) {
         return;
@@ -202,7 +218,7 @@ export function createNativeTerminalOutputDrain(
     },
 
     flush(): Promise<void> {
-      if (!drainScheduled && !draining && pendingText.length === 0) {
+      if (!drainScheduled && !draining && pendingText.length === 0 && !resetBeforeNextWrite) {
         return Promise.resolve();
       }
       scheduleDrain();

packages/app/src/terminal/runtime/terminal-emulator-runtime.browser.test.ts

@@ -795,3 +795,48 @@ describe("terminal emulator runtime in a real browser", () => {
     expect(confirm).not.toHaveBeenCalled();
   });
 });
+
+describe("incremental replay lifecycle", () => {
+  it.each(["clear", "remount"] as const)(
+    "recovers live input after interrupted replay and %s",
+    async (cleanup) => {
+      const mounted = createTerminalHost({ width: 720, height: 360 });
+      mounted.runtime.replay({ type: "begin" });
+      mounted.runtime.replay({ type: "data", data: terminalOutput("interrupted") });
+      if (cleanup === "clear")
+        await new Promise<void>((resolve) => mounted.runtime.clear({ onCommitted: resolve }));
+      else {
+        mounted.runtime.unmount();
+        mounted.runtime.mount({
+          root: mounted.root,
+          host: mounted.host,
+          initialSnapshot: null,
+          scrollback: 1000,
+          theme: {},
+        });
+      }
+      await new Promise<void>((resolve) =>
+        mounted.runtime.write({ data: terminalOutput("live"), onCommitted: resolve }),
+      );
+      getBrowserTerminal().input("user-input", true);
+      expect(mounted.inputs).toContain("user-input");
+    },
+  );
+
+  it("suppresses generated replies until queued replay chunks commit after end", async () => {
+    const mounted = createTerminalHost({ width: 720, height: 360 });
+    mounted.runtime.replay({ type: "begin" });
+    mounted.runtime.replay({ type: "data", data: terminalOutput("\x1b]4;1;?\x07") });
+    mounted.runtime.replay({ type: "data", data: terminalOutput("\x1b]4;1;?\x07") });
+    mounted.runtime.replay({ type: "end" });
+    await new Promise<void>((resolve) =>
+      mounted.runtime.write({ data: terminalOutput("committed"), onCommitted: resolve }),
+    );
+    expect(mounted.inputs).toEqual([]);
+    await new Promise<void>((resolve) =>
+      mounted.runtime.write({ data: terminalOutput("\x1b]4;1;?\x07"), onCommitted: resolve }),
+    );
+    expect(mounted.inputs).toHaveLength(1);
+    expect(mounted.inputs[0]?.startsWith("\x1b]4;1;rgb:")).toBe(true);
+  });
+});

packages/app/src/terminal/runtime/terminal-emulator-runtime.ts

@@ -911,6 +911,14 @@ export class TerminalEmulatorRuntime {
     });
   }
 
+  replay(event: import("@getpaseo/client").TerminalReplayEvent): void {
+    if (event.type === "begin") {
+      this.restoreOutput({ data: EMPTY_TERMINAL_OUTPUT, rows: event.rows, cols: event.cols });
+    } else if (event.type === "data") {
+      this.write({ data: event.data, suppressInput: true });
+    }
+  }
+
   restoreOutput(input: {
     data: TerminalOutputData;
     rows?: number;

packages/app/src/terminal/runtime/terminal-restore-options.test.ts

@@ -6,6 +6,7 @@ describe("terminal restore options", () => {
   it("omits restore options for daemons without terminal restore modes", () => {
     expect(
       resolveTerminalRestoreOptions({
+        scrollbackLines: 10000,
         supportsTerminalRestoreModes: false,
         canClaimSize: true,
         size: { rows: 24, cols: 80 },
@@ -13,16 +14,17 @@ describe("terminal restore options", () => {
     ).toBeUndefined();
   });
 
-  it("requests visible snapshot restore with bounded scrollback for capable daemons", () => {
+  it("requests visible snapshot restore with configured scrollback for capable daemons", () => {
     expect(
       resolveTerminalRestoreOptions({
+        scrollbackLines: 10000,
         supportsTerminalRestoreModes: true,
         canClaimSize: true,
         size: { rows: 24, cols: 80 },
       }),
     ).toEqual({
       mode: "visible-snapshot",
-      scrollbackLines: 200,
+      scrollbackLines: 10000,
       size: { rows: 24, cols: 80 },
     });
   });
@@ -30,26 +32,39 @@ describe("terminal restore options", () => {
   it("omits size until the terminal has been measured", () => {
     expect(
       resolveTerminalRestoreOptions({
+        scrollbackLines: 10000,
         supportsTerminalRestoreModes: true,
         canClaimSize: true,
         size: null,
       }),
     ).toEqual({
       mode: "visible-snapshot",
-      scrollbackLines: 200,
+      scrollbackLines: 10000,
     });
   });
 
   it("does not let a background attach resize the PTY", () => {
     expect(
       resolveTerminalRestoreOptions({
+        scrollbackLines: 10000,
         supportsTerminalRestoreModes: true,
         canClaimSize: false,
         size: { rows: 24, cols: 80 },
       }),
     ).toEqual({
       mode: "visible-snapshot",
-      scrollbackLines: 200,
+      scrollbackLines: 10000,
     });
   });
 });
+
+it.each([0, 5, 400, 10000])("requests exactly %s configured history rows", (scrollbackLines) => {
+  expect(
+    resolveTerminalRestoreOptions({
+      supportsTerminalRestoreModes: true,
+      scrollbackLines,
+      canClaimSize: false,
+      size: null,
+    }),
+  ).toEqual({ mode: "visible-snapshot", scrollbackLines });
+});

packages/app/src/terminal/runtime/terminal-restore-options.ts

@@ -1,9 +1,8 @@
 import type { SubscribeTerminalRequest } from "@getpaseo/protocol/messages";
 
-export const TERMINAL_VISIBLE_RESTORE_SCROLLBACK_LINES = 200;
-
 export interface ResolveTerminalRestoreOptionsInput {
   supportsTerminalRestoreModes: boolean;
+  scrollbackLines: number;
   canClaimSize: boolean;
   size: { rows: number; cols: number } | null;
 }
@@ -17,7 +16,7 @@ export function resolveTerminalRestoreOptions(
 
   return {
     mode: "visible-snapshot",
-    scrollbackLines: TERMINAL_VISIBLE_RESTORE_SCROLLBACK_LINES,
+    scrollbackLines: input.scrollbackLines,
     ...(input.canClaimSize && input.size ? { size: input.size } : {}),
   };
 }

packages/app/src/terminal/runtime/terminal-stream-controller.test.ts

@@ -7,34 +7,16 @@ import {
   type TerminalStreamControllerStatus,
 } from "./terminal-stream-controller";
 
-interface TerminalSnapshot {
-  rows: number;
-  cols: number;
-  grid: Array<Array<{ char: string }>>;
-  scrollback: Array<Array<{ char: string }>>;
-  cursor: { row: number; col: number };
-}
-
-function terminalCellText(cell: { char: string }): string {
-  return cell.char;
-}
-
-function terminalRowText(row: Array<{ char: string }>): string {
-  return row.map(terminalCellText).join("");
-}
-
-function terminalSnapshotText(state: TerminalSnapshot): string {
-  return state.grid.map(terminalRowText).join("\n");
-}
-
 function terminalOutput(text: string): Uint8Array {
   return new TextEncoder().encode(text);
 }
 
-type TerminalStreamEvent =
-  | { terminalId: string; type: "output"; data: Uint8Array }
-  | { terminalId: string; type: "snapshot"; state: TerminalSnapshot }
-  | { terminalId: string; type: "restore"; data: Uint8Array };
+type StreamEvent = import("@getpaseo/client").TerminalStreamEvent;
+type TerminalStreamEvent = StreamEvent extends infer Event
+  ? Event extends StreamEvent
+    ? Omit<Event, "subscriptionId">
+    : never
+  : never;
 
 class FakeTerminalStreamClient implements TerminalStreamControllerClient {
   private readonly updates = new Set<(message: SessionOutboundMessage) => void>();
@@ -115,32 +97,23 @@ class FakeTerminalStreamClient implements TerminalStreamControllerClient {
 function createHarness(input?: { client?: FakeTerminalStreamClient }) {
   const client = input?.client ?? new FakeTerminalStreamClient();
   const outputs: Array<{ terminalId: string; data: Uint8Array }> = [];
-  const restores: Array<{ terminalId: string; data: Uint8Array }> = [];
-  const snapshots: Array<{ terminalId: string; text: string }> = [];
+  const replays: import("@getpaseo/client").TerminalReplayEvent[] = [];
   const statuses: TerminalStreamControllerStatus[] = [];
   const exits: string[] = [];
   const controller = new TerminalStreamController({
     client,
+    onReplay: ({ replay }) => replays.push(replay),
     onExit: (terminalId) => exits.push(terminalId),
     getPreferredSize: () => ({ rows: 24, cols: 80 }),
     onOutput: (output) => {
       outputs.push(output);
     },
-    onRestore: (restore) => {
-      restores.push(restore);
-    },
-    onSnapshot: ({ terminalId, state }) => {
-      snapshots.push({
-        terminalId,
-        text: terminalSnapshotText(state),
-      });
-    },
     onStatusChange: (status) => {
       statuses.push(status);
     },
   });
 
-  return { client, controller, outputs, restores, snapshots, statuses, exits };
+  return { client, controller, outputs, replays, statuses, exits };
 }
 
 async function flushAsyncWork(): Promise<void> {
@@ -149,24 +122,20 @@ async function flushAsyncWork(): Promise<void> {
 }
 
 describe("terminal-stream-controller", () => {
-  it("subscribes, resizes, and forwards snapshot/output events", async () => {
+  it("subscribes, resizes, and forwards replay/output events", async () => {
     const harness = createHarness();
     harness.client.nextSubscribeResults.push({ terminalId: "term-1", error: null });
 
     harness.controller.setTerminal({ terminalId: "term-1" });
     await flushAsyncWork();
 
-    harness.client.emit({
-      terminalId: "term-1",
-      type: "snapshot",
-      state: {
-        rows: 1,
-        cols: 5,
-        grid: [[{ char: "h" }, { char: "e" }, { char: "l" }, { char: "l" }, { char: "o" }]],
-        scrollback: [],
-        cursor: { row: 0, col: 5 },
-      },
-    });
+    const replay: import("@getpaseo/client").TerminalReplayEvent[] = [
+      { type: "begin", rows: 24, cols: 80, retainedHistoryLines: 400 },
+      { type: "data", data: terminalOutput("hello") },
+      { type: "end" },
+    ];
+    for (const event of replay)
+      harness.client.emit({ terminalId: "term-1", type: "replay", replay: event });
     const outputData = terminalOutput(" world");
     harness.client.emit({
       terminalId: "term-1",
@@ -178,7 +147,7 @@ describe("terminal-stream-controller", () => {
     expect(harness.client.resizeCalls).toEqual([
       { terminalId: "term-1", rows: 24, cols: 80, intent: "claim" },
     ]);
-    expect(harness.snapshots).toEqual([{ terminalId: "term-1", text: "hello" }]);
+    expect(harness.replays).toEqual(replay);
     expect(harness.outputs[0]?.data).toBe(outputData);
     expect(harness.outputs).toEqual([{ terminalId: "term-1", data: terminalOutput(" world") }]);
     expect(harness.statuses.at(-1)).toEqual({
@@ -236,23 +205,19 @@ describe("terminal-stream-controller", () => {
         size: { rows: 24, cols: 80 },
       }),
       onOutput: (output) => harness.outputs.push(output),
-      onRestore: (restore) => harness.restores.push(restore),
-      onSnapshot: ({ terminalId, state }) => {
-        harness.snapshots.push({
-          terminalId,
-          text: terminalSnapshotText(state),
-        });
-      },
+      onReplay: ({ replay }) => harness.replays.push(replay),
     });
 
     controller.setTerminal({ terminalId: "term-1" });
     await flushAsyncWork();
     const restoreData = terminalOutput("restored");
-    client.emit({
-      terminalId: "term-1",
-      type: "restore",
-      data: restoreData,
-    });
+    const replay: import("@getpaseo/client").TerminalReplayEvent[] = [
+      { type: "begin" },
+      { type: "data", data: restoreData },
+      { type: "end" },
+    ];
+    for (const event of replay)
+      client.emit({ terminalId: "term-1", type: "replay", replay: event });
     controller.dispose();
 
     expect(client.subscribeCalls).toEqual([
@@ -270,8 +235,7 @@ describe("terminal-stream-controller", () => {
     expect(client.resizeCalls).toEqual([
       { terminalId: "term-1", rows: 24, cols: 80, intent: "claim" },
     ]);
-    expect(harness.restores[0]?.data).toBe(restoreData);
-    expect(harness.restores).toEqual([{ terminalId: "term-1", data: terminalOutput("restored") }]);
+    expect(harness.replays).toEqual(replay);
     expect(harness.outputs).toEqual([]);
   });
 

packages/app/src/terminal/runtime/terminal-stream-controller.ts

@@ -1,5 +1,5 @@
 import type { DaemonClient } from "@getpaseo/client/internal/daemon-client";
-import type { SubscribeTerminalRequest, TerminalState } from "@getpaseo/protocol/messages";
+import type { SubscribeTerminalRequest } from "@getpaseo/protocol/messages";
 import type { TerminalOutputData } from "./terminal-emulator-runtime";
 import { i18n } from "@/i18n/i18next";
 
@@ -23,9 +23,11 @@ export interface TerminalStreamControllerOptions {
   client: TerminalStreamControllerClient;
   getPreferredSize: () => TerminalStreamControllerSize | null;
   onOutput: (input: { terminalId: string; data: TerminalOutputData }) => void;
-  onSnapshot: (input: { terminalId: string; state: TerminalState }) => void;
   onExit?: (terminalId: string) => void;
-  onRestore?: (input: { terminalId: string; data: TerminalOutputData }) => void;
+  onReplay?: (input: {
+    terminalId: string;
+    replay: import("@getpaseo/client").TerminalReplayEvent;
+  }) => void;
   getRestoreOptions?: () => SubscribeTerminalRequest["restore"] | undefined;
   onStatusChange?: (status: TerminalStreamControllerStatus) => void;
 }
@@ -43,17 +45,11 @@ export class TerminalStreamController {
     if (this.disposed || event.terminalId !== this.terminalId) {
       return;
     }
-    if (event.type === "snapshot") {
-      this.options.onSnapshot({ terminalId: event.terminalId, state: event.state });
+    if (event.type === "replay") {
+      this.options.onReplay?.({ terminalId: event.terminalId, replay: event.replay });
       return;
     }
-    if (event.type === "restore") {
-      if (event.data.length > 0) {
-        this.options.onRestore?.({ terminalId: event.terminalId, data: event.data });
-      }
-      return;
-    }
-    if (event.data.length > 0) {
+    if (event.type === "output" && event.data.length > 0) {
       this.options.onOutput({ terminalId: event.terminalId, data: event.data });
     }
   };

packages/app/src/terminal/runtime/workspace-terminal-session.test.ts

@@ -1,75 +0,0 @@
-import { describe, expect, it } from "vitest";
-
-import {
-  getWorkspaceTerminalSession,
-  releaseWorkspaceTerminalSession,
-  retainWorkspaceTerminalSession,
-} from "./workspace-terminal-session";
-
-describe("workspace-terminal-session", () => {
-  it("returns the same workspace session instance for the same scope", () => {
-    const first = getWorkspaceTerminalSession({
-      scopeKey: "workspace-a",
-    });
-    const second = getWorkspaceTerminalSession({
-      scopeKey: "workspace-a",
-    });
-
-    expect(second).toBe(first);
-  });
-
-  it("preserves snapshots across repeated lookups", () => {
-    const first = getWorkspaceTerminalSession({
-      scopeKey: "workspace-snapshots",
-    });
-    first.snapshots.set({
-      terminalId: "term-1",
-      state: {
-        rows: 1,
-        cols: 1,
-        grid: [[{ char: "A" }]],
-        scrollback: [],
-        cursor: { row: 0, col: 0 },
-      },
-    });
-
-    const second = getWorkspaceTerminalSession({
-      scopeKey: "workspace-snapshots",
-    });
-
-    expect(second.snapshots.get({ terminalId: "term-1" })).toEqual({
-      rows: 1,
-      cols: 1,
-      grid: [[{ char: "A" }]],
-      scrollback: [],
-      cursor: { row: 0, col: 0 },
-    });
-  });
-
-  it("evicts workspace terminal session state when the retain count returns to zero", () => {
-    const scopeKey = "workspace-release";
-    const first = getWorkspaceTerminalSession({
-      scopeKey,
-    });
-    first.snapshots.set({
-      terminalId: "term-1",
-      state: {
-        rows: 1,
-        cols: 1,
-        grid: [[{ char: "A" }]],
-        scrollback: [],
-        cursor: { row: 0, col: 0 },
-      },
-    });
-
-    retainWorkspaceTerminalSession({ scopeKey });
-    releaseWorkspaceTerminalSession({ scopeKey });
-
-    const second = getWorkspaceTerminalSession({
-      scopeKey,
-    });
-
-    expect(second).not.toBe(first);
-    expect(second.snapshots.get({ terminalId: "term-1" })).toBeNull();
-  });
-});

packages/app/src/terminal/runtime/workspace-terminal-session.ts

@@ -1,79 +0,0 @@
-import type { TerminalState } from "@getpaseo/protocol/messages";
-
-export interface WorkspaceTerminalSnapshots {
-  get: (input: { terminalId: string }) => TerminalState | null;
-  set: (input: { terminalId: string; state: TerminalState }) => void;
-  clear: (input: { terminalId: string }) => void;
-  prune: (input: { terminalIds: string[] }) => void;
-}
-
-export interface WorkspaceTerminalSession {
-  scopeKey: string;
-  snapshots: WorkspaceTerminalSnapshots;
-}
-
-interface WorkspaceTerminalSessionRecord {
-  snapshotByTerminalId: Map<string, TerminalState>;
-  session: WorkspaceTerminalSession;
-}
-
-const sessionsByScopeKey = new Map<string, WorkspaceTerminalSessionRecord>();
-const refCountByScopeKey = new Map<string, number>();
-
-function createSnapshots(input: {
-  snapshotByTerminalId: Map<string, TerminalState>;
-}): WorkspaceTerminalSnapshots {
-  return {
-    get: ({ terminalId }) => input.snapshotByTerminalId.get(terminalId) ?? null,
-    set: ({ terminalId, state }) => {
-      input.snapshotByTerminalId.set(terminalId, state);
-    },
-    clear: ({ terminalId }) => {
-      input.snapshotByTerminalId.delete(terminalId);
-    },
-    prune: ({ terminalIds }) => {
-      const terminalIdSet = new Set(terminalIds);
-      for (const terminalId of Array.from(input.snapshotByTerminalId.keys())) {
-        if (!terminalIdSet.has(terminalId)) {
-          input.snapshotByTerminalId.delete(terminalId);
-        }
-      }
-    },
-  };
-}
-
-export function getWorkspaceTerminalSession(input: { scopeKey: string }): WorkspaceTerminalSession {
-  const existing = sessionsByScopeKey.get(input.scopeKey);
-  if (existing) {
-    return existing.session;
-  }
-
-  const snapshotByTerminalId = new Map<string, TerminalState>();
-  const session: WorkspaceTerminalSession = {
-    scopeKey: input.scopeKey,
-    snapshots: createSnapshots({
-      snapshotByTerminalId,
-    }),
-  };
-
-  sessionsByScopeKey.set(input.scopeKey, {
-    snapshotByTerminalId,
-    session,
-  });
-  return session;
-}
-
-export function retainWorkspaceTerminalSession(input: { scopeKey: string }): void {
-  const current = refCountByScopeKey.get(input.scopeKey) ?? 0;
-  refCountByScopeKey.set(input.scopeKey, current + 1);
-}
-
-export function releaseWorkspaceTerminalSession(input: { scopeKey: string }): void {
-  const current = refCountByScopeKey.get(input.scopeKey) ?? 0;
-  if (current > 1) {
-    refCountByScopeKey.set(input.scopeKey, current - 1);
-    return;
-  }
-  refCountByScopeKey.delete(input.scopeKey);
-  sessionsByScopeKey.delete(input.scopeKey);
-}

packages/client/src/connection/index.ts

@@ -125,6 +125,7 @@ export class ConnectionSubscriptions extends OwnedSubscriptions {
 // Protocol support belongs to the installed client. Only browser hosting needs
 // a resource supplied by the caller. Keep this exhaustive as the protocol evolves.
 export const DEFAULT_CLIENT_CAPABILITIES = {
+  [CLIENT_CAPS.terminalChunkedReplay]: true,
   [CLIENT_CAPS.helloRejection]: true,
   [CLIENT_CAPS.ownedSubscriptions]: true,
   [CLIENT_CAPS.allProviders]: true,

packages/client/src/daemon-client.test.ts

@@ -1101,6 +1101,7 @@ test("advertises client capabilities in hello", async () => {
       projected_subagent_timeline: true,
       reasoning_merge_enum: true,
       terminal_reflowable_snapshot: true,
+      terminal_chunked_replay: true,
       timeline_notifications: true,
       plugin_timeline_items: true,
       workspace_setup_blocked: true,
@@ -6387,66 +6388,80 @@ test("emits output events for the active terminal stream", async () => {
   unsubscribe();
 });
 
-test("emits snapshot events for the subscribed terminal stream", async () => {
-  const logger = createMockLogger();
-  const mock = createMockTransport();
+test.each([5, 500, 10000])(
+  "preserves explicit %s history demand on an old ANSI host and normalizes restore",
+  async (history) => {
+    const logger = createMockLogger();
+    const mock = createMockTransport();
 
-  const client = new DaemonClient({
-    url: "ws://test",
-    clientId: "clsk_unit_test",
-    logger,
-    reconnect: { enabled: false },
-    transportFactory: () => mock.transport,
-  });
-  clients.push(client);
+    const client = new DaemonClient({
+      url: "ws://test",
+      clientId: "clsk_unit_test",
+      logger,
+      reconnect: { enabled: false },
+      transportFactory: () => mock.transport,
+    });
+    clients.push(client);
 
-  const connectPromise = client.connect();
-  mock.triggerOpen();
-  await connectPromise;
+    const connectPromise = client.connect();
+    mock.triggerOpen();
+    await connectPromise;
 
-  const snapshots: unknown[] = [];
-  client.onTerminalStreamEvent((event) => {
-    if (event.type !== "snapshot") {
-      return;
-    }
-    snapshots.push(event.state);
-  });
+    const events: unknown[] = [];
+    const replayEvents: unknown[] = [];
+    client.onTerminalStreamEvent((event) => {
+      if (event.type === "replay") replayEvents.push(event.replay);
+      events.push(event);
+    });
 
-  const subscribePromise = client.subscribeTerminal("term-1", { requestId: "sub-2" });
-  await vi.waitFor(() =>
-    expect(parseSentFrame(mock.sent.at(-1)).type).toBe("subscribe_terminal_request"),
-  );
-  mock.triggerMessage(
-    wrapSessionMessage({
-      type: "subscribe_terminal_response",
-      payload: {
-        subscriptionId: "server-" + String(parseSentFrame(mock.sent.at(-1)).requestId),
-        terminalId: "term-1",
+    const subscribePromise = client.subscribeTerminal("term-1", {
+      requestId: "sub-2",
+      restore: { mode: "visible-snapshot", scrollbackLines: history },
+    });
+    await vi.waitFor(() =>
+      expect(parseSentFrame(mock.sent.at(-1)).type).toBe("subscribe_terminal_request"),
+    );
+    expect(parseSentFrame(mock.sent.at(-1)).restore).toEqual({
+      mode: "visible-snapshot",
+      scrollbackLines: history,
+    });
+    mock.triggerMessage(
+      wrapSessionMessage({
+        type: "subscribe_terminal_response",
+        payload: {
+          subscriptionId: "server-" + String(parseSentFrame(mock.sent.at(-1)).requestId),
+          terminalId: "term-1",
+          slot: 12,
+          error: null,
+          requestId: "sub-2",
+        },
+      }),
+    );
+    await subscribePromise;
+
+    const state = {
+      rows: 1,
+      cols: 5,
+      grid: [[{ char: "h" }, { char: "e" }, { char: "l" }, { char: "l" }, { char: "o" }]],
+      scrollback: [],
+      cursor: { row: 0, col: 5 },
+    };
+    mock.triggerMessage(
+      encodeTerminalStreamFrame({
+        opcode: TerminalStreamOpcode.Snapshot,
         slot: 12,
-        error: null,
-        requestId: "sub-2",
-      },
-    }),
-  );
-  await subscribePromise;
+        payload: encodeTerminalSnapshotPayload(state),
+      }),
+    );
 
-  const state = {
-    rows: 1,
-    cols: 5,
-    grid: [[{ char: "h" }, { char: "e" }, { char: "l" }, { char: "l" }, { char: "o" }]],
-    scrollback: [],
-    cursor: { row: 0, col: 5 },
-  };
-  mock.triggerMessage(
-    encodeTerminalStreamFrame({
-      opcode: TerminalStreamOpcode.Snapshot,
-      slot: 12,
-      payload: encodeTerminalSnapshotPayload(state),
-    }),
-  );
-
-  expect(snapshots).toEqual([state]);
-});
+    expect(events).toEqual([]);
+    const data = new TextEncoder().encode("\x1b[31mold ANSI host界🙂");
+    mock.triggerMessage(
+      encodeTerminalStreamFrame({ opcode: TerminalStreamOpcode.Restore, slot: 12, payload: data }),
+    );
+    expect(replayEvents).toEqual([{ type: "begin" }, { type: "data", data }, { type: "end" }]);
+  },
+);
 
 test("sends explicit terminal input and resize commands", async () => {
   const logger = createMockLogger();

packages/client/src/daemon-client.ts

@@ -6414,7 +6414,7 @@ export class DaemonClient {
   }
 
   /**
-   * Snapshot/restore and output arrive in receive. Subscribe to the returned handle
+   * Replay begin/data/end and live output arrive in receive. Subscribe to the returned handle
    * for terminal_stream_exit: payload.error means observation failure, not PTY exit.
    * Either outcome detaches this slot and releases the handle automatically.
    */

packages/client/src/index.ts

@@ -1,3 +1,4 @@
+export type { TerminalReplayEvent, TerminalStreamEvent } from "./terminal-stream-router.js";
 import type { AgentAddress } from "@getpaseo/protocol/addresses";
 import { parentAddressLabels } from "@getpaseo/protocol/agent-labels";
 export type { AgentAddress } from "@getpaseo/protocol/addresses";

packages/client/src/terminal-stream-router.test.ts

@@ -4,7 +4,7 @@ import { describe, expect, test } from "vitest";
 import { TerminalStreamRouter, type TerminalStreamEvent } from "./terminal-stream-router.js";
 
 describe("terminal-stream-router", () => {
-  test("routes restore frames as restore events", () => {
+  test("normalizes old ANSI restore into the replay lifecycle", () => {
     const router = new TerminalStreamRouter();
     const events: TerminalStreamEvent[] = [];
     const payload = new TextEncoder().encode("restored screen");
@@ -16,14 +16,14 @@ describe("terminal-stream-router", () => {
       payload,
     });
 
-    expect(events).toEqual([
-      {
+    expect(events).toEqual(
+      ["begin", "data", "end"].map((type) => ({
         terminalId: "term-1",
         subscriptionId: "subscription-1",
-        type: "restore",
-        data: payload,
-      },
-    ]);
+        type: "replay",
+        replay: type === "data" ? { type, data: payload } : { type },
+      })),
+    );
   });
 });
 
@@ -61,3 +61,45 @@ test("legacy listeners share a terminal slot without releasing each other", () =
   router.handleFrame(frame);
   expect(received).toEqual(["first", "second", "second"]);
 });
+
+test("streams chunks without joining and ignores released slots during replay", () => {
+  const router = new TerminalStreamRouter();
+  const events: TerminalStreamEvent[] = [];
+  const release = router.attach("old", "terminal", 4, (event) => events.push(event));
+  const payload = new TextEncoder().encode(
+    JSON.stringify({ rows: 24, cols: 80, retainedHistoryLines: 1000 }),
+  );
+  router.handleFrame({ opcode: TerminalStreamOpcode.ReplayBegin, slot: 4, payload });
+  const data = new TextEncoder().encode("\x1b[31m界🙂");
+  router.handleFrame({
+    opcode: TerminalStreamOpcode.ReplayData,
+    slot: 4,
+    payload: data.subarray(0, 7),
+  });
+  release();
+  router.attach("new", "terminal", 5, (event) => events.push(event));
+  router.handleFrame({
+    opcode: TerminalStreamOpcode.ReplayData,
+    slot: 4,
+    payload: data.subarray(7),
+  });
+  router.handleFrame({
+    opcode: TerminalStreamOpcode.ReplayEnd,
+    slot: 4,
+    payload: new Uint8Array(),
+  });
+  expect(events).toHaveLength(2);
+  expect(events[1]).toMatchObject({
+    subscriptionId: "old",
+    type: "replay",
+    replay: { type: "data", data: data.subarray(0, 7) },
+  });
+  router.handleFrame({ opcode: TerminalStreamOpcode.ReplayBegin, slot: 5, payload });
+  router.handleFrame({ opcode: TerminalStreamOpcode.ReplayData, slot: 5, payload: data });
+  router.handleFrame({
+    opcode: TerminalStreamOpcode.ReplayEnd,
+    slot: 5,
+    payload: new Uint8Array(),
+  });
+  expect(events.slice(2).map((event) => event.subscriptionId)).toEqual(["new", "new", "new"]);
+});

packages/client/src/terminal-stream-router.ts

@@ -1,14 +1,17 @@
 import {
-  decodeTerminalSnapshotPayload,
   TerminalStreamOpcode,
+  TerminalReplayMetadataSchema,
   type TerminalStreamFrame,
 } from "@getpaseo/protocol/binary-frames/index";
-import type { TerminalState } from "@getpaseo/protocol/messages";
+
+export type TerminalReplayEvent =
+  | { type: "begin"; rows?: number; cols?: number; retainedHistoryLines?: number }
+  | { type: "data"; data: Uint8Array }
+  | { type: "end" };
 
 export type TerminalStreamEvent = { terminalId: string; subscriptionId: string } & (
   | { type: "output"; data: Uint8Array }
-  | { type: "snapshot"; state: TerminalState }
-  | { type: "restore"; data: Uint8Array }
+  | { type: "replay"; replay: TerminalReplayEvent }
 );
 
 export class TerminalStreamRouter {
@@ -61,20 +64,42 @@ export class TerminalStreamRouter {
       let event: TerminalStreamEvent;
       if (frame.opcode === TerminalStreamOpcode.Output)
         event = { ...identity, type: "output", data: frame.payload };
-      else if (frame.opcode === TerminalStreamOpcode.Restore)
-        event = { ...identity, type: "restore", data: frame.payload };
-      else if (frame.opcode === TerminalStreamOpcode.Snapshot) {
-        const state = decodeTerminalSnapshotPayload(frame.payload);
-        if (!state) return;
-        event = { ...identity, type: "snapshot", state };
-      } else return;
-      registration.receive(event);
-      for (const listener of this.listeners) {
+      else if (frame.opcode === TerminalStreamOpcode.Restore) {
+        // COMPAT(terminalSingleRestore): added after v0.14.0; remove when ANSI host floor supports chunked replay after 2027-04-30.
+        for (const replay of [
+          { type: "begin" },
+          { type: "data", data: frame.payload },
+          { type: "end" },
+        ] as TerminalReplayEvent[])
+          this.deliver(registration.receive, { ...identity, type: "replay", replay });
+        continue;
+      } else if (frame.opcode === TerminalStreamOpcode.ReplayBegin) {
+        let raw: unknown;
         try {
-          listener(event);
+          raw = JSON.parse(new TextDecoder().decode(frame.payload));
         } catch {
-          /* Passive diagnostics cannot interrupt delivery. */
+          return;
         }
+        const parsed = TerminalReplayMetadataSchema.safeParse(raw);
+        if (!parsed.success) return;
+        const metadata = parsed.data;
+        event = { ...identity, type: "replay", replay: { type: "begin", ...metadata } };
+      } else if (frame.opcode === TerminalStreamOpcode.ReplayData)
+        event = { ...identity, type: "replay", replay: { type: "data", data: frame.payload } };
+      else if (frame.opcode === TerminalStreamOpcode.ReplayEnd)
+        event = { ...identity, type: "replay", replay: { type: "end" } };
+      else return;
+      this.deliver(registration.receive, event);
+    }
+  }
+
+  private deliver(receive: (event: TerminalStreamEvent) => void, event: TerminalStreamEvent): void {
+    receive(event);
+    for (const listener of this.listeners) {
+      try {
+        listener(event);
+      } catch {
+        /* Passive diagnostics cannot interrupt delivery. */
       }
     }
   }

packages/protocol/src/binary-frames/demux.test.ts

@@ -89,3 +89,18 @@ describe("host route binary framing", () => {
     ).toThrow("Invalid host route ID");
   });
 });
+
+it.each([
+  TerminalStreamOpcode.ReplayBegin,
+  TerminalStreamOpcode.ReplayData,
+  TerminalStreamOpcode.ReplayEnd,
+])("decodes replay opcode %s directly and inside a host route", (opcode) => {
+  const payload = new TextEncoder().encode("界 replay");
+  const bytes = encodeTerminalStreamFrame({ opcode, slot: 12, payload });
+  const expected = { kind: "terminal", frame: { opcode, slot: 12, payload } };
+  expect(decodeBinaryFrame(bytes)).toEqual(expected);
+  const routed = decodeBinaryFrame(encodeHostRouteFrame("host", bytes));
+  expect(routed?.kind).toBe("host_route");
+  if (routed?.kind !== "host_route") throw new Error("Missing host route");
+  expect(decodeBinaryFrame(routed.frame.payload)).toEqual(expected);
+});

packages/protocol/src/binary-frames/demux.ts

@@ -25,6 +25,9 @@ export function decodeBinaryFrame(bytes: Uint8Array): BinaryFrame | null {
     case TerminalStreamOpcode.Input:
     case TerminalStreamOpcode.Resize:
     case TerminalStreamOpcode.Snapshot:
+    case TerminalStreamOpcode.ReplayBegin:
+    case TerminalStreamOpcode.ReplayData:
+    case TerminalStreamOpcode.ReplayEnd:
     case TerminalStreamOpcode.Restore: {
       const frame = decodeTerminalStreamFrame(bytes);
       return frame ? { kind: "terminal", frame } : null;

packages/protocol/src/binary-frames/terminal.ts

@@ -1,6 +1,12 @@
 import { z } from "zod";
 import { TerminalStateSchema } from "../messages.js";
 
+export const TerminalReplayMetadataSchema = z.object({
+  rows: z.number().int().positive(),
+  cols: z.number().int().positive(),
+  retainedHistoryLines: z.number().int().nonnegative(),
+});
+
 export const TerminalStreamResizeSchema = z.object({
   rows: z.number().int().positive(),
   cols: z.number().int().positive(),
@@ -13,6 +19,9 @@ export const TerminalStreamOpcode = {
   Resize: 0x03,
   Snapshot: 0x04,
   Restore: 0x05,
+  ReplayBegin: 0x06,
+  ReplayData: 0x07,
+  ReplayEnd: 0x08,
 } as const;
 
 export type TerminalStreamOpcode = (typeof TerminalStreamOpcode)[keyof typeof TerminalStreamOpcode];
@@ -58,6 +67,9 @@ function isTerminalStreamOpcode(value: number): value is TerminalStreamOpcode {
     value === TerminalStreamOpcode.Input ||
     value === TerminalStreamOpcode.Resize ||
     value === TerminalStreamOpcode.Snapshot ||
+    value === TerminalStreamOpcode.ReplayBegin ||
+    value === TerminalStreamOpcode.ReplayData ||
+    value === TerminalStreamOpcode.ReplayEnd ||
     value === TerminalStreamOpcode.Restore
   );
 }

packages/protocol/src/client-capabilities.ts

@@ -1,4 +1,5 @@
 export const CLIENT_CAPS = {
+  terminalChunkedReplay: "terminal_chunked_replay",
   helloRejection: "hello_rejection",
   // COMPAT(ownedSubscriptions): added in v0.8.0, remove legacy ownership after 2027-03-09.
   ownedSubscriptions: "owned_subscriptions",

packages/protocol/src/messages.ts

@@ -3740,6 +3740,7 @@ export const ServerInfoStatusPayloadSchema = z
         resumeOnStartupSetting: z.boolean().optional(),
         // COMPAT(terminalRestoreModes): added in v0.1.81, remove gate after 2026-11-23.
         "terminal-restore-modes": z.boolean().optional(),
+        terminalChunkedReplay: z.boolean().optional(),
         // COMPAT(terminalInputModeReplay): added in v0.2.6, remove gate after 2027-02-02.
         "terminal-input-mode-replay": z.boolean().optional(),
         // COMPAT(terminalSizeOwnership): added in v0.2.6, remove gate after 2027-02-02.

packages/server/src/server/daemon-e2e/terminal-byte-headless-parity.e2e.test.ts

@@ -7,7 +7,6 @@ import { Terminal as HeadlessTerminal, type IBufferCell, type IBufferLine } from
 import { expect, test } from "vitest";
 
 import type { TerminalCell, TerminalState } from "@getpaseo/protocol/messages";
-import { renderTerminalSnapshotToAnsi } from "@getpaseo/protocol/terminal-snapshot";
 import type { TerminalStreamEvent } from "@getpaseo/client/internal/daemon-client";
 import { DaemonClient } from "../test-utils/daemon-client.js";
 import { createTestPaseoDaemon } from "../test-utils/paseo-daemon.js";
@@ -46,7 +45,7 @@ test("byte-stream headless terminal matches daemon state after high-output attac
       terminalId: terminal.id,
       headless: liveHeadless,
     });
-    const initialSnapshot = waitForTerminalStreamEvent(client, terminal.id, "snapshot");
+    const initialSnapshot = waitForReplayEnd(client, terminal.id);
 
     const liveSubscription = await subscribeTerminal(client, terminal.id);
     await initialSnapshot;
@@ -60,13 +59,13 @@ test("byte-stream headless terminal matches daemon state after high-output attac
       text: BYTE_DONE_MARKER,
       rows: BYTE_TEST_SIZE.rows,
     });
-    const daemonSnapshot = await readTerminalSnapshot({
+    const daemonSnapshot = await readReplayViewport({
       port: daemon.port,
       terminalId: terminal.id,
     });
     await liveHeadless.flush();
 
-    expect(liveHeadless.visibleLines()).toEqual(visibleTerminalLines(daemonSnapshot));
+    expect(liveHeadless.visibleLines()).toEqual(daemonSnapshot.lines);
     expect(liveHeadless.cursor()).toEqual(daemonSnapshot.cursor);
     expect(liveHeadless.visibleLines()).toEqual(capturedViewport.lines);
 
@@ -79,7 +78,7 @@ test("byte-stream headless terminal matches daemon state after high-output attac
       terminalId: terminal.id,
       headless: restoreHeadless,
     });
-    const restoreFrame = waitForTerminalStreamEvent(client, terminal.id, "restore");
+    const restoreFrame = waitForReplayEnd(client, terminal.id);
 
     await subscribeTerminal(client, terminal.id, {
       restore: { mode: "visible-snapshot", scrollbackLines: 200, size: BYTE_TEST_SIZE },
@@ -116,12 +115,10 @@ class ClientHeadlessTerminal {
   }
 
   applyEvent(event: TerminalStreamEvent): void {
-    if (event.type === "snapshot") {
-      this.enqueueText(renderTerminalSnapshotToAnsi(event.state), { resetDecoder: true });
-      return;
-    }
-    if (event.type === "restore") {
-      this.enqueueText(this.decoder.decode(event.data, { stream: false }), { resetDecoder: true });
+    if (event.type === "replay") {
+      if (event.replay.type === "begin") this.enqueueText("\x1bc", { resetDecoder: true });
+      if (event.replay.type === "data")
+        this.enqueueText(this.decoder.decode(event.replay.data, { stream: true }));
       return;
     }
     this.enqueueText(this.decoder.decode(event.data, { stream: true }));
@@ -187,35 +184,32 @@ async function subscribeTerminal(
   return response.subscription;
 }
 
-async function readTerminalSnapshot(input: {
-  port: number;
-  terminalId: string;
-}): Promise<TerminalState> {
-  const client = new DaemonClient({
-    url: `ws://127.0.0.1:${input.port}/ws`,
-    appVersion: "0.1.96",
-    clientType: "mobile",
-  });
+async function readReplayViewport(input: { port: number; terminalId: string }): Promise<{
+  lines: string[];
+  cursor: TerminalState["cursor"];
+}> {
+  const client = new DaemonClient({ url: `ws://127.0.0.1:${input.port}/ws`, clientType: "mobile" });
+  const headless = new ClientHeadlessTerminal(BYTE_TEST_SIZE);
+  const stop = pipeTerminalStreamToHeadless({ client, terminalId: input.terminalId, headless });
   try {
     await client.connect();
-    const snapshot = waitForTerminalStreamEvent(client, input.terminalId, "snapshot");
+    const completed = waitForReplayEnd(client, input.terminalId);
     await subscribeTerminal(client, input.terminalId);
-    const event = await snapshot;
-    return event.state;
+    await completed;
+    await headless.flush();
+    return { lines: headless.visibleLines(), cursor: headless.cursor() };
   } finally {
+    stop();
     await client.close();
   }
 }
 
-function waitForTerminalStreamEvent<TType extends TerminalStreamEvent["type"]>(
-  client: DaemonClient,
-  terminalId: string,
-  type: TType,
-): Promise<Extract<TerminalStreamEvent, { type: TType }>> {
-  return client.waitForTerminalStreamEvent(
-    (event) => event.terminalId === terminalId && event.type === type,
-    10_000,
-  ) as Promise<Extract<TerminalStreamEvent, { type: TType }>>;
+async function waitForReplayEnd(client: DaemonClient, terminalId: string): Promise<void> {
+  await client.waitForTerminalStreamEvent(
+    (event) =>
+      event.terminalId === terminalId && event.type === "replay" && event.replay.type === "end",
+    10000,
+  );
 }
 
 async function createPackageLockTerminalCwd(): Promise<PackageLockTerminalCwd> {
@@ -287,24 +281,16 @@ async function waitForCondition<T>(
   throw new Error(`Timed out after ${timeoutMs}ms waiting for terminal byte parity`);
 }
 
-function visibleTerminalLines(state: TerminalState): string[] {
-  return state.grid.map(terminalRowText);
-}
-
-function terminalRowText(row: TerminalState["grid"][number]): string {
-  return row
-    .map((cell) => cell.char)
-    .join("")
-    .trimEnd();
-}
-
 function bufferLineText(line: IBufferLine | undefined, reusableCell: IBufferCell): string {
   const cells: TerminalCell[] = [];
   for (let col = 0; col < BYTE_TEST_SIZE.cols; col += 1) {
     const cell = line?.getCell(col, reusableCell);
     cells.push({ char: cell?.getChars() || " " });
   }
-  return terminalRowText(cells);
+  return cells
+    .map((cell) => cell.char)
+    .join("")
+    .trimEnd();
 }
 
 function packageLockStreamScript(): string {

packages/server/src/server/daemon-e2e/terminal.e2e.test.ts

@@ -1,3 +1,4 @@
+import { Terminal as HeadlessTerminal } from "@xterm/headless";
 import { afterEach, beforeEach, describe, expect, test } from "vitest";
 import { mkdtempSync, rmSync } from "fs";
 import { tmpdir } from "os";
@@ -80,6 +81,24 @@ async function waitForCondition(
   throw new Error(`Timed out after ${timeoutMs}ms waiting for condition`);
 }
 
+function readHeadlessState(terminal: HeadlessTerminal): TerminalState {
+  const buffer = terminal.buffer.active;
+  const lines: TerminalState["grid"] = [];
+  for (let row = 0; row < buffer.length; row++) {
+    const cells: TerminalState["grid"][number] = [];
+    for (let col = 0; col < terminal.cols; col++)
+      cells.push({ char: buffer.getLine(row)?.getCell(col)?.getChars() ?? "" });
+    lines.push(cells);
+  }
+  return {
+    rows: terminal.rows,
+    cols: terminal.cols,
+    grid: lines.slice(buffer.baseY),
+    scrollback: lines.slice(0, buffer.baseY),
+    cursor: { row: buffer.cursorY, col: buffer.cursorX },
+  };
+}
+
 async function waitForTerminalSnapshot(
   client: DaemonClient,
   terminalId: string,
@@ -92,16 +111,34 @@ async function waitForTerminalSnapshot(
       reject(new Error(`Timeout waiting for terminal snapshot (${timeout}ms)`));
     }, timeout);
 
+    let terminal: HeadlessTerminal | null = null;
+    let writes = Promise.resolve();
     const unsubscribe = client.onTerminalStreamEvent((event) => {
-      if (event.terminalId !== terminalId || event.type !== "snapshot") {
-        return;
+      if (event.terminalId !== terminalId || event.type !== "replay") return;
+      const replay = event.replay;
+      if (replay.type === "begin") {
+        terminal?.dispose();
+        terminal = new HeadlessTerminal({
+          rows: replay.rows ?? 24,
+          cols: replay.cols ?? 80,
+          scrollback: 1000,
+          allowProposedApi: true,
+        });
+      } else if (replay.type === "data") {
+        const active = terminal!;
+        writes = writes.then(() => new Promise<void>((done) => active.write(replay.data, done)));
+      } else {
+        void writes.then(() => {
+          const active = terminal!;
+          const state = readHeadlessState(active);
+          if (!predicate(state)) return null;
+          clearTimeout(timeoutHandle);
+          unsubscribe();
+          active.dispose();
+          resolve(state);
+          return null;
+        });
       }
-      if (!predicate(event.state)) {
-        return;
-      }
-      clearTimeout(timeoutHandle);
-      unsubscribe();
-      resolve(event.state);
     });
   });
 }
@@ -1836,3 +1873,68 @@ describe("list terminals across directories", () => {
     ]);
   });
 });
+
+test.each([400, 3000])(
+  "chunked SDK replay retains requested history for %s printed lines",
+  async (count) => {
+    const cwd = tmpCwd();
+    tempDirs.push(cwd);
+    const created = await createTerminalInWorkspace(ctx.client, {
+      cwd,
+      options: {
+        command: "/bin/sh",
+        args: [
+          "-lc",
+          `i=1; while [ $i -le ${count} ]; do printf '\\033[31mreplay-%04d界🙂 payload-abcdefghijklmnopqrstuvwxyz0123456789\\033[0m\\n' $i; i=$((i+1)); done; sleep 30`,
+        ],
+      },
+    });
+    const id = created.terminal!.id;
+    await waitForCondition(
+      async () =>
+        (await ctx.client.captureTerminal(id)).lines
+          .join("\n")
+          .includes(`replay-${String(count).padStart(4, "0")}`),
+      10000,
+    );
+    const events: import("@getpaseo/client").TerminalStreamEvent[] = [];
+    let end!: () => void;
+    const completed = new Promise<void>((resolve) => {
+      end = resolve;
+    });
+    const subscription = ctx.client.observeTerminal(
+      id,
+      (event) => {
+        events.push(event);
+        if (event.type === "replay" && event.replay.type === "end") end();
+      },
+      { restore: { mode: "visible-snapshot", scrollbackLines: 10000 } },
+    );
+    try {
+      await subscription.ready;
+      await completed;
+      const replay = events.flatMap((event) => (event.type === "replay" ? [event.replay] : []));
+      expect(replay[0]).toMatchObject({
+        type: "begin",
+        retainedHistoryLines: count === 3000 ? 1000 : expect.any(Number),
+      });
+      expect(replay.at(-1)).toEqual({ type: "end" });
+      const chunks = replay.flatMap((event) => (event.type === "data" ? [event.data] : []));
+      expect(chunks.every((chunk) => chunk.length <= 65536)).toBe(true);
+      const text = Buffer.concat(chunks).toString("utf8");
+      const begin = replay[0];
+      if (begin?.type !== "begin" || begin.rows === undefined)
+        throw new Error("Missing replay dimensions");
+      expect(text.match(/replay-\d{4}/g)).toHaveLength(Math.min(count, 1000 + begin.rows - 1));
+      expect(text).toContain(`replay-${String(count).padStart(4, "0")}界🙂`);
+      if (count === 400) expect(text).toContain("replay-0001界🙂");
+      else {
+        expect(text).not.toContain("replay-0001");
+        expect(chunks.length).toBeGreaterThan(1);
+      }
+    } finally {
+      await subscription.release();
+    }
+  },
+  30000,
+);

packages/server/src/server/session.ts

@@ -1129,6 +1129,8 @@ export class Session {
       terminalManager,
       emit: (msg) => this.emit(msg),
       hasBinaryChannel: () => this.onBinaryMessage !== null,
+      supportsChunkedReplay: (source) =>
+        this.supportsForSource(CLIENT_CAPS.terminalChunkedReplay, source),
       isPathWithinRoot: (rootPath, candidatePath) => this.isPathWithinRoot(rootPath, candidatePath),
       sessionLogger: this.sessionLogger,
       listTerminalWorkspaceRefs: () => this.listActiveWorkspaceRefs(),

packages/server/src/server/websocket-server.ts

@@ -2016,6 +2016,7 @@ export class VoiceAssistantWebSocketServer {
         resumeOnStartupSetting: true,
         // COMPAT(terminalRestoreModes): added in v0.1.81, remove gate after 2026-11-23.
         "terminal-restore-modes": true,
+        terminalChunkedReplay: true,
         // COMPAT(terminalInputModeReplay): added in v0.2.6, remove gate after 2027-02-02.
         "terminal-input-mode-replay": true,
         // COMPAT(terminalSizeOwnership): added in v0.2.6, remove gate after 2027-02-02.

packages/server/src/terminal/terminal-replay.ts

@@ -21,7 +21,7 @@ export type TerminalReplayEvent =
   | { type: "begin"; metadata: TerminalReplayMetadata }
   | { type: "data"; data: Uint8Array }
   | { type: "end" };
-export type TerminalReplaySink = (event: TerminalReplayEvent) => void;
+export type TerminalReplaySink = (event: TerminalReplayEvent) => void | Promise<void>;
 export const TERMINAL_REPLAY_CHUNK_BYTES = 64 * 1024;
 
 export function* createTerminalReplay(
@@ -45,15 +45,15 @@ export function* createTerminalReplay(
   return metadata;
 }
 
-export function replayTerminal(
+export async function replayTerminal(
   session: LocalTerminalSession,
   options: TerminalReplayOptions | undefined,
   sink: TerminalReplaySink,
-): TerminalReplayMetadata {
+): Promise<TerminalReplayMetadata> {
   const replay = createTerminalReplay(session, options);
   let next = replay.next();
   while (!next.done) {
-    sink(next.value);
+    await sink(next.value);
     next = replay.next();
   }
   return next.value;
@@ -67,6 +67,7 @@ interface TerminalReplayPorts {
 /** Owns the worker's replay/live cut, bounded live tail and controller lifetime. */
 export function createTerminalReplayController(ports: TerminalReplayPorts) {
   let controller: FramedSocket | null = null;
+  const acknowledgements = new Map<string, { resolve(): void; reject(error: Error): void }>();
   // Only the live tail of a replaying terminal is held. Replay chunks use the socket's
   // write completion directly; they never enter this buffer or fill the shared socket.
   interface ReplayTail {
@@ -142,11 +143,18 @@ export function createTerminalReplayController(ports: TerminalReplayPorts) {
       while (!next.done) {
         if (tail.overflow)
           throw new Error("Terminal output exceeded the replay buffer; attach again");
+        const acknowledged = new Promise<void>((resolve, reject) => {
+          acknowledgements.set(message.requestId, { resolve, reject });
+        });
+        void acknowledged.catch(() => {});
+        // Register before sending: even a synchronous controller cannot race the acknowledgement.
         await connection.sendAndWait({
           type: "terminalReplay",
           requestId: message.requestId,
           event: next.value,
         });
+        await acknowledged;
+        acknowledgements.delete(message.requestId);
         next = replay.next();
       }
       released = true;
@@ -161,6 +169,8 @@ export function createTerminalReplayController(ports: TerminalReplayPorts) {
       tail.failure = error;
       if (!released) await releaseReplayTail(session, tail);
       throw error;
+    } finally {
+      acknowledgements.delete(message.requestId);
     }
   }
 
@@ -230,6 +240,11 @@ export function createTerminalReplayController(ports: TerminalReplayPorts) {
   }
 
   return {
+    acknowledge(requestId: string, error?: string): void {
+      const pending = acknowledgements.get(requestId);
+      if (error) pending?.reject(new Error(error));
+      else pending?.resolve();
+    },
     setConnection(connection: FramedSocket | null): void {
       const previous = controller;
       controller = connection;
@@ -237,6 +252,9 @@ export function createTerminalReplayController(ports: TerminalReplayPorts) {
       // Old writes settle on their original socket; new output and replay belong
       // exclusively to the replacement controller.
       replayTails.clear();
+      for (const pending of acknowledgements.values())
+        pending.reject(new Error("Terminal replay controller disconnected"));
+      acknowledgements.clear();
     },
     send: sendToController,
     async replay(

packages/server/src/terminal/terminal-restore.ts

@@ -3,7 +3,7 @@ import {
   TerminalStreamOpcode,
   encodeTerminalStreamFrame,
 } from "@getpaseo/protocol/binary-frames/index";
-import type { TerminalReplayOptions } from "./terminal-replay.js";
+import type { TerminalReplaySink, TerminalReplayOptions } from "./terminal-replay.js";
 
 export const MAX_TERMINAL_OUTPUT_FRAME_BYTES = 256 * 1024;
 
@@ -64,3 +64,37 @@ function resolveVisibleRestoreScrollbackLines(value: number | undefined): number
   }
   return Math.min(Math.max(0, value), MAX_VISIBLE_RESTORE_SCROLLBACK_LINES);
 }
+
+/** The daemon's only old-app adapter. Capable delivery never assembles the replay. */
+export function createTerminalRestoreDelivery(input: {
+  slot: number;
+  chunked: boolean;
+  send(frame: Uint8Array): Promise<void>;
+}): TerminalReplaySink {
+  // COMPAT(terminalSingleRestore): added after v0.14.0; remove after 2027-04-30 when client floor supports chunked replay.
+  const legacyChunks: Uint8Array[] = [];
+  return async (event) => {
+    if (!input.chunked) {
+      if (event.type === "data") legacyChunks.push(event.data);
+      if (event.type === "end")
+        await input.send(
+          encodeTerminalRestoreFrame({
+            slot: input.slot,
+            data: Buffer.concat(legacyChunks),
+          }),
+        );
+      return;
+    }
+    const opcodes = {
+      begin: TerminalStreamOpcode.ReplayBegin,
+      data: TerminalStreamOpcode.ReplayData,
+      end: TerminalStreamOpcode.ReplayEnd,
+    };
+    let payload: string | Uint8Array | undefined;
+    if (event.type === "begin") payload = JSON.stringify(event.metadata);
+    if (event.type === "data") payload = event.data;
+    await input.send(
+      encodeTerminalStreamFrame({ slot: input.slot, opcode: opcodes[event.type], payload }),
+    );
+  };
+}

packages/server/src/terminal/terminal-session-controller.test.ts

@@ -35,9 +35,9 @@ function replayFixture(
   return async (_id, _options, sink) => {
     const replay = await read();
     if (!replay) return null;
-    sink({ type: "begin", metadata: replay.metadata });
-    sink({ type: "data", data: replay.data });
-    sink({ type: "end" });
+    await sink({ type: "begin", metadata: replay.metadata });
+    await sink({ type: "data", data: replay.data });
+    await sink({ type: "end" });
     return replay.metadata;
   };
 }

packages/server/src/terminal/terminal-session-controller.ts

@@ -28,7 +28,7 @@ import { TerminalOutputCoalescer } from "./terminal-output-coalescer.js";
 import {
   MAX_CLIENT_BUFFERED_BYTES,
   MAX_TERMINAL_OUTPUT_FRAME_BYTES,
-  encodeTerminalRestoreFrame,
+  createTerminalRestoreDelivery,
   resolveRestoreAfterOutputOverflow,
   resolveTerminalRestoreSnapshotOptions,
   resolveTerminalSubscriptionSnapshotMode,
@@ -70,6 +70,7 @@ interface ActiveTerminalStream {
   readyRevision?: number;
   restore?: TerminalRestoreOptions;
   bufferedOutputs: BufferedTerminalOutput[];
+  bufferedOutputBytes: number;
   outputBytesSinceSnapshot: number;
   outputCoalescer: TerminalOutputCoalescer;
 }
@@ -83,6 +84,7 @@ export interface TerminalSessionControllerOptions {
   terminalManager: TerminalManager | null;
   emit: (msg: SessionOutboundMessage) => void;
   hasBinaryChannel: () => boolean;
+  supportsChunkedReplay?: (source: object) => boolean;
   isPathWithinRoot: (rootPath: string, candidatePath: string) => boolean;
   sessionLogger: pino.Logger;
   listTerminalWorkspaceRefs?: () => Promise<readonly TerminalWorkspaceRef[]>;
@@ -146,7 +148,7 @@ export class TerminalSessionController {
   private readonly activeStreams = new Map<number, ActiveTerminalStream>();
   private nextSlot = 0;
 
-  constructor(options: TerminalSessionControllerOptions) {
+  constructor(private readonly options: TerminalSessionControllerOptions) {
     this.terminalManager = options.terminalManager;
     this.emit = options.emit;
     this.hasBinaryChannel = options.hasBinaryChannel;
@@ -899,6 +901,7 @@ export class TerminalSessionController {
       readyRevision: undefined,
       restore: options?.restore,
       bufferedOutputs: [],
+      bufferedOutputBytes: 0,
       outputBytesSinceSnapshot: 0,
       outputCoalescer: new TerminalOutputCoalescer({
         timers: { setTimeout, clearTimeout },
@@ -971,6 +974,19 @@ export class TerminalSessionController {
           return;
         }
         if (activeStream.needsSnapshot || activeStream.snapshotInFlight) {
+          activeStream.bufferedOutputBytes += Buffer.byteLength(message.data);
+          if (activeStream.bufferedOutputBytes > MAX_CLIENT_BUFFERED_BYTES) {
+            activeStream.owner.emit({
+              type: "terminal_stream_exit",
+              payload: {
+                terminalId: activeStream.terminalId,
+                error: "Terminal replay live tail exceeded the buffer; attach again",
+              },
+            });
+            this.detachRegistration(activeStream);
+            void activeStream.owner.release();
+            return;
+          }
           activeStream.bufferedOutputs.push({
             data: message.data,
             revision: message.revision,
@@ -1075,19 +1091,45 @@ export class TerminalSessionController {
     terminalManager: TerminalManager,
     restore: TerminalRestoreOptions,
   ): Promise<SnapshotSendResult> {
-    const snapshotOptions = resolveTerminalRestoreSnapshotOptions(restore);
+    const chunked = this.options.supportsChunkedReplay?.(activeStream.owner.source) === true;
+    const snapshotOptions =
+      chunked && restore.mode !== "live"
+        ? { scrollbackLines: restore.scrollbackLines }
+        : resolveTerminalRestoreSnapshotOptions(restore);
     if (snapshotOptions === null) {
       return { shouldContinue: true };
     }
 
-    const chunks: Uint8Array[] = [];
-    // COMPAT(terminalSingleRestore): ANSI clients through v0.14 collect one restore;
-    // remove after the supported client floor implements chunked replay.
+    const deliver = createTerminalRestoreDelivery({
+      slot: activeStream.slot,
+      chunked,
+      send: (frame) => activeStream.owner.emitBinaryAndWait(frame),
+    });
     const snapshot = await terminalManager.replayTerminal(
       activeStream.terminalId,
       snapshotOptions,
-      (event) => {
-        if (event.type === "data") chunks.push(event.data);
+      async (event) => {
+        if (this.activeStreams.get(activeStream.slot) !== activeStream) return;
+        const buffered = this.options.getClientBufferedAmount?.(activeStream.owner.source);
+        if (
+          chunked &&
+          buffered !== null &&
+          buffered !== undefined &&
+          buffered > MAX_CLIENT_BUFFERED_BYTES
+        ) {
+          activeStream.owner.emit({
+            type: "terminal_stream_exit",
+            payload: {
+              terminalId: activeStream.terminalId,
+              error: "Terminal replay transport overflow; attach again",
+            },
+          });
+          this.detachRegistration(activeStream);
+          void activeStream.owner.release();
+
+          return;
+        }
+        await deliver(event);
       },
     );
     if (this.activeStreams.get(activeStream.slot) !== activeStream) {
@@ -1098,12 +1140,6 @@ export class TerminalSessionController {
       return { shouldContinue: false };
     }
 
-    activeStream.owner.emitBinary(
-      encodeTerminalRestoreFrame({
-        slot: activeStream.slot,
-        data: Buffer.concat(chunks),
-      }),
-    );
     // The restore frame went out-of-band; keep the replay that follows on the
     // coalescer's trailing path so it doesn't flush back-to-back with it.
     activeStream.outputCoalescer.markFlushed();
@@ -1120,6 +1156,7 @@ export class TerminalSessionController {
       activeStream.outputCoalescer.handle(replayPreamble);
     }
 
+    activeStream.bufferedOutputBytes = 0;
     const bufferedOutputs = activeStream.bufferedOutputs.splice(
       0,
       activeStream.bufferedOutputs.length,

packages/server/src/terminal/terminal-worker-process.ts

@@ -552,6 +552,11 @@ function runWorker(argv: string[]): void {
         return;
       }
 
+      case "replayAcknowledged": {
+        replayController.acknowledge(message.requestId, message.error);
+        return;
+      }
+
       case "replayTerminal": {
         await replayController.replay(message);
         return;

packages/server/src/terminal/terminal-worker-protocol.test.ts

@@ -4,6 +4,7 @@ import { classifyTerminalWorkerProtocol } from "./terminal-worker-protocol.js";
 describe("classifyTerminalWorkerProtocol", () => {
   it("rejects the unreleased cell protocol without a draining adapter", () => {
     expect(classifyTerminalWorkerProtocol(1, 2)).toBe("obsolete");
+    expect(classifyTerminalWorkerProtocol(2, 3)).toBe("obsolete");
   });
   it.each([
     [5, "current"],

packages/server/src/terminal/terminal-worker-protocol.ts

@@ -43,7 +43,7 @@ export interface WorkerCreateTerminalOptions {
 // `shutdown`. A daemon drives a worker of its own version, drains one a version older (no new
 // terminals; it exits after its last terminal), shuts down anything older, and leaves a newer
 // worker running untouched. See docs/terminal-worker.md.
-export const TERMINAL_WORKER_PROTOCOL_VERSION = 2;
+export const TERMINAL_WORKER_PROTOCOL_VERSION = 3;
 
 // Test-only: the protocol version a worker reports, so tests can stand up older and newer
 // workers from one build.
@@ -59,8 +59,8 @@ export function classifyTerminalWorkerProtocol(
   // A version this daemon cannot read comes from a Paseo it does not know: treat it as newer.
   if (typeof reported !== "number" || !Number.isSafeInteger(reported)) return "newer";
   if (reported === current) return "current";
-  // Protocol 1 was unreleased and transported cells; it has no draining adapter.
-  if (reported === current - 1 && reported >= 2) return "previous";
+  // Protocols 1 and 2 were unreleased; they have no draining adapter.
+  if (reported === current - 1 && reported >= 3) return "previous";
   return reported < current ? "obsolete" : "newer";
 }
 
@@ -122,6 +122,11 @@ export type TerminalWorkerRequest =
       terminalId: string;
       options?: WorkerKillAndWaitOptions;
     }
+  | {
+      type: "replayAcknowledged";
+      requestId: string;
+      error?: string;
+    }
   | {
       type: "replayTerminal";
       requestId: string;

packages/server/src/terminal/worker-terminal-manager.test.ts

@@ -1570,18 +1570,18 @@ it("hard cuts the unreleased cell transport, closing its terminals", async () =>
   expect(manager.getTerminal(old.terminalId)).toBeUndefined();
   const workers = await workerRecords(paseoHome);
   expect(workers).toHaveLength(1);
-  expect(workers[0]!.protocolVersion).toBe(2);
+  expect(workers[0]!.protocolVersion).toBe(3);
 });
 
 it("leaves a worker from a newer Paseo running, reports it incompatible, and closes it on a kill stop", async () => {
   const paseoHome = createTemporaryHome();
-  const newer = await leaveWorkerWithTerminal(paseoHome, 3);
+  const newer = await leaveWorkerWithTerminal(paseoHome, 4);
 
   manager = await startRealWorkerManager({ paseoHome });
 
   const unavailable = manager.getUnavailableError?.();
   expect(unavailable).toBeInstanceOf(TerminalWorkerIncompatibleError);
-  expect(unavailable?.message).toContain("worker protocol 3");
+  expect(unavailable?.message).toContain("worker protocol 4");
   await expect(manager.getTerminals(newer.cwd)).rejects.toBeInstanceOf(
     TerminalWorkerIncompatibleError,
   );
@@ -1799,9 +1799,12 @@ it("completes a replay larger than the socket budget while a sibling stays usabl
     if (event.type === "output") seen.push(event.data);
   });
   let bytes = 0;
-  const metadata = await manager.replayTerminal(terminal.id, undefined, (event) => {
+  const metadata = await manager.replayTerminal(terminal.id, undefined, async (event) => {
     if (event.type === "data") bytes += event.data.byteLength;
-    if (event.type === "begin") sibling.send({ type: "input", data: "go\r" });
+    if (event.type === "begin") {
+      sibling.send({ type: "input", data: "go\r" });
+      await waitForCondition(() => seen.join("").includes("SIBLING-ALIVE"), 10000);
+    }
   });
   expect(bytes).toBeGreaterThan(4 * 1024 * 1024);
   expect(metadata?.cols).toBe(1024);
@@ -1840,6 +1843,7 @@ it("completes a replay larger than the socket budget while a sibling stays usabl
     if (message.type === "helloAck") {
       framed.send({ type: "replayTerminal", terminalId: terminal.id, requestId: "stalled-replay" });
     } else if (message.type === "terminalReplay") {
+      framed.send({ type: "replayAcknowledged", requestId: message.requestId });
       if (message.event.type === "begin") {
         began = true;
         socket.pause();
@@ -1853,7 +1857,7 @@ it("completes a replay larger than the socket budget while a sibling stays usabl
       completed = message.ok;
   });
   try {
-    framed.send({ type: "hello", secret: record!.secret, protocolVersion: 2 });
+    framed.send({ type: "hello", secret: record!.secret, protocolVersion: 3 });
     await waitForCondition(() => began, 10000);
     framed.send({
       type: "send",
@@ -1903,6 +1907,8 @@ it("completes a replay larger than the socket budget while a sibling stays usabl
         terminalId: terminal.id,
         requestId: "overflow-replay",
       });
+    if (message.type === "terminalReplay")
+      stalledFrames.send({ type: "replayAcknowledged", requestId: message.requestId });
     if (message.type === "terminalReplay" && message.event.type === "begin") {
       overflowBegan = true;
       stalled.pause();
@@ -1911,7 +1917,7 @@ it("completes a replay larger than the socket budget while a sibling stays usabl
       overflowError = message.error;
   });
   try {
-    stalledFrames.send({ type: "hello", secret: record!.secret, protocolVersion: 2 });
+    stalledFrames.send({ type: "hello", secret: record!.secret, protocolVersion: 3 });
     await waitForCondition(() => overflowBegan, 10000);
     stalledFrames.send({
       type: "send",

packages/server/src/terminal/worker-terminal-manager.ts

@@ -599,7 +599,22 @@ export function createWorkerTerminalManager(
   function attachWorker(): void {
     worker.on("message", (message: TerminalWorkerToParentMessage) => {
       if (message.type === "terminalReplay") {
-        replaySinks.get(message.requestId)?.(message.event);
+        const sink = replaySinks.get(message.requestId);
+        void Promise.resolve()
+          .then(() => sink?.(message.event))
+          .then(
+            () =>
+              worker.send({ type: "replayAcknowledged", requestId: message.requestId }, () => {}),
+            (error: unknown) =>
+              worker.send(
+                {
+                  type: "replayAcknowledged",
+                  requestId: message.requestId,
+                  error: error instanceof Error ? error.message : String(error),
+                },
+                () => {},
+              ),
+          );
         return;
       }
       if (isResponse(message)) {
@@ -678,6 +693,11 @@ export function createWorkerTerminalManager(
     const request = new Promise((resolve, reject) => {
       const timeout = setTimeout(() => {
         pendingRequests.delete(requestId);
+        if (sink)
+          worker.send(
+            { type: "replayAcknowledged", requestId, error: "Terminal replay delivery timed out" },
+            () => {},
+          );
         reject(new Error(`Terminal worker request timed out: ${input.type}`));
       }, requestTimeoutMs);
       pendingRequests.set(requestId, { resolve, reject, timeout });