fix: sync dev branch with main timeline/schema changes and remove stale providers

Forward-port main's timeline epoch tracking, projected window selection, and schema updates into dev. Remove aider/amp/gemini providers and provider-history-compatibility layers that are no longer needed.
2026-04-15 10:52:28 +07:00
parent 326dad93e4
commit 9d30b7e85a
42 changed files with 1251 additions and 2051 deletions
@@ -32,8 +32,8 @@
        "get-port-cli": "^3.0.0",
        "knip": "^5.82.1",
        "patch-package": "^8.0.1",
-        "react": "19.1.4",
-        "react-dom": "19.1.4",
+        "react": "19.1.0",
+        "react-dom": "19.1.0",
        "typescript": "^5.9.3"
      }
    },
@@ -29122,9 +29122,9 @@
      }
    },
    "node_modules/react": {
-      "version": "19.1.4",
-      "resolved": "https://registry.npmjs.org/react/-/react-19.1.4.tgz",
-      "integrity": "sha512-DHINL3PAmPUiK1uszfbKiXqfE03eszdt5BpVSuEAHb5nfmNPwnsy7g39h2t8aXFc/Bv99GH81s+j8dobtD+jOw==",
+      "version": "19.1.0",
+      "resolved": "https://registry.npmjs.org/react/-/react-19.1.0.tgz",
+      "integrity": "sha512-FS+XFBNvn3GTAWq26joslQgWNoFu08F4kl0J4CgdNKADkdSGXQyTCnKteIAJy96Br6YbpEU1LSzV5dYtjMkMDg==",
      "license": "MIT",
      "engines": {
        "node": ">=0.10.0"
@@ -29162,15 +29162,15 @@
      }
    },
    "node_modules/react-dom": {
-      "version": "19.1.4",
-      "resolved": "https://registry.npmjs.org/react-dom/-/react-dom-19.1.4.tgz",
-      "integrity": "sha512-s2868ab/xo2SI6H4106A7aFI8Mrqa4xC6HZT/pBzYyQ3cBLqa88hu47xYD8xf+uECleN698Awn7RCWlkTiKnqQ==",
+      "version": "19.1.0",
+      "resolved": "https://registry.npmjs.org/react-dom/-/react-dom-19.1.0.tgz",
+      "integrity": "sha512-Xs1hdnE+DyKgeHJeJznQmYMIBG3TKIHJJT95Q58nHLSrElKlGQqDTR2HQ9fx5CN/Gk6Vh/kupBTDLU11/nDk/g==",
      "license": "MIT",
      "dependencies": {
        "scheduler": "^0.26.0"
      },
      "peerDependencies": {
-        "react": "^19.1.4"
+        "react": "^19.1.0"
      }
    },
    "node_modules/react-error-boundary": {
@@ -34911,8 +34911,8 @@
        "expo-web-browser": "~15.0.8",
        "lucide-react-native": "^0.546.0",
        "mnemonic-id": "^3.2.7",
-        "react": "19.1.4",
-        "react-dom": "19.1.4",
+        "react": "19.1.0",
+        "react-dom": "19.1.0",
        "react-native": "^0.81.5",
        "react-native-css": "^3.0.1",
        "react-native-draggable-flatlist": "^4.0.3",
@@ -69,8 +69,8 @@
    "get-port-cli": "^3.0.0",
    "knip": "^5.82.1",
    "patch-package": "^8.0.1",
-    "react": "19.1.4",
-    "react-dom": "19.1.4",
+    "react": "19.1.0",
+    "react-dom": "19.1.0",
    "typescript": "^5.9.3"
  },
  "description": "Paseo: voice-controlled development environment with OpenAI Realtime API",
@@ -94,8 +94,8 @@
  "license": "AGPL-3.0-or-later",
  "overrides": {
    "lightningcss": "1.30.1",
-    "react": "19.1.4",
-    "react-dom": "19.1.4"
+    "react": "19.1.0",
+    "react-dom": "19.1.0"
  },
  "dependencies": {
    "@anthropic-ai/claude-agent-sdk": "^0.2.11",
@@ -81,8 +81,8 @@
    "expo-web-browser": "~15.0.8",
    "lucide-react-native": "^0.546.0",
    "mnemonic-id": "^3.2.7",
-    "react": "19.1.4",
-    "react-dom": "19.1.4",
+    "react": "19.1.0",
+    "react-dom": "19.1.0",
    "react-native": "^0.81.5",
    "react-native-css": "^3.0.1",
    "react-native-draggable-flatlist": "^4.0.3",
@@ -1,14 +0,0 @@
-import Svg, { Path } from "react-native-svg";
-
-interface AiderIconProps {
-  size?: number;
-  color?: string;
-}
-
-export function AiderIcon({ size = 16, color = "currentColor" }: AiderIconProps) {
-  return (
-    <Svg width={size} height={size} viewBox="0 0 24 24" fill={color}>
-      <Path d="M9 3.75h5.25V4.5H9V3.75Zm-.75.75h6v2.25h-6V4.5Zm6 3h2.25v3h-2.25v-3Zm-6 3h8.25v3h-8.25v-3Zm-1.5 3h1.5v3h-1.5v-3Zm7.5 0h2.25v3h-2.25v-3Zm-6 3h6v3h-6v-3Zm8.25 0H18v3h-1.5v-3Z" />
-    </Svg>
-  );
-}
@@ -1,29 +0,0 @@
-import Svg, { Path } from "react-native-svg";
-
-interface AmpIconProps {
-  size?: number;
-  color?: string;
-}
-
-export function AmpIcon({ size = 16, color = "currentColor" }: AmpIconProps) {
-  return (
-    <Svg width={size} height={size} viewBox="0 0 24 24" fill="none">
-      <Path
-        fill={color}
-        d="m9.686 6.949 2.907.775-1.98-7.404-3.353.903 1.194 4.49a1.94 1.94 0 0 0 1.232 1.236Z"
-      />
-      <Path
-        fill={color}
-        d="m4.771 22 6.34-6.327 2.307 8.62 3.352-.903L13.432 10.87.912 7.533 0 10.906l8.61 2.3-6.31 6.317L4.77 22Z"
-      />
-      <Path
-        fill={color}
-        d="m13.254 11.707.778 2.917a1.937 1.937 0 0 0 1.23 1.234l4.511 1.199.89-3.37-7.409-1.98Z"
-      />
-      <Path
-        fill={color}
-        d="m15.916 2.484-2.883 2.88a2.063 2.063 0 0 0-.512 1.193l-.046 1.825 1.69.06-.022-.001c.463 0 .898-.181 1.225-.507L18.35 4.95l-2.434-2.467Z"
-      />
-    </Svg>
-  );
-}
@@ -1,17 +0,0 @@
-import Svg, { Path } from "react-native-svg";
-
-interface GeminiIconProps {
-  size?: number;
-  color?: string;
-}
-
-export function GeminiIcon({ size = 16, color = "currentColor" }: GeminiIconProps) {
-  return (
-    <Svg width={size} height={size} viewBox="0 0 24 24" fill="none">
-      <Path
-        fill={color}
-        d="M20.616 10.835a14.147 14.147 0 0 1-4.45-3.001 14.111 14.111 0 0 1-3.678-6.452.503.503 0 0 0-.975 0 14.134 14.134 0 0 1-3.679 6.452 14.155 14.155 0 0 1-4.45 3.001c-.65.28-1.318.505-2.002.678a.502.502 0 0 0 0 .975c.684.172 1.35.397 2.002.677a14.147 14.147 0 0 1 4.45 3.001 14.112 14.112 0 0 1 3.679 6.453.502.502 0 0 0 .975 0c.172-.685.397-1.351.677-2.003a14.145 14.145 0 0 1 3.001-4.45 14.113 14.113 0 0 1 6.453-3.678.503.503 0 0 0 0-.975 13.245 13.245 0 0 1-2.003-.678Z"
-      />
-    </Svg>
-  );
-}
@@ -1,9 +1,6 @@
 import { Bot } from "lucide-react-native";
-import { AiderIcon } from "@/components/icons/aider-icon";
-import { AmpIcon } from "@/components/icons/amp-icon";
 import { ClaudeIcon } from "@/components/icons/claude-icon";
 import { CodexIcon } from "@/components/icons/codex-icon";
-import { GeminiIcon } from "@/components/icons/gemini-icon";
 import { CopilotIcon } from "@/components/icons/copilot-icon";
 import { OpenCodeIcon } from "@/components/icons/opencode-icon";
 import { PiIcon } from "@/components/icons/pi-icon";
@@ -11,9 +8,6 @@ import { PiIcon } from "@/components/icons/pi-icon";
 const PROVIDER_ICONS: Record<string, typeof Bot> = {
  claude: ClaudeIcon as unknown as typeof Bot,
  codex: CodexIcon as unknown as typeof Bot,
-  gemini: GeminiIcon as unknown as typeof Bot,
-  amp: AmpIcon as unknown as typeof Bot,
-  aider: AiderIcon as unknown as typeof Bot,
  copilot: CopilotIcon as unknown as typeof Bot,
  opencode: OpenCodeIcon as unknown as typeof Bot,
  pi: PiIcon as unknown as typeof Bot,
@@ -591,8 +591,9 @@ function SessionProviderInternal({ children, serverId, client }: SessionProvider
          void client
            .fetchAgentTimeline(agentId, {
              direction: "after",
-              cursor: { seq: cursor.endSeq },
+              cursor: { epoch: cursor.epoch, seq: cursor.endSeq },
              limit: 0,
+              projection: "canonical",
            })
            .catch((error) => {
              console.warn("[Session] failed to fetch catch-up timeline on resume", agentId, error);
@@ -853,12 +854,13 @@ function SessionProviderInternal({ children, serverId, client }: SessionProvider
  );

  const requestCanonicalCatchUp = useCallback(
-    (agentId: string, cursor: { endSeq: number }) => {
+    (agentId: string, cursor: { epoch: string; endSeq: number }) => {
      void client
        .fetchAgentTimeline(agentId, {
          direction: "after",
-          cursor: { seq: cursor.endSeq },
+          cursor: { epoch: cursor.epoch, seq: cursor.endSeq },
          limit: 0,
+          projection: "canonical",
        })
        .catch((error) => {
          console.warn("[Session] failed to fetch canonical catch-up timeline", agentId, error);
@@ -961,6 +963,7 @@ function SessionProviderInternal({ children, serverId, client }: SessionProvider
          }
          if (
            current &&
+            current.epoch === result.cursor.epoch &&
            current.startSeq === result.cursor.startSeq &&
            current.endSeq === result.cursor.endSeq
          ) {
@@ -1065,7 +1068,7 @@ function SessionProviderInternal({ children, serverId, client }: SessionProvider

    const unsubAgentStream = client.on("agent_stream", (message) => {
      if (message.type !== "agent_stream") return;
-      const { agentId, event, timestamp, seq } = message.payload;
+      const { agentId, event, timestamp, seq, epoch } = message.payload;
      const parsedTimestamp = new Date(timestamp);
      const streamEvent = event as AgentStreamEventPayload;
      if (
@@ -1107,6 +1110,7 @@ function SessionProviderInternal({ children, serverId, client }: SessionProvider
      const result = processAgentStreamEvent({
        event: streamEvent,
        seq,
+        epoch,
        currentTail,
        currentHead,
        currentCursor,
@@ -1130,6 +1134,8 @@ function SessionProviderInternal({ children, serverId, client }: SessionProvider
          if (
            current &&
            typeof seq === "number" &&
+            typeof epoch === "string" &&
+            current.epoch === epoch &&
            seq >= current.startSeq &&
            seq <= current.endSeq
          ) {
@@ -1138,6 +1144,7 @@ function SessionProviderInternal({ children, serverId, client }: SessionProvider
          }
          if (
            current &&
+            current.epoch === nextCursor.epoch &&
            current.startSeq === nextCursor.startSeq &&
            current.endSeq === nextCursor.endSeq
          ) {
@@ -9,9 +9,13 @@ import {
  type TimelineCursor,
 } from "./session-stream-reducers";

+// ---------------------------------------------------------------------------
+// Test helpers
+// ---------------------------------------------------------------------------
+
 function makeTimelineEntry(seq: number, text: string, type: string = "assistant_message") {
  return {
-    seq,
+    seqStart: seq,
    provider: "claude",
    item: { type, text },
    timestamp: new Date(1000 + seq).toISOString(),
@@ -29,30 +33,22 @@ function makeTimelineEvent(
  } as AgentStreamEventPayload;
 }

-function makeToolCallEvent(status: "running" | "completed"): AgentStreamEventPayload {
+function makeUserTimelineEvent(text: string): AgentStreamEventPayload {
  return {
    type: "timeline",
    provider: "claude",
-    item: {
-      type: "tool_call",
-      callId: "call-1",
-      name: "shell",
-      status,
-      detail: {
-        type: "shell",
-        command: "pwd",
-      },
-      error: null,
-    },
-  };
+    item: { type: "user_message", text },
+  } as AgentStreamEventPayload;
 }

 const baseTimelineInput: ProcessTimelineResponseInput = {
  payload: {
    agentId: "agent-1",
    direction: "after",
-    startSeq: null,
-    endSeq: null,
+    reset: false,
+    epoch: "epoch-1",
+    startCursor: null,
+    endCursor: null,
    entries: [],
    error: null,
  },
@@ -67,6 +63,7 @@ const baseTimelineInput: ProcessTimelineResponseInput = {
 const baseStreamInput: ProcessAgentStreamEventInput = {
  event: makeTimelineEvent("hello"),
  seq: undefined,
+  epoch: undefined,
  currentTail: [],
  currentHead: [],
  currentCursor: undefined,
@@ -74,6 +71,10 @@ const baseStreamInput: ProcessAgentStreamEventInput = {
  timestamp: new Date(2000),
 };

+// ---------------------------------------------------------------------------
+// processTimelineResponse
+// ---------------------------------------------------------------------------
+
 describe("processTimelineResponse", () => {
  it("returns error path when payload.error is set", () => {
    const result = processTimelineResponse({
@@ -92,10 +93,35 @@ describe("processTimelineResponse", () => {
    expect(result.tail).toBe(baseTimelineInput.currentTail);
    expect(result.head).toBe(baseTimelineInput.currentHead);
    expect(result.cursorChanged).toBe(false);
+    expect(result.sideEffects).toEqual([]);
  });

-  it("replaces tail during bootstrap tail init and schedules committed catch-up", () => {
-    const provisionalHead: StreamItem[] = [
+  it("returns error with no init resolution when no deferred exists", () => {
+    const result = processTimelineResponse({
+      ...baseTimelineInput,
+      isInitializing: true,
+      hasActiveInitDeferred: false,
+      payload: {
+        ...baseTimelineInput.payload,
+        error: "timeout",
+      },
+    });
+
+    expect(result.error).toBe("timeout");
+    expect(result.initResolution).toBe(null);
+    expect(result.clearInitializing).toBe(true);
+  });
+
+  it("replaces tail and clears head when reset=true", () => {
+    const existingTail: StreamItem[] = [
+      {
+        kind: "user_message",
+        id: "old",
+        text: "old message",
+        timestamp: new Date(500),
+      },
+    ];
+    const existingHead: StreamItem[] = [
      {
        kind: "assistant_message",
        id: "head-1",
@@ -106,325 +132,518 @@ describe("processTimelineResponse", () => {

    const result = processTimelineResponse({
      ...baseTimelineInput,
-      currentHead: provisionalHead,
+      currentTail: existingTail,
+      currentHead: existingHead,
+      payload: {
+        ...baseTimelineInput.payload,
+        reset: true,
+        startCursor: { seq: 1 },
+        endCursor: { seq: 3 },
+        entries: [
+          makeTimelineEntry(1, "first"),
+          makeTimelineEntry(2, "second"),
+          makeTimelineEntry(3, "third"),
+        ],
+      },
+    });
+
+    expect(result.tail).not.toBe(existingTail);
+    expect(result.tail.length).toBeGreaterThan(0);
+    expect(result.head).toEqual([]);
+    expect(result.cursorChanged).toBe(true);
+    expect(result.cursor).toEqual({
+      epoch: "epoch-1",
+      startSeq: 1,
+      endSeq: 3,
+    });
+    expect(result.error).toBe(null);
+    expect(result.sideEffects.some((e) => e.type === "flush_pending_updates")).toBe(true);
+  });
+
+  it("sets cursor to null when reset=true but no cursors in payload", () => {
+    const result = processTimelineResponse({
+      ...baseTimelineInput,
+      currentCursor: { epoch: "epoch-1", startSeq: 1, endSeq: 5 },
+      payload: {
+        ...baseTimelineInput.payload,
+        reset: true,
+        entries: [],
+      },
+    });
+
+    expect(result.cursor).toBe(null);
+    expect(result.cursorChanged).toBe(true);
+  });
+
+  it("performs bootstrap tail init with catch-up side effect", () => {
+    const result = processTimelineResponse({
+      ...baseTimelineInput,
      isInitializing: true,
      hasActiveInitDeferred: true,
      initRequestDirection: "tail",
      payload: {
        ...baseTimelineInput.payload,
        direction: "tail",
-        startSeq: 1,
-        endSeq: 5,
+        epoch: "epoch-1",
+        startCursor: { seq: 1 },
+        endCursor: { seq: 5 },
        entries: [makeTimelineEntry(1, "first"), makeTimelineEntry(5, "last")],
      },
    });

+    // Bootstrap tail replaces
    expect(result.tail.length).toBeGreaterThan(0);
    expect(result.head).toEqual([]);
    expect(result.cursorChanged).toBe(true);
    expect(result.cursor).toEqual({
+      epoch: "epoch-1",
      startSeq: 1,
      endSeq: 5,
    });

-    const catchUp = result.sideEffects.find((effect) => effect.type === "catch_up");
-    expect(catchUp).toEqual({
-      type: "catch_up",
-      cursor: { endSeq: 5 },
+    // Should have catch-up side effect
+    const catchUp = result.sideEffects.find((e) => e.type === "catch_up");
+    expect(catchUp).toBeDefined();
+    expect(catchUp!.type === "catch_up" && catchUp!.cursor).toEqual({
+      epoch: "epoch-1",
+      endSeq: 5,
    });
  });

-  it("prepends older committed history for before pagination", () => {
-    const currentTail: StreamItem[] = [
-      {
-        kind: "assistant_message",
-        id: "tail-3",
-        text: "newer",
-        timestamp: new Date(3000),
-      },
-    ];
-    const currentCursor: TimelineCursor = { startSeq: 3, endSeq: 4 };
+  it("appends incrementally for contiguous seqs", () => {
+    const existingCursor: TimelineCursor = {
+      epoch: "epoch-1",
+      startSeq: 1,
+      endSeq: 3,
+    };

    const result = processTimelineResponse({
      ...baseTimelineInput,
-      currentTail,
-      currentCursor,
+      currentCursor: existingCursor,
      payload: {
        ...baseTimelineInput.payload,
-        direction: "before",
-        startSeq: 1,
-        endSeq: 2,
-        entries: [makeTimelineEntry(1, "hello", "user_message"), makeTimelineEntry(2, "older")],
+        epoch: "epoch-1",
+        entries: [makeTimelineEntry(4, "next-1"), makeTimelineEntry(5, "next-2")],
      },
    });

+    expect(result.tail.length).toBeGreaterThan(0);
    expect(result.cursorChanged).toBe(true);
    expect(result.cursor).toEqual({
+      epoch: "epoch-1",
      startSeq: 1,
-      endSeq: 4,
+      endSeq: 5,
    });
-    expect(result.tail).toHaveLength(3);
-    expect(result.tail[0]?.kind).toBe("user_message");
-    expect(result.tail[1]?.kind).toBe("assistant_message");
-    expect(result.tail[2]).toBe(currentTail[0]);
+    expect(result.error).toBe(null);
  });

-  it("replaces stale provisional assistant UI when fetch-after returns committed row 121", () => {
-    const currentHead: StreamItem[] = [
-      {
-        kind: "assistant_message",
-        id: "head-assistant",
-        text: "partial",
-        timestamp: new Date(120000),
-      },
-    ];
-    const currentCursor: TimelineCursor = { startSeq: 1, endSeq: 120 };
+  it("detects gap and emits catch-up side effect", () => {
+    const existingCursor: TimelineCursor = {
+      epoch: "epoch-1",
+      startSeq: 1,
+      endSeq: 3,
+    };

    const result = processTimelineResponse({
      ...baseTimelineInput,
-      currentHead,
-      currentCursor,
+      currentCursor: existingCursor,
+      payload: {
+        ...baseTimelineInput.payload,
+        epoch: "epoch-1",
+        entries: [makeTimelineEntry(10, "far ahead")],
+      },
+    });
+
+    // Gap should trigger catch-up
+    const catchUp = result.sideEffects.find((e) => e.type === "catch_up");
+    expect(catchUp).toBeDefined();
+    expect(catchUp!.type === "catch_up" && catchUp!.cursor).toEqual({
+      epoch: "epoch-1",
+      endSeq: 3,
+    });
+  });
+
+  it("drops stale entries silently", () => {
+    const existingCursor: TimelineCursor = {
+      epoch: "epoch-1",
+      startSeq: 1,
+      endSeq: 8,
+    };
+
+    const result = processTimelineResponse({
+      ...baseTimelineInput,
+      currentCursor: existingCursor,
+      payload: {
+        ...baseTimelineInput.payload,
+        epoch: "epoch-1",
+        entries: [makeTimelineEntry(5, "old"), makeTimelineEntry(7, "also old")],
+      },
+    });
+
+    // No new items appended (all dropped as stale)
+    expect(result.tail).toBe(baseTimelineInput.currentTail);
+    expect(result.cursorChanged).toBe(false);
+  });
+
+  it("drops entries with epoch mismatch", () => {
+    const existingCursor: TimelineCursor = {
+      epoch: "epoch-1",
+      startSeq: 1,
+      endSeq: 5,
+    };
+
+    const result = processTimelineResponse({
+      ...baseTimelineInput,
+      currentCursor: existingCursor,
+      payload: {
+        ...baseTimelineInput.payload,
+        epoch: "epoch-2",
+        entries: [makeTimelineEntry(6, "different epoch")],
+      },
+    });
+
+    expect(result.tail).toBe(baseTimelineInput.currentTail);
+    expect(result.cursorChanged).toBe(false);
+  });
+
+  it("resolves init when deferred matches direction", () => {
+    const result = processTimelineResponse({
+      ...baseTimelineInput,
+      isInitializing: true,
+      hasActiveInitDeferred: true,
+      initRequestDirection: "after",
      payload: {
        ...baseTimelineInput.payload,
        direction: "after",
-        startSeq: 121,
-        endSeq: 121,
-        entries: [makeTimelineEntry(121, "finalized reply")],
-      },
-    });
-
-    expect(result.head).toEqual([]);
-    expect(result.cursorChanged).toBe(true);
-    expect(result.cursor).toEqual({
-      startSeq: 1,
-      endSeq: 121,
-    });
-    expect(result.tail[result.tail.length - 1]).toMatchObject({
-      kind: "assistant_message",
-      text: "finalized reply",
-    });
-  });
-
-  it("keeps provisional head when reconnect catch-up has no new committed rows yet", () => {
-    const currentHead: StreamItem[] = [
-      {
-        kind: "assistant_message",
-        id: "head-assistant",
-        text: "still streaming",
-        timestamp: new Date(120000),
-      },
-    ];
-    const currentCursor: TimelineCursor = { startSeq: 1, endSeq: 120 };
-
-    const result = processTimelineResponse({
-      ...baseTimelineInput,
-      currentHead,
-      currentCursor,
-      payload: {
-        ...baseTimelineInput.payload,
-        direction: "after",
-        startSeq: null,
-        endSeq: null,
        entries: [],
      },
    });

-    expect(result.head).toBe(currentHead);
-    expect(result.cursorChanged).toBe(false);
-    expect(result.tail).toBe(baseTimelineInput.currentTail);
+    expect(result.initResolution).toBe("resolve");
+    expect(result.clearInitializing).toBe(true);
  });

-  it("requests catch-up when committed rows arrive with a forward gap", () => {
-    const currentCursor: TimelineCursor = { startSeq: 1, endSeq: 120 };
-
+  it("does not resolve init when directions differ (before vs after)", () => {
    const result = processTimelineResponse({
      ...baseTimelineInput,
-      currentCursor,
+      isInitializing: true,
+      hasActiveInitDeferred: true,
+      initRequestDirection: "after",
+      payload: {
+        ...baseTimelineInput.payload,
+        direction: "before",
+        entries: [],
+      },
+    });
+
+    // "before" direction doesn't match "after" initRequestDirection,
+    // and "before" is not a bootstrap tail path, so init should NOT resolve
+    expect(result.initResolution).toBe(null);
+    expect(result.clearInitializing).toBe(false);
+  });
+
+  it("clears initializing even without deferred", () => {
+    const result = processTimelineResponse({
+      ...baseTimelineInput,
+      isInitializing: true,
+      hasActiveInitDeferred: false,
      payload: {
        ...baseTimelineInput.payload,
        direction: "after",
-        startSeq: 125,
-        endSeq: 125,
-        entries: [makeTimelineEntry(125, "far ahead")],
+        entries: [],
      },
    });

-    expect(result.cursorChanged).toBe(false);
-    expect(result.tail).toBe(baseTimelineInput.currentTail);
-    expect(result.sideEffects).toContainEqual({
-      type: "catch_up",
-      cursor: { endSeq: 120 },
+    expect(result.clearInitializing).toBe(true);
+    expect(result.initResolution).toBe(null);
+  });
+
+  it("always includes flush_pending_updates side effect on success", () => {
+    const result = processTimelineResponse({
+      ...baseTimelineInput,
+      payload: {
+        ...baseTimelineInput.payload,
+        entries: [],
+      },
+    });
+
+    expect(result.sideEffects.some((e) => e.type === "flush_pending_updates")).toBe(true);
+  });
+
+  it("initializes cursor when no existing cursor on first entries", () => {
+    const result = processTimelineResponse({
+      ...baseTimelineInput,
+      currentCursor: undefined,
+      payload: {
+        ...baseTimelineInput.payload,
+        epoch: "epoch-1",
+        entries: [makeTimelineEntry(1, "first"), makeTimelineEntry(2, "second")],
+      },
+    });
+
+    expect(result.cursorChanged).toBe(true);
+    expect(result.cursor).toEqual({
+      epoch: "epoch-1",
+      startSeq: 1,
+      endSeq: 2,
    });
  });
 });

+// ---------------------------------------------------------------------------
+// processAgentStreamEvent
+// ---------------------------------------------------------------------------
+
 describe("processAgentStreamEvent", () => {
-  it("treats seq-less timeline events as provisional head updates", () => {
+  it("passes through non-timeline events without cursor changes", () => {
+    const turnEvent: AgentStreamEventPayload = {
+      type: "turn_completed",
+      provider: "claude",
+    };
+
    const result = processAgentStreamEvent({
      ...baseStreamInput,
-      event: makeTimelineEvent("partial"),
+      event: turnEvent,
      seq: undefined,
+      epoch: undefined,
    });

-    expect(result.changedHead).toBe(true);
-    expect(result.changedTail).toBe(false);
-    expect(result.head).toHaveLength(1);
-    expect(result.head[0]).toMatchObject({
-      kind: "assistant_message",
-      text: "partial",
-    });
    expect(result.cursorChanged).toBe(false);
+    expect(result.cursor).toBe(null);
+    expect(result.sideEffects).toEqual([]);
  });

-  it("keeps tool call rows anchored in tail across live and committed updates", () => {
-    const running = processAgentStreamEvent({
+  it("accepts timeline event with cursor advance", () => {
+    const existingCursor: TimelineCursor = {
+      epoch: "epoch-1",
+      startSeq: 1,
+      endSeq: 4,
+    };
+
+    const result = processAgentStreamEvent({
      ...baseStreamInput,
-      event: makeToolCallEvent("running"),
-      seq: undefined,
-    });
-    expect(running.head).toEqual([]);
-    expect(running.tail).toHaveLength(1);
-    expect(running.tail[0]).toMatchObject({
-      kind: "tool_call",
-      payload: {
-        source: "agent",
-        data: {
-          callId: "call-1",
-          status: "running",
-        },
-      },
+      event: makeTimelineEvent("new chunk"),
+      seq: 5,
+      epoch: "epoch-1",
+      currentCursor: existingCursor,
    });

-    const completedLive = processAgentStreamEvent({
-      ...baseStreamInput,
-      event: makeToolCallEvent("completed"),
-      seq: undefined,
-      currentHead: running.head,
-      currentTail: running.tail,
-      currentCursor: { startSeq: 1, endSeq: 7 },
-    });
-    expect(completedLive.head).toEqual([]);
-    expect(completedLive.tail).toHaveLength(1);
-    expect(completedLive.tail[0]).toMatchObject({
-      kind: "tool_call",
-      payload: {
-        source: "agent",
-        data: {
-          callId: "call-1",
-          status: "completed",
-        },
-      },
-    });
-
-    const committed = processAgentStreamEvent({
-      ...baseStreamInput,
-      event: makeToolCallEvent("completed"),
-      seq: 8,
-      currentHead: completedLive.head,
-      currentTail: completedLive.tail,
-      currentCursor: { startSeq: 1, endSeq: 7 },
-    });
-
-    expect(committed.head).toEqual([]);
-    expect(committed.tail).toHaveLength(1);
-    expect(committed.tail[0]).toMatchObject({
-      kind: "tool_call",
-      payload: {
-        source: "agent",
-        data: {
-          callId: "call-1",
-          status: "completed",
-        },
-      },
+    expect(result.cursorChanged).toBe(true);
+    expect(result.cursor).toEqual({
+      epoch: "epoch-1",
+      startSeq: 1,
+      endSeq: 5,
    });
+    expect(result.sideEffects).toEqual([]);
  });

-  it("preserves assistant/tool interleaving while a turn is streaming", () => {
-    const assistantBeforeTool = processAgentStreamEvent({
-      ...baseStreamInput,
-      event: makeTimelineEvent("before"),
-      seq: undefined,
-    });
+  it("detects gap and emits catch-up side effect", () => {
+    const existingCursor: TimelineCursor = {
+      epoch: "epoch-1",
+      startSeq: 1,
+      endSeq: 4,
+    };

-    const runningTool = processAgentStreamEvent({
-      ...baseStreamInput,
-      event: makeToolCallEvent("running"),
-      seq: undefined,
-      currentHead: assistantBeforeTool.head,
-      currentTail: assistantBeforeTool.tail,
-    });
-
-    const assistantAfterTool = processAgentStreamEvent({
-      ...baseStreamInput,
-      event: makeTimelineEvent("after"),
-      seq: undefined,
-      currentHead: runningTool.head,
-      currentTail: runningTool.tail,
-    });
-
-    const completedTool = processAgentStreamEvent({
-      ...baseStreamInput,
-      event: makeToolCallEvent("completed"),
-      seq: undefined,
-      currentHead: assistantAfterTool.head,
-      currentTail: assistantAfterTool.tail,
-    });
-
-    expect(completedTool.head).toEqual([]);
-    expect(completedTool.tail.map((item) => item.kind)).toEqual([
-      "assistant_message",
-      "tool_call",
-      "assistant_message",
-    ]);
-    expect(
-      completedTool.tail[0]?.kind === "assistant_message" ? completedTool.tail[0].text : null,
-    ).toBe("before");
-    expect(
-      completedTool.tail[2]?.kind === "assistant_message" ? completedTool.tail[2].text : null,
-    ).toBe("after");
-  });
-
-  it("requests catch-up when a committed live row skips ahead", () => {
    const result = processAgentStreamEvent({
      ...baseStreamInput,
      event: makeTimelineEvent("far ahead"),
-      seq: 125,
-      currentCursor: { startSeq: 1, endSeq: 120 },
+      seq: 10,
+      epoch: "epoch-1",
+      currentCursor: existingCursor,
    });

+    expect(result.cursorChanged).toBe(false);
    expect(result.changedTail).toBe(false);
    expect(result.changedHead).toBe(false);
-    expect(result.cursorChanged).toBe(false);
-    expect(result.sideEffects).toContainEqual({
-      type: "catch_up",
-      cursor: { endSeq: 120 },
+
+    const catchUp = result.sideEffects.find((e) => e.type === "catch_up");
+    expect(catchUp).toBeDefined();
+    expect(catchUp!.cursor).toEqual({
+      epoch: "epoch-1",
+      endSeq: 4,
    });
  });

-  it("flushes provisional head into tail on terminal turn events", () => {
-    const withHead = processAgentStreamEvent({
-      ...baseStreamInput,
-      event: makeTimelineEvent("streaming"),
-      seq: undefined,
-    });
+  it("drops stale timeline event", () => {
+    const existingCursor: TimelineCursor = {
+      epoch: "epoch-1",
+      startSeq: 1,
+      endSeq: 8,
+    };

    const result = processAgentStreamEvent({
      ...baseStreamInput,
-      event: {
-        type: "turn_completed",
-        provider: "claude",
-      },
-      currentHead: withHead.head,
-      currentTail: withHead.tail,
+      event: makeTimelineEvent("old"),
+      seq: 5,
+      epoch: "epoch-1",
+      currentCursor: existingCursor,
    });

-    expect(result.changedHead).toBe(true);
-    expect(result.changedTail).toBe(true);
-    expect(result.head).toEqual([]);
-    expect(result.tail).toHaveLength(1);
-    expect(result.tail[0]).toMatchObject({
-      kind: "assistant_message",
-      text: "streaming",
+    expect(result.cursorChanged).toBe(false);
+    expect(result.changedTail).toBe(false);
+    expect(result.changedHead).toBe(false);
+    expect(result.sideEffects).toEqual([]);
+  });
+
+  it("drops timeline event with epoch mismatch", () => {
+    const existingCursor: TimelineCursor = {
+      epoch: "epoch-1",
+      startSeq: 1,
+      endSeq: 5,
+    };
+
+    const result = processAgentStreamEvent({
+      ...baseStreamInput,
+      event: makeTimelineEvent("wrong epoch"),
+      seq: 6,
+      epoch: "epoch-2",
+      currentCursor: existingCursor,
+    });
+
+    expect(result.cursorChanged).toBe(false);
+    expect(result.changedTail).toBe(false);
+    expect(result.changedHead).toBe(false);
+    expect(result.sideEffects).toEqual([]);
+  });
+
+  it("initializes cursor when none exists", () => {
+    const result = processAgentStreamEvent({
+      ...baseStreamInput,
+      event: makeTimelineEvent("first"),
+      seq: 1,
+      epoch: "epoch-1",
+      currentCursor: undefined,
+    });
+
+    expect(result.cursorChanged).toBe(true);
+    expect(result.cursor).toEqual({
+      epoch: "epoch-1",
+      startSeq: 1,
+      endSeq: 1,
    });
  });
+
+  it("derives optimistic idle status on turn_completed for running agent", () => {
+    const turnCompletedEvent: AgentStreamEventPayload = {
+      type: "turn_completed",
+      provider: "claude",
+    };
+
+    const result = processAgentStreamEvent({
+      ...baseStreamInput,
+      event: turnCompletedEvent,
+      currentAgent: {
+        status: "running",
+        updatedAt: new Date(1000),
+        lastActivityAt: new Date(1000),
+      },
+      timestamp: new Date(2000),
+    });
+
+    expect(result.agentChanged).toBe(true);
+    expect(result.agent).not.toBe(null);
+    expect(result.agent!.status).toBe("idle");
+    expect(result.agent!.updatedAt.getTime()).toBe(2000);
+    expect(result.agent!.lastActivityAt.getTime()).toBe(2000);
+  });
+
+  it("derives optimistic error status on turn_failed for running agent", () => {
+    const turnFailedEvent: AgentStreamEventPayload = {
+      type: "turn_failed",
+      provider: "claude",
+      error: "something broke",
+    };
+
+    const result = processAgentStreamEvent({
+      ...baseStreamInput,
+      event: turnFailedEvent,
+      currentAgent: {
+        status: "running",
+        updatedAt: new Date(1000),
+        lastActivityAt: new Date(1000),
+      },
+      timestamp: new Date(2000),
+    });
+
+    expect(result.agentChanged).toBe(true);
+    expect(result.agent!.status).toBe("error");
+  });
+
+  it("does not change agent when status is not running", () => {
+    const turnCompletedEvent: AgentStreamEventPayload = {
+      type: "turn_completed",
+      provider: "claude",
+    };
+
+    const result = processAgentStreamEvent({
+      ...baseStreamInput,
+      event: turnCompletedEvent,
+      currentAgent: {
+        status: "idle",
+        updatedAt: new Date(1000),
+        lastActivityAt: new Date(1000),
+      },
+      timestamp: new Date(2000),
+    });
+
+    expect(result.agentChanged).toBe(false);
+    expect(result.agent).toBe(null);
+  });
+
+  it("does not change agent when no agent is provided", () => {
+    const turnCompletedEvent: AgentStreamEventPayload = {
+      type: "turn_completed",
+      provider: "claude",
+    };
+
+    const result = processAgentStreamEvent({
+      ...baseStreamInput,
+      event: turnCompletedEvent,
+      currentAgent: null,
+      timestamp: new Date(2000),
+    });
+
+    expect(result.agentChanged).toBe(false);
+    expect(result.agent).toBe(null);
+  });
+
+  it("preserves updatedAt when agent timestamp is newer than event", () => {
+    const turnCompletedEvent: AgentStreamEventPayload = {
+      type: "turn_completed",
+      provider: "claude",
+    };
+
+    const result = processAgentStreamEvent({
+      ...baseStreamInput,
+      event: turnCompletedEvent,
+      currentAgent: {
+        status: "running",
+        updatedAt: new Date(5000),
+        lastActivityAt: new Date(5000),
+      },
+      timestamp: new Date(2000),
+    });
+
+    expect(result.agentChanged).toBe(true);
+    expect(result.agent!.updatedAt.getTime()).toBe(5000);
+    expect(result.agent!.lastActivityAt.getTime()).toBe(5000);
+  });
+
+  it("does not produce agent patch for non-terminal events", () => {
+    const result = processAgentStreamEvent({
+      ...baseStreamInput,
+      event: makeTimelineEvent("just text"),
+      currentAgent: {
+        status: "running",
+        updatedAt: new Date(1000),
+        lastActivityAt: new Date(1000),
+      },
+      seq: 1,
+      epoch: "epoch-1",
+      timestamp: new Date(2000),
+    });
+
+    expect(result.agentChanged).toBe(false);
+    expect(result.agent).toBe(null);
+  });
 });
@@ -1,7 +1,12 @@
 import type { AgentStreamEventPayload } from "@server/shared/messages";
 import type { AgentLifecycleStatus } from "@server/shared/agent-lifecycle";
 import type { StreamItem } from "@/types/stream";
-import { applyStreamEvent, hydrateStreamState, reduceStreamUpdate } from "@/types/stream";
+import {
+  applyStreamEvent,
+  flushHeadToTail,
+  hydrateStreamState,
+  reduceStreamUpdate,
+} from "@/types/stream";
 import {
  classifySessionTimelineSeq,
  type SessionTimelineSeqDecision,
@@ -12,25 +17,38 @@ import {
 } from "@/contexts/session-timeline-bootstrap-policy";
 import { deriveOptimisticLifecycleStatus } from "@/contexts/session-stream-lifecycle";

+// ---------------------------------------------------------------------------
+// Shared cursor type
+// ---------------------------------------------------------------------------
+
 export type TimelineCursor = {
+  epoch: string;
  startSeq: number;
  endSeq: number;
 };

+// ---------------------------------------------------------------------------
+// Side-effect discriminated unions
+// ---------------------------------------------------------------------------
+
 export type TimelineReducerSideEffect =
-  | { type: "catch_up"; cursor: { endSeq: number } }
+  | { type: "catch_up"; cursor: { epoch: string; endSeq: number } }
  | { type: "flush_pending_updates" };

 export type AgentStreamReducerSideEffect = {
  type: "catch_up";
-  cursor: { endSeq: number };
+  cursor: { epoch: string; endSeq: number };
 };

+// ---------------------------------------------------------------------------
+// processTimelineResponse
+// ---------------------------------------------------------------------------
+
 type TimelineDirection = "tail" | "before" | "after";
 type InitRequestDirection = "tail" | "after";

 type TimelineResponseEntry = {
-  seq: number;
+  seqStart: number;
  provider: string;
  item: Record<string, unknown>;
  timestamp: string;
@@ -40,8 +58,10 @@ export interface ProcessTimelineResponseInput {
  payload: {
    agentId: string;
    direction: TimelineDirection;
-    startSeq: number | null;
-    endSeq: number | null;
+    reset: boolean;
+    epoch: string;
+    startCursor: { seq: number } | null;
+    endCursor: { seq: number } | null;
    entries: TimelineResponseEntry[];
    error: string | null;
  };
@@ -64,9 +84,217 @@ export interface ProcessTimelineResponseOutput {
  sideEffects: TimelineReducerSideEffect[];
 }

+export function processTimelineResponse(
+  input: ProcessTimelineResponseInput,
+): ProcessTimelineResponseOutput {
+  const {
+    payload,
+    currentTail,
+    currentHead,
+    currentCursor,
+    isInitializing,
+    hasActiveInitDeferred,
+    initRequestDirection,
+  } = input;
+
+  // ------------------------------------------------------------------
+  // Error path: reject init and leave stream state unchanged
+  // ------------------------------------------------------------------
+  if (payload.error) {
+    return {
+      tail: currentTail,
+      head: currentHead,
+      cursor: currentCursor,
+      cursorChanged: false,
+      initResolution: hasActiveInitDeferred ? "reject" : null,
+      clearInitializing: isInitializing,
+      error: payload.error,
+      sideEffects: [],
+    };
+  }
+
+  // ------------------------------------------------------------------
+  // Convert entries to timeline units
+  // ------------------------------------------------------------------
+  const timelineUnits = payload.entries.map((entry) => ({
+    seq: entry.seqStart,
+    event: {
+      type: "timeline",
+      provider: entry.provider,
+      item: entry.item,
+    } as AgentStreamEventPayload,
+    timestamp: new Date(entry.timestamp),
+  }));
+
+  const toHydratedEvents = (
+    units: typeof timelineUnits,
+  ): Array<{ event: AgentStreamEventPayload; timestamp: Date }> =>
+    units.map(({ event, timestamp }) => ({ event, timestamp }));
+
+  // ------------------------------------------------------------------
+  // Derive bootstrap policy (replace vs incremental)
+  // ------------------------------------------------------------------
+  const bootstrapPolicy = deriveBootstrapTailTimelinePolicy({
+    direction: payload.direction,
+    reset: payload.reset,
+    epoch: payload.epoch,
+    endCursor: payload.endCursor,
+    isInitializing,
+    hasActiveInitDeferred,
+  });
+  const replace = bootstrapPolicy.replace;
+
+  let nextTail = currentTail;
+  let nextHead = currentHead;
+  let nextCursor: TimelineCursor | null | undefined = currentCursor;
+  let cursorChanged = false;
+  const sideEffects: TimelineReducerSideEffect[] = [];
+
+  if (replace) {
+    // ----------------------------------------------------------------
+    // Replace path: full hydration from scratch
+    // ----------------------------------------------------------------
+    nextTail = hydrateStreamState(toHydratedEvents(timelineUnits), {
+      source: "canonical",
+    });
+    nextHead = [];
+
+    if (payload.startCursor && payload.endCursor) {
+      nextCursor = {
+        epoch: payload.epoch,
+        startSeq: payload.startCursor.seq,
+        endSeq: payload.endCursor.seq,
+      };
+      cursorChanged = true;
+    } else {
+      nextCursor = null;
+      cursorChanged = true;
+    }
+
+    if (bootstrapPolicy.catchUpCursor) {
+      sideEffects.push({
+        type: "catch_up",
+        cursor: bootstrapPolicy.catchUpCursor,
+      });
+    }
+  } else if (timelineUnits.length > 0) {
+    // ----------------------------------------------------------------
+    // Incremental append path
+    // ----------------------------------------------------------------
+    const acceptedUnits: typeof timelineUnits = [];
+    let cursor = currentCursor;
+    let gapCursor: { epoch: string; endSeq: number } | null = null;
+
+    for (const unit of timelineUnits) {
+      const decision: SessionTimelineSeqDecision = classifySessionTimelineSeq({
+        cursor: cursor ? { epoch: cursor.epoch, endSeq: cursor.endSeq } : null,
+        epoch: payload.epoch,
+        seq: unit.seq,
+      });
+
+      if (decision === "gap") {
+        gapCursor = cursor ? { epoch: cursor.epoch, endSeq: cursor.endSeq } : null;
+        break;
+      }
+      if (decision === "drop_stale" || decision === "drop_epoch") {
+        continue;
+      }
+
+      acceptedUnits.push(unit);
+      if (decision === "init") {
+        cursor = {
+          epoch: payload.epoch,
+          startSeq: unit.seq,
+          endSeq: unit.seq,
+        };
+        continue;
+      }
+      if (!cursor) {
+        continue;
+      }
+      cursor = {
+        ...cursor,
+        endSeq: unit.seq,
+      };
+    }
+
+    if (acceptedUnits.length > 0) {
+      // Flush head to tail before appending canonical entries so that
+      // chronological ordering is preserved.  This matters on mobile where
+      // the server drops live events for backgrounded/unfocused agents:
+      // when the client catches up, the head may still hold stale live
+      // items from before the gap that must be committed ahead of the
+      // canonical gap-fill entries.
+      const baseTail =
+        currentHead.length > 0 ? flushHeadToTail(currentTail, currentHead) : currentTail;
+      if (currentHead.length > 0) {
+        nextHead = [];
+      }
+
+      nextTail = acceptedUnits.reduce<StreamItem[]>(
+        (state, { event, timestamp }) =>
+          reduceStreamUpdate(state, event, timestamp, {
+            source: "canonical",
+          }),
+        baseTail,
+      );
+    }
+
+    if (
+      cursor &&
+      (!currentCursor ||
+        currentCursor.epoch !== cursor.epoch ||
+        currentCursor.startSeq !== cursor.startSeq ||
+        currentCursor.endSeq !== cursor.endSeq)
+    ) {
+      nextCursor = cursor;
+      cursorChanged = true;
+    }
+
+    if (gapCursor) {
+      sideEffects.push({ type: "catch_up", cursor: gapCursor });
+    }
+  }
+
+  // ------------------------------------------------------------------
+  // Flush pending agent updates side effect
+  // ------------------------------------------------------------------
+  sideEffects.push({ type: "flush_pending_updates" });
+
+  // ------------------------------------------------------------------
+  // Init resolution
+  // ------------------------------------------------------------------
+  const shouldResolveDeferredInit = shouldResolveTimelineInit({
+    hasActiveInitDeferred,
+    isInitializing,
+    initRequestDirection,
+    responseDirection: payload.direction,
+    reset: payload.reset,
+  });
+  const clearInitializing = shouldResolveDeferredInit || (isInitializing && !hasActiveInitDeferred);
+
+  const initResolution: "resolve" | "reject" | null = shouldResolveDeferredInit ? "resolve" : null;
+
+  return {
+    tail: nextTail,
+    head: nextHead,
+    cursor: nextCursor,
+    cursorChanged,
+    initResolution,
+    clearInitializing,
+    error: null,
+    sideEffects,
+  };
+}
+
+// ---------------------------------------------------------------------------
+// processAgentStreamEvent
+// ---------------------------------------------------------------------------
+
 export interface ProcessAgentStreamEventInput {
  event: AgentStreamEventPayload;
  seq: number | undefined;
+  epoch: string | undefined;
  currentTail: StreamItem[];
  currentHead: StreamItem[];
  currentCursor: TimelineCursor | undefined;
@@ -96,229 +324,57 @@ export interface ProcessAgentStreamEventOutput {
  sideEffects: AgentStreamReducerSideEffect[];
 }

-function cursorsEqual(
-  left: TimelineCursor | null | undefined,
-  right: TimelineCursor | null | undefined,
-): boolean {
-  if (!left || !right) {
-    return left === right;
-  }
-  return left.startSeq === right.startSeq && left.endSeq === right.endSeq;
-}
-
-function removeSupersededProvisionalItems(
-  head: StreamItem[],
-  event: AgentStreamEventPayload,
-): StreamItem[] {
-  if (head.length === 0 || event.type !== "timeline") {
-    return head;
-  }
-
-  let nextHead = head;
-  if (event.item.type === "assistant_message") {
-    nextHead = head.filter((item) => item.kind !== "assistant_message");
-  } else if (event.item.type === "tool_call") {
-    const committedToolCall = event.item;
-    nextHead = head.filter(
-      (item) =>
-        item.kind !== "tool_call" ||
-        item.payload.source !== "agent" ||
-        item.payload.data.callId !== committedToolCall.callId,
-    );
-  }
-
-  return nextHead.length === head.length ? head : nextHead;
-}
-
-export function processTimelineResponse(
-  input: ProcessTimelineResponseInput,
-): ProcessTimelineResponseOutput {
-  const {
-    payload,
-    currentTail,
-    currentHead,
-    currentCursor,
-    isInitializing,
-    hasActiveInitDeferred,
-    initRequestDirection,
-  } = input;
-
-  if (payload.error) {
-    return {
-      tail: currentTail,
-      head: currentHead,
-      cursor: currentCursor,
-      cursorChanged: false,
-      initResolution: hasActiveInitDeferred ? "reject" : null,
-      clearInitializing: isInitializing,
-      error: payload.error,
-      sideEffects: [],
-    };
-  }
-
-  const timelineUnits = payload.entries.map((entry) => ({
-    seq: entry.seq,
-    event: {
-      type: "timeline",
-      provider: entry.provider,
-      item: entry.item,
-    } as AgentStreamEventPayload,
-    timestamp: new Date(entry.timestamp),
-  }));
-
-  const bootstrapPolicy = deriveBootstrapTailTimelinePolicy({
-    direction: payload.direction,
-    endSeq: payload.endSeq,
-    isInitializing,
-    hasActiveInitDeferred,
-  });
-
-  let nextTail = currentTail;
-  let nextHead = currentHead;
-  let nextCursor: TimelineCursor | null | undefined = currentCursor;
-  let cursorChanged = false;
-  const sideEffects: TimelineReducerSideEffect[] = [];
-
-  if (bootstrapPolicy.replace) {
-    nextTail = hydrateStreamState(
-      timelineUnits.map(({ event, timestamp }) => ({ event, timestamp })),
-      { source: "canonical" },
-    );
-    nextHead = [];
-    nextCursor =
-      typeof payload.startSeq === "number" && typeof payload.endSeq === "number"
-        ? {
-            startSeq: payload.startSeq,
-            endSeq: payload.endSeq,
-          }
-        : null;
-    cursorChanged = !cursorsEqual(currentCursor, nextCursor);
-
-    if (bootstrapPolicy.catchUpCursor) {
-      sideEffects.push({
-        type: "catch_up",
-        cursor: bootstrapPolicy.catchUpCursor,
-      });
-    }
-  } else if (payload.direction === "before") {
-    const prepended = hydrateStreamState(
-      timelineUnits.map(({ event, timestamp }) => ({ event, timestamp })),
-      { source: "canonical" },
-    );
-    nextTail = prepended.length > 0 ? [...prepended, ...currentTail] : currentTail;
-    const derivedCursor =
-      typeof payload.startSeq === "number"
-        ? {
-            startSeq: payload.startSeq,
-            endSeq: currentCursor?.endSeq ?? payload.endSeq ?? payload.startSeq,
-          }
-        : currentCursor;
-    nextCursor = derivedCursor;
-    cursorChanged = !cursorsEqual(currentCursor, derivedCursor);
-  } else if (timelineUnits.length > 0) {
-    const acceptedUnits: typeof timelineUnits = [];
-    let cursor = currentCursor;
-    let gapCursor: { endSeq: number } | null = null;
-
-    for (const unit of timelineUnits) {
-      const decision: SessionTimelineSeqDecision = classifySessionTimelineSeq({
-        cursor: cursor ? { endSeq: cursor.endSeq } : null,
-        seq: unit.seq,
-      });
-
-      if (decision === "gap") {
-        gapCursor = cursor ? { endSeq: cursor.endSeq } : null;
-        break;
-      }
-      if (decision === "drop_stale") {
-        continue;
-      }
-
-      acceptedUnits.push(unit);
-      cursor =
-        decision === "init"
-          ? { startSeq: unit.seq, endSeq: unit.seq }
-          : { ...(cursor ?? { startSeq: unit.seq, endSeq: unit.seq }), endSeq: unit.seq };
-      nextHead = removeSupersededProvisionalItems(nextHead, unit.event);
-    }
-
-    if (acceptedUnits.length > 0) {
-      nextTail = acceptedUnits.reduce<StreamItem[]>(
-        (state, { event, timestamp }) =>
-          reduceStreamUpdate(state, event, timestamp, {
-            source: "canonical",
-          }),
-        currentTail,
-      );
-    }
-
-    if (cursor && !cursorsEqual(currentCursor, cursor)) {
-      nextCursor = cursor;
-      cursorChanged = true;
-    }
-
-    if (gapCursor) {
-      sideEffects.push({ type: "catch_up", cursor: gapCursor });
-    }
-  }
-
-  sideEffects.push({ type: "flush_pending_updates" });
-
-  const shouldResolveDeferredInit = shouldResolveTimelineInit({
-    hasActiveInitDeferred,
-    isInitializing,
-    initRequestDirection,
-    responseDirection: payload.direction,
-  });
-  const clearInitializing = shouldResolveDeferredInit || (isInitializing && !hasActiveInitDeferred);
-
-  return {
-    tail: nextTail,
-    head: nextHead,
-    cursor: nextCursor,
-    cursorChanged,
-    initResolution: shouldResolveDeferredInit ? "resolve" : null,
-    clearInitializing,
-    error: null,
-    sideEffects,
-  };
-}
-
 export function processAgentStreamEvent(
  input: ProcessAgentStreamEventInput,
 ): ProcessAgentStreamEventOutput {
-  const { event, seq, currentTail, currentHead, currentCursor, currentAgent, timestamp } = input;
+  const { event, seq, epoch, currentTail, currentHead, currentCursor, currentAgent, timestamp } =
+    input;

  let shouldApplyStreamEvent = true;
  let nextTimelineCursor: TimelineCursor | null = null;
  let cursorChanged = false;
  const sideEffects: AgentStreamReducerSideEffect[] = [];

-  if (event.type === "timeline" && typeof seq === "number") {
+  // ------------------------------------------------------------------
+  // Timeline sequencing gate
+  // ------------------------------------------------------------------
+  if (event.type === "timeline" && typeof seq === "number" && typeof epoch === "string") {
    const decision = classifySessionTimelineSeq({
-      cursor: currentCursor ? { endSeq: currentCursor.endSeq } : null,
+      cursor: currentCursor ? { epoch: currentCursor.epoch, endSeq: currentCursor.endSeq } : null,
+      epoch,
      seq,
    });

-    if (decision === "gap") {
+    if (decision === "init") {
+      nextTimelineCursor = { epoch, startSeq: seq, endSeq: seq };
+      cursorChanged = true;
+    } else if (decision === "accept") {
+      nextTimelineCursor = {
+        ...(currentCursor ?? { epoch, startSeq: seq, endSeq: seq }),
+        epoch,
+        endSeq: seq,
+      };
+      cursorChanged = true;
+    } else if (decision === "gap") {
      shouldApplyStreamEvent = false;
      if (currentCursor) {
        sideEffects.push({
          type: "catch_up",
-          cursor: { endSeq: currentCursor.endSeq },
+          cursor: {
+            epoch: currentCursor.epoch,
+            endSeq: currentCursor.endSeq,
+          },
        });
      }
-    } else if (decision === "drop_stale") {
-      shouldApplyStreamEvent = false;
    } else {
-      nextTimelineCursor =
-        decision === "init"
-          ? { startSeq: seq, endSeq: seq }
-          : { ...(currentCursor ?? { startSeq: seq, endSeq: seq }), endSeq: seq };
-      cursorChanged = !cursorsEqual(currentCursor, nextTimelineCursor);
+      // drop_stale or drop_epoch
+      shouldApplyStreamEvent = false;
    }
  }

+  // ------------------------------------------------------------------
+  // Apply stream event to tail/head
+  // ------------------------------------------------------------------
  const { tail, head, changedTail, changedHead } = shouldApplyStreamEvent
    ? applyStreamEvent({
        tail: currentTail,
@@ -334,6 +390,9 @@ export function processAgentStreamEvent(
        changedHead: false,
      };

+  // ------------------------------------------------------------------
+  // Optimistic lifecycle status
+  // ------------------------------------------------------------------
  let agentPatch: AgentPatch | null = null;
  let agentChanged = false;

@@ -2,42 +2,26 @@ import { describe, expect, it } from "vitest";
 import { classifySessionTimelineSeq } from "./session-timeline-seq-gate";
 import {
  deriveBootstrapTailTimelinePolicy,
-  deriveInitialTimelineRequest,
  shouldResolveTimelineInit,
 } from "./session-timeline-bootstrap-policy";

-describe("deriveInitialTimelineRequest", () => {
-  it("uses tail bootstrap when history has not synced yet", () => {
-    expect(
-      deriveInitialTimelineRequest({
-        cursor: { seq: 42 },
-        hasAuthoritativeHistory: false,
-        initialTimelineLimit: 200,
-      }),
-    ).toEqual({
-      direction: "tail",
-      limit: 200,
-    });
-  });
-
-  it("uses catch-up after the committed cursor once history is synced", () => {
-    expect(
-      deriveInitialTimelineRequest({
-        cursor: { seq: 42 },
-        hasAuthoritativeHistory: true,
-        initialTimelineLimit: 200,
-      }),
-    ).toEqual({
-      direction: "after",
-      cursor: { seq: 42 },
-      limit: 0,
-    });
-  });
-});
-
 describe("deriveBootstrapTailTimelinePolicy", () => {
+  it("always replaces on explicit reset without catch-up cursor", () => {
+    const policy = deriveBootstrapTailTimelinePolicy({
+      direction: "after",
+      reset: true,
+      epoch: "epoch-1",
+      endCursor: { seq: 200 },
+      isInitializing: false,
+      hasActiveInitDeferred: false,
+    });
+
+    expect(policy.replace).toBe(true);
+    expect(policy.catchUpCursor).toBeNull();
+  });
+
  it("forces baseline replace and canonical catch-up for init tail race", () => {
-    const advancedCursor = { endSeq: 205 };
+    const advancedCursor = { epoch: "epoch-1", endSeq: 205 };
    const tailSeqStart = 101;
    const tailSeqEnd = 200;

@@ -45,6 +29,7 @@ describe("deriveBootstrapTailTimelinePolicy", () => {
    for (let seq = tailSeqStart; seq <= tailSeqEnd; seq += 1) {
      const decision = classifySessionTimelineSeq({
        cursor: advancedCursor,
+        epoch: "epoch-1",
        seq,
      });
      if (decision === "accept" || decision === "init") {
@@ -55,13 +40,16 @@ describe("deriveBootstrapTailTimelinePolicy", () => {

    const policy = deriveBootstrapTailTimelinePolicy({
      direction: "tail",
-      endSeq: 200,
+      reset: false,
+      epoch: "epoch-1",
+      endCursor: { seq: 200 },
      isInitializing: true,
      hasActiveInitDeferred: true,
    });

    expect(policy.replace).toBe(true);
    expect(policy.catchUpCursor).toEqual({
+      epoch: "epoch-1",
      endSeq: 200,
    });
  });
@@ -69,7 +57,9 @@ describe("deriveBootstrapTailTimelinePolicy", () => {
  it("does not replace non-bootstrap, non-reset responses", () => {
    const policy = deriveBootstrapTailTimelinePolicy({
      direction: "tail",
-      endSeq: 200,
+      reset: false,
+      epoch: "epoch-1",
+      endCursor: { seq: 200 },
      isInitializing: false,
      hasActiveInitDeferred: false,
    });
@@ -87,6 +77,7 @@ describe("shouldResolveTimelineInit", () => {
        isInitializing: true,
        initRequestDirection: "tail",
        responseDirection: "tail",
+        reset: false,
      }),
    ).toBe(true);
  });
@@ -98,6 +89,7 @@ describe("shouldResolveTimelineInit", () => {
        isInitializing: true,
        initRequestDirection: "tail",
        responseDirection: "after",
+        reset: false,
      }),
    ).toBe(false);
  });
@@ -109,6 +101,7 @@ describe("shouldResolveTimelineInit", () => {
        isInitializing: true,
        initRequestDirection: "after",
        responseDirection: "after",
+        reset: false,
      }),
    ).toBe(true);
  });
@@ -6,6 +6,7 @@ type BootstrapTailCursor = {
 } | null;

 type InitialTimelineCursor = {
+  epoch: string;
  seq: number;
 } | null;

@@ -19,37 +20,48 @@ export function deriveInitialTimelineRequest({
  initialTimelineLimit: number;
 }): {
  direction: "tail" | "after";
-  cursor?: { seq: number };
+  cursor?: { epoch: string; seq: number };
  limit: number;
+  projection: "canonical";
 } {
  if (!hasAuthoritativeHistory || !cursor) {
    return {
      direction: "tail",
      limit: initialTimelineLimit,
+      projection: "canonical",
    };
  }

  return {
    direction: "after",
-    cursor: { seq: cursor.seq },
+    cursor: { epoch: cursor.epoch, seq: cursor.seq },
    limit: 0,
+    projection: "canonical",
  };
 }

 export function deriveBootstrapTailTimelinePolicy({
  direction,
-  endSeq,
+  reset,
+  epoch,
+  endCursor,
  isInitializing,
  hasActiveInitDeferred,
 }: {
  direction: TimelineDirection;
-  endSeq: number | null;
+  reset: boolean;
+  epoch: string;
+  endCursor: BootstrapTailCursor;
  isInitializing: boolean;
  hasActiveInitDeferred: boolean;
 }): {
  replace: boolean;
-  catchUpCursor: { endSeq: number } | null;
+  catchUpCursor: { epoch: string; endSeq: number } | null;
 } {
+  if (reset) {
+    return { replace: true, catchUpCursor: null };
+  }
+
  const isBootstrapTailInit = direction === "tail" && isInitializing && hasActiveInitDeferred;
  if (!isBootstrapTailInit) {
    return { replace: false, catchUpCursor: null };
@@ -57,7 +69,7 @@ export function deriveBootstrapTailTimelinePolicy({

  return {
    replace: true,
-    catchUpCursor: typeof endSeq === "number" ? { endSeq } : null,
+    catchUpCursor: endCursor ? { epoch, endSeq: endCursor.seq } : null,
  };
 }

@@ -66,14 +78,19 @@ export function shouldResolveTimelineInit({
  isInitializing,
  initRequestDirection,
  responseDirection,
+  reset,
 }: {
  hasActiveInitDeferred: boolean;
  isInitializing: boolean;
  initRequestDirection: InitRequestDirection;
  responseDirection: TimelineDirection;
+  reset: boolean;
 }): boolean {
  if (!hasActiveInitDeferred || !isInitializing) {
    return false;
  }
+  if (reset) {
+    return true;
+  }
  return responseDirection === initRequestDirection;
 }
@@ -5,7 +5,8 @@ describe("classifySessionTimelineSeq", () => {
  it("accepts contiguous forward seq", () => {
    expect(
      classifySessionTimelineSeq({
-        cursor: { endSeq: 4 },
+        cursor: { epoch: "epoch-1", endSeq: 4 },
+        epoch: "epoch-1",
        seq: 5,
      }),
    ).toBe("accept");
@@ -14,7 +15,8 @@ describe("classifySessionTimelineSeq", () => {
  it("drops stale seq older than the current end", () => {
    expect(
      classifySessionTimelineSeq({
-        cursor: { endSeq: 8 },
+        cursor: { epoch: "epoch-1", endSeq: 8 },
+        epoch: "epoch-1",
        seq: 7,
      }),
    ).toBe("drop_stale");
@@ -23,16 +25,28 @@ describe("classifySessionTimelineSeq", () => {
  it("drops duplicate replay seq equal to the current end", () => {
    expect(
      classifySessionTimelineSeq({
-        cursor: { endSeq: 8 },
+        cursor: { epoch: "epoch-1", endSeq: 8 },
+        epoch: "epoch-1",
        seq: 8,
      }),
    ).toBe("drop_stale");
  });

+  it("drops epoch mismatch", () => {
+    expect(
+      classifySessionTimelineSeq({
+        cursor: { epoch: "epoch-1", endSeq: 4 },
+        epoch: "epoch-2",
+        seq: 5,
+      }),
+    ).toBe("drop_epoch");
+  });
+
  it("initializes when cursor is null", () => {
    expect(
      classifySessionTimelineSeq({
        cursor: null,
+        epoch: "epoch-1",
        seq: 1,
      }),
    ).toBe("init");
@@ -41,7 +55,8 @@ describe("classifySessionTimelineSeq", () => {
  it("classifies forward gaps", () => {
    expect(
      classifySessionTimelineSeq({
-        cursor: { endSeq: 4 },
+        cursor: { epoch: "epoch-1", endSeq: 4 },
+        epoch: "epoch-1",
        seq: 9,
      }),
    ).toBe("gap");
@@ -1,22 +1,28 @@
 export type SessionTimelineSeqCursor =
  | {
+      epoch: string;
      endSeq: number;
    }
  | null
  | undefined;

-export type SessionTimelineSeqDecision = "accept" | "drop_stale" | "gap" | "init";
+export type SessionTimelineSeqDecision = "accept" | "drop_stale" | "drop_epoch" | "gap" | "init";

 export function classifySessionTimelineSeq({
  cursor,
+  epoch,
  seq,
 }: {
  cursor: SessionTimelineSeqCursor;
+  epoch: string;
  seq: number;
 }): SessionTimelineSeqDecision {
  if (!cursor) {
    return "init";
  }
+  if (cursor.epoch !== epoch) {
+    return "drop_epoch";
+  }
  if (seq <= cursor.endSeq) {
    return "drop_stale";
  }
@@ -2,10 +2,11 @@ import { describe, expect, it } from "vitest";
 import { __private__ } from "./use-agent-initialization";

 describe("useAgentInitialization timeline request policy", () => {
-  it("uses committed tail bootstrap when history has not synced yet", () => {
+  it("uses canonical tail bootstrap when history has not synced yet", () => {
    expect(
      __private__.deriveInitialTimelineRequest({
        cursor: {
+          epoch: "epoch-1",
          seq: 42,
        },
        hasAuthoritativeHistory: false,
@@ -14,10 +15,11 @@ describe("useAgentInitialization timeline request policy", () => {
    ).toEqual({
      direction: "tail",
      limit: 200,
+      projection: "canonical",
    });
  });

-  it("uses committed tail bootstrap when cursor is missing", () => {
+  it("uses canonical tail bootstrap when cursor is missing", () => {
    expect(
      __private__.deriveInitialTimelineRequest({
        cursor: null,
@@ -27,13 +29,15 @@ describe("useAgentInitialization timeline request policy", () => {
    ).toEqual({
      direction: "tail",
      limit: 200,
+      projection: "canonical",
    });
  });

-  it("uses committed catch-up after the current cursor once history is synced", () => {
+  it("uses canonical catch-up after the current cursor once history is synced", () => {
    expect(
      __private__.deriveInitialTimelineRequest({
        cursor: {
+          epoch: "epoch-1",
          seq: 42,
        },
        hasAuthoritativeHistory: true,
@@ -41,8 +45,9 @@ describe("useAgentInitialization timeline request policy", () => {
      }),
    ).toEqual({
      direction: "after",
-      cursor: { seq: 42 },
+      cursor: { epoch: "epoch-1", seq: 42 },
      limit: 0,
+      projection: "canonical",
    });
  });

@@ -56,6 +61,7 @@ describe("useAgentInitialization timeline request policy", () => {
    ).toEqual({
      direction: "tail",
      limit: 0,
+      projection: "canonical",
    });
  });

@@ -60,7 +60,7 @@ export function useAgentInitialization({
      const hasAuthoritativeHistory =
        session?.agentAuthoritativeHistoryApplied.get(agentId) === true;
      const timelineRequest = deriveInitialTimelineRequest({
-        cursor: cursor ? { seq: cursor.endSeq } : null,
+        cursor: cursor ? { epoch: cursor.epoch, seq: cursor.endSeq } : null,
        hasAuthoritativeHistory,
        initialTimelineLimit,
      });
@@ -107,6 +107,7 @@ export function useAgentInitialization({
        await client.fetchAgentTimeline(agentId, {
          direction: "tail",
          limit: initialTimelineLimit,
+          projection: "canonical",
        });
      } catch (error) {
        setAgentInitializing(agentId, false);
@@ -1,61 +0,0 @@
-import { beforeEach, describe, expect, it, vi } from "vitest";
-
-vi.mock("@react-native-async-storage/async-storage", () => {
-  const storage = new Map<string, string>();
-  return {
-    default: {
-      getItem: vi.fn(async (key: string) => storage.get(key) ?? null),
-      setItem: vi.fn(async (key: string, value: string) => {
-        storage.set(key, value);
-      }),
-      removeItem: vi.fn(async (key: string) => {
-        storage.delete(key);
-      }),
-    },
-  };
-});
-
-import { AGENT_PROVIDER_DEFINITIONS } from "@server/server/agent/provider-manifest";
-import {
-  __providerRecencyStoreTestUtils,
-  sortProvidersByRecency,
-  useProviderRecencyStore,
-} from "./provider-recency-store";
-
-describe("provider-recency-store", () => {
-  beforeEach(() => {
-    useProviderRecencyStore.setState({
-      recentProviderIds: [],
-      recordUsage: useProviderRecencyStore.getState().recordUsage,
-    });
-  });
-
-  it("sorts used providers first and keeps unused providers in default order", () => {
-    const sorted = sortProvidersByRecency(AGENT_PROVIDER_DEFINITIONS, ["codex"]);
-
-    expect(sorted.map((provider) => provider.id)).toEqual([
-      "codex",
-      ...AGENT_PROVIDER_DEFINITIONS.filter((provider) => provider.id !== "codex").map(
-        (provider) => provider.id,
-      ),
-    ]);
-  });
-
-  it("moves the latest provider to the front without duplicating prior entries", () => {
-    useProviderRecencyStore.getState().recordUsage("codex");
-    useProviderRecencyStore.getState().recordUsage("opencode");
-    useProviderRecencyStore.getState().recordUsage("codex");
-
-    expect(useProviderRecencyStore.getState().recentProviderIds).toEqual(["codex", "opencode"]);
-  });
-
-  it("filters invalid and duplicate providers during migration", () => {
-    expect(
-      __providerRecencyStoreTestUtils.migratePersistedState({
-        recentProviderIds: ["codex", "invalid", "codex", "claude"],
-      }),
-    ).toEqual({
-      recentProviderIds: ["codex", "claude"],
-    });
-  });
-});
@@ -1,131 +0,0 @@
-import { useMemo } from "react";
-import AsyncStorage from "@react-native-async-storage/async-storage";
-import type { AgentProvider } from "@server/server/agent/agent-sdk-types";
-import {
-  AGENT_PROVIDER_DEFINITIONS,
-  isValidAgentProvider,
-  type AgentProviderDefinition,
-} from "@server/server/agent/provider-manifest";
-import { create } from "zustand";
-import { createJSONStorage, persist } from "zustand/middleware";
-
-const PROVIDER_RECENCY_STORE_VERSION = 1;
-
-interface ProviderRecencyStoreState {
-  recentProviderIds: AgentProvider[];
-  recordUsage: (providerId: AgentProvider) => void;
-}
-
-function sanitizeRecentProviderIds(providerIds: readonly string[] | undefined): AgentProvider[] {
-  if (!providerIds || providerIds.length === 0) {
-    return [];
-  }
-
-  const seen = new Set<AgentProvider>();
-  const sanitized: AgentProvider[] = [];
-  for (const providerId of providerIds) {
-    if (!isValidAgentProvider(providerId)) {
-      continue;
-    }
-    if (seen.has(providerId)) {
-      continue;
-    }
-    seen.add(providerId);
-    sanitized.push(providerId);
-  }
-  return sanitized;
-}
-
-export function sortProvidersByRecency<T extends { id: string }>(
-  providers: readonly T[],
-  recentProviderIds: readonly string[],
-): T[] {
-  if (providers.length <= 1) {
-    return [...providers];
-  }
-
-  const recentRank = new Map<string, number>();
-  for (const providerId of recentProviderIds) {
-    if (recentRank.has(providerId)) {
-      continue;
-    }
-    recentRank.set(providerId, recentRank.size);
-  }
-
-  return providers
-    .map((provider, defaultIndex) => ({
-      provider,
-      defaultIndex,
-      recentIndex: recentRank.get(provider.id) ?? Number.POSITIVE_INFINITY,
-    }))
-    .sort((left, right) => {
-      if (left.recentIndex !== right.recentIndex) {
-        return left.recentIndex - right.recentIndex;
-      }
-      return left.defaultIndex - right.defaultIndex;
-    })
-    .map((entry) => entry.provider);
-}
-
-function migratePersistedState(
-  state: unknown,
-): Pick<ProviderRecencyStoreState, "recentProviderIds"> {
-  const record = state as { recentProviderIds?: string[] } | null | undefined;
-  return {
-    recentProviderIds: sanitizeRecentProviderIds(record?.recentProviderIds),
-  };
-}
-
-export const useProviderRecencyStore = create<ProviderRecencyStoreState>()(
-  persist(
-    (set) => ({
-      recentProviderIds: [],
-      recordUsage: (providerId) => {
-        if (!isValidAgentProvider(providerId)) {
-          return;
-        }
-
-        set((state) => ({
-          recentProviderIds: [
-            providerId,
-            ...state.recentProviderIds.filter((id) => id !== providerId),
-          ],
-        }));
-      },
-    }),
-    {
-      name: "agent-provider-recency",
-      version: PROVIDER_RECENCY_STORE_VERSION,
-      storage: createJSONStorage(() => AsyncStorage),
-      partialize: (state) => ({
-        recentProviderIds: state.recentProviderIds,
-      }),
-      migrate: (persistedState) => migratePersistedState(persistedState),
-    },
-  ),
-);
-
-export function useProviderRecency(
-  availableProviders: readonly AgentProviderDefinition[] = AGENT_PROVIDER_DEFINITIONS,
-): {
-  providers: AgentProviderDefinition[];
-  recordUsage: (providerId: AgentProvider) => void;
-} {
-  const recentProviderIds = useProviderRecencyStore((state) => state.recentProviderIds);
-  const recordUsage = useProviderRecencyStore((state) => state.recordUsage);
-
-  const providers = useMemo(
-    () => sortProvidersByRecency(availableProviders, recentProviderIds),
-    [availableProviders, recentProviderIds],
-  );
-
-  return {
-    providers,
-    recordUsage,
-  };
-}
-
-export const __providerRecencyStoreTestUtils = {
-  migratePersistedState,
-  sanitizeRecentProviderIds,
-};
@@ -212,6 +212,7 @@ export type DaemonServerInfo = {
 };

 export interface AgentTimelineCursorState {
+  epoch: string;
  startSeq: number;
  endSeq: number;
 }
@@ -729,7 +729,7 @@ function finalizeHeadItems(head: StreamItem[]): StreamItem[] {
 /**
 * Flush head items to tail, avoiding duplicates.
 */
-function flushHeadToTail(tail: StreamItem[], head: StreamItem[]): StreamItem[] {
+export function flushHeadToTail(tail: StreamItem[], head: StreamItem[]): StreamItem[] {
  if (head.length === 0) {
    return tail;
  }
@@ -11,6 +11,7 @@ export async function fetchProjectedTimelineItems(
  const timeline = await input.client.fetchAgentTimeline(input.agentId, {
    direction: "tail",
    limit: 0,
+    projection: "projected",
  });
  return timeline.entries.map((entry) => entry.item);
 }
@@ -2032,15 +2032,24 @@ describe("DaemonClient", () => {
          agentId: "agent_cli",
          agent: null,
          direction: "tail",
-          startSeq: 1,
-          endSeq: 1,
+          projection: "projected",
+          epoch: "epoch-1",
+          reset: false,
+          staleCursor: false,
+          gap: false,
+          window: { minSeq: 1, maxSeq: 1, nextSeq: 2 },
+          startCursor: { epoch: "epoch-1", seq: 1 },
+          endCursor: { epoch: "epoch-1", seq: 1 },
          hasOlder: false,
          hasNewer: false,
          entries: [
            {
              timestamp: "2026-02-08T20:20:00.000Z",
              provider: "codex",
-              seq: 1,
+              seqStart: 1,
+              seqEnd: 1,
+              sourceSeqRanges: [{ startSeq: 1, endSeq: 1 }],
+              collapsed: [],
              item: {
                type: "tool_call",
                callId: "call_cli_snapshot",
@@ -2117,15 +2126,24 @@ describe("DaemonClient", () => {
          agentId: "agent_cli",
          agent: null,
          direction: "tail",
-          startSeq: 1,
-          endSeq: 1,
+          projection: "projected",
+          epoch: "epoch-1",
+          reset: false,
+          staleCursor: false,
+          gap: false,
+          window: { minSeq: 1, maxSeq: 1, nextSeq: 2 },
+          startCursor: { epoch: "epoch-1", seq: 1 },
+          endCursor: { epoch: "epoch-1", seq: 1 },
          hasOlder: false,
          hasNewer: false,
          entries: [
            {
              timestamp: "2026-02-08T20:20:00.000Z",
              provider: "codex",
-              seq: 1,
+              seqStart: 1,
+              seqEnd: 1,
+              sourceSeqRanges: [{ startSeq: 1, endSeq: 1 }],
+              collapsed: [],
              item: {
                type: "tool_call",
                callId: "call_cli_invalid",
@@ -152,6 +152,7 @@ export type DaemonEvent =
      event: AgentStreamEventPayload;
      timestamp: string;
      seq?: number;
+      epoch?: string;
    }
  | { type: "status"; payload: { status: string } & Record<string, unknown> }
  | { type: "agent_deleted"; agentId: string }
@@ -336,13 +337,13 @@ type ScheduleDeletePayload = Extract<
 export type FetchAgentTimelinePayload = FetchAgentTimelineResponseMessage["payload"];

 export type FetchAgentTimelineDirection = FetchAgentTimelinePayload["direction"];
-export type FetchAgentTimelineCursor = NonNullable<
-  Extract<SessionInboundMessage, { type: "fetch_agent_timeline_request" }>["cursor"]
->;
+export type FetchAgentTimelineProjection = FetchAgentTimelinePayload["projection"];
+export type FetchAgentTimelineCursor = NonNullable<FetchAgentTimelinePayload["startCursor"]>;
 export type FetchAgentTimelineOptions = {
  direction?: FetchAgentTimelineDirection;
  cursor?: FetchAgentTimelineCursor;
  limit?: number;
+  projection?: FetchAgentTimelineProjection;
  requestId?: string;
 };

@@ -1673,6 +1674,7 @@ export class DaemonClient {
      ...(options.direction ? { direction: options.direction } : {}),
      ...(options.cursor ? { cursor: options.cursor } : {}),
      ...(typeof options.limit === "number" ? { limit: options.limit } : {}),
+      ...(options.projection ? { projection: options.projection } : {}),
    });

    const payload = await this.sendRequest({
@@ -3899,6 +3901,7 @@ export class DaemonClient {
          event: msg.payload.event,
          timestamp: msg.payload.timestamp,
          ...(typeof msg.payload.seq === "number" ? { seq: msg.payload.seq } : {}),
+          ...(typeof msg.payload.epoch === "string" ? { epoch: msg.payload.epoch } : {}),
        };
      case "status":
        return { type: "status", payload: msg.payload };
@@ -1273,7 +1273,7 @@ describe("AgentManager", () => {
    }
  });

-  test("fetchTimeline returns committed rows after a known seq without reset metadata", async () => {
+  test("fetchTimeline returns full timeline with reset when cursor epoch is stale", async () => {
    const workdir = mkdtempSync(join(tmpdir(), "agent-manager-timeline-stale-"));
    const storagePath = join(workdir, "agents");
    const storage = new AgentStorage(storagePath, logger);
@@ -1291,42 +1291,40 @@ describe("AgentManager", () => {
      cwd: workdir,
    });

-    for (let seq = 1; seq <= 120; seq += 1) {
-      await manager.appendTimelineItem(snapshot.id, {
-        type: "assistant_message",
-        text: `committed row ${seq}`,
-      });
-    }
-
-    const baseline = await manager.fetchTimeline(snapshot.id, {
-      direction: "tail",
-      limit: 0,
-    });
-    expect(baseline.rows).toHaveLength(120);
-
-    await manager.emitLiveTimelineItem(snapshot.id, {
+    await manager.appendTimelineItem(snapshot.id, {
      type: "assistant_message",
-      text: "partial reply",
+      text: "one",
    });
    await manager.appendTimelineItem(snapshot.id, {
      type: "assistant_message",
-      text: "finalized reply",
+      text: "two",
+    });
+    await manager.appendTimelineItem(snapshot.id, {
+      type: "assistant_message",
+      text: "three",
    });

-    const result = await manager.fetchTimeline(snapshot.id, {
+    const baseline = manager.fetchTimeline(snapshot.id, {
+      direction: "tail",
+      limit: 2,
+    });
+    expect(baseline.rows).toHaveLength(2);
+
+    const result = manager.fetchTimeline(snapshot.id, {
      direction: "after",
      cursor: {
-        seq: 120,
+        epoch: "stale-epoch",
+        seq: baseline.rows[baseline.rows.length - 1]!.seq,
      },
-      limit: 0,
+      limit: 1,
    });

-    expect(result.rows).toHaveLength(1);
-    expect(result.rows[0]?.seq).toBe(121);
-    expect(result.rows[0]?.item).toEqual({
-      type: "assistant_message",
-      text: "finalized reply",
-    });
+    expect(result.reset).toBe(true);
+    expect(result.staleCursor).toBe(true);
+    expect(result.gap).toBe(false);
+    expect(result.rows).toHaveLength(3);
+    expect(result.rows[0]?.seq).toBe(1);
+    expect(result.rows[result.rows.length - 1]?.seq).toBe(3);
  });

  test("getTimelineRows falls back to the in-memory timeline when no durable store is configured", async () => {
@@ -1448,6 +1446,7 @@ describe("AgentManager", () => {

    const streamEvents: Array<{
      seq?: number;
+      epoch?: string;
      eventType?: string;
      itemType?: string;
      text?: string;
@@ -1459,6 +1458,7 @@ describe("AgentManager", () => {
        }
        streamEvents.push({
          seq: event.seq,
+          epoch: event.epoch,
          eventType: event.event.type,
          itemType: event.event.type === "timeline" ? event.event.item.type : undefined,
          text:
@@ -1487,12 +1487,14 @@ describe("AgentManager", () => {
      itemType: "assistant_message",
      text: "final ",
      seq: 1,
+      epoch: expect.any(String),
    });
    expect(assistantTimelineEvents[1]).toMatchObject({
      eventType: "timeline",
      itemType: "assistant_message",
      text: "reply",
      seq: 2,
+      epoch: expect.any(String),
    });

    expect(manager.getTimeline(snapshot.id)).toEqual([
@@ -1510,6 +1512,8 @@ describe("AgentManager", () => {
      limit: 0,
    });
    expect(fetched.rows).toHaveLength(2);
+    expect(assistantTimelineEvents[0]?.epoch).toBe(fetched.epoch);
+    expect(assistantTimelineEvents[1]?.epoch).toBe(fetched.epoch);
    expect(fetched.rows[0]?.item).toEqual({
      type: "assistant_message",
      text: "final ",
@@ -63,6 +63,7 @@ export type AgentManagerEvent =
      agentId: string;
      event: AgentStreamEvent;
      seq?: number;
+      epoch?: string;
    };

 export type AgentSubscriber = (event: AgentManagerEvent) => void;
@@ -584,18 +585,8 @@ export class AgentManager {
    return this.timelineStore.getRows(id);
  }

-  async fetchTimeline(
-    id: string,
-    options?: AgentTimelineFetchOptions,
-  ): Promise<AgentTimelineFetchResult> {
+  fetchTimeline(id: string, options?: AgentTimelineFetchOptions): AgentTimelineFetchResult {
    this.requireAgent(id);
-    const agent = this.agents.get(id);
-    if (agent && !agent.historyPrimed) {
-      await this.hydrateTimelineFromLegacyProviderHistory(agent);
-    }
-    if (this.durableTimelineStore) {
-      return await this.durableTimelineStore.fetchCommitted(id, options);
-    }
    return this.timelineStore.fetch(id, options);
  }

@@ -1053,6 +1044,7 @@ export class AgentManager {
      },
      {
        seq: row.seq,
+        epoch: this.timelineStore.getEpoch(agentId),
      },
    );
    if (options?.emitState !== false) {
@@ -1073,6 +1065,7 @@ export class AgentManager {
      },
      {
        seq: row.seq,
+        epoch: this.timelineStore.getEpoch(agentId),
      },
    );
    await this.persistSnapshot(agent);
@@ -2404,6 +2397,7 @@ export class AgentManager {
        timelineRow
          ? {
              seq: timelineRow.seq,
+              epoch: this.timelineStore.getEpoch(agent.id),
            }
          : undefined,
      );
@@ -2445,6 +2439,7 @@ export class AgentManager {
      },
      {
        seq: row.seq,
+        epoch: this.timelineStore.getEpoch(agent.id),
      },
    );
  }
@@ -2604,7 +2599,7 @@ export class AgentManager {
  private dispatchStream(
    agentId: string,
    event: AgentStreamEvent,
-    metadata?: { seq?: number },
+    metadata?: { seq?: number; epoch?: string },
  ): void {
    this.dispatch({ type: "agent_stream", agentId, event, ...metadata });
  }
@@ -7,6 +7,7 @@ export type AgentTimelineRow = {
 };

 export type AgentTimelineCursor = {
+  epoch: string;
  seq: number;
 };

@@ -30,7 +31,11 @@ export type AgentTimelineWindow = {
 };

 export type AgentTimelineFetchResult = {
+  epoch: string;
  direction: AgentTimelineFetchDirection;
+  reset: boolean;
+  staleCursor: boolean;
+  gap: boolean;
  window: AgentTimelineWindow;
  hasOlder: boolean;
  hasNewer: boolean;
@@ -1,3 +1,4 @@
+import { randomUUID } from "node:crypto";
 import type { AgentTimelineItem } from "./agent-sdk-types.js";
 import type {
  AgentTimelineFetchOptions,
@@ -8,11 +9,13 @@ import type {
 export type SeedAgentTimelineOptions = {
  items?: readonly AgentTimelineItem[];
  rows?: readonly AgentTimelineRow[];
+  epoch?: string;
  nextSeq?: number;
  timestamp?: string;
 };

 type AgentTimelineState = {
+  epoch: string;
  rows: AgentTimelineRow[];
  nextSeq: number;
 };
@@ -45,6 +48,7 @@ export class InMemoryAgentTimelineStore {
      : this.buildRowsFromItems(options?.items ?? [], options?.nextSeq ?? 1, timestamp);
    const nextSeq = options?.nextSeq ?? (rows.length ? rows[rows.length - 1]!.seq + 1 : 1);
    this.states.set(agentId, {
+      epoch: options?.epoch ?? randomUUID(),
      rows,
      nextSeq,
    });
@@ -62,6 +66,10 @@ export class InMemoryAgentTimelineStore {
    return this.requireState(agentId).rows.map(cloneRow);
  }

+  getEpoch(agentId: string): string {
+    return this.requireState(agentId).epoch;
+  }
+
  fetch(agentId: string, options?: AgentTimelineFetchOptions): AgentTimelineFetchResult {
    const state = this.requireState(agentId);
    const direction = options?.direction ?? "tail";
@@ -81,9 +89,43 @@ export class InMemoryAgentTimelineStore {
      nextSeq: state.nextSeq,
    };

+    if (cursor && typeof cursor.epoch === "string" && cursor.epoch !== state.epoch) {
+      return {
+        epoch: state.epoch,
+        direction,
+        reset: true,
+        staleCursor: true,
+        gap: false,
+        window,
+        hasOlder: false,
+        hasNewer: false,
+        rows: state.rows.map(cloneRow),
+      };
+    }
+
+    const cloneRows = (items: AgentTimelineRow[]) => items.map(cloneRow);
+
+    if (direction === "after" && cursor && state.rows.length > 0 && cursor.seq < minSeq - 1) {
+      return {
+        epoch: state.epoch,
+        direction,
+        reset: true,
+        staleCursor: false,
+        gap: true,
+        window,
+        hasOlder: false,
+        hasNewer: false,
+        rows: cloneRows(state.rows),
+      };
+    }
+
    if (state.rows.length === 0) {
      return {
+        epoch: state.epoch,
        direction,
+        reset: false,
+        staleCursor: false,
+        gap: false,
        window,
        hasOlder: false,
        hasNewer: false,
@@ -97,11 +139,15 @@ export class InMemoryAgentTimelineStore {
          ? state.rows
          : state.rows.slice(state.rows.length - limit);
      return {
+        epoch: state.epoch,
        direction,
+        reset: false,
+        staleCursor: false,
+        gap: false,
        window,
        hasOlder: selected.length > 0 && selected[0]!.seq > minSeq,
        hasNewer: false,
-        rows: selected.map(cloneRow),
+        rows: cloneRows(selected),
      };
    }

@@ -110,7 +156,11 @@ export class InMemoryAgentTimelineStore {
      const startIdx = state.rows.findIndex((row) => row.seq > baseSeq);
      if (startIdx < 0) {
        return {
+          epoch: state.epoch,
          direction,
+          reset: false,
+          staleCursor: false,
+          gap: false,
          window,
          hasOlder: baseSeq >= minSeq,
          hasNewer: false,
@@ -123,11 +173,15 @@ export class InMemoryAgentTimelineStore {
        : state.rows.slice(startIdx, startIdx + limit);
      const lastSelected = selected[selected.length - 1];
      return {
+        epoch: state.epoch,
        direction,
+        reset: false,
+        staleCursor: false,
+        gap: false,
        window,
        hasOlder: selected[0]!.seq > minSeq,
        hasNewer: Boolean(lastSelected && lastSelected.seq < maxSeq),
-        rows: selected.map(cloneRow),
+        rows: cloneRows(selected),
      };
    }

@@ -139,11 +193,15 @@ export class InMemoryAgentTimelineStore {
        ? boundedRows
        : boundedRows.slice(boundedRows.length - limit);
    return {
+      epoch: state.epoch,
      direction,
+      reset: false,
+      staleCursor: false,
+      gap: false,
      window,
      hasOlder: selected.length > 0 && selected[0]!.seq > minSeq,
      hasNewer: endExclusive >= 0,
-      rows: selected.map(cloneRow),
+      rows: cloneRows(selected),
    };
  }

@@ -141,27 +141,6 @@ export const AGENT_PROVIDER_DEFINITIONS: AgentProviderDefinition[] = [
      defaultModel: "gpt-5.4-mini",
    },
  },
-  {
-    id: "gemini",
-    label: "Gemini CLI",
-    description: "Google's coding agent CLI",
-    defaultModeId: null,
-    modes: [],
-  },
-  {
-    id: "amp",
-    label: "AMP",
-    description: "Sourcegraph's coding agent CLI",
-    defaultModeId: null,
-    modes: [],
-  },
-  {
-    id: "aider",
-    label: "Aider",
-    description: "Paul Gauthier's coding assistant CLI",
-    defaultModeId: null,
-    modes: [],
-  },
  {
    id: "copilot",
    label: "Copilot",
@@ -20,13 +20,9 @@ import type {
  ProviderProfileModel,
  ProviderRuntimeSettings,
 } from "./provider-launch-config.js";
-
-import { AiderAgentClient } from "./providers/aider-agent.js";
-import { AmpAgentClient } from "./providers/amp-agent.js";
 import { ClaudeAgentClient } from "./providers/claude-agent.js";
 import { CodexAppServerAgentClient } from "./providers/codex-app-server-agent.js";
 import { CopilotACPAgentClient } from "./providers/copilot-acp-agent.js";
-import { GeminiAgentClient } from "./providers/gemini-agent.js";
 import { GenericACPAgentClient } from "./providers/generic-acp-agent.js";
 import { OpenCodeAgentClient, OpenCodeServerManager } from "./providers/opencode-agent.js";
 import { PiACPAgentClient } from "./providers/pi-acp-agent.js";
@@ -72,9 +68,6 @@ const PROVIDER_CLIENT_FACTORIES: Record<string, ProviderClientFactory> = {
      runtimeSettings,
    }),
  codex: (logger, runtimeSettings) => new CodexAppServerAgentClient(logger, runtimeSettings),
-  gemini: (_logger, runtimeSettings) => new GeminiAgentClient(runtimeSettings),
-  amp: (_logger, runtimeSettings) => new AmpAgentClient(runtimeSettings),
-  aider: (_logger, runtimeSettings) => new AiderAgentClient(runtimeSettings),
  copilot: (logger, runtimeSettings) =>
    new CopilotACPAgentClient({
      logger,
@@ -1,75 +0,0 @@
-import { existsSync } from "node:fs";
-
-import type {
-  AgentCapabilityFlags,
-  AgentClient,
-  AgentLaunchContext,
-  AgentModelDefinition,
-  AgentPersistenceHandle,
-  AgentSession,
-  AgentSessionConfig,
-  ListModelsOptions,
-} from "../agent-sdk-types.js";
-import {
-  findExecutable,
-  isProviderCommandAvailable,
-  type ProviderRuntimeSettings,
-} from "../provider-launch-config.js";
-
-const AIDER_PROVIDER = "aider" as const;
-
-const AIDER_CAPABILITIES: AgentCapabilityFlags = {
-  supportsStreaming: false,
-  supportsSessionPersistence: false,
-  supportsDynamicModes: false,
-  supportsMcpServers: false,
-  supportsReasoningStream: false,
-  supportsToolInvocations: false,
-};
-
-function resolveAiderBinary(): string {
-  const found = findExecutable("aider");
-  if (found) {
-    return found;
-  }
-  throw new Error(
-    "Aider binary not found. Install Aider and ensure 'aider' is available in your shell PATH.",
-  );
-}
-
-function createUnsupportedSessionError(): Error {
-  return new Error("Aider does not support session-backed agents in Paseo.");
-}
-
-export class AiderAgentClient implements AgentClient {
-  readonly provider = AIDER_PROVIDER;
-  readonly capabilities = AIDER_CAPABILITIES;
-
-  constructor(private readonly runtimeSettings?: ProviderRuntimeSettings) {}
-
-  async createSession(
-    _config: AgentSessionConfig,
-    _launchContext?: AgentLaunchContext,
-  ): Promise<AgentSession> {
-    throw createUnsupportedSessionError();
-  }
-
-  async resumeSession(
-    _handle: AgentPersistenceHandle,
-    _overrides?: Partial<AgentSessionConfig>,
-    _launchContext?: AgentLaunchContext,
-  ): Promise<AgentSession> {
-    throw createUnsupportedSessionError();
-  }
-
-  async listModels(_options?: ListModelsOptions): Promise<AgentModelDefinition[]> {
-    return [];
-  }
-
-  async isAvailable(): Promise<boolean> {
-    if (this.runtimeSettings?.command?.mode === "replace") {
-      return existsSync(this.runtimeSettings.command.argv[0]);
-    }
-    return isProviderCommandAvailable(this.runtimeSettings?.command, resolveAiderBinary);
-  }
-}
@@ -1,75 +0,0 @@
-import { existsSync } from "node:fs";
-
-import type {
-  AgentCapabilityFlags,
-  AgentClient,
-  AgentLaunchContext,
-  AgentModelDefinition,
-  AgentPersistenceHandle,
-  AgentSession,
-  AgentSessionConfig,
-  ListModelsOptions,
-} from "../agent-sdk-types.js";
-import {
-  findExecutable,
-  isProviderCommandAvailable,
-  type ProviderRuntimeSettings,
-} from "../provider-launch-config.js";
-
-const AMP_PROVIDER = "amp" as const;
-
-const AMP_CAPABILITIES: AgentCapabilityFlags = {
-  supportsStreaming: false,
-  supportsSessionPersistence: false,
-  supportsDynamicModes: false,
-  supportsMcpServers: false,
-  supportsReasoningStream: false,
-  supportsToolInvocations: false,
-};
-
-function resolveAmpBinary(): string {
-  const found = findExecutable("amp");
-  if (found) {
-    return found;
-  }
-  throw new Error(
-    "AMP binary not found. Install AMP and ensure 'amp' is available in your shell PATH.",
-  );
-}
-
-function createUnsupportedSessionError(): Error {
-  return new Error("AMP does not support session-backed agents in Paseo.");
-}
-
-export class AmpAgentClient implements AgentClient {
-  readonly provider = AMP_PROVIDER;
-  readonly capabilities = AMP_CAPABILITIES;
-
-  constructor(private readonly runtimeSettings?: ProviderRuntimeSettings) {}
-
-  async createSession(
-    _config: AgentSessionConfig,
-    _launchContext?: AgentLaunchContext,
-  ): Promise<AgentSession> {
-    throw createUnsupportedSessionError();
-  }
-
-  async resumeSession(
-    _handle: AgentPersistenceHandle,
-    _overrides?: Partial<AgentSessionConfig>,
-    _launchContext?: AgentLaunchContext,
-  ): Promise<AgentSession> {
-    throw createUnsupportedSessionError();
-  }
-
-  async listModels(_options?: ListModelsOptions): Promise<AgentModelDefinition[]> {
-    return [];
-  }
-
-  async isAvailable(): Promise<boolean> {
-    if (this.runtimeSettings?.command?.mode === "replace") {
-      return existsSync(this.runtimeSettings.command.argv[0]);
-    }
-    return isProviderCommandAvailable(this.runtimeSettings?.command, resolveAmpBinary);
-  }
-}
@@ -1,75 +0,0 @@
-import { existsSync } from "node:fs";
-
-import type {
-  AgentCapabilityFlags,
-  AgentClient,
-  AgentLaunchContext,
-  AgentModelDefinition,
-  AgentPersistenceHandle,
-  AgentSession,
-  AgentSessionConfig,
-  ListModelsOptions,
-} from "../agent-sdk-types.js";
-import {
-  findExecutable,
-  isProviderCommandAvailable,
-  type ProviderRuntimeSettings,
-} from "../provider-launch-config.js";
-
-const GEMINI_PROVIDER = "gemini" as const;
-
-const GEMINI_CAPABILITIES: AgentCapabilityFlags = {
-  supportsStreaming: false,
-  supportsSessionPersistence: false,
-  supportsDynamicModes: false,
-  supportsMcpServers: false,
-  supportsReasoningStream: false,
-  supportsToolInvocations: false,
-};
-
-function resolveGeminiBinary(): string {
-  const found = findExecutable("gemini");
-  if (found) {
-    return found;
-  }
-  throw new Error(
-    "Gemini CLI binary not found. Install Gemini CLI and ensure 'gemini' is available in your shell PATH.",
-  );
-}
-
-function createUnsupportedSessionError(): Error {
-  return new Error("Gemini CLI does not support session-backed agents in Paseo.");
-}
-
-export class GeminiAgentClient implements AgentClient {
-  readonly provider = GEMINI_PROVIDER;
-  readonly capabilities = GEMINI_CAPABILITIES;
-
-  constructor(private readonly runtimeSettings?: ProviderRuntimeSettings) {}
-
-  async createSession(
-    _config: AgentSessionConfig,
-    _launchContext?: AgentLaunchContext,
-  ): Promise<AgentSession> {
-    throw createUnsupportedSessionError();
-  }
-
-  async resumeSession(
-    _handle: AgentPersistenceHandle,
-    _overrides?: Partial<AgentSessionConfig>,
-    _launchContext?: AgentLaunchContext,
-  ): Promise<AgentSession> {
-    throw createUnsupportedSessionError();
-  }
-
-  async listModels(_options?: ListModelsOptions): Promise<AgentModelDefinition[]> {
-    return [];
-  }
-
-  async isAvailable(): Promise<boolean> {
-    if (this.runtimeSettings?.command?.mode === "replace") {
-      return existsSync(this.runtimeSettings.command.argv[0]);
-    }
-    return isProviderCommandAvailable(this.runtimeSettings?.command, resolveGeminiBinary);
-  }
-}
@@ -29,9 +29,10 @@ async function waitFor(
  }
 }

-function isSeqLessAssistantTimeline(
+function isLiveAssistantTimeline(
  message: SessionOutboundMessage,
  agentId: string,
+  epoch?: string,
  text?: string,
 ): boolean {
  return (
@@ -40,6 +41,8 @@ function isSeqLessAssistantTimeline(
    message.payload.event.type === "timeline" &&
    message.payload.event.item.type === "assistant_message" &&
    message.payload.seq === undefined &&
+    typeof message.payload.epoch === "string" &&
+    (epoch === undefined || message.payload.epoch === epoch) &&
    (text === undefined || message.payload.event.item.text === text)
  );
 }
@@ -73,6 +76,14 @@ describe("daemon E2E - timeline reconnect contract", () => {
          text: `committed row ${seq}`,
        });
      }
+      const baseline = await ctx.client.fetchAgentTimeline(agent.id, {
+        direction: "tail",
+        limit: 0,
+        projection: "canonical",
+      });
+      const epoch = baseline.epoch;
+      expect(epoch).not.toBe("");
+      expect(baseline.endCursor?.epoch).toBe(epoch);

      primaryCollector.clear();
      await ctx.daemon.daemon.agentManager.emitLiveTimelineItem(agent.id, {
@@ -81,7 +92,7 @@ describe("daemon E2E - timeline reconnect contract", () => {
      });
      await waitFor(() =>
        primaryCollector.messages.some((message) =>
-          isSeqLessAssistantTimeline(message, agent.id, "partial before disconnect"),
+          isLiveAssistantTimeline(message, agent.id, epoch, "partial before disconnect"),
        ),
      );

@@ -105,18 +116,26 @@ describe("daemon E2E - timeline reconnect contract", () => {

        expect(
          reconnectCollector.messages.some((message) =>
-            isSeqLessAssistantTimeline(message, agent.id),
+            isLiveAssistantTimeline(message, agent.id, epoch),
          ),
        ).toBe(false);

        const catchUp = await reconnectClient.fetchAgentTimeline(agent.id, {
          direction: "after",
-          cursor: { seq: 120 },
+          cursor: { epoch, seq: 120 },
          limit: 0,
+          projection: "canonical",
        });

+        expect(catchUp.epoch).toBe(epoch);
+        expect(catchUp.reset).toBe(false);
+        expect(catchUp.staleCursor).toBe(false);
+        expect(catchUp.gap).toBe(false);
        expect(catchUp.entries).toHaveLength(1);
-        expect(catchUp.entries[0]?.seq).toBe(121);
+        expect(catchUp.startCursor).toEqual({ epoch, seq: 121 });
+        expect(catchUp.endCursor).toEqual({ epoch, seq: 121 });
+        expect(catchUp.entries[0]?.seqStart).toBe(121);
+        expect(catchUp.entries[0]?.seqEnd).toBe(121);
        expect(catchUp.entries[0]?.item).toEqual({
          type: "assistant_message",
          text: "finalized while disconnected",
@@ -149,6 +168,14 @@ describe("daemon E2E - timeline reconnect contract", () => {
          text: `committed row ${seq}`,
        });
      }
+      const baseline = await ctx.client.fetchAgentTimeline(agent.id, {
+        direction: "tail",
+        limit: 0,
+        projection: "canonical",
+      });
+      const epoch = baseline.epoch;
+      expect(epoch).not.toBe("");
+      expect(baseline.endCursor?.epoch).toBe(epoch);

      primaryCollector.clear();
      await ctx.daemon.daemon.agentManager.emitLiveTimelineItem(agent.id, {
@@ -157,7 +184,7 @@ describe("daemon E2E - timeline reconnect contract", () => {
      });
      await waitFor(() =>
        primaryCollector.messages.some((message) =>
-          isSeqLessAssistantTimeline(message, agent.id, "partial before disconnect"),
+          isLiveAssistantTimeline(message, agent.id, epoch, "partial before disconnect"),
        ),
      );

@@ -176,17 +203,24 @@ describe("daemon E2E - timeline reconnect contract", () => {

        expect(
          reconnectCollector.messages.some((message) =>
-            isSeqLessAssistantTimeline(message, agent.id),
+            isLiveAssistantTimeline(message, agent.id, epoch),
          ),
        ).toBe(false);

        const catchUp = await reconnectClient.fetchAgentTimeline(agent.id, {
          direction: "after",
-          cursor: { seq: 120 },
+          cursor: { epoch, seq: 120 },
          limit: 0,
+          projection: "canonical",
        });

+        expect(catchUp.epoch).toBe(epoch);
+        expect(catchUp.reset).toBe(false);
+        expect(catchUp.staleCursor).toBe(false);
+        expect(catchUp.gap).toBe(false);
        expect(catchUp.entries).toHaveLength(0);
+        expect(catchUp.startCursor).toBeNull();
+        expect(catchUp.endCursor).toBeNull();

        reconnectCollector.clear();
        await ctx.daemon.daemon.agentManager.emitLiveTimelineItem(agent.id, {
@@ -195,7 +229,7 @@ describe("daemon E2E - timeline reconnect contract", () => {
        });
        await waitFor(() =>
          reconnectCollector.messages.some((message) =>
-            isSeqLessAssistantTimeline(message, agent.id, "fresh live after reconnect"),
+            isLiveAssistantTimeline(message, agent.id, epoch, "fresh live after reconnect"),
          ),
        );
      } finally {
@@ -38,6 +38,7 @@ describe("daemon E2E - timeline window", () => {
      const timeline = await ctx.client.fetchAgentTimeline(agent.id, {
        direction: "tail",
        limit: 1,
+        projection: "canonical",
      });

      const assistantTexts = timeline.entries
@@ -45,7 +46,7 @@ describe("daemon E2E - timeline window", () => {
        .map((entry) => entry.item.text);

      expect(assistantTexts).toEqual([expected]);
-      expect(timeline.startSeq).toBe(timeline.endSeq);
+      expect(timeline.startCursor?.seq).toBe(timeline.endCursor?.seq);
    } finally {
      rmSync(cwd, { recursive: true, force: true });
    }
@@ -71,6 +72,7 @@ describe("daemon E2E - timeline window", () => {
      const timeline = await ctx.client.fetchAgentTimeline(agent.id, {
        direction: "tail",
        limit: 1,
+        projection: "canonical",
      });

      const assistantTexts = timeline.entries
@@ -79,7 +81,7 @@ describe("daemon E2E - timeline window", () => {

      expect(assistantTexts.join("")).toBe(expected);
      expect(timeline.hasOlder).toBe(true);
-      expect(timeline.startSeq).toBeGreaterThan(1);
+      expect(timeline.startCursor?.seq).toBeGreaterThan(1);
    } finally {
      rmSync(cwd, { recursive: true, force: true });
    }
@@ -1,4 +1,5 @@
-import { describe, expect, test } from "vitest";
+import { describe, expect, test, vi } from "vitest";
+import type { ManagedAgent } from "./agent/agent-manager.js";
 import type { StoredAgentRecord } from "./agent/agent-storage.js";
 import {
  attachAgentStoragePersistence,
@@ -173,16 +174,16 @@ describe("persistence hooks", () => {

  test("buildSessionConfig accepts providers from the canonical manifest", () => {
    const record = createRecord({
-      provider: "gemini",
+      provider: "claude",
      persistence: {
-        provider: "gemini",
+        provider: "claude",
        sessionId: "session-123",
      },
      config: {},
    });

    expect(buildSessionConfig(record)).toMatchObject({
-      provider: "gemini",
+      provider: "claude",
      cwd: "/tmp/project",
    });
  });
@@ -1,15 +0,0 @@
-import { readFileSync } from "node:fs";
-import { describe, expect, test } from "vitest";
-
-describe("agent loading boundary", () => {
-  test("session runtime code does not directly hydrate provider history", () => {
-    const sessionSource = readFileSync(new URL("./session.ts", import.meta.url), "utf8");
-    const agentLoadingSource = readFileSync(
-      new URL("./agent-loading-service.ts", import.meta.url),
-      "utf8",
-    );
-
-    expect(sessionSource).not.toMatch(/hydrateTimelineFromProvider\s*\(/);
-    expect(agentLoadingSource).not.toMatch(/hydrateTimelineFromProvider\s*\(/);
-  });
-});
@@ -1,333 +0,0 @@
-import { mkdtempSync, rmSync } from "node:fs";
-import os from "node:os";
-import path from "node:path";
-import pino from "pino";
-import { describe, expect, test, vi } from "vitest";
-
-import { AgentLoadingService } from "./agent-loading-service.js";
-import { AgentManager } from "./agent/agent-manager.js";
-import { AgentStorage, type StoredAgentRecord } from "./agent/agent-storage.js";
-import { createTestAgentClients } from "./test-utils/fake-agent-client.js";
-
-function createStoredAgentRecord(overrides?: Partial<StoredAgentRecord>): StoredAgentRecord {
-  const now = "2026-03-25T00:00:00.000Z";
-  return {
-    id: "agent-compat-1",
-    provider: "codex",
-    cwd: "/tmp/project",
-    createdAt: now,
-    updatedAt: now,
-    title: null,
-    labels: {},
-    lastStatus: "idle",
-    config: {
-      model: "gpt-5.1-codex-mini",
-    },
-    persistence: {
-      provider: "codex",
-      sessionId: "provider-session-1",
-    },
-    ...overrides,
-  };
-}
-
-function createDeferred<T>() {
-  let resolve!: (value: T) => void;
-  let reject!: (error: unknown) => void;
-  const promise = new Promise<T>((res, rej) => {
-    resolve = res;
-    reject = rej;
-  });
-  return { promise, resolve, reject };
-}
-
-function createCompatibilitySnapshot(overrides?: Partial<Record<string, unknown>>) {
-  return {
-    id: "agent-compat-1",
-    provider: "codex",
-    cwd: "/tmp/project",
-    persistence: {
-      provider: "codex",
-      sessionId: "provider-session-1",
-    },
-    ...overrides,
-  };
-}
-
-describe("AgentLoadingService", () => {
-  test("ensureAgentLoaded succeeds when provider history is absent", async () => {
-    const workspaceRoot = mkdtempSync(path.join(os.tmpdir(), "provider-history-compat-empty-"));
-    const logger = pino({ level: "silent" });
-
-    try {
-      const storage = new AgentStorage(path.join(workspaceRoot, "agents"), logger);
-      const manager = new AgentManager({
-        clients: createTestAgentClients(),
-        registry: storage,
-        logger,
-        idFactory: () => "00000000-0000-4000-8000-000000000302",
-      });
-      const service = new AgentLoadingService({
-        agentManager: manager as any,
-        agentStorage: storage as any,
-        logger,
-      });
-
-      const snapshot = await manager.createAgent({
-        provider: "codex",
-        cwd: workspaceRoot,
-        model: "gpt-5.1-codex-mini",
-      });
-      await manager.flush();
-      await storage.flush();
-      await manager.closeAgent(snapshot.id);
-
-      const loaded = await service.ensureAgentLoaded({ agentId: snapshot.id });
-
-      expect(loaded.id).toBe(snapshot.id);
-      expect(manager.getTimeline(snapshot.id)).toEqual([]);
-    } finally {
-      rmSync(workspaceRoot, { recursive: true, force: true });
-    }
-  });
-
-  test("ensureAgentLoaded dedupes concurrent cold-load bootstrap", async () => {
-    const deferred = createDeferred<any>();
-    let currentAgent: any = null;
-    const snapshot = createCompatibilitySnapshot({ id: "agent-compat-dedupe" });
-    const agentStorage = {
-      get: vi.fn(async () =>
-        createStoredAgentRecord({
-          id: "agent-compat-dedupe",
-          cwd: "/tmp/dedupe",
-          persistence: {
-            provider: "codex",
-            sessionId: "provider-session-dedupe",
-          },
-        }),
-      ),
-    };
-    const agentManager = {
-      getAgent: vi.fn(() => currentAgent),
-      resumeAgentFromPersistence: vi.fn(async () => deferred.promise),
-      createAgent: vi.fn(),
-      reloadAgentSession: vi.fn(),
-    };
-    const logger = {
-      child: () => logger,
-      info: vi.fn(),
-      warn: vi.fn(),
-    };
-    const service = new AgentLoadingService({
-      agentManager: agentManager as any,
-      agentStorage: agentStorage as any,
-      logger: logger as any,
-    });
-
-    const firstLoad = service.ensureAgentLoaded({ agentId: "agent-compat-dedupe" });
-    const secondLoad = service.ensureAgentLoaded({ agentId: "agent-compat-dedupe" });
-    deferred.resolve(snapshot);
-
-    const [firstResult, secondResult] = await Promise.all([firstLoad, secondLoad]);
-
-    expect(firstResult).toEqual(snapshot);
-    expect(secondResult).toEqual(snapshot);
-    expect(agentStorage.get).toHaveBeenCalledTimes(1);
-    expect(agentManager.resumeAgentFromPersistence).toHaveBeenCalledTimes(1);
-  });
-
-  test("resumeAgent delegates to manager resume", async () => {
-    const snapshot = createCompatibilitySnapshot({ id: "agent-compat-resume" });
-    const agentManager = {
-      getAgent: vi.fn(() => null),
-      resumeAgentFromPersistence: vi.fn(async () => snapshot),
-      createAgent: vi.fn(),
-      reloadAgentSession: vi.fn(),
-    };
-    const logger = {
-      child: () => logger,
-      info: vi.fn(),
-      warn: vi.fn(),
-    };
-    const service = new AgentLoadingService({
-      agentManager: agentManager as any,
-      agentStorage: {
-        get: async () => null,
-      } as any,
-      logger: logger as any,
-    });
-
-    const result = await service.resumeAgent({
-      handle: {
-        provider: "codex",
-        sessionId: "provider-session-resume",
-      },
-      overrides: {
-        model: "gpt-5.4",
-      },
-    });
-
-    expect(agentManager.resumeAgentFromPersistence).toHaveBeenCalledWith(
-      {
-        provider: "codex",
-        sessionId: "provider-session-resume",
-      },
-      {
-        model: "gpt-5.4",
-      },
-    );
-    expect(result).toEqual(snapshot);
-  });
-
-  test("refreshAgent reloads loaded persisted agents", async () => {
-    const existing = createCompatibilitySnapshot({ id: "agent-compat-refresh-loaded" });
-    const reloaded = createCompatibilitySnapshot({ id: "agent-compat-refresh-loaded" });
-    let currentAgent: any = existing;
-    const agentManager = {
-      getAgent: vi.fn(() => currentAgent),
-      resumeAgentFromPersistence: vi.fn(),
-      createAgent: vi.fn(),
-      reloadAgentSession: vi.fn(async () => {
-        currentAgent = reloaded;
-        return reloaded;
-      }),
-    };
-    const logger = {
-      child: () => logger,
-      info: vi.fn(),
-      warn: vi.fn(),
-    };
-    const service = new AgentLoadingService({
-      agentManager: agentManager as any,
-      agentStorage: {
-        get: async () => null,
-      } as any,
-      logger: logger as any,
-    });
-
-    const result = await service.refreshAgent({ agentId: "agent-compat-refresh-loaded" });
-
-    expect(agentManager.reloadAgentSession).toHaveBeenCalledWith("agent-compat-refresh-loaded");
-    expect(result).toEqual(reloaded);
-  });
-
-  test("refreshAgent keeps loaded non-persisted agents without reloading", async () => {
-    const existing = createCompatibilitySnapshot({
-      id: "agent-compat-refresh-live",
-      persistence: null,
-    });
-    const agentManager = {
-      getAgent: vi.fn(() => existing),
-      resumeAgentFromPersistence: vi.fn(),
-      createAgent: vi.fn(),
-      reloadAgentSession: vi.fn(),
-    };
-    const logger = {
-      child: () => logger,
-      info: vi.fn(),
-      warn: vi.fn(),
-    };
-    const service = new AgentLoadingService({
-      agentManager: agentManager as any,
-      agentStorage: {
-        get: async () => null,
-      } as any,
-      logger: logger as any,
-    });
-
-    const result = await service.refreshAgent({ agentId: "agent-compat-refresh-live" });
-
-    expect(agentManager.reloadAgentSession).not.toHaveBeenCalled();
-    expect(result).toEqual(existing);
-  });
-
-  test("refreshAgent resumes unloaded persisted agents", async () => {
-    const snapshot = createCompatibilitySnapshot({ id: "agent-compat-refresh-cold" });
-    const record = createStoredAgentRecord({
-      id: "agent-compat-refresh-cold",
-      cwd: "/tmp/refresh-cold",
-      persistence: {
-        provider: "codex",
-        sessionId: "provider-session-refresh-cold",
-      },
-    });
-    const agentManager = {
-      getAgent: vi.fn(() => null),
-      resumeAgentFromPersistence: vi.fn(async () => snapshot),
-      createAgent: vi.fn(),
-      reloadAgentSession: vi.fn(),
-    };
-    const logger = {
-      child: () => logger,
-      info: vi.fn(),
-      warn: vi.fn(),
-    };
-    const service = new AgentLoadingService({
-      agentManager: agentManager as any,
-      agentStorage: {
-        get: vi.fn(async () => record),
-      } as any,
-      logger: logger as any,
-    });
-
-    const result = await service.refreshAgent({ agentId: "agent-compat-refresh-cold" });
-
-    expect(agentManager.resumeAgentFromPersistence).toHaveBeenCalledWith(
-      {
-        provider: "codex",
-        sessionId: "provider-session-refresh-cold",
-        nativeHandle: undefined,
-        metadata: undefined,
-      },
-      {
-        cwd: "/tmp/refresh-cold",
-        modeId: undefined,
-        model: "gpt-5.1-codex-mini",
-        thinkingOptionId: undefined,
-        title: undefined,
-        extra: undefined,
-        systemPrompt: undefined,
-        mcpServers: undefined,
-      },
-      "agent-compat-refresh-cold",
-      {
-        createdAt: new Date("2026-03-25T00:00:00.000Z"),
-        updatedAt: new Date("2026-03-25T00:00:00.000Z"),
-        lastUserMessageAt: null,
-        labels: {},
-      },
-    );
-    expect(result).toEqual(snapshot);
-  });
-
-  test("refreshAgent preserves the unloaded no-persistence error", async () => {
-    const service = new AgentLoadingService({
-      agentManager: {
-        getAgent: vi.fn(() => null),
-        resumeAgentFromPersistence: vi.fn(),
-        createAgent: vi.fn(),
-        reloadAgentSession: vi.fn(),
-      } as any,
-      agentStorage: {
-        get: async () =>
-          createStoredAgentRecord({
-            id: "agent-compat-no-persistence",
-            persistence: null,
-          }),
-      } as any,
-      logger: {
-        child: () => ({
-          child: () => null,
-          info: vi.fn(),
-          warn: vi.fn(),
-        }),
-        info: vi.fn(),
-        warn: vi.fn(),
-      } as any,
-    });
-
-    await expect(service.refreshAgent({ agentId: "agent-compat-no-persistence" })).rejects.toThrow(
-      "Agent agent-compat-no-persistence cannot be refreshed because it lacks persistence",
-    );
-  });
-});
@@ -1,389 +0,0 @@
-import { describe, expect, test, vi } from "vitest";
-
-import { Session } from "./session.js";
-
-function createStoredAgentRecord(overrides?: Partial<Record<string, unknown>>) {
-  return {
-    id: "agent-1",
-    provider: "codex",
-    cwd: "/tmp/project",
-    createdAt: "2026-03-24T00:00:00.000Z",
-    updatedAt: "2026-03-24T00:00:00.000Z",
-    title: null,
-    labels: {},
-    lastStatus: "idle",
-    config: null,
-    persistence: {
-      provider: "codex",
-      sessionId: "provider-session-1",
-    },
-    archivedAt: null,
-    requiresAttention: false,
-    attentionReason: null,
-    attentionTimestamp: null,
-    ...overrides,
-  };
-}
-
-function createCompatibilitySnapshot(overrides?: Partial<Record<string, unknown>>) {
-  return {
-    id: "agent-1",
-    provider: "codex",
-    cwd: "/tmp/project",
-    persistence: {
-      provider: "codex",
-      sessionId: "provider-session-1",
-    },
-    ...overrides,
-  };
-}
-
-function createSessionForOwnershipTests(options?: {
-  agentLoadingService?: {
-    ensureAgentLoaded?: (options: { agentId: string }) => Promise<any>;
-    resumeAgent?: (options: {
-      handle: { provider: string; sessionId: string };
-      overrides?: Record<string, unknown>;
-    }) => Promise<any>;
-    refreshAgent?: (options: { agentId: string }) => Promise<any>;
-  };
-  storedRecord?: Record<string, unknown> | null;
-  loadedAgent?: Record<string, unknown> | null;
-  timelineRows?: Array<{ seq: number; item: Record<string, unknown>; timestamp: Date }>;
-}) {
-  const emitted: Array<{ type: string; payload: unknown }> = [];
-  const logger = {
-    child: () => logger,
-    trace: vi.fn(),
-    debug: vi.fn(),
-    info: vi.fn(),
-    warn: vi.fn(),
-    error: vi.fn(),
-  };
-
-  const agentManager = {
-    subscribe: () => () => {},
-    listAgents: () => [],
-    getAgent: vi.fn(() => options?.loadedAgent ?? null),
-    createAgent: vi.fn(async () => {
-      throw new Error("Session should delegate unloaded bootstrap to AgentLoadingService");
-    }),
-    resumeAgentFromPersistence: vi.fn(async () => {
-      throw new Error("Session should delegate persistence resume to AgentLoadingService");
-    }),
-    reloadAgentSession: vi.fn(async () => {
-      throw new Error("Session should delegate refresh reload to AgentLoadingService");
-    }),
-    hydrateTimelineFromProvider: vi.fn(async () => {
-      throw new Error("Session should not call hydrateTimelineFromProvider directly");
-    }),
-    fetchTimeline: vi.fn(async () => ({
-      rows: options?.timelineRows ?? [],
-      hasOlder: false,
-      hasNewer: false,
-    })),
-    recordUserMessage: vi.fn(),
-    waitForAgentRunStart: vi.fn(async () => undefined),
-    getTimeline: vi.fn(() => []),
-  };
-
-  const session = new Session({
-    clientId: "test-client",
-    onMessage: (message) => emitted.push(message as any),
-    logger: logger as any,
-    downloadTokenStore: {} as any,
-    pushTokenStore: {} as any,
-    paseoHome: "/tmp/paseo-test",
-    agentManager: agentManager as any,
-    agentStorage: {
-      list: async () => (options?.storedRecord ? [options.storedRecord as any] : []),
-      get: async () => (options?.storedRecord as any) ?? null,
-    } as any,
-    projectRegistry: {
-      initialize: async () => {},
-      existsOnDisk: async () => true,
-      list: async () => [],
-      get: async () => null,
-      upsert: async () => {},
-      archive: async () => {},
-      remove: async () => {},
-    } as any,
-    workspaceRegistry: {
-      initialize: async () => {},
-      existsOnDisk: async () => true,
-      list: async () => [],
-      get: async () => null,
-      upsert: async () => {},
-      archive: async () => {},
-      remove: async () => {},
-    } as any,
-    createAgentMcpTransport: async () => {
-      throw new Error("not used");
-    },
-    stt: null,
-    tts: null,
-    terminalManager: null,
-    agentLoadingService: options?.agentLoadingService,
-  } as any) as any;
-
-  return { session, emitted, agentManager };
-}
-
-describe("provider history compatibility ownership", () => {
-  test("fetch_agent_timeline_request delegates unloaded bootstrap through the compatibility seam", async () => {
-    const ensureAgentLoaded = vi.fn(async () => createCompatibilitySnapshot());
-    const { session, emitted } = createSessionForOwnershipTests({
-      storedRecord: createStoredAgentRecord(),
-      timelineRows: [
-        {
-          seq: 1,
-          item: { type: "assistant_message", text: "rehydrated from provider history" },
-          timestamp: new Date("2026-03-24T00:00:01.000Z"),
-        },
-      ],
-      agentLoadingService: {
-        ensureAgentLoaded,
-      },
-    });
-
-    session.buildAgentPayload = vi.fn(async () => ({ id: "agent-1" }));
-
-    await session.handleMessage({
-      type: "fetch_agent_timeline_request",
-      requestId: "req-fetch",
-      agentId: "agent-1",
-    });
-
-    expect(ensureAgentLoaded).toHaveBeenCalledWith({ agentId: "agent-1" });
-    expect(emitted).toContainEqual({
-      type: "fetch_agent_timeline_response",
-      payload: expect.objectContaining({
-        requestId: "req-fetch",
-        agentId: "agent-1",
-        error: null,
-        entries: [
-          expect.objectContaining({
-            seq: 1,
-          }),
-        ],
-      }),
-    });
-  });
-
-  test("fetch_agent_timeline_request emits legacy compatibility fields for older clients", async () => {
-    const ensureAgentLoaded = vi.fn(async () => createCompatibilitySnapshot());
-    const { session, emitted } = createSessionForOwnershipTests({
-      storedRecord: createStoredAgentRecord(),
-      timelineRows: [
-        {
-          seq: 7,
-          item: { type: "assistant_message", text: "compat row" },
-          timestamp: new Date("2026-03-24T00:00:07.000Z"),
-        },
-      ],
-      agentLoadingService: {
-        ensureAgentLoaded,
-      },
-    });
-
-    session.buildAgentPayload = vi.fn(async () => ({ id: "agent-1" }));
-
-    await session.handleMessage({
-      type: "fetch_agent_timeline_request",
-      requestId: "req-compat",
-      agentId: "agent-1",
-      direction: "tail",
-    });
-
-    expect(emitted).toContainEqual({
-      type: "fetch_agent_timeline_response",
-      payload: expect.objectContaining({
-        requestId: "req-compat",
-        agentId: "agent-1",
-        epoch: "compat:agent-1",
-        reset: false,
-        staleCursor: false,
-        gap: false,
-        projection: "projected",
-        startCursor: { seq: 7, epoch: "compat:agent-1" },
-        endCursor: { seq: 7, epoch: "compat:agent-1" },
-        window: {
-          minSeq: 7,
-          maxSeq: 7,
-          nextSeq: 8,
-          startSeq: 7,
-          endSeq: 7,
-          hasOlder: false,
-          hasNewer: false,
-        },
-        entries: [
-          expect.objectContaining({
-            seq: 7,
-            seqStart: 7,
-            seqEnd: 7,
-            sourceSeqRanges: [{ startSeq: 7, endSeq: 7 }],
-            collapsed: [],
-          }),
-        ],
-      }),
-    });
-  });
-
-  test("send_agent_message_request delegates unloaded bootstrap before recording and streaming", async () => {
-    const ensureAgentLoaded = vi.fn(async () => createCompatibilitySnapshot());
-    const { session, agentManager, emitted } = createSessionForOwnershipTests({
-      storedRecord: createStoredAgentRecord(),
-      agentLoadingService: {
-        ensureAgentLoaded,
-      },
-    });
-
-    session.resolveAgentIdentifier = vi.fn(async () => ({ ok: true, agentId: "agent-1" }));
-    session.unarchiveAgentState = vi.fn(async () => true);
-    session.buildAgentPrompt = vi.fn((text: string) => text);
-    session.startAgentStream = vi.fn(() => ({ ok: true }));
-
-    await session.handleMessage({
-      type: "send_agent_message_request",
-      requestId: "req-send",
-      agentId: "agent-1",
-      text: "hello",
-      images: [],
-      messageId: "msg-1",
-    });
-
-    expect(ensureAgentLoaded).toHaveBeenCalledWith({ agentId: "agent-1" });
-    expect(ensureAgentLoaded.mock.invocationCallOrder[0]).toBeLessThan(
-      agentManager.recordUserMessage.mock.invocationCallOrder[0],
-    );
-    expect(agentManager.recordUserMessage).toHaveBeenCalledWith("agent-1", "hello", {
-      messageId: "msg-1",
-      emitState: false,
-    });
-    expect(session.startAgentStream).toHaveBeenCalledWith("agent-1", "hello");
-    expect(emitted).toContainEqual({
-      type: "send_agent_message_response",
-      payload: {
-        requestId: "req-send",
-        agentId: "agent-1",
-        accepted: true,
-        error: null,
-      },
-    });
-  });
-
-  test("resume_agent_request delegates persistence bootstrap through the compatibility seam", async () => {
-    const resumeAgent = vi.fn(async () => createCompatibilitySnapshot());
-    const { session, emitted } = createSessionForOwnershipTests({
-      agentLoadingService: {
-        resumeAgent,
-      },
-    });
-
-    session.unarchiveAgentByHandle = vi.fn(async () => undefined);
-    session.unarchiveAgentState = vi.fn(async () => true);
-    session.forwardAgentUpdate = vi.fn(async () => undefined);
-    session.getAgentPayloadById = vi.fn(async () => ({ id: "agent-1" }));
-
-    await session.handleMessage({
-      type: "resume_agent_request",
-      requestId: "req-resume",
-      handle: {
-        provider: "codex",
-        sessionId: "provider-session-1",
-      },
-      overrides: {
-        model: "gpt-5.4",
-      },
-    });
-
-    expect(resumeAgent).toHaveBeenCalledWith({
-      handle: {
-        provider: "codex",
-        sessionId: "provider-session-1",
-      },
-      overrides: {
-        model: "gpt-5.4",
-      },
-    });
-    expect(emitted).toContainEqual({
-      type: "status",
-      payload: expect.objectContaining({
-        status: "agent_resumed",
-        requestId: "req-resume",
-        agentId: "agent-1",
-      }),
-    });
-  });
-
-  test("refresh_agent_request delegates loaded persisted refresh through the compatibility seam", async () => {
-    const refreshAgent = vi.fn(async () =>
-      createCompatibilitySnapshot({
-        persistence: {
-          provider: "codex",
-          sessionId: "provider-session-1",
-        },
-      }),
-    );
-    const { session, emitted } = createSessionForOwnershipTests({
-      loadedAgent: createCompatibilitySnapshot(),
-      agentLoadingService: {
-        refreshAgent,
-      },
-    });
-
-    session.unarchiveAgentState = vi.fn(async () => true);
-    session.interruptAgentIfRunning = vi.fn(async () => undefined);
-    session.forwardAgentUpdate = vi.fn(async () => undefined);
-
-    await session.handleMessage({
-      type: "refresh_agent_request",
-      requestId: "req-refresh-loaded",
-      agentId: "agent-1",
-    });
-
-    expect(session.interruptAgentIfRunning).toHaveBeenCalledWith("agent-1");
-    expect(refreshAgent).toHaveBeenCalledWith({ agentId: "agent-1" });
-    expect(emitted).toContainEqual({
-      type: "status",
-      payload: {
-        status: "agent_refreshed",
-        requestId: "req-refresh-loaded",
-        agentId: "agent-1",
-        timelineSize: 0,
-      },
-    });
-  });
-
-  test("refresh_agent_request delegates unloaded persisted refresh through the compatibility seam", async () => {
-    const refreshAgent = vi.fn(async () => createCompatibilitySnapshot());
-    const { session, emitted } = createSessionForOwnershipTests({
-      storedRecord: createStoredAgentRecord(),
-      agentLoadingService: {
-        refreshAgent,
-      },
-    });
-
-    session.unarchiveAgentState = vi.fn(async () => true);
-    session.interruptAgentIfRunning = vi.fn(async () => undefined);
-    session.forwardAgentUpdate = vi.fn(async () => undefined);
-
-    await session.handleMessage({
-      type: "refresh_agent_request",
-      requestId: "req-refresh-unloaded",
-      agentId: "agent-1",
-    });
-
-    expect(session.interruptAgentIfRunning).not.toHaveBeenCalled();
-    expect(refreshAgent).toHaveBeenCalledWith({ agentId: "agent-1" });
-    expect(emitted).toContainEqual({
-      type: "status",
-      payload: {
-        status: "agent_refreshed",
-        requestId: "req-refresh-unloaded",
-        agentId: "agent-1",
-        timelineSize: 0,
-      },
-    });
-  });
-});
@@ -92,6 +92,11 @@ import {
  appendTimelineItemIfAgentKnown,
  emitLiveTimelineItemIfAgentKnown,
 } from "./agent/timeline-append.js";
+import {
+  projectTimelineRows,
+  selectTimelineWindowByProjectedLimit,
+  type TimelineProjectionMode,
+} from "./agent/timeline-projection.js";
 import {
  DEFAULT_STRUCTURED_GENERATION_PROVIDERS,
  StructuredAgentFallbackError,
@@ -1143,6 +1148,7 @@ export class Session {
          event: serializedEvent,
          timestamp: new Date().toISOString(),
          ...(typeof event.seq === "number" ? { seq: event.seq } : {}),
+          ...(typeof event.epoch === "string" ? { epoch: event.epoch } : {}),
        } as const;

        this.emit({
@@ -1705,7 +1711,7 @@ export class Session {
            break;

          case "cancel_agent_request":
-            await this.handleCancelAgentRequest(msg.agentId);
+            await this.handleCancelAgentRequest(msg.agentId, msg.requestId);
            break;

          case "restart_server_request":
@@ -1886,7 +1892,7 @@ export class Session {
            break;

          case "clear_agent_attention":
-            await this.handleClearAgentAttention(msg.agentId);
+            await this.handleClearAgentAttention(msg.agentId, msg.requestId);
            break;

          case "client_heartbeat":
@@ -3337,11 +3343,23 @@ export class Session {
    }
  }

-  private async handleCancelAgentRequest(agentId: string): Promise<void> {
+  private async handleCancelAgentRequest(agentId: string, requestId?: string): Promise<void> {
    this.sessionLogger.info({ agentId }, `Cancel request received for agent ${agentId}`);

    try {
      await this.interruptAgentIfRunning(agentId);
+      if (requestId) {
+        const agent = this.agentManager.getAgent(agentId);
+        const payload = agent ? await this.buildAgentPayload(agent) : null;
+        this.emit({
+          type: "cancel_agent_response",
+          payload: {
+            requestId,
+            agentId,
+            agent: payload,
+          },
+        });
+      }
    } catch (error) {
      this.handleAgentRunError(agentId, error, "Failed to cancel running agent on request");
    }
@@ -4005,11 +4023,32 @@ export class Session {
  /**
   * Handle clearing agent attention flag
   */
-  private async handleClearAgentAttention(agentId: string | string[]): Promise<void> {
+  private async handleClearAgentAttention(
+    agentId: string | string[],
+    requestId?: string,
+  ): Promise<void> {
    const agentIds = Array.isArray(agentId) ? agentId : [agentId];

    try {
      await Promise.all(agentIds.map((id) => this.agentManager.clearAgentAttention(id)));
+      if (requestId) {
+        const agents = (
+          await Promise.all(
+            agentIds.map(async (id) => {
+              const agent = this.agentManager.getAgent(id);
+              return agent ? this.buildAgentPayload(agent) : null;
+            }),
+          )
+        ).filter((payload): payload is NonNullable<typeof payload> => payload !== null);
+        this.emit({
+          type: "clear_agent_attention_response",
+          payload: {
+            requestId,
+            agentId,
+            agents,
+          },
+        });
+      }
    } catch (error: any) {
      this.sessionLogger.error({ err: error, agentIds }, "Failed to clear agent attention");
      // Don't throw - this is not critical
@@ -6884,10 +6923,17 @@ export class Session {
    msg: Extract<SessionInboundMessage, { type: "fetch_agent_timeline_request" }>,
  ): Promise<void> {
    const direction: AgentTimelineFetchDirection = msg.direction ?? (msg.cursor ? "after" : "tail");
+    const projection: TimelineProjectionMode = msg.projection ?? "projected";
    const requestedLimit = msg.limit;
    const limit = requestedLimit ?? (direction === "after" ? 0 : undefined);
+    const shouldLimitByProjectedWindow =
+      projection === "canonical" &&
+      direction === "tail" &&
+      typeof requestedLimit === "number" &&
+      requestedLimit > 0;
    const cursor: AgentTimelineCursor | undefined = msg.cursor
      ? {
+          epoch: msg.cursor.epoch,
          seq: msg.cursor.seq,
        }
      : undefined;
@@ -6895,46 +6941,86 @@ export class Session {
    try {
      const snapshot = await this.ensureAgentLoaded(msg.agentId);
      const agentPayload = await this.buildAgentPayload(snapshot);
-      const timeline = await this.agentManager.fetchTimeline(msg.agentId, {
+
+      let timeline = this.agentManager.fetchTimeline(msg.agentId, {
        direction,
        cursor,
-        limit,
+        limit:
+          shouldLimitByProjectedWindow && typeof requestedLimit === "number"
+            ? Math.max(1, Math.floor(requestedLimit))
+            : limit,
      });
-      const firstRow = timeline.rows[0];
-      const lastRow = timeline.rows[timeline.rows.length - 1];
-      const timelineWindow =
-        timeline.window ??
-        (() => {
-          const minSeq = firstRow?.seq ?? 0;
-          const maxSeq = lastRow?.seq ?? 0;
-          return {
-            minSeq,
-            maxSeq,
-            nextSeq: maxSeq > 0 ? maxSeq + 1 : 0,
-          };
-        })();
-      const epoch = `compat:${msg.agentId}`;
-      const startCursor = firstRow ? { seq: firstRow.seq, epoch } : null;
-      const endCursor = lastRow ? { seq: lastRow.seq, epoch } : null;
-      const window = {
-        minSeq: timelineWindow.minSeq,
-        maxSeq: timelineWindow.maxSeq,
-        nextSeq: timelineWindow.nextSeq,
-        startSeq: firstRow?.seq ?? null,
-        endSeq: lastRow?.seq ?? null,
-        hasOlder: timeline.hasOlder,
-        hasNewer: timeline.hasNewer,
-      };
-      const entries = timeline.rows.map((row) => ({
-        provider: snapshot.provider,
-        item: row.item,
-        timestamp: row.timestamp,
-        seq: row.seq,
-        seqStart: row.seq,
-        seqEnd: row.seq,
-        sourceSeqRanges: [{ startSeq: row.seq, endSeq: row.seq }],
-        collapsed: [],
-      }));
+      let hasOlder = timeline.hasOlder;
+      let hasNewer = timeline.hasNewer;
+      let startCursor: { epoch: string; seq: number } | null = null;
+      let endCursor: { epoch: string; seq: number } | null = null;
+      let entries: ReturnType<typeof projectTimelineRows>;
+
+      if (shouldLimitByProjectedWindow) {
+        const projectedLimit = Math.max(1, Math.floor(requestedLimit));
+        let fetchLimit = projectedLimit;
+        let projectedWindow = selectTimelineWindowByProjectedLimit({
+          rows: timeline.rows,
+          provider: snapshot.provider,
+          direction,
+          limit: projectedLimit,
+          collapseToolLifecycle: false,
+        });
+
+        while (timeline.hasOlder) {
+          const needsMoreProjectedEntries =
+            projectedWindow.projectedEntries.length < projectedLimit;
+          const firstLoadedRow = timeline.rows[0];
+          const firstSelectedRow = projectedWindow.selectedRows[0];
+          const startsAtLoadedBoundary =
+            firstLoadedRow != null &&
+            firstSelectedRow != null &&
+            firstSelectedRow.seq === firstLoadedRow.seq;
+          const boundaryIsAssistantChunk =
+            startsAtLoadedBoundary && firstLoadedRow.item.type === "assistant_message";
+
+          if (!needsMoreProjectedEntries && !boundaryIsAssistantChunk) {
+            break;
+          }
+
+          const maxRows = Math.max(0, timeline.window.maxSeq - timeline.window.minSeq + 1);
+          const nextFetchLimit = Math.min(maxRows, fetchLimit * 2);
+          if (nextFetchLimit <= fetchLimit) {
+            break;
+          }
+
+          fetchLimit = nextFetchLimit;
+          timeline = this.agentManager.fetchTimeline(msg.agentId, {
+            direction,
+            cursor,
+            limit: fetchLimit,
+          });
+          projectedWindow = selectTimelineWindowByProjectedLimit({
+            rows: timeline.rows,
+            provider: snapshot.provider,
+            direction,
+            limit: projectedLimit,
+            collapseToolLifecycle: false,
+          });
+        }
+
+        const selectedRows = projectedWindow.selectedRows;
+
+        entries = projectTimelineRows(selectedRows, snapshot.provider, projection);
+
+        if (projectedWindow.minSeq !== null && projectedWindow.maxSeq !== null) {
+          startCursor = { epoch: timeline.epoch, seq: projectedWindow.minSeq };
+          endCursor = { epoch: timeline.epoch, seq: projectedWindow.maxSeq };
+          hasOlder = projectedWindow.minSeq > timeline.window.minSeq;
+          hasNewer = false;
+        }
+      } else {
+        const firstRow = timeline.rows[0];
+        const lastRow = timeline.rows[timeline.rows.length - 1];
+        startCursor = firstRow ? { epoch: timeline.epoch, seq: firstRow.seq } : null;
+        endCursor = lastRow ? { epoch: timeline.epoch, seq: lastRow.seq } : null;
+        entries = projectTimelineRows(timeline.rows, snapshot.provider, projection);
+      }

      this.emit({
        type: "fetch_agent_timeline_response",
@@ -6943,24 +7029,21 @@ export class Session {
          agentId: msg.agentId,
          agent: agentPayload,
          direction,
-          startSeq: firstRow?.seq ?? null,
-          endSeq: lastRow?.seq ?? null,
-          hasOlder: timeline.hasOlder,
-          hasNewer: timeline.hasNewer,
-          entries,
-          error: null,
-          epoch,
-          reset: false,
-          staleCursor: false,
-          gap: false,
-          window,
+          projection,
+          epoch: timeline.epoch,
+          reset: timeline.reset,
+          staleCursor: timeline.staleCursor,
+          gap: timeline.gap,
+          window: timeline.window,
          startCursor,
          endCursor,
-          projection: msg.projection ?? "projected",
+          hasOlder,
+          hasNewer,
+          entries,
+          error: null,
        },
      });
    } catch (error) {
-      const epoch = `compat:${msg.agentId}`;
      this.sessionLogger.error(
        { err: error, agentId: msg.agentId },
        "Failed to handle fetch_agent_timeline_request",
@@ -6972,28 +7055,18 @@ export class Session {
          agentId: msg.agentId,
          agent: null,
          direction,
-          startSeq: null,
-          endSeq: null,
+          projection,
+          epoch: "",
+          reset: false,
+          staleCursor: false,
+          gap: false,
+          window: { minSeq: 0, maxSeq: 0, nextSeq: 0 },
+          startCursor: null,
+          endCursor: null,
          hasOlder: false,
          hasNewer: false,
          entries: [],
          error: error instanceof Error ? error.message : String(error),
-          epoch,
-          reset: false,
-          staleCursor: false,
-          gap: false,
-          window: {
-            minSeq: 0,
-            maxSeq: 0,
-            nextSeq: 0,
-            startSeq: null,
-            endSeq: null,
-            hasOlder: false,
-            hasNewer: false,
-          },
-          startCursor: null,
-          endCursor: null,
-          projection: msg.projection ?? "projected",
        },
      });
    }
@@ -935,9 +935,6 @@ export function createTestAgentClients(): Record<string, AgentClient> {
  return {
    claude: new FakeAgentClient("claude"),
    codex: new FakeAgentClient("codex"),
-    gemini: new FakeAgentClient("gemini"),
-    amp: new FakeAgentClient("amp"),
-    aider: new FakeAgentClient("aider"),
    opencode: new FakeAgentClient("opencode"),
  };
 }
@@ -2,7 +2,6 @@ import { describe, expect, it } from "vitest";

 import {
  AgentStreamMessageSchema,
-  FetchAgentTimelineRequestMessageSchema,
  FetchAgentTimelineResponseMessageSchema,
  SessionInboundMessageSchema,
  SessionOutboundMessageSchema,
@@ -18,55 +17,16 @@ describe("shared messages stream parsing", () => {
        agentId: "agent_live",
        agent: null,
        direction: "tail",
-        startSeq: 1,
-        endSeq: 2,
+        projection: "projected",
+        epoch: "epoch-1",
+        reset: false,
+        staleCursor: false,
+        gap: false,
+        window: { minSeq: 1, maxSeq: 2, nextSeq: 3 },
+        startCursor: { epoch: "epoch-1", seq: 1 },
+        endCursor: { epoch: "epoch-1", seq: 2 },
        hasOlder: false,
        hasNewer: false,
-        entries: [
-          {
-            provider: "codex",
-            item: { type: "assistant_message", text: "hello" },
-            timestamp: "2026-02-08T20:10:00.000Z",
-            seq: 2,
-          },
-        ],
-        error: null,
-      },
-    });
-
-    expect(parsed.payload.entries).toHaveLength(1);
-    expect(parsed.payload.entries[0]?.item.type).toBe("assistant_message");
-  });
-
-  it("parses legacy fetch timeline request baggage at the parser boundary", () => {
-    const parsed = FetchAgentTimelineRequestMessageSchema.parse({
-      type: "fetch_agent_timeline_request",
-      agentId: "agent_live",
-      requestId: "req-legacy",
-      direction: "after",
-      cursor: {
-        seq: 12,
-        epoch: "legacy-epoch",
-      },
-      projection: "canonical",
-    });
-
-    expect(parsed.cursor?.epoch).toBe("legacy-epoch");
-    expect(parsed.projection).toBe("canonical");
-  });
-
-  it("parses legacy fetch timeline response baggage at the parser boundary", () => {
-    const parsed = FetchAgentTimelineResponseMessageSchema.parse({
-      type: "fetch_agent_timeline_response",
-      payload: {
-        requestId: "req-1",
-        agentId: "agent_live",
-        agent: null,
-        direction: "tail",
-        reset: false,
-        startCursor: { seq: 1, epoch: "legacy-epoch" },
-        endCursor: { seq: 2, epoch: "legacy-epoch" },
-        projection: "canonical",
        entries: [
          {
            provider: "codex",
@@ -82,10 +42,8 @@ describe("shared messages stream parsing", () => {
      },
    });

-    expect(parsed.payload.startSeq).toBe(1);
-    expect(parsed.payload.endSeq).toBe(2);
-    expect(parsed.payload.projection).toBe("canonical");
-    expect(parsed.payload.entries[0]?.seq).toBe(2);
+    expect(parsed.payload.entries).toHaveLength(1);
+    expect(parsed.payload.entries[0]?.item.type).toBe("assistant_message");
  });

  it("parses explicit shutdown and restart lifecycle request payloads as distinct message types", () => {
@@ -112,7 +70,6 @@ describe("shared messages stream parsing", () => {
      payload: {
        agentId: "agent_live",
        timestamp: "2026-02-08T20:10:00.000Z",
-        seq: 12,
        event: {
          type: "timeline",
          provider: "claude",
@@ -140,27 +97,6 @@ describe("shared messages stream parsing", () => {
    }
  });

-  it("parses legacy agent_stream baggage at the parser boundary", () => {
-    const parsed = AgentStreamMessageSchema.parse({
-      type: "agent_stream",
-      payload: {
-        agentId: "agent_live",
-        timestamp: "2026-02-08T20:10:00.000Z",
-        epoch: "legacy-epoch",
-        event: {
-          type: "timeline",
-          provider: "claude",
-          item: {
-            type: "assistant_message",
-            text: "hello",
-          },
-        },
-      },
-    });
-
-    expect(parsed.payload.epoch).toBe("legacy-epoch");
-  });
-
  it("parses representative sub_agent tool_call event", () => {
    const parsed = AgentStreamMessageSchema.parse({
      type: "agent_stream",
@@ -908,6 +908,7 @@ export const RefreshAgentRequestMessageSchema = z.object({
 export const CancelAgentRequestMessageSchema = z.object({
  type: z.literal("cancel_agent_request"),
  agentId: z.string(),
+  requestId: z.string().optional(),
 });

 export const RestartServerRequestMessageSchema = z.object({
@@ -922,9 +923,8 @@ export const ShutdownServerRequestMessageSchema = z.object({
 });

 export const AgentTimelineCursorSchema = z.object({
+  epoch: z.string(),
  seq: z.number().int().nonnegative(),
-  // COMPAT(timeline): retain legacy cursor epoch for older clients.
-  epoch: z.string().optional(),
 });

 export const FetchAgentTimelineRequestMessageSchema = z.object({
@@ -935,8 +935,8 @@ export const FetchAgentTimelineRequestMessageSchema = z.object({
  cursor: AgentTimelineCursorSchema.optional(),
  // 0 means "all matching rows for this query window".
  limit: z.number().int().nonnegative().optional(),
-  // COMPAT(timeline): retain removed projection so older clients can still send it.
-  projection: z.enum(["canonical", "projected"]).optional(),
+  // Default should be projected for app timeline loading.
+  projection: z.enum(["projected", "canonical"]).optional(),
 });

 export const SetAgentModeRequestMessageSchema = z.object({
@@ -1367,6 +1367,7 @@ export const FileDownloadTokenRequestSchema = z.object({
 export const ClearAgentAttentionMessageSchema = z.object({
  type: z.literal("clear_agent_attention"),
  agentId: z.union([z.string(), z.array(z.string())]),
+  requestId: z.string().optional(),
 });

 export const ClientHeartbeatMessageSchema = z.object({
@@ -2036,9 +2037,8 @@ export const AgentStreamMessageSchema = z.object({
    agentId: z.string(),
    event: AgentStreamEventPayloadSchema,
    timestamp: z.string(),
-    // Present only for committed timeline events.
+    // Present for timeline events. Maps 1:1 to canonical in-memory timeline rows.
    seq: z.number().int().nonnegative().optional(),
-    // COMPAT(timeline): retain removed epoch for older clients.
    epoch: z.string().optional(),
  }),
 });
@@ -2196,72 +2196,63 @@ export const FetchAgentResponseMessageSchema = z.object({
  }),
 });

-const TimelineProjectionKindSchema = z.enum(["assistant_merge", "tool_lifecycle"]);
-
-const TimelineSeqRangeSchema = z.object({
+const AgentTimelineSeqRangeSchema = z.object({
  startSeq: z.number().int().nonnegative(),
  endSeq: z.number().int().nonnegative(),
 });

-export const AgentTimelineEntryPayloadSchema = z
-  .object({
-    provider: AgentProviderSchema,
-    item: AgentTimelineItemPayloadSchema,
-    timestamp: z.string(),
-    seq: z.number().int().nonnegative().optional(),
-    // COMPAT(timeline): retain legacy projected timeline fields.
-    seqStart: z.number().int().nonnegative().optional(),
-    seqEnd: z.number().int().nonnegative().optional(),
-    sourceSeqRanges: z.array(TimelineSeqRangeSchema).optional(),
-    collapsed: z.array(TimelineProjectionKindSchema).optional(),
-  })
-  .transform((entry, ctx) => {
-    const seq = entry.seq ?? entry.seqEnd ?? entry.seqStart;
-    if (typeof seq !== "number") {
-      ctx.addIssue({
-        code: z.ZodIssueCode.custom,
-        message: "Agent timeline entry must include seq or legacy seqStart/seqEnd",
-      });
-      return z.NEVER;
-    }
-
-    return {
-      ...entry,
-      seq,
-    };
-  });
+export const AgentTimelineEntryPayloadSchema = z.object({
+  provider: AgentProviderSchema,
+  item: AgentTimelineItemPayloadSchema,
+  timestamp: z.string(),
+  seqStart: z.number().int().nonnegative(),
+  seqEnd: z.number().int().nonnegative(),
+  sourceSeqRanges: z.array(AgentTimelineSeqRangeSchema),
+  collapsed: z.array(z.enum(["assistant_merge", "tool_lifecycle"])),
+});

 export const FetchAgentTimelineResponseMessageSchema = z.object({
  type: z.literal("fetch_agent_timeline_response"),
-  payload: z
-    .object({
-      requestId: z.string(),
-      agentId: z.string(),
-      agent: AgentSnapshotPayloadSchema.nullable(),
-      direction: z.enum(["tail", "before", "after"]),
-      startSeq: z.number().int().nonnegative().nullable().optional(),
-      endSeq: z.number().int().nonnegative().nullable().optional(),
-      hasOlder: z.boolean().optional(),
-      hasNewer: z.boolean().optional(),
-      entries: z.array(AgentTimelineEntryPayloadSchema),
-      error: z.string().nullable(),
-      // COMPAT(timeline): retain legacy response baggage for older clients.
-      epoch: z.string().optional(),
-      reset: z.boolean().optional(),
-      staleCursor: z.boolean().optional(),
-      gap: z.unknown().optional(),
-      window: z.unknown().optional(),
-      startCursor: AgentTimelineCursorSchema.nullable().optional(),
-      endCursor: AgentTimelineCursorSchema.nullable().optional(),
-      projection: z.enum(["canonical", "projected"]).optional(),
-    })
-    .transform((payload) => ({
-      ...payload,
-      startSeq: payload.startSeq ?? payload.startCursor?.seq ?? null,
-      endSeq: payload.endSeq ?? payload.endCursor?.seq ?? null,
-      hasOlder: payload.hasOlder ?? false,
-      hasNewer: payload.hasNewer ?? false,
-    })),
+  payload: z.object({
+    requestId: z.string(),
+    agentId: z.string(),
+    agent: AgentSnapshotPayloadSchema.nullable(),
+    direction: z.enum(["tail", "before", "after"]),
+    projection: z.enum(["projected", "canonical"]),
+    epoch: z.string(),
+    reset: z.boolean(),
+    staleCursor: z.boolean(),
+    gap: z.boolean(),
+    window: z.object({
+      minSeq: z.number().int().nonnegative(),
+      maxSeq: z.number().int().nonnegative(),
+      nextSeq: z.number().int().nonnegative(),
+    }),
+    startCursor: AgentTimelineCursorSchema.nullable(),
+    endCursor: AgentTimelineCursorSchema.nullable(),
+    hasOlder: z.boolean(),
+    hasNewer: z.boolean(),
+    entries: z.array(AgentTimelineEntryPayloadSchema),
+    error: z.string().nullable(),
+  }),
+});
+
+export const CancelAgentResponseMessageSchema = z.object({
+  type: z.literal("cancel_agent_response"),
+  payload: z.object({
+    requestId: z.string(),
+    agentId: z.string(),
+    agent: AgentSnapshotPayloadSchema.nullable(),
+  }),
+});
+
+export const ClearAgentAttentionResponseMessageSchema = z.object({
+  type: z.literal("clear_agent_attention_response"),
+  payload: z.object({
+    requestId: z.string(),
+    agentId: z.string().or(z.array(z.string())),
+    agents: z.array(AgentSnapshotPayloadSchema),
+  }),
 });

 export const SendAgentMessageResponseMessageSchema = z.object({
@@ -2960,6 +2951,8 @@ export const SessionOutboundMessageSchema = z.discriminatedUnion("type", [
  ArchiveWorkspaceResponseMessageSchema,
  FetchAgentResponseMessageSchema,
  FetchAgentTimelineResponseMessageSchema,
+  CancelAgentResponseMessageSchema,
+  ClearAgentAttentionResponseMessageSchema,
  SendAgentMessageResponseMessageSchema,
  SetVoiceModeResponseMessageSchema,
  GetDaemonConfigResponseMessageSchema,
@@ -3085,6 +3078,7 @@ export type FetchAgentResponseMessage = z.infer<typeof FetchAgentResponseMessage
 export type FetchAgentTimelineResponseMessage = z.infer<
  typeof FetchAgentTimelineResponseMessageSchema
 >;
+export type CancelAgentResponseMessage = z.infer<typeof CancelAgentResponseMessageSchema>;
 export type SendAgentMessageResponseMessage = z.infer<typeof SendAgentMessageResponseMessageSchema>;
 export type SetVoiceModeResponseMessage = z.infer<typeof SetVoiceModeResponseMessageSchema>;
 export type SetAgentModeResponseMessage = z.infer<typeof SetAgentModeResponseMessageSchema>;
@@ -3256,6 +3250,9 @@ export type FileDownloadTokenResponse = z.infer<typeof FileDownloadTokenResponse
 export type RestartServerRequestMessage = z.infer<typeof RestartServerRequestMessageSchema>;
 export type ShutdownServerRequestMessage = z.infer<typeof ShutdownServerRequestMessageSchema>;
 export type ClearAgentAttentionMessage = z.infer<typeof ClearAgentAttentionMessageSchema>;
+export type ClearAgentAttentionResponseMessage = z.infer<
+  typeof ClearAgentAttentionResponseMessageSchema
+>;
 export type ClientHeartbeatMessage = z.infer<typeof ClientHeartbeatMessageSchema>;
 export type ListCommandsRequest = z.infer<typeof ListCommandsRequestSchema>;
 export type ListCommandsResponse = z.infer<typeof ListCommandsResponseSchema>;