Open existing agents from links and the CLI (#2324)

* feat(desktop): open existing agents from links

Register a stable agent deep link and route it through the existing Desktop window. Add a matching CLI command that resolves the local server and activates the requested agent without creating or messaging it.

* fix(desktop): recover agent link delivery

docs/development.md

@@ -390,6 +390,7 @@ npm run cli -- ls -a -g              # List all agents globally
 npm run cli -- ls -a -g --json       # Same, as JSON
 npm run cli -- inspect <id>          # Show detailed agent info
 npm run cli -- logs <id>             # View agent timeline
+npm run cli -- agent open <id>       # Focus an existing agent in Paseo Desktop
 npm run cli -- daemon status         # Check daemon status
 npm run cli -- clone owner/repo --dir ~/workspace # Clone GitHub repo and register project
 ```
@@ -400,6 +401,11 @@ Use `--host <host:port>` to point the CLI at a different daemon:
 npm run cli -- --host localhost:7777 ls -a
 ```
 
+Desktop integrations can focus an existing agent without creating one or
+sending a message. Use `paseo://h/<server-id>/agent/<agent-id>`, or run
+`paseo agent open <agent-id>`. The CLI reads the local daemon's server ID by
+default; pass `--server <server-id>` when targeting another server.
+
 ## Agent state
 
 Agent data lives at:

packages/app/src/app/_layout.tsx

@@ -66,6 +66,7 @@ import {
 import { registerWorkspaceRouteNavigationRef } from "@/navigation/workspace-route-navigation";
 import { ThemedStack } from "@/navigation/themed-stack";
 import { shouldUseDesktopDaemon } from "@/desktop/daemon/desktop-daemon";
+import { AgentNavigationListener } from "@/desktop/agent-navigation";
 import { listenToDesktopEvent } from "@/desktop/electron/events";
 import { updateDesktopWindowControls } from "@/desktop/electron/window";
 import { getDesktopHost } from "@/desktop/host";
@@ -908,6 +909,7 @@ function AppShell() {
     <MobilePanelsProvider>
       <HorizontalScrollProvider>
         <OpenProjectListener />
+        <AgentNavigationListener />
         <AppWithSidebar>
           <WorkspaceRouteNavigationBridge />
           <RootStack />

packages/app/src/desktop/agent-navigation.tsx

@@ -0,0 +1,69 @@
+import { useEffect } from "react";
+import { listenToDesktopEvent } from "@/desktop/electron/events";
+import { getDesktopHost } from "@/desktop/host";
+import { useStableEvent } from "@/hooks/use-stable-event";
+import { navigateToAgent } from "@/utils/navigate-to-agent";
+
+interface OpenAgentEventPayload {
+  serverId?: unknown;
+  agentId?: unknown;
+}
+
+export function AgentNavigationListener() {
+  const openAgent = useStableEvent((payload: OpenAgentEventPayload | null) => {
+    const serverId = typeof payload?.serverId === "string" ? payload.serverId.trim() : "";
+    const agentId = typeof payload?.agentId === "string" ? payload.agentId.trim() : "";
+    if (!serverId || !agentId) {
+      return;
+    }
+    navigateToAgent({ serverId, agentId });
+  });
+
+  useEffect(() => {
+    const host = getDesktopHost();
+    const ready = host?.agentNavigation?.ready;
+    if (typeof host?.events?.on !== "function" || typeof ready !== "function") {
+      return;
+    }
+
+    let disposed = false;
+    let unlisten: (() => void) | null = null;
+    let retryTimer: ReturnType<typeof setTimeout> | null = null;
+
+    const connect = async () => {
+      let dispose: (() => void) | null = null;
+      try {
+        dispose = await listenToDesktopEvent<OpenAgentEventPayload>("open-agent", openAgent);
+        if (disposed) {
+          dispose();
+          return;
+        }
+        unlisten = dispose;
+        const pending = await ready();
+        if (!disposed && pending) {
+          openAgent(pending);
+        }
+      } catch {
+        dispose?.();
+        if (unlisten === dispose) {
+          unlisten = null;
+        }
+        if (!disposed) {
+          retryTimer = setTimeout(() => void connect(), 1_000);
+        }
+      }
+    };
+
+    void connect();
+
+    return () => {
+      disposed = true;
+      if (retryTimer) {
+        clearTimeout(retryTimer);
+      }
+      unlisten?.();
+    };
+  }, [openAgent]);
+
+  return null;
+}

packages/app/src/desktop/host.ts

@@ -123,6 +123,10 @@ export interface DesktopEventsBridge {
   on?: (event: string, handler: (payload: unknown) => void) => Promise<() => void> | (() => void);
 }
 
+export interface DesktopAgentNavigationBridge {
+  ready?: () => Promise<{ serverId: string; agentId: string } | null>;
+}
+
 export type DesktopBrowserShortcutEvent =
   | { browserId?: string; action: "focus-url" }
   | { browserId: string; action: "new-tab" };
@@ -169,6 +173,7 @@ export interface DesktopHostBridge {
   platform?: string;
   invoke?: DesktopInvokeBridge["invoke"];
   getPendingOpenProject?: () => Promise<string | null>;
+  agentNavigation?: DesktopAgentNavigationBridge;
   events?: DesktopEventsBridge;
   window?: DesktopWindowModuleBridge;
   dialog?: DesktopDialogBridge;

packages/cli/src/cli-surface.test.ts

@@ -34,4 +34,12 @@ describe("canonical CLI surface", () => {
     expect(run?.helpInformation()).toContain("--background");
     expect(run?.helpInformation()).not.toContain("--detach");
   });
+
+  it("offers opening an existing agent in the desktop app", () => {
+    const agent = createCli().commands.find((command) => command.name() === "agent");
+    const open = agent?.commands.find((command) => command.name() === "open");
+
+    expect(open?.helpInformation()).toContain("<agent-id>");
+    expect(open?.helpInformation()).toContain("--server <server-id>");
+  });
 });

packages/cli/src/commands/agent/index.ts

@@ -14,6 +14,7 @@ import { addReloadOptions, runReloadCommand } from "./reload.js";
 import { addImportOptions, runImportCommand } from "./import.js";
 import { runUpdateCommand } from "./update.js";
 import { runDetachCommand } from "./detach.js";
+import { addOpenOptions, runOpenCommand } from "./open.js";
 import { withOutput } from "../../output/index.js";
 import {
   addDaemonHostOption,
@@ -39,6 +40,10 @@ export function createAgentCommand(): Command {
 
   addDaemonHostOption(addLogsOptions(agent.command("logs"))).action(runLogsCommand);
 
+  addJsonAndDaemonHostOptions(addOpenOptions(agent.command("open"))).action(
+    withOutput(runOpenCommand),
+  );
+
   addJsonAndDaemonHostOptions(addStopOptions(agent.command("stop"))).action(
     withOutput(runStopCommand),
   );

packages/cli/src/commands/agent/open.ts

@@ -0,0 +1,82 @@
+import type { Command } from "commander";
+import { buildDaemonConnectionCommandError, connectToDaemon } from "../../utils/client.js";
+import { openDesktopWithAgent } from "../open.js";
+import type {
+  CommandError,
+  CommandOptions,
+  OutputSchema,
+  SingleResult,
+} from "../../output/index.js";
+
+interface OpenAgentResult {
+  agentId: string;
+  serverId: string;
+  status: "opened";
+}
+
+const openAgentSchema: OutputSchema<OpenAgentResult> = {
+  idField: "agentId",
+  columns: [
+    { header: "AGENT ID", field: "agentId" },
+    { header: "SERVER ID", field: "serverId" },
+    { header: "STATUS", field: "status" },
+  ],
+};
+
+export function addOpenOptions(command: Command): Command {
+  return command
+    .description("Open an existing agent in Paseo Desktop")
+    .argument("<agent-id>", "Existing agent ID")
+    .option("--server <server-id>", "Server ID (defaults to the local daemon)");
+}
+
+async function resolveServerId(options: CommandOptions): Promise<string> {
+  const explicitServerId = typeof options.server === "string" ? options.server.trim() : "";
+  if (explicitServerId) {
+    return explicitServerId;
+  }
+
+  let client;
+  try {
+    client = await connectToDaemon({ host: options.host });
+  } catch (error) {
+    throw buildDaemonConnectionCommandError({ host: options.host, error });
+  }
+  try {
+    const serverId = client.getLastServerInfoMessage()?.serverId.trim();
+    if (!serverId) {
+      const error: CommandError = {
+        code: "SERVER_ID_UNAVAILABLE",
+        message: "The daemon did not report a server ID.",
+      };
+      throw error;
+    }
+    return serverId;
+  } finally {
+    await client.close().catch(() => {});
+  }
+}
+
+export async function runOpenCommand(
+  agentIdArg: string,
+  options: CommandOptions,
+  _command: Command,
+): Promise<SingleResult<OpenAgentResult>> {
+  const agentId = agentIdArg.trim();
+  if (!agentId) {
+    const error: CommandError = {
+      code: "MISSING_AGENT_ID",
+      message: "Agent ID is required.",
+    };
+    throw error;
+  }
+
+  const serverId = await resolveServerId(options);
+  await openDesktopWithAgent({ serverId, agentId });
+
+  return {
+    type: "single",
+    data: { agentId, serverId, status: "opened" },
+    schema: openAgentSchema,
+  };
+}

packages/cli/src/commands/open.ts

@@ -2,6 +2,7 @@ import { existsSync } from "node:fs";
 import { homedir } from "node:os";
 import path from "node:path";
 import { spawnProcess } from "@getpaseo/server";
+import { buildAgentDeepLink, type AgentDeepLinkTarget } from "@getpaseo/protocol/agent-deep-link";
 
 function findDesktopApp(): string | null {
   if (process.platform === "darwin") {
@@ -67,35 +68,39 @@ function spawnDetached(command: string, args: string[]): void {
   }).unref();
 }
 
+function launchDesktop(args: string[]): void {
+  if (process.env.PASEO_DESKTOP_CLI === "1") {
+    throw new Error("Cannot open Paseo Desktop while running in desktop CLI passthrough mode.");
+  }
+
+  const desktopApp = findDesktopApp();
+  if (!desktopApp) {
+    throw new Error(
+      "Paseo desktop app not found. Install it from https://github.com/getpaseo/paseo/releases",
+    );
+  }
+
+  if (process.platform === "darwin") {
+    // -n forces a new instance even if the app is already running. The new
+    // instance relays its argv to the existing one through Electron's
+    // single-instance lock. -g keeps the terminal in the foreground.
+    spawnDetached("open", ["-n", "-g", "-a", desktopApp, "--args", ...args]);
+    return;
+  }
+
+  spawnDetached(desktopApp, args);
+}
+
 export async function openDesktopWithProject(projectPath: string): Promise<void> {
   try {
-    if (process.env.PASEO_DESKTOP_CLI === "1") {
-      throw new Error(
-        "Cannot open a desktop project while running in desktop CLI passthrough mode.",
-      );
-    }
-
-    const desktopApp = findDesktopApp();
-    if (!desktopApp) {
-      throw new Error(
-        "Paseo desktop app not found. Install it from https://github.com/getpaseo/paseo/releases",
-      );
-    }
-
-    if (process.platform === "darwin") {
-      // -n forces a new instance even if the app is already running.
-      // The new instance hits requestSingleInstanceLock(), fails, and relays
-      // the argv to the first instance via the second-instance event.
-      // -g keeps the terminal in the foreground (better CLI UX).
-      // Without -n, macOS just activates the existing window and drops --args.
-      spawnDetached("open", ["-n", "-g", "-a", desktopApp, "--args", projectPath]);
-      return;
-    }
-
-    spawnDetached(desktopApp, [projectPath]);
+    launchDesktop([projectPath]);
   } catch (error) {
     const message = error instanceof Error ? error.message : String(error);
     process.stderr.write(`${message}\n`);
     process.exitCode = 1;
   }
 }
+
+export async function openDesktopWithAgent(target: AgentDeepLinkTarget): Promise<void> {
+  launchDesktop([buildAgentDeepLink(target)]);
+}

packages/desktop/electron-builder.yml

@@ -2,6 +2,10 @@ npmRebuild: false
 appId: sh.paseo.desktop
 productName: Paseo
 executableName: Paseo
+protocols:
+  - name: Paseo agent link
+    schemes:
+      - paseo
 afterPack: ./scripts/after-pack.js
 afterSign: ./scripts/after-sign.js
 directories:

packages/desktop/src/agent-navigation.test.ts

@@ -0,0 +1,33 @@
+import { describe, expect, it } from "vitest";
+import { AgentNavigationInbox, parseAgentDeepLinkFromArgv } from "./agent-navigation.js";
+
+describe("desktop agent navigation", () => {
+  it("finds an agent deep link among Electron launch arguments", () => {
+    expect(
+      parseAgentDeepLinkFromArgv([
+        "/Applications/Paseo.app/Contents/MacOS/Paseo",
+        "--no-sandbox",
+        "paseo://h/server-1/agent/agent-2",
+      ]),
+    ).toEqual({ serverId: "server-1", agentId: "agent-2" });
+  });
+
+  it("holds navigation until the existing renderer is ready", () => {
+    const inbox = new AgentNavigationInbox();
+    const target = { serverId: "server-1", agentId: "agent-2" };
+
+    expect(inbox.deliverOrQueue(7, target)).toBeNull();
+    expect(inbox.windowReady(7)).toEqual(target);
+    expect(inbox.deliverOrQueue(7, target)).toEqual(target);
+  });
+
+  it("returns only the newest navigation queued during startup", () => {
+    const inbox = new AgentNavigationInbox();
+
+    inbox.deliverOrQueue(7, { serverId: "server-1", agentId: "agent-1" });
+    inbox.deliverOrQueue(7, { serverId: "server-1", agentId: "agent-2" });
+
+    expect(inbox.windowReady(7)).toEqual({ serverId: "server-1", agentId: "agent-2" });
+    expect(inbox.windowReady(7)).toBeNull();
+  });
+});

packages/desktop/src/agent-navigation.ts

@@ -0,0 +1,40 @@
+import { parseAgentDeepLink, type AgentDeepLinkTarget } from "@getpaseo/protocol/agent-deep-link";
+
+export function parseAgentDeepLinkFromArgv(argv: string[]): AgentDeepLinkTarget | null {
+  for (const arg of argv) {
+    const target = parseAgentDeepLink(arg);
+    if (target) {
+      return target;
+    }
+  }
+  return null;
+}
+
+export class AgentNavigationInbox {
+  private readonly readyWindows = new Set<number>();
+  private readonly pendingByWindow = new Map<number, AgentDeepLinkTarget>();
+
+  windowLoading(webContentsId: number): void {
+    this.readyWindows.delete(webContentsId);
+  }
+
+  windowReady(webContentsId: number): AgentDeepLinkTarget | null {
+    this.readyWindows.add(webContentsId);
+    const pending = this.pendingByWindow.get(webContentsId) ?? null;
+    this.pendingByWindow.delete(webContentsId);
+    return pending;
+  }
+
+  deliverOrQueue(webContentsId: number, target: AgentDeepLinkTarget): AgentDeepLinkTarget | null {
+    if (this.readyWindows.has(webContentsId)) {
+      return target;
+    }
+    this.pendingByWindow.set(webContentsId, target);
+    return null;
+  }
+
+  removeWindow(webContentsId: number): void {
+    this.readyWindows.delete(webContentsId);
+    this.pendingByWindow.delete(webContentsId);
+  }
+}

packages/desktop/src/daemon/desktop-packaging.test.ts

@@ -89,6 +89,13 @@ describe("desktop packaging", () => {
     expect(config).toContain("!node_modules/@getpaseo/server/dist/server/web-ui/**");
   });
 
+  it("registers Paseo agent links with the operating system", () => {
+    const config = readFileSync(join(packageRoot, "electron-builder.yml"), "utf8");
+
+    expect(config).toContain("name: Paseo agent link");
+    expect(config).toContain("- paseo");
+  });
+
   // electron-builder packs production dependencies declared in package.json into
   // app.asar. Runtime code in runtime-paths.ts and bin/paseo dynamically resolves
   // these workspace packages by string, so static analysis (TypeScript, Knip) cannot

packages/desktop/src/desktop-startup.test.ts

@@ -5,7 +5,7 @@ describe("desktop startup", () => {
   it("runs CLI passthrough before GUI login-shell env inheritance", async () => {
     const calls: string[] = [];
     await runDesktopStartup({
-      hasPendingOpenProjectPath: false,
+      hasPendingGuiLaunchRequest: false,
       runCliPassthroughIfRequested: vi.fn(async () => {
         calls.push("cli");
         return true;
@@ -22,7 +22,7 @@ describe("desktop startup", () => {
   it("keeps login-shell env inheritance on normal GUI startup", async () => {
     const calls: string[] = [];
     await runDesktopStartup({
-      hasPendingOpenProjectPath: false,
+      hasPendingGuiLaunchRequest: false,
       runCliPassthroughIfRequested: vi.fn(async () => {
         calls.push("cli");
         return false;
@@ -39,7 +39,7 @@ describe("desktop startup", () => {
   it("starts skills auto-update after GUI startup", async () => {
     const calls: string[] = [];
     await runDesktopStartup({
-      hasPendingOpenProjectPath: false,
+      hasPendingGuiLaunchRequest: false,
       runCliPassthroughIfRequested: vi.fn(async () => {
         calls.push("cli");
         return false;
@@ -59,7 +59,7 @@ describe("desktop startup", () => {
     const calls: string[] = [];
 
     await runDesktopStartup({
-      hasPendingOpenProjectPath: true,
+      hasPendingGuiLaunchRequest: true,
       runCliPassthroughIfRequested,
       inheritLoginShellEnv: vi.fn(() => calls.push("env")),
       bootstrapGui: vi.fn(async () => {

packages/desktop/src/desktop-startup.ts

@@ -1,5 +1,5 @@
 export interface DesktopStartupDependencies {
-  hasPendingOpenProjectPath: boolean;
+  hasPendingGuiLaunchRequest: boolean;
   runCliPassthroughIfRequested: () => Promise<boolean>;
   inheritLoginShellEnv: () => void;
   bootstrapGui: () => Promise<void>;
@@ -7,7 +7,7 @@ export interface DesktopStartupDependencies {
 }
 
 export async function runDesktopStartup(deps: DesktopStartupDependencies): Promise<void> {
-  if (!deps.hasPendingOpenProjectPath && (await deps.runCliPassthroughIfRequested())) {
+  if (!deps.hasPendingGuiLaunchRequest && (await deps.runCliPassthroughIfRequested())) {
     return;
   }
 

packages/desktop/src/main.ts

@@ -90,6 +90,12 @@ import { autoUpdateInstalledSkills } from "./integrations/skills/index.js";
 import { registerBrowserAutomationIpc } from "./features/browser-automation/ipc.js";
 import { BrowserKeyboard } from "./features/browser-keyboard/index.js";
 import { installAppUpdateOnQuit } from "./features/auto-updater.js";
+import {
+  buildAgentDeepLinkRoute,
+  parseAgentDeepLink,
+  type AgentDeepLinkTarget,
+} from "@getpaseo/protocol/agent-deep-link";
+import { AgentNavigationInbox, parseAgentDeepLinkFromArgv } from "./agent-navigation.js";
 
 const DEV_SERVER_URL = process.env.EXPO_DEV_URL ?? "http://localhost:8081";
 const APP_SCHEME = "paseo";
@@ -98,6 +104,16 @@ const DISABLE_SINGLE_INSTANCE_LOCK = process.env.PASEO_DISABLE_SINGLE_INSTANCE_L
 const APP_NAME = process.env.PASEO_TEST_APP_NAME?.trim() || "Paseo";
 const UPDATE_QUIT_DEADLINE_MS = 5_000;
 const pendingBrowserWindowOpenRequests = new PendingBrowserWindowOpenRequests();
+const agentNavigationInbox = new AgentNavigationInbox();
+
+// A second-instance launch can arrive before the packaged protocol handler,
+// IPC handlers, and first window exist. Wait for full bootstrap, not just
+// app.whenReady(), before delivering navigation to the renderer.
+let resolveBootstrapComplete: () => void;
+const bootstrapComplete = new Promise<void>((resolve) => {
+  resolveBootstrapComplete = resolve;
+});
+let bootstrapIsComplete = false;
 
 app.setName(APP_NAME);
 
@@ -316,6 +332,7 @@ let pendingOpenProjectPath = parseOpenProjectPathFromArgv({
   argv: process.argv,
   isDefaultApp: process.defaultApp,
 });
+let pendingAgentNavigation = parseAgentDeepLinkFromArgv(process.argv);
 
 // Each window pulls its own pending open-project path on mount, keyed by
 // webContents id, so deep-linked windows (second-instance launches, the
@@ -341,6 +358,10 @@ ipcMain.handle("paseo:get-pending-open-project", (event) => {
   return result;
 });
 
+ipcMain.handle("paseo:agent-navigation:ready", (event) => {
+  return agentNavigationInbox.windowReady(event.sender.id);
+});
+
 function normalizeBrowserCaptureRect(
   rect: unknown,
 ): { x: number; y: number; width: number; height: number } | null {
@@ -653,6 +674,7 @@ function getWorkAreasPrimaryFirst(): Electron.Rectangle[] {
 
 async function createWindow(
   options: {
+    initialRoute?: string | null;
     pendingOpenProjectPath?: string | null;
     restoreWindowState?: boolean;
   } = {},
@@ -694,8 +716,14 @@ async function createWindow(
 
   const webContentsId = mainWindow.webContents.id;
   pendingOpenProjectStore.set(webContentsId, options.pendingOpenProjectPath);
+  mainWindow.webContents.on("did-start-navigation", (_event, _url, isSameDocument, isMainFrame) => {
+    if (isMainFrame && !isSameDocument) {
+      agentNavigationInbox.windowLoading(webContentsId);
+    }
+  });
   mainWindow.on("closed", () => {
     pendingOpenProjectStore.delete(webContentsId);
+    agentNavigationInbox.removeWindow(webContentsId);
     unregisterPaseoBrowserHost(webContentsId);
     browserKeyboard.detachHost(webContentsId);
   });
@@ -759,11 +787,14 @@ async function createWindow(
   if (!app.isPackaged) {
     const { loadReactDevTools } = await import("./features/react-devtools.js");
     await loadReactDevTools();
-    await mainWindow.loadURL(DEV_SERVER_URL);
+    const initialUrl = options.initialRoute
+      ? new URL(options.initialRoute, `${DEV_SERVER_URL}/`).toString()
+      : DEV_SERVER_URL;
+    await mainWindow.loadURL(initialUrl);
     return mainWindow;
   }
 
-  await mainWindow.loadURL(`${APP_SCHEME}://app/`);
+  await mainWindow.loadURL(`${APP_SCHEME}://app${options.initialRoute ?? "/"}`);
   return mainWindow;
 }
 
@@ -771,14 +802,72 @@ async function createWindow(
 // App lifecycle
 // ---------------------------------------------------------------------------
 
-// Resolves once bootstrap() has registered the custom protocol handler and IPC
-// handlers and created the first window. second-instance window creation waits
-// on this rather than app.whenReady(): in packaged mode createWindow loads
-// `paseo://app/`, which fails if the protocol handler isn't registered yet, and
-// a second instance can arrive mid-cold-start.
-let resolveBootstrapComplete: () => void;
-const bootstrapComplete = new Promise<void>((resolve) => {
-  resolveBootstrapComplete = resolve;
+let agentNavigationWindowCreation: Promise<BrowserWindow> | null = null;
+
+function focusExistingWindowOnAgent(target: AgentDeepLinkTarget): void {
+  const windows = BrowserWindow.getAllWindows();
+  const mainWindow =
+    BrowserWindow.getFocusedWindow() ?? windows.find((window) => window.isVisible()) ?? windows[0];
+  if (!mainWindow || mainWindow.isDestroyed()) {
+    if (!agentNavigationWindowCreation) {
+      const creation = createWindow({
+        initialRoute: buildAgentDeepLinkRoute(target),
+        restoreWindowState: true,
+      });
+      agentNavigationWindowCreation = creation;
+      void creation
+        .catch((error) => log.error("[window] failed to create window for agent link", error))
+        .finally(() => {
+          if (agentNavigationWindowCreation === creation) {
+            agentNavigationWindowCreation = null;
+          }
+        });
+      return;
+    }
+
+    void agentNavigationWindowCreation
+      .then(() => focusExistingWindowOnAgent(target))
+      .catch((error) => log.error("[window] failed to deliver queued agent link", error));
+    return;
+  }
+
+  if (mainWindow.isMinimized()) {
+    mainWindow.restore();
+  }
+  mainWindow.show();
+  mainWindow.focus();
+
+  const deliverable = agentNavigationInbox.deliverOrQueue(mainWindow.webContents.id, target);
+  if (deliverable) {
+    mainWindow.webContents.send("paseo:event:open-agent", deliverable);
+  }
+}
+
+function receiveAgentDeepLink(input: string): void {
+  const target = parseAgentDeepLink(input);
+  if (!target) {
+    return;
+  }
+
+  if (bootstrapIsComplete) {
+    focusExistingWindowOnAgent(target);
+    return;
+  }
+
+  pendingAgentNavigation = target;
+  void bootstrapComplete.then(() => {
+    if (pendingAgentNavigation !== target) {
+      return undefined;
+    }
+    pendingAgentNavigation = null;
+    focusExistingWindowOnAgent(target);
+    return undefined;
+  });
+}
+
+app.on("open-url", (event, url) => {
+  event.preventDefault();
+  receiveAgentDeepLink(url);
 });
 
 function setupSingleInstanceLock(): boolean {
@@ -794,6 +883,12 @@ function setupSingleInstanceLock(): boolean {
   }
 
   app.on("second-instance", (_event, commandLine) => {
+    const agentTarget = parseAgentDeepLinkFromArgv(commandLine);
+    if (agentTarget) {
+      void bootstrapComplete.then(() => focusExistingWindowOnAgent(agentTarget));
+      return;
+    }
+
     log.info("[open-project] second-instance commandLine:", commandLine);
     const openProjectPath = parseOpenProjectPathFromArgv({
       argv: commandLine,
@@ -895,13 +990,26 @@ async function bootstrap(): Promise<void> {
   });
 
   // The first window of the session restores and persists saved geometry.
-  await createWindow({ pendingOpenProjectPath, restoreWindowState: true });
+  const initialAgentNavigation = pendingAgentNavigation;
+  pendingAgentNavigation = null;
+  await createWindow({
+    initialRoute: initialAgentNavigation ? buildAgentDeepLinkRoute(initialAgentNavigation) : null,
+    pendingOpenProjectPath,
+    restoreWindowState: true,
+  });
   pendingOpenProjectPath = null;
 
   // Protocol + IPC handlers and the first window now exist: release any
   // second-instance launches that arrived during cold start.
+  bootstrapIsComplete = true;
   resolveBootstrapComplete();
 
+  if (pendingAgentNavigation) {
+    const target = pendingAgentNavigation;
+    pendingAgentNavigation = null;
+    focusExistingWindowOnAgent(target);
+  }
+
   app.on("activate", async () => {
     if (BrowserWindow.getAllWindows().length === 0) {
       await createWindow({ restoreWindowState: true });
@@ -910,7 +1018,7 @@ async function bootstrap(): Promise<void> {
 }
 
 void runDesktopStartup({
-  hasPendingOpenProjectPath: Boolean(pendingOpenProjectPath),
+  hasPendingGuiLaunchRequest: Boolean(pendingOpenProjectPath || pendingAgentNavigation),
   runCliPassthroughIfRequested,
   inheritLoginShellEnv,
   bootstrapGui: bootstrap,

packages/desktop/src/preload.ts

@@ -23,6 +23,13 @@ contextBridge.exposeInMainWorld("paseoDesktop", {
     ipcRenderer.invoke("paseo:invoke", command, args),
   getPendingOpenProject: () =>
     ipcRenderer.invoke("paseo:get-pending-open-project") as Promise<string | null>,
+  agentNavigation: {
+    ready: () =>
+      ipcRenderer.invoke("paseo:agent-navigation:ready") as Promise<{
+        serverId: string;
+        agentId: string;
+      } | null>,
+  },
   events: {
     on: (event: string, handler: EventHandler): Promise<() => void> => {
       const listener = (_ipcEvent: Electron.IpcRendererEvent, payload: unknown) => {

packages/protocol/src/agent-deep-link.test.ts

@@ -0,0 +1,25 @@
+import { describe, expect, it } from "vitest";
+import {
+  buildAgentDeepLink,
+  buildAgentDeepLinkRoute,
+  parseAgentDeepLink,
+} from "./agent-deep-link.js";
+
+describe("agent deep links", () => {
+  it("round-trips an existing agent target", () => {
+    const target = { serverId: "server/main", agentId: "agent 123" };
+
+    const link = buildAgentDeepLink(target);
+
+    expect(link).toBe("paseo://h/server%2Fmain/agent/agent%20123");
+    expect(buildAgentDeepLinkRoute(target)).toBe("/h/server%2Fmain/agent/agent%20123");
+    expect(parseAgentDeepLink(link)).toEqual(target);
+  });
+
+  it("rejects links outside the exact agent route", () => {
+    expect(parseAgentDeepLink("https://h/server/agent/agent-1")).toBeNull();
+    expect(parseAgentDeepLink("paseo://app/h/server/agent/agent-1")).toBeNull();
+    expect(parseAgentDeepLink("paseo://h/server/agent/agent-1?message=hello")).toBeNull();
+    expect(parseAgentDeepLink("paseo://h/server/agent/agent-1/extra")).toBeNull();
+  });
+});

packages/protocol/src/agent-deep-link.ts

@@ -0,0 +1,56 @@
+export interface AgentDeepLinkTarget {
+  serverId: string;
+  agentId: string;
+}
+
+function normalizeSegment(value: string): string {
+  return value.trim();
+}
+
+export function buildAgentDeepLink(target: AgentDeepLinkTarget): string {
+  const serverId = normalizeSegment(target.serverId);
+  const agentId = normalizeSegment(target.agentId);
+  if (!serverId || !agentId) {
+    throw new Error("Agent deep links require a server ID and agent ID.");
+  }
+  return `paseo://h/${encodeURIComponent(serverId)}/agent/${encodeURIComponent(agentId)}`;
+}
+
+export function buildAgentDeepLinkRoute(target: AgentDeepLinkTarget): string {
+  const link = new URL(buildAgentDeepLink(target));
+  return `/h${link.pathname}`;
+}
+
+export function parseAgentDeepLink(input: string): AgentDeepLinkTarget | null {
+  let url: URL;
+  try {
+    url = new URL(input);
+  } catch {
+    return null;
+  }
+
+  if (
+    url.protocol !== "paseo:" ||
+    url.hostname !== "h" ||
+    url.username ||
+    url.password ||
+    url.port ||
+    url.search ||
+    url.hash
+  ) {
+    return null;
+  }
+
+  const segments = url.pathname.split("/").filter(Boolean);
+  if (segments.length !== 3 || segments[1] !== "agent") {
+    return null;
+  }
+
+  try {
+    const serverId = normalizeSegment(decodeURIComponent(segments[0] ?? ""));
+    const agentId = normalizeSegment(decodeURIComponent(segments[2] ?? ""));
+    return serverId && agentId ? { serverId, agentId } : null;
+  } catch {
+    return null;
+  }
+}