diff --git a/docs/plugin-architecture.md b/docs/plugin-architecture.md
index 36329b254..62e9b7440 100644
--- a/docs/plugin-architecture.md
+++ b/docs/plugin-architecture.md
@@ -294,6 +294,21 @@ active registered types appear there; plugin activation remains owned by
 Settings → Plugins → Manage plugins. Provider defaults are versioned device preferences, not
 agent-record migrations; blank per-agent values inherit them.
 
+Code that agents need while they run, such as an agent type's runtime, tools,
+wakes and Attention sources, belongs in the plugin's optional `agent` export:
+`export const agent = { inject, apply(ctx) }`, with its own `inject`. `apply`
+stays the plugin's UI. Both parts now start in the same page, under the same
+plugin identity; the plugin is active once both are, and fails if either does.
+This separation lets agents later run apart from the UI page.
+
+A harness plugin registers its type from its `agent` entry and presents it
+from `apply`: `ctx.agents.present(typeId, (exposed) => ({ icon, Peek, Create,
+CreateModel, tabs, provider: { DialogBody, DefaultControl } }))`. The type's
+readers see one type with both halves. `exposed` is the type's `expose`: the
+handles its UI reaches of the runtime. Each is JSON, a store (`snapshot` and
+`subscribe`) or a call returning a promise, so it can later cross to another
+page. Claude is the first harness split this way.
+
 A plugin, bundled or installed, can add a tab to the settings of every agent
 running on this device, whatever its type, with
 `ctx.agents.registerTab({ id, title, component })`. The component receives
@@ -353,7 +368,7 @@ plugin is replaced, so ask for it when acting rather than keeping it. Like any t
 
 Plugins can discover active Attention source registrations through `ctx.agents.attentionProviders()`. Each entry includes its `provider` key and optional `description` and JSON-object `configExample` supplied to `addAttentionSource`. The catalog omits executable callbacks and inactive registrations; discovery tools belong in external plugins.
 
-A source may also `present` its watches on the Agent Attention page. Given a watch and its display name, it returns the watch's kind and, optionally, an icon, a target with a subtitle, an external link, and a details component that replaces the name in the expanded row. When a provider has no `present`, or it throws, Buzz shows the watch by its name. The GitHub plugin presents pull request watches this way, linking to its comment author settings.
+A plugin's UI entry may also present its source's watches on the Agent Attention page with `ctx.agents.presentSource(sourceId, present)`. The source runs in the agent entry, but how its watches look is a screen concern, so it stays with the screens. Given a watch and its display name, `present` returns the watch's kind and, optionally, an icon, a target with a subtitle, an external link, and a details component that replaces the name in the expanded row. When a source has no presentation, or it throws, Buzz shows the watch by its name. The GitHub plugin presents pull request watches this way, linking to its comment author settings.
 
 Each Attention source `run` receives `spawn(processId, options)` for commands using that watch's owning agent. The host binds agent identity, watch destination and run lifetime; plugins cannot select another agent or obtain the raw authenticated connection. Declare the process in `host.processes` and request `host.mcp`, plus `host.files` for tools reading local paths. Options supply arguments, working directory, environment and output callbacks.
 
diff --git a/src/app/pages.integration.test.mjs b/src/app/pages.integration.test.mjs
index 98fd08707..58019a375 100644
--- a/src/app/pages.integration.test.mjs
+++ b/src/app/pages.integration.test.mjs
@@ -29,6 +29,7 @@ test("the app runtime exposes ready bundled pages and removes them on disable",
     value: {
       getItem: (key) => values.get(key) ?? null,
       setItem: (key, value) => values.set(key, value),
+      removeItem: (key) => values.delete(key),
     },
   });
   let services;
diff --git a/src/bundled/agents/AgentsPage.test.tsx b/src/bundled/agents/AgentsPage.test.tsx
index c530b1c9c..383d27eea 100644
--- a/src/bundled/agents/AgentsPage.test.tsx
+++ b/src/bundled/agents/AgentsPage.test.tsx
@@ -292,6 +292,7 @@ function setup(
     session: vi.fn(async () => {}),
     register: vi.fn(),
     addTool: vi.fn(),
+    present: vi.fn(),
     tools: () => [],
     create: vi.fn(async () => {
       // `shown: false`: it was made for a community no longer selected.
@@ -373,6 +374,7 @@ function setup(
     }),
     attentionProviders: () => [],
     presentWatch: () => undefined,
+    presentSource: () => {},
     addAttentionSource: vi.fn(),
     storage: localStore(),
     resumeInterrupted: vi.fn(),
diff --git a/src/bundled/agents/ProviderDialog.tsx b/src/bundled/agents/ProviderDialog.tsx
index 96761eb77..f480357e2 100644
--- a/src/bundled/agents/ProviderDialog.tsx
+++ b/src/bundled/agents/ProviderDialog.tsx
@@ -82,7 +82,7 @@ function ManagedProviderDialog({
       finalFocus={() => finalFocus.current}
     >
       <ProviderDialogFooter value={footer}>
-        <Body onClose={onClose} />
+        {Body && <Body onClose={onClose} />}
       </ProviderDialogFooter>
     </Dialog>
   );
diff --git a/src/bundled/claude-code/index.test.ts b/src/bundled/claude-code/index.test.ts
index 7f7261618..53d9b0db5 100644
--- a/src/bundled/claude-code/index.test.ts
+++ b/src/bundled/claude-code/index.test.ts
@@ -1,8 +1,8 @@
 // @vitest-environment jsdom
 import { afterEach, expect, it, vi } from "vitest";
-import type { AgentType } from "../../features/agents/service";
 import { ClaudeRuntime } from "./runtime";
-import { apply } from "./index";
+import * as claude from "./index";
+import { appliedType } from "../../features/agents/plugin-testing";
 
 vi.mock("@tauri-apps/api/core", () => ({ isTauri: () => true }));
 afterEach(() => vi.restoreAllMocks());
@@ -26,18 +26,12 @@ it("observes saved sessions with the live status of running ones", () => {
     { key: "room/r", busy: true },
     { key: "dm", busy: false },
   ]);
-  let type: AgentType | undefined;
-  apply({
+  const type = appliedType(claude, {
     pluginOwner: { id: "buzz.claude-code", revision: "r1" },
     host: { request: vi.fn() },
-    agents: {
-      register: (registered: AgentType) => {
-        type = registered;
-      },
-      relay: () => undefined,
-    },
+    agents: { relay: () => undefined },
     effect: vi.fn(),
-  } as never);
+  });
   expect(type?.sessions?.list(agent)).toEqual([
     { channelId: "room", root: "r", at: 3, status: "Working" },
     { channelId: "dm", at: 2, status: "Idle" },
@@ -48,18 +42,12 @@ it("observes saved sessions with the live status of running ones", () => {
 
 it("shares a Claude agent's model as the claude runtime and imports it back", () => {
   vi.spyOn(navigator, "platform", "get").mockReturnValue("MacIntel");
-  let type: AgentType | undefined;
-  apply({
+  const type = appliedType(claude, {
     pluginOwner: { id: "buzz.claude-code", revision: "r1" },
     host: { request: vi.fn() },
-    agents: {
-      register: (registered: AgentType) => {
-        type = registered;
-      },
-      relay: () => undefined,
-    },
+    agents: { relay: () => undefined },
     effect: vi.fn(),
-  } as never);
+  });
   const shared = type?.exportShared?.({ model: "opus", workspace: "/private" });
   expect(shared).toEqual({ runtime: "claude", model: "opus" });
   expect(type?.importShared?.(shared ?? { model: "" })).toMatchObject({
diff --git a/src/bundled/claude-code/index.ts b/src/bundled/claude-code/index.ts
index 4c4ef9160..49f413578 100644
--- a/src/bundled/claude-code/index.ts
+++ b/src/bundled/claude-code/index.ts
@@ -19,11 +19,65 @@ export { TYPE_ID };
 /** How often Buzz's copy of Claude looks for a new release. */
 const UPDATE_MS = 6 * 60 * 60_000;
 
-export const inject = ["agents", "host"];
+// Only the desktop app can start `claude`, and setup and file uploads run
+// `bash` and `base64`, which stock Windows lacks; no unusable type elsewhere.
+const supported = () => isTauri() && /Mac|Linux/i.test(navigator.platform);
+
+/** What the type's UI reaches of its runtime. */
+export type ClaudeExposed = Parameters<typeof createTabs>[0];
+
+export const inject = ["agents"];
 export const apply: PluginModule["apply"] = (ctx) => {
-  // Only the desktop app can start `claude`, and setup and file uploads run
-  // `bash` and `base64`, which stock Windows lacks; no unusable type elsewhere.
-  if (!isTauri() || !/Mac|Linux/i.test(navigator.platform)) return;
+  if (!supported()) return;
+  ctx.agents.present<ClaudeExposed, Config>(TYPE_ID, (exposed) => {
+    const {
+      Create,
+      CreateModel,
+      DefaultControl,
+      ProviderDialogBody,
+      SettingsTab,
+      ActivityTab,
+    } = createTabs(exposed);
+    return {
+      icon: ClaudeLogoIcon,
+      Create,
+      CreateModel,
+      importShared: (source) =>
+        source.runtime === "claude" &&
+        (!source.provider || source.provider === "anthropic")
+          ? { ...DEFAULT_CONFIG, model: source.model }
+          : undefined,
+      exportShared: (saved) => ({
+        runtime: "claude",
+        model: config(saved).model,
+      }),
+      provider: { DialogBody: ProviderDialogBody, DefaultControl },
+      tabs: [
+        {
+          id: "settings",
+          title: "Settings",
+          role: "settings",
+          splitSettings: true,
+          component: SettingsTab,
+        },
+        {
+          id: "activity",
+          title: "Activity",
+          role: "activity",
+          component: ActivityTab,
+        },
+      ],
+    };
+  });
+};
+
+// The runtime, which runs where the agents do.
+export const agent: NonNullable<PluginModule["agent"]> = {
+  inject: ["agents", "host"],
+  apply: (ctx) => applyAgent(ctx),
+};
+function applyAgent(ctx: Parameters<PluginModule["apply"]>[0]) {
+  if (!supported()) return;
   const { agents, host } = ctx;
   const typeKey = `${ctx.pluginOwner?.id ?? "buzz.claude-code"}/${TYPE_ID}`;
   const spawn = host.spawn && withScript(host.spawn.bind(host));
@@ -88,37 +142,18 @@ export const apply: PluginModule["apply"] = (ctx) => {
     });
   }
 
-  const {
-    Create,
-    CreateModel,
-    DefaultControl,
-    ProviderDialogBody,
-    SettingsTab,
-    ActivityTab,
-  } = createTabs({
-    setup,
-    defaults: providerDefaults,
-    runtime,
-  });
   agents.register<Config>({
     id: TYPE_ID,
     hooks: { events: CLAUDE_HOOK_EVENTS },
     title: "Claude",
-    icon: ClaudeLogoIcon,
     description:
       "Claude on this computer. Each thread it is mentioned in is one continuing session.",
     defaults: () => ({ config: DEFAULT_CONFIG }),
-    Create,
-    CreateModel,
-    importShared: (source) =>
-      source.runtime === "claude" &&
-      (!source.provider || source.provider === "anthropic")
-        ? { ...DEFAULT_CONFIG, model: source.model }
-        : undefined,
-    exportShared: (saved) => ({
-      runtime: "claude",
-      model: config(saved).model,
-    }),
+    expose: {
+      setup,
+      defaults: providerDefaults,
+      runtime,
+    } satisfies ClaudeExposed,
     adopt: (carry, saved) => ({
       ...saved,
       instructions: carry.instructions ?? saved.instructions,
@@ -171,8 +206,6 @@ export const apply: PluginModule["apply"] = (ctx) => {
             ? () => void setup.run("login")
             : undefined;
       },
-      DialogBody: ProviderDialogBody,
-      DefaultControl,
     },
     sessions: {
       list: (key) => {
@@ -195,22 +228,7 @@ export const apply: PluginModule["apply"] = (ctx) => {
       },
       subscribe: (listener) => runtime.subscribe(listener),
     },
-    tabs: [
-      {
-        id: "settings",
-        title: "Settings",
-        role: "settings",
-        splitSettings: true,
-        component: SettingsTab,
-      },
-      {
-        id: "activity",
-        title: "Activity",
-        role: "activity",
-        component: ActivityTab,
-      },
-    ],
     // A mention during the first download waits for it, within its deadline.
     ...claudeRun(runtime, (signal) => setup.installed(signal)),
   });
-};
+}
diff --git a/src/bundled/claude-code/tabs.test.tsx b/src/bundled/claude-code/tabs.test.tsx
index 2432aea68..2537bfcc7 100644
--- a/src/bundled/claude-code/tabs.test.tsx
+++ b/src/bundled/claude-code/tabs.test.tsx
@@ -38,7 +38,8 @@ import type { ChannelSummary } from "../../features/relay/contracts";
 import type { RelayData } from "../../features/relay/service";
 import { ClaudeLogoIcon } from "../../shared/design-system/icons";
 import { manifestProcesses } from "./claude-testing";
-import { apply, inject } from "./index";
+import * as claude from "./index";
+import { appliedType } from "../../features/agents/plugin-testing";
 import { type Config, DEFAULT_CONFIG } from "./runtime";
 import { ClaudeSetup } from "./setup";
 import { ClaudeDefaults } from "./defaults";
@@ -145,7 +146,6 @@ function applied({
   /** Whether Claude lists its models when asked. */
   catalog?: { listed: boolean; ready?: Promise<void> };
 } = {}) {
-  let type: AgentType<Config> | undefined;
   const home = mkdtempSync(join(tmpdir(), "claude-tabs-"));
   homes.push(home);
   for (const [path, content] of Object.entries(files)) {
@@ -256,9 +256,6 @@ function applied({
     },
     agents: {
       storage,
-      register: (registered: AgentType<Config>) => {
-        type = registered;
-      },
       snapshot: () => ({ status: "ready", agents: [], running: [] }),
       relay: () =>
         channels &&
@@ -272,7 +269,7 @@ function applied({
     },
     effect: vi.fn(),
   };
-  apply(ctx as never);
+  const type = appliedType<Config>(claude, ctx);
   return { type, spawn, home };
 }
 function installed(options?: Parameters<typeof applied>[0]) {
@@ -286,8 +283,9 @@ function tab(type: AgentType<Config>, index: number) {
   return component;
 }
 function providerSetup(type: AgentType<Config>) {
-  if (!type.provider) throw new Error("no provider contribution");
-  return type.provider.DialogBody;
+  const body = type.provider?.DialogBody;
+  if (!body) throw new Error("no provider contribution");
+  return body;
 }
 async function choose(label: string, option: string) {
   const user = userEvent.setup();
@@ -652,7 +650,8 @@ it("shows the channel's current kind for a session another build started", async
 });
 
 it("is an agent type on the desktop app", () => {
-  expect(inject).toEqual(["agents", "host"]);
+  expect(claude.inject).toEqual(["agents"]);
+  expect(claude.agent.inject).toEqual(["agents", "host"]);
   const { type } = installed();
   expect(type).toMatchObject({
     id: "claude-code",
diff --git a/src/bundled/claude-code/tabs.tsx b/src/bundled/claude-code/tabs.tsx
index 1bceaab5a..b24fac3ab 100644
--- a/src/bundled/claude-code/tabs.tsx
+++ b/src/bundled/claude-code/tabs.tsx
@@ -50,6 +50,29 @@ import {
 import type { ClaudeModel } from "./claude";
 import type { ClaudeSetup } from "./setup";
 import type { ClaudeDefaults } from "./defaults";
+
+// What the tabs reach of the runtime: stores and calls returning promises,
+// as an agent type's `expose` allows.
+type SetupHandle = Pick<
+  ClaudeSetup,
+  | "snapshot"
+  | "subscribe"
+  | "check"
+  | "loadModels"
+  | "run"
+  | "answer"
+  | "cancel"
+>;
+type DefaultsHandle = Pick<ClaudeDefaults, "snapshot" | "subscribe" | "save">;
+type ActivityHandle = Pick<
+  ClaudeRuntime,
+  | "subscribe"
+  | "sessions"
+  | "conversations"
+  | "find"
+  | "transcript"
+  | "channelLabel"
+>;
 import { type ClaudeTranscript, TURN_LIMIT } from "./transcript";
 
 const message = (error: unknown) =>
@@ -139,7 +162,7 @@ function ClaudeSignIn({
   setup,
   disabled,
 }: {
-  setup: ClaudeSetup;
+  setup: SetupHandle;
   disabled: boolean;
 }) {
   const [open, setOpen] = useState(false);
@@ -180,7 +203,7 @@ function ClaudeSetupPanel({
   disabled = false,
   variant = "full",
 }: {
-  setup: ClaudeSetup;
+  setup: SetupHandle;
   disabled?: boolean;
   variant?: "full" | "compact";
 }) {
@@ -325,9 +348,9 @@ export function createTabs({
   defaults,
   runtime,
 }: Readonly<{
-  setup: ClaudeSetup;
-  defaults: ClaudeDefaults;
-  runtime: ClaudeRuntime;
+  setup: SetupHandle;
+  defaults: DefaultsHandle;
+  runtime: ActivityHandle;
 }>) {
   function useSetupCatalog() {
     const state = useSyncExternalStore(
diff --git a/src/bundled/codex/index.test.ts b/src/bundled/codex/index.test.ts
index 35f4c7366..be52d61e7 100644
--- a/src/bundled/codex/index.test.ts
+++ b/src/bundled/codex/index.test.ts
@@ -1,11 +1,11 @@
 // @vitest-environment jsdom
 import { afterEach, beforeEach, expect, it, vi } from "vitest";
-import type { AgentType } from "../../features/agents/service";
 import { CodexLogoIcon } from "../../shared/design-system/icons";
 import { CodexRuntime } from "./runtime";
 import { CodexSetup } from "./setup";
 import { CodexProvider } from "./tabs";
-import { apply } from "./index";
+import * as codex from "./index";
+import { appliedType } from "../../features/agents/plugin-testing";
 
 const desktop = vi.hoisted(() => ({ tauri: true }));
 vi.mock("@tauri-apps/api/core", () => ({ isTauri: () => desktop.tauri }));
@@ -21,23 +21,18 @@ afterEach(() => {
 
 /** Applies the plugin to a stand-in context and returns the registered type. */
 function applied() {
-  let type: AgentType | undefined;
   const subscribe = () => () => undefined;
   const ctx = {
     pluginOwner: { id: "buzz.codex", revision: "r1" },
     host: { spawn: vi.fn(), request: vi.fn() },
     agents: {
-      register: (registered: AgentType) => {
-        type = registered;
-      },
       snapshot: () => ({ status: "ready", agents: [], running: [] }),
       relay: () => undefined,
       subscribe,
     },
     effect: vi.fn(),
   };
-  apply(ctx as never);
-  return type;
+  return appliedType(codex, ctx);
 }
 
 it("registers only where the desktop app can run codex and base64", () => {
@@ -123,7 +118,7 @@ it("stops agents that stop running even when the agent list could not be read",
   const agent = { pubkey: "agent", type: "buzz.codex/codex" };
   let state = { status: "ready", agents: [agent], running: [agent] };
   let notify = () => undefined;
-  apply({
+  codex.agent.apply({
     pluginOwner: { id: "buzz.codex" },
     host: { spawn: vi.fn(), request: vi.fn() },
     agents: {
@@ -187,7 +182,7 @@ it("starts the server once Codex is updated and checked, only while a Codex agen
     notify();
   };
   let cleanup: () => void = () => undefined;
-  apply({
+  codex.agent.apply({
     pluginOwner: { id: "buzz.codex" },
     host: { spawn: vi.fn(), request: vi.fn() },
     agents: {
diff --git a/src/bundled/codex/index.ts b/src/bundled/codex/index.ts
index 0d64dabb7..baca58ba4 100644
--- a/src/bundled/codex/index.ts
+++ b/src/bundled/codex/index.ts
@@ -9,15 +9,77 @@ import { type Config, config, defaults, validWorkspace } from "./config";
 import { codexRun, TYPE_ID } from "./run";
 import { CodexRuntime } from "./runtime";
 import { CodexSetup, withScript } from "./setup";
-import { CodexProvider, createTabs } from "./tabs";
+import { CodexProvider, createTabs, transcripts } from "./tabs";
 import { readUsage } from "./usage";
 /** How often Buzz's copy of Codex looks for a new release. */
 const UPDATE_MS = 6 * 60 * 60_000;
-export const inject = ["agents", "host"];
+// Only the desktop app can start `codex`, and setup and file uploads run
+// `bash` and `base64`, which stock Windows lacks; no unusable type elsewhere.
+const supported = () => isTauri() && /Mac|Linux/i.test(navigator.platform);
+
+/** What the type's UI reaches of its runtime. */
+type CodexExposed = Readonly<{
+  provider: Parameters<typeof createTabs>[0];
+  runtime: Parameters<typeof createTabs>[1];
+  transcript: Parameters<typeof createTabs>[2];
+  setup: Parameters<typeof createTabs>[3];
+}>;
+
+export const inject = ["agents"];
 export const apply: PluginModule["apply"] = (ctx) => {
-  // Only the desktop app can start `codex`, and setup and file uploads run
-  // `bash` and `base64`, which stock Windows lacks; no unusable type elsewhere.
-  if (!isTauri() || !/Mac|Linux/i.test(navigator.platform)) return;
+  if (!supported()) return;
+  ctx.agents.present<CodexExposed, Config>(
+    TYPE_ID,
+    ({ provider, runtime, transcript, setup }) => {
+      const {
+        Create,
+        CreateModel,
+        DefaultControl,
+        ProviderDialogBody,
+        SettingsTab,
+        ActivityTab,
+      } = createTabs(provider, runtime, transcript, setup);
+      return {
+        icon: CodexLogoIcon,
+        Create,
+        CreateModel,
+        importShared: (source) =>
+          source.runtime === "codex" &&
+          (!source.provider || source.provider === "openai")
+            ? { ...defaults, model: source.model }
+            : undefined,
+        exportShared: (saved) => ({
+          runtime: "codex",
+          model: config(saved).model,
+        }),
+        provider: { DialogBody: ProviderDialogBody, DefaultControl },
+        tabs: [
+          {
+            id: "settings",
+            title: "Settings",
+            role: "settings",
+            splitSettings: true,
+            component: SettingsTab,
+          },
+          {
+            id: "activity",
+            title: "Activity",
+            role: "activity",
+            component: ActivityTab,
+          },
+        ],
+      };
+    },
+  );
+};
+
+// The runtime, which runs where the agents do.
+export const agent: NonNullable<PluginModule["agent"]> = {
+  inject: ["agents", "host"],
+  apply: (ctx) => applyAgent(ctx),
+};
+function applyAgent(ctx: Parameters<PluginModule["apply"]>[0]) {
+  if (!supported()) return;
   const spawn = ctx.host.spawn && withScript(ctx.host.spawn.bind(ctx.host));
   const readFile = ctx.host.readFile?.bind(ctx.host);
   const setup = new CodexSetup(spawn, (input) => ctx.host.request(input));
@@ -110,30 +172,19 @@ export const apply: PluginModule["apply"] = (ctx) => {
     runtime.dispose();
     setup.dispose();
   });
-  const {
-    Create,
-    CreateModel,
-    DefaultControl,
-    ProviderDialogBody,
-    SettingsTab,
-    ActivityTab,
-  } = createTabs(providerController, runtime, start, setup);
   ctx.agents.register<Config>({
     id: TYPE_ID,
     hooks: { events: CODEX_HOOK_EVENTS },
     title: "Codex",
-    icon: CodexLogoIcon,
     description:
       "Codex on this computer, using its native coding tools and your account.",
     defaults: () => ({ config: { ...defaults } }),
-    Create,
-    CreateModel,
-    importShared: (source) =>
-      source.runtime === "codex" &&
-      (!source.provider || source.provider === "openai")
-        ? { ...defaults, model: source.model }
-        : undefined,
-    exportShared: (saved) => ({ runtime: "codex", model: config(saved).model }),
+    expose: {
+      provider: providerController,
+      runtime,
+      transcript: transcripts(start, runtime),
+      setup,
+    } satisfies CodexExposed,
     adopt: (carry, saved) => ({
       ...saved,
       instructions: carry.instructions ?? saved.instructions,
@@ -178,8 +229,6 @@ export const apply: PluginModule["apply"] = (ctx) => {
       snapshot: providerController.snapshot,
       subscribe: providerController.subscribe,
       check: () => providerController.check(),
-      DialogBody: ProviderDialogBody,
-      DefaultControl,
     },
     sessions: {
       list: (key) => {
@@ -200,21 +249,6 @@ export const apply: PluginModule["apply"] = (ctx) => {
       },
       subscribe: runtime.subscribe,
     },
-    tabs: [
-      {
-        id: "settings",
-        title: "Settings",
-        role: "settings",
-        splitSettings: true,
-        component: SettingsTab,
-      },
-      {
-        id: "activity",
-        title: "Activity",
-        role: "activity",
-        component: ActivityTab,
-      },
-    ],
     // A mention during the first download waits for it, within its deadline.
     ...codexRun(runtime, async (signal) => {
       await setup.installed(signal);
@@ -222,4 +256,4 @@ export const apply: PluginModule["apply"] = (ctx) => {
         await providerController.check();
     }),
   });
-};
+}
diff --git a/src/bundled/codex/runtime.test.ts b/src/bundled/codex/runtime.test.ts
index dd77547db..bce2a1a65 100644
--- a/src/bundled/codex/runtime.test.ts
+++ b/src/bundled/codex/runtime.test.ts
@@ -1,7 +1,7 @@
 import { createHash } from "node:crypto";
 import { schnorr } from "@noble/curves/secp256k1.js";
 import { bytesToHex } from "nostr-tools/utils";
-import { apply } from "./index";
+import { agent as codexAgent } from "./index";
 import { describe, afterEach, expect, it, vi } from "vitest";
 import { pubkeyOf } from "../../features/agents/membership";
 import { ownerReads } from "../../features/agents/reads";
@@ -456,7 +456,7 @@ function fixture(
   if (plugin) {
     vi.stubGlobal("localStorage", local);
     vi.stubGlobal("navigator", { platform: "MacIntel" });
-    apply({
+    codexAgent.apply({
       host: { spawn },
       agents: {
         snapshot: () => ({ status: "ready", agents: [], running }),
@@ -474,7 +474,7 @@ function fixture(
       effect: (effect: () => () => void) => {
         pluginDispose = effect();
       },
-    } as unknown as Parameters<typeof apply>[0]);
+    } as unknown as Parameters<typeof codexAgent.apply>[0]);
   }
   const starts = () => sent.filter((wire) => wire.method === "turn/start");
   const interrupt = () => {
diff --git a/src/bundled/codex/tabs.test.tsx b/src/bundled/codex/tabs.test.tsx
index 381594e5b..d0c4ee250 100644
--- a/src/bundled/codex/tabs.test.tsx
+++ b/src/bundled/codex/tabs.test.tsx
@@ -31,7 +31,7 @@ import type { RelayData } from "../../features/relay/service";
 import { PanelWorkspace } from "../../features/panels/PanelWorkspace";
 import { defaults, type Config } from "./config";
 import { sessionTag } from "./prompt";
-import { CodexProvider, createTabs } from "./tabs";
+import { CodexProvider, createTabs, transcripts } from "./tabs";
 import { CodexRuntime } from "./runtime";
 import type { Wire } from "./rpc";
 import { CodexSetup } from "./setup";
@@ -204,7 +204,12 @@ function fixture({
     sessions,
     (raw) => provider.resolve(raw),
   );
-  const tabs = createTabs(provider, runtime, spawn, setup);
+  const tabs = createTabs(
+    provider,
+    runtime,
+    transcripts(spawn, runtime),
+    setup,
+  );
   const props = (settings = defaults, save = vi.fn(async () => {})) =>
     ({
       agent: {
@@ -1474,7 +1479,7 @@ it("installs and signs in Buzz's copy of Codex from its provider settings", asyn
   const { ProviderDialogBody } = createTabs(
     provider,
     f.runtime,
-    f.spawn,
+    transcripts(f.spawn, f.runtime),
     f.setup,
   );
   render(<ProviderDialogBody onClose={vi.fn()} />);
diff --git a/src/bundled/codex/tabs.tsx b/src/bundled/codex/tabs.tsx
index a0092908e..d3dd10f2c 100644
--- a/src/bundled/codex/tabs.tsx
+++ b/src/bundled/codex/tabs.tsx
@@ -53,7 +53,12 @@ import {
 import { AppServer, listModels, needsSignIn, type Spawn } from "./rpc";
 import type { CodexRuntime, SavedConversation } from "./runtime";
 import type { CodexSetup } from "./setup";
-import { readTranscript, TURN_LIMIT, type CodexTranscript } from "./transcript";
+import {
+  readTranscript,
+  TURN_LIMIT,
+  type CodexTranscript,
+  type Lookup,
+} from "./transcript";
 
 const label = ({ channelId, name, root }: SavedConversation) =>
   `${name || channelId.slice(0, 8)} · ${root ? `thread ${root.slice(0, 8)}` : "channel"}`;
@@ -311,7 +316,7 @@ function CodexSignIn({
   check,
   disabled,
 }: {
-  login: CodexSetup;
+  login: SetupHandle;
   step: "install" | "login";
   checking: boolean;
   check(): void;
@@ -413,11 +418,39 @@ function CodexSignIn({
   );
 }
 
+// What the tabs reach of the runtime: stores and calls returning promises,
+// as an agent type's `expose` allows.
+type ProviderHandle = Pick<
+  CodexProvider,
+  "snapshot" | "subscribe" | "check" | "resolve" | "saveDefaults"
+>;
+type ActivityHandle = Pick<
+  CodexRuntime,
+  "subscribe" | "sessions" | "conversations" | "find" | "channelLabel"
+>;
+type SetupHandle = Pick<
+  CodexSetup,
+  "snapshot" | "subscribe" | "run" | "cancel"
+>;
+/** Reads one conversation's Codex thread. */
+export type TranscriptRead = (
+  agent: Lookup["agent"],
+  conversation: SavedConversation,
+  signal: AbortSignal,
+) => Promise<CodexTranscript | undefined>;
+/** Transcripts read with `spawn`, named by the runtime. */
+export const transcripts =
+  (spawn: Spawn, runtime: Pick<CodexRuntime, "name">): TranscriptRead =>
+  (agent, conversation, signal) =>
+    readTranscript(spawn, { agent, ...conversation }, signal, (pubkey) =>
+      runtime.name(agent.key, pubkey),
+    );
+
 export function createTabs(
-  provider: CodexProvider,
-  runtime: CodexRuntime,
-  spawn: Spawn,
-  setup: CodexSetup,
+  provider: ProviderHandle,
+  runtime: ActivityHandle,
+  transcript: TranscriptRead,
+  setup: SetupHandle,
 ) {
   const login = setup;
 
@@ -739,11 +772,10 @@ export function createTabs(
     useEffect(() => {
       const abort = new AbortController();
       setLoading(true);
-      void readTranscript(
-        spawn,
-        { agent: { key: agent.key, name: agent.name }, ...conversation },
+      void transcript(
+        { key: agent.key, name: agent.name },
+        conversation,
         abort.signal,
-        (pubkey) => runtime.name(agent.key, pubkey),
       )
         .then(
           (transcript): Read =>
diff --git a/src/bundled/github/SoloPull.test.tsx b/src/bundled/github/SoloPull.test.tsx
index 2009b326e..ddbe3f227 100644
--- a/src/bundled/github/SoloPull.test.tsx
+++ b/src/bundled/github/SoloPull.test.tsx
@@ -8,7 +8,7 @@ import type { RelayData } from "../../features/relay/service";
 import type { RelaySession } from "../../features/relay/session";
 import type { AddedTool } from "../../buzz-mcp/session-tools";
 import type { BuzzClient } from "../../buzz-mcp/client";
-import { apply } from "./index";
+import { agent, apply } from "./index";
 import type { SoloPull, SoloPulls } from "./solo-pull";
 import { SoloPullIcon, SoloPullLink, SoloPullMenu } from "./SoloPull";
 
@@ -161,7 +161,14 @@ it("gives agents a github_link_pr tool for the Solo chat they work in", async ()
     { id: team, channelType: "stream" },
   ]);
   let tool: AddedTool | undefined;
-  const inject = vi.fn();
+  const agents = {
+    addTool: (added: AddedTool) => {
+      if (added.name === "github_link_pr") tool = added;
+    },
+    relay: () => relay,
+    // The agent side also lets agents follow pull requests.
+    addAttentionSource: () => {},
+  };
   apply({
     host: {},
     panels: { register: () => {} },
@@ -171,22 +178,15 @@ it("gives agents a github_link_pr tool for the Solo chat they work in", async ()
       registerLink: () => {},
     },
     relay,
-    agents: {
-      addTool: (added: AddedTool) => {
-        if (added.name === "github_link_pr") tool = added;
-      },
-      relay: () => relay,
-    },
-    inject,
+    agents,
+    inject: () => {},
   } as never);
+  void agent.apply({ host: {}, agents, effect: () => {} } as never);
   const client = {
     key: "a".repeat(64),
     pubkey: "a".repeat(64),
   } as BuzzClient;
-  expect(inject).toHaveBeenCalledWith(
-    ["agents", "host", "navigation"],
-    expect.any(Function),
-  );
+  expect(agent.inject).toEqual(["agents", "host"]);
   expect(tool?.name).toBe("github_link_pr");
   await expect(
     tool?.call(client, { channel: chat }, { url: "https://github.com/block" }),
diff --git a/src/bundled/github/attention.tsx b/src/bundled/github/attention.tsx
index 860113aa2..efd139c0c 100644
--- a/src/bundled/github/attention.tsx
+++ b/src/bundled/github/attention.tsx
@@ -1,7 +1,8 @@
 // How a pull request watch looks in Agent Attention.
 import { GitPullRequestIcon } from "../../shared/design-system/icons";
 import { Button } from "../../shared/design-system/ui/Button";
-import type { AttentionSource } from "../../features/agents/attention-sources";
+import type { SourcePresentation } from "../../features/agents/attention-sources";
+import type { SourceWatch } from "../../features/agents/attention";
 import type { Navigation } from "../../features/navigation/controller";
 import { pullOf } from "./watch";
 
@@ -9,7 +10,7 @@ import { pullOf } from "./watch";
  * feedback wakes agents. */
 export function presentPull(
   navigation: Pick<Navigation, "open">,
-): NonNullable<AttentionSource["present"]> {
+): (watch: SourceWatch, title: string) => SourcePresentation {
   const Authors = () => (
     <Button
       variant="link"
diff --git a/src/bundled/github/index.tsx b/src/bundled/github/index.tsx
index 61d916de4..f7393f621 100644
--- a/src/bundled/github/index.tsx
+++ b/src/bundled/github/index.tsx
@@ -54,8 +54,8 @@ export const inject = ["panels", "host", "conversation", "relay", "agents"];
 export const apply: PluginModule["apply"] = (ctx) => {
   const gh = gitHubCli(ctx.host);
   // A pull request's state is nobody's community's: one store serves every
-  // session's sidebar, every link in messages, the panel and agents, so one
-  // shown in several places costs one read.
+  // session's sidebar, every link in messages and the panel, so one shown in
+  // several places costs one read. Agents keep their own where they run.
   const states = createPullStates(gh);
   const pulls = new WeakMap<RelaySession, SoloPulls>();
   const pullsFor = (session: RelaySession) => {
@@ -184,10 +184,9 @@ export const apply: PluginModule["apply"] = (ctx) => {
         : "Unlinked this chat's pull request.";
     },
   });
-  addPullStateTool(ctx.agents, states);
-  // Agents can watch pull requests where the app runs them.
-  ctx.inject(["agents", "host", "navigation"], (scope) =>
-    watchPulls(scope, states, gh, presentPull(scope.navigation)),
+  // How a pull request watch shows in Agent Attention.
+  ctx.inject(["navigation"], (scope) =>
+    ctx.agents.presentSource("github-pr", presentPull(scope.navigation)),
   );
   // Whose comments and reviews wake them.
   ctx.inject(["settingsCards"], (scope) => {
@@ -200,6 +199,16 @@ export const apply: PluginModule["apply"] = (ctx) => {
     });
   });
 };
+// Agents can read and watch pull requests where the app runs them.
+export const agent: NonNullable<PluginModule["agent"]> = {
+  inject: ["agents", "host"],
+  apply(ctx) {
+    const gh = gitHubCli(ctx.host);
+    const states = createPullStates(gh);
+    addPullStateTool(ctx.agents, states);
+    watchPulls(ctx, states, gh);
+  },
+};
 /** A repository, issue or commit, read when the panel opens. */
 function useGitHubObject(
   reference: GitHubReference,
diff --git a/src/bundled/github/watcher.test.ts b/src/bundled/github/watcher.test.ts
index 9fe467323..9bf706734 100644
--- a/src/bundled/github/watcher.test.ts
+++ b/src/bundled/github/watcher.test.ts
@@ -144,10 +144,7 @@ const asks = (app: ReturnType<typeof setup>, login: string) =>
     ([query]) => membershipRead(query) && query.includes(`login:"${login}"`),
   ).length;
 
-function setup(
-  initial: Pull | null = answer(),
-  present?: AttentionSource["present"],
-) {
+function setup(initial: Pull | null = answer()) {
   let gh = initial;
   let texts = true;
   let members: readonly string[] | null = [];
@@ -289,7 +286,7 @@ function setup(
     },
     effect: (fn: () => () => void) => disposers.push(fn()),
   } as unknown as Context;
-  watchPulls(ctx, states, github as unknown as GitHubCli, present);
+  watchPulls(ctx, states, github as unknown as GitHubCli);
   const tool = tools[0] as AddedTool;
   const call = (
     args: Record<string, unknown>,
@@ -358,15 +355,10 @@ describe("github_watch_pr", () => {
   });
   afterEach(() => vi.useRealTimers());
 
-  it("registers PR watching as an Attention source with its presenter", () => {
-    const present = vi.fn();
-    const app = setup(answer(), present);
+  it("registers PR watching as an Attention source", () => {
+    const app = setup(answer());
     expect(app.addAttentionSource).toHaveBeenCalledWith(
-      expect.objectContaining({
-        id: "github-pr",
-        run: expect.any(Function),
-        present,
-      }),
+      expect.objectContaining({ id: "github-pr", run: expect.any(Function) }),
     );
     app.dispose();
   });
diff --git a/src/bundled/github/watcher.ts b/src/bundled/github/watcher.ts
index 7ce30462e..b49b28d11 100644
--- a/src/bundled/github/watcher.ts
+++ b/src/bundled/github/watcher.ts
@@ -3,7 +3,6 @@
 // and delivery.
 import type { Context } from "@deepseek-ai/cordis";
 import { callAttentionTool } from "../../buzz-mcp/attention";
-import type { AttentionSource } from "../../features/agents/attention-sources";
 import type { GitHubCli } from "./gh";
 import type { Feedback, PullStates } from "./pull-states";
 import {
@@ -92,7 +91,6 @@ export function watchPulls(
   ctx: Context,
   states: PullStates,
   gh: GitHubCli | undefined,
-  present?: AttentionSource["present"],
 ) {
   localStorage.removeItem(RETIRED_STORAGE_KEY);
   const cursors = load();
@@ -229,7 +227,6 @@ export function watchPulls(
     id: "github-pr",
     description: "Follow GitHub pull request feedback and CI",
     configExample: { pr: "https://github.com/OWNER/REPO/pull/NUMBER" },
-    ...(present && { present }),
     async run({ id, agent, watch: source, signal, emit }) {
       const pull =
         typeof source.config.pr === "string"
diff --git a/src/bundled/goose/index.test.ts b/src/bundled/goose/index.test.ts
index e7825ec88..e110b19e1 100644
--- a/src/bundled/goose/index.test.ts
+++ b/src/bundled/goose/index.test.ts
@@ -1,8 +1,8 @@
 // @vitest-environment jsdom
 import { afterEach, expect, it, vi } from "vitest";
-import type { AgentType } from "../../features/agents/service";
 import { GooseRuntime } from "./runtime";
-import { apply } from "./index";
+import * as goose from "./index";
+import { appliedType } from "../../features/agents/plugin-testing";
 
 vi.mock("@tauri-apps/api/core", () => ({ isTauri: () => true }));
 afterEach(() => vi.restoreAllMocks());
@@ -22,18 +22,12 @@ it("observes saved conversations with the status of open sessions", () => {
     // A one-off turn joins no conversation.
     { key: "timer/x #1", busy: true },
   ]);
-  let type: AgentType | undefined;
-  apply({
+  const type = appliedType(goose, {
     pluginOwner: { id: "buzz.goose", revision: "r1" },
     host: { request: vi.fn() },
-    agents: {
-      register: (registered: AgentType) => {
-        type = registered;
-      },
-      relay: () => undefined,
-    },
+    agents: { relay: () => undefined },
     effect: vi.fn(),
-  } as never);
+  });
   // A reload stops its turns, so the owner is asked to resume them.
   expect(type?.resumes).toBe(true);
   expect(
diff --git a/src/bundled/goose/index.ts b/src/bundled/goose/index.ts
index 2fc3ea870..ea7d8a6cd 100644
--- a/src/bundled/goose/index.ts
+++ b/src/bundled/goose/index.ts
@@ -15,9 +15,64 @@ import { readUsage } from "./usage";
 
 export const TYPE_ID = "goose";
 
-export const inject = ["agents", "host"];
+/** What the type's UI reaches of its runtime. */
+type GooseExposed = Parameters<typeof createTabs>[0];
+
+export const inject = ["agents"];
 export const apply: PluginModule["apply"] = (ctx) => {
   // Only the desktop app can start `goose-acp`; no unusable type elsewhere.
+  if (!isTauri()) return;
+  ctx.agents.present<GooseExposed, Config>(TYPE_ID, (exposed) => {
+    const {
+      Create,
+      CreateModel,
+      SettingsTab,
+      ActivityTab,
+      DefaultControl,
+      ProviderDialogBody,
+    } = createTabs(exposed);
+    return {
+      icon: GooseLogoIcon,
+      Create,
+      CreateModel,
+      importShared: (source) =>
+        source.runtime === "goose" || source.runtime === "goose-ai"
+          ? {
+              ...DEFAULT_CONFIG,
+              model: source.model,
+              provider: source.provider ?? "",
+            }
+          : undefined,
+      exportShared: (saved) => {
+        const { provider, model } = config(saved);
+        return { runtime: "goose", ...(provider && { provider }), model };
+      },
+      provider: { DialogBody: ProviderDialogBody, DefaultControl },
+      tabs: [
+        {
+          id: "settings",
+          title: "Settings",
+          role: "settings",
+          splitSettings: true,
+          component: SettingsTab,
+        },
+        {
+          id: "activity",
+          title: "Activity",
+          role: "activity",
+          component: ActivityTab,
+        },
+      ],
+    };
+  });
+};
+
+// The runtime, which runs where the agents do.
+export const agent: NonNullable<PluginModule["agent"]> = {
+  inject: ["agents", "host"],
+  apply: (ctx) => applyAgent(ctx),
+};
+function applyAgent(ctx: Parameters<PluginModule["apply"]>[0]) {
   if (!isTauri()) return;
   const { agents, host } = ctx;
   const typeKey = `${ctx.pluginOwner?.id ?? "buzz.goose"}/${TYPE_ID}`;
@@ -38,18 +93,6 @@ export const apply: PluginModule["apply"] = (ctx) => {
       : undefined;
   const setup = new GooseSetup(desktop, () => runtime.defaultsChanged());
   const history = new GooseHistory(desktop);
-  const {
-    Create,
-    CreateModel,
-    SettingsTab,
-    ActivityTab,
-    DefaultControl,
-    ProviderDialogBody,
-  } = createTabs({
-    setup,
-    runtime,
-    history,
-  });
   const sync = () => {
     const snapshot = agents.snapshot();
     if (snapshot.status === "loading") return;
@@ -67,30 +110,14 @@ export const apply: PluginModule["apply"] = (ctx) => {
   agents.register<Config>({
     id: TYPE_ID,
     title: "Goose",
-    icon: GooseLogoIcon,
     description:
       "goose on this computer, with any provider goose supports. Each thread it is mentioned in is one continuing session.",
     defaults: () => ({ config: DEFAULT_CONFIG }),
-    importShared: (source) =>
-      source.runtime === "goose" || source.runtime === "goose-ai"
-        ? {
-            ...DEFAULT_CONFIG,
-            model: source.model,
-            provider: source.provider ?? "",
-          }
-        : undefined,
-    exportShared: (saved) => {
-      const { provider, model } = config(saved);
-      return { runtime: "goose", ...(provider && { provider }), model };
-    },
-    Create,
-    CreateModel,
+    expose: { setup, runtime, history } satisfies GooseExposed,
     provider: {
       snapshot: setup.snapshot,
       subscribe: setup.subscribe,
       check: setup.check,
-      DialogBody: ProviderDialogBody,
-      DefaultControl,
     },
     adopt: (carry, saved) => ({
       ...saved,
@@ -145,22 +172,7 @@ export const apply: PluginModule["apply"] = (ctx) => {
           signal,
         ),
     }),
-    tabs: [
-      {
-        id: "settings",
-        title: "Settings",
-        role: "settings",
-        splitSettings: true,
-        component: SettingsTab,
-      },
-      {
-        id: "activity",
-        title: "Activity",
-        role: "activity",
-        component: ActivityTab,
-      },
-    ],
     models: (agent) => setup.picks(config(agent.config)),
     ...gooseRun(runtime),
   });
-};
+}
diff --git a/src/bundled/goose/tabs.tsx b/src/bundled/goose/tabs.tsx
index aca6b7acc..694d57cba 100644
--- a/src/bundled/goose/tabs.tsx
+++ b/src/bundled/goose/tabs.tsx
@@ -131,14 +131,30 @@ const placeOf = (key: string): Place => {
 const titled = (name: string, title: string) =>
   title.startsWith(`${name} · `) ? title.slice(name.length + 3) : title;
 
+// What the tabs reach of the runtime: stores and calls returning promises,
+// as an agent type's `expose` allows.
+type SetupHandle = Pick<
+  GooseSetup,
+  | "snapshot"
+  | "subscribe"
+  | "check"
+  | "providers"
+  | "models"
+  | "efforts"
+  | "saved"
+  | "save"
+  | "saveDefaults"
+  | "test"
+>;
+
 export function createTabs({
   setup,
   runtime,
   history,
 }: Readonly<{
-  setup: GooseSetup;
-  runtime: GooseRuntime;
-  history: GooseHistory;
+  setup: SetupHandle;
+  runtime: Pick<GooseRuntime, "subscribe" | "sessions">;
+  history: Pick<GooseHistory, "find" | "recent" | "transcript">;
 }>) {
   function DefaultControl({ onConfigure }: { onConfigure(): void }) {
     const state = useSyncExternalStore(setup.subscribe, setup.snapshot);
diff --git a/src/bundled/pi/index.test.ts b/src/bundled/pi/index.test.ts
index 461e97602..54ec841bc 100644
--- a/src/bundled/pi/index.test.ts
+++ b/src/bundled/pi/index.test.ts
@@ -1,23 +1,34 @@
 // @vitest-environment jsdom
 import { expect, it, vi } from "vitest";
-import type { AgentType } from "../../features/agents/service";
-import { apply } from "./index";
+import { appliedType } from "../../features/agents/plugin-testing";
+import * as pi from "./index";
 
 vi.mock("@tauri-apps/api/core", () => ({ isTauri: () => true }));
 
+it("shows the Pi type's screens from the runtime its agent entry registers", () => {
+  // The UI needs no host; only the runtime starts Pi.
+  expect(pi.inject).toEqual(["agents"]);
+  expect(pi.agent.inject).toEqual(["agents", "host"]);
+  const type = appliedType(pi, {
+    pluginOwner: { id: "buzz.pi", revision: "r1" },
+    host: { request: vi.fn() },
+    agents: { relay: () => undefined },
+    effect: vi.fn(),
+  });
+  expect(type).toMatchObject({ id: "pi", title: "Pi", timeoutMs: 120_000 });
+  expect(type?.Create).toBeTypeOf("function");
+  expect(type?.CreateModel).toBeTypeOf("function");
+  expect(type?.icon).toBeDefined();
+  expect(type?.tabs?.map((tab) => tab.id)).toEqual(["settings", "activity"]);
+});
+
 it("shares a Pi agent's provider and model as the pi runtime and imports them back", () => {
-  let type: AgentType | undefined;
-  apply({
+  const type = appliedType(pi, {
     pluginOwner: { id: "buzz.pi", revision: "r1" },
     host: { request: vi.fn() },
-    agents: {
-      register: (registered: AgentType) => {
-        type = registered;
-      },
-      relay: () => undefined,
-    },
+    agents: { relay: () => undefined },
     effect: vi.fn(),
-  } as never);
+  });
   const shared = type?.exportShared?.({
     provider: "anthropic",
     model: "sonnet",
diff --git a/src/bundled/pi/index.ts b/src/bundled/pi/index.ts
index edbed2adb..eec5f67d4 100644
--- a/src/bundled/pi/index.ts
+++ b/src/bundled/pi/index.ts
@@ -16,9 +16,57 @@ export const TYPE_ID = "pi";
  * which includes the first install of Pi's packages. */
 const HANDOVER_MS = 2 * 60_000;
 
-export const inject = ["agents", "host"];
+/** What the type's UI reaches of its runtime. */
+type PiExposed = Parameters<typeof createTabs>[0];
+
+export const inject = ["agents"];
 export const apply: PluginModule["apply"] = (ctx) => {
   // Only the desktop app can start the Pi host; no unusable type elsewhere.
+  if (!isTauri()) return;
+  ctx.agents.present<PiExposed, Config>(TYPE_ID, (exposed) => {
+    const { ActivityTab, Create, CreateModel, SettingsTab } =
+      createTabs(exposed);
+    return {
+      icon: PiLogoIcon,
+      Create,
+      CreateModel,
+      importShared: (source) =>
+        source.runtime === "pi"
+          ? {
+              ...DEFAULT_CONFIG,
+              model: source.model,
+              provider: source.provider ?? "",
+            }
+          : undefined,
+      exportShared: (saved) => {
+        const { provider, model } = config(saved);
+        return { runtime: "pi", ...(provider && { provider }), model };
+      },
+      tabs: [
+        {
+          id: "settings",
+          title: "Settings",
+          role: "settings",
+          splitSettings: true,
+          component: SettingsTab,
+        },
+        {
+          id: "activity",
+          title: "Activity",
+          role: "activity",
+          component: ActivityTab,
+        },
+      ],
+    };
+  });
+};
+
+// The runtime, which runs where the agents do.
+export const agent: NonNullable<PluginModule["agent"]> = {
+  inject: ["agents", "host"],
+  apply: (ctx) => applyAgent(ctx),
+};
+function applyAgent(ctx: Parameters<PluginModule["apply"]>[0]) {
   if (!isTauri()) return;
   const { agents, host } = ctx;
   const typeKey = `${ctx.pluginOwner?.id ?? "buzz.pi"}/${TYPE_ID}`;
@@ -42,10 +90,6 @@ export const apply: PluginModule["apply"] = (ctx) => {
     },
     (key, listener) => agents.relay(key)?.subscribe(listener) ?? (() => {}),
   );
-  const { ActivityTab, Create, CreateModel, SettingsTab } = createTabs({
-    setup: runtime.setup,
-    runtime,
-  });
   const sync = () => {
     const snapshot = agents.snapshot();
     if (snapshot.status === "loading") return;
@@ -64,24 +108,10 @@ export const apply: PluginModule["apply"] = (ctx) => {
     id: TYPE_ID,
     hooks: { events: ["beforeTool", "afterTool"] },
     title: "Pi",
-    icon: PiLogoIcon,
     description:
       "Pi on this computer, with any provider Pi supports. Each thread it is mentioned in is one continuing conversation.",
     defaults: () => ({ config: DEFAULT_CONFIG }),
-    Create,
-    CreateModel,
-    importShared: (source) =>
-      source.runtime === "pi"
-        ? {
-            ...DEFAULT_CONFIG,
-            model: source.model,
-            provider: source.provider ?? "",
-          }
-        : undefined,
-    exportShared: (saved) => {
-      const { provider, model } = config(saved);
-      return { runtime: "pi", ...(provider && { provider }), model };
-    },
+    expose: { setup: runtime.setup, runtime } satisfies PiExposed,
     adopt: (carry, saved) => ({
       ...saved,
       instructions: carry.instructions ?? saved.instructions,
@@ -106,21 +136,6 @@ export const apply: PluginModule["apply"] = (ctx) => {
       list: (key) => runtime.sessions(key),
       subscribe: (listener) => runtime.subscribe(listener),
     },
-    tabs: [
-      {
-        id: "settings",
-        title: "Settings",
-        role: "settings",
-        splitSettings: true,
-        component: SettingsTab,
-      },
-      {
-        id: "activity",
-        title: "Activity",
-        role: "activity",
-        component: ActivityTab,
-      },
-    ],
     sessionControls: {
       scope: (agent) => config(agent.config).scope,
       state: (agent, place) => runtime.sessionState(agent, place),
@@ -132,4 +147,4 @@ export const apply: PluginModule["apply"] = (ctx) => {
     runOnce: (turn) => runtime.runOnce(turn),
     timeoutMs: HANDOVER_MS,
   });
-};
+}
diff --git a/src/bundled/pi/tabs.tsx b/src/bundled/pi/tabs.tsx
index 7e2abe926..dded9c78d 100644
--- a/src/bundled/pi/tabs.tsx
+++ b/src/bundled/pi/tabs.tsx
@@ -194,7 +194,7 @@ export function createTabs({
   setup,
   runtime,
 }: Readonly<{
-  setup: PiSetup;
+  setup: Pick<PiSetup, "providers" | "models" | "login" | "test">;
   runtime: Pick<
     PiRuntime,
     | "places"
diff --git a/src/features/agents/attention-sources.ts b/src/features/agents/attention-sources.ts
index e65854f8f..2865e65a9 100644
--- a/src/features/agents/attention-sources.ts
+++ b/src/features/agents/attention-sources.ts
@@ -24,8 +24,6 @@ export type AttentionSource = Readonly<{
   /** Discovery metadata for tools that configure this provider. */
   description?: string;
   configExample?: Readonly<Record<string, unknown>>;
-  /** `title` is the watch's display name. */
-  present?(watch: SourceWatch, title: string): SourcePresentation;
   run(
     input: Readonly<{
       /** Stable Attention object slug, unique within the agent. */
diff --git a/src/features/agents/plugin-testing.ts b/src/features/agents/plugin-testing.ts
new file mode 100644
index 000000000..6de02adcb
--- /dev/null
+++ b/src/features/agents/plugin-testing.ts
@@ -0,0 +1,24 @@
+import type { PluginModule } from "../../plugins/api";
+import { presented, type AgentPresentation, type AgentType } from "./service";
+
+/** Starts a harness plugin's agent entry, then its UI entry, on `ctx`, and
+ * returns the type it registered as the service shows it, with what it
+ * presents. Undefined when it registered none. */
+export function appliedType<Config>(
+  module: Pick<PluginModule, "apply" | "agent">,
+  ctx: Readonly<{ agents: object }> & Record<string, unknown>,
+): AgentType<Config> | undefined {
+  let type: AgentType<Config> | undefined;
+  let present: ((exposed: unknown) => AgentPresentation<Config>) | undefined;
+  Object.assign(ctx.agents, {
+    register: (registered: AgentType<Config>) => {
+      type = registered;
+    },
+    present: (_id: string, shown: typeof present) => {
+      present = shown;
+    },
+  });
+  void module.agent?.apply(ctx as never);
+  void module.apply(ctx as never);
+  return type && present ? presented(type, present(type.expose)) : type;
+}
diff --git a/src/features/agents/service.test.ts b/src/features/agents/service.test.ts
index 685943f63..6a23fb0cf 100644
--- a/src/features/agents/service.test.ts
+++ b/src/features/agents/service.test.ts
@@ -366,6 +366,69 @@ beforeEach(() => {
 });
 afterEach(() => vi.useRealTimers());
 
+it("shows a type with what its plugin presents, from the handles the type exposes", async () => {
+  const { service, plugin } = await setup();
+  const ready = { readiness: "ready" as const };
+  let attention: (() => void) | undefined;
+  const handles = { count: 1 };
+  const shown = vi.fn((exposed: typeof handles) => ({
+    icon: () => null,
+    tabs: [{ id: "t", title: "T", component: () => null }],
+    provider: { DialogBody: () => null },
+    // Only what a type shows is taken from `present`.
+    run: () => {},
+    title: "Wrong",
+    exposed,
+  }));
+  plugin.agents.register({
+    id: "shown",
+    title: "Shown",
+    defaults: () => ({ config: {} }),
+    expose: handles,
+    provider: {
+      snapshot: () => ready,
+      subscribe: () => () => {},
+      check: () => {},
+      get attentionAction() {
+        return attention;
+      },
+    },
+  });
+  const runtimeOnly = service.types().find((t) => t.key === "example/shown");
+  expect(runtimeOnly?.tabs).toBeUndefined();
+  plugin.agents.present("shown", shown as never);
+  const type = service.types().find((t) => t.key === "example/shown");
+  expect(shown).toHaveBeenCalledExactlyOnceWith(handles);
+  expect(type).toMatchObject({ title: "Shown", tabs: [{ id: "t" }] });
+  expect(type?.run).toBeUndefined();
+  expect(type?.icon).toBeTypeOf("function");
+  expect(type?.provider?.DialogBody).toBeTypeOf("function");
+  // The runtime's provider stays live, and readers see one stable type.
+  expect(type?.provider?.attentionAction).toBeUndefined();
+  attention = () => {};
+  expect(type?.provider?.attentionAction).toBe(attention);
+  expect(service.types().find((t) => t.key === "example/shown")).toBe(type);
+  expect(shown).toHaveBeenCalledOnce();
+});
+
+it("still runs a type whose present throws", async () => {
+  const { service, plugin } = await setup();
+  const error = vi.spyOn(console, "error").mockImplementation(() => {});
+  plugin.agents.register({
+    id: "broken",
+    title: "Broken",
+    defaults: () => ({ config: {} }),
+  });
+  plugin.agents.present("broken", () => {
+    throw new Error("no UI");
+  });
+  expect(service.types().find((t) => t.key === "example/broken")).toMatchObject(
+    { title: "Broken" },
+  );
+  expect(error).toHaveBeenCalledOnce();
+  error.mockRestore();
+});
+
 it("creates an agent in the community shown, with its type's defaults, and publishes its profile", async () => {
   const { service, native } = await setup();
   const agent = await service.create({ type: "example/echo", name: " Echo " });
@@ -11479,7 +11542,6 @@ it("rejects invalid source discovery metadata", async () => {
     { configExample: [] },
     { configExample: { value: 1n } },
     { configExample: circular },
-    { present: "GitHub PR" },
   ])
     expect(() =>
       plugin.agents.addAttentionSource({
@@ -12087,13 +12149,11 @@ it("presents a watch through its provider, and plainly when that fails", async (
   const present = vi.fn((_watch: unknown, title: string) => ({
     type: `GitHub PR ${title}`,
   }));
-  plugin
-    .extend({ pluginOwner: { id: "buzz.github", revision: "bundled" } })
-    .agents.addAttentionSource({
-      id: "github-pr",
-      present,
-      run: async () => {},
-    });
+  const github = plugin.extend({
+    pluginOwner: { id: "buzz.github", revision: "bundled" },
+  });
+  github.agents.addAttentionSource({ id: "github-pr", run: async () => {} });
+  github.agents.presentSource("github-pr", present);
   expect(service.presentWatch(watch, "Release")).toEqual({
     type: "GitHub PR Release",
   });
diff --git a/src/features/agents/service.ts b/src/features/agents/service.ts
index 6b5fd7183..b0fb45e95 100644
--- a/src/features/agents/service.ts
+++ b/src/features/agents/service.ts
@@ -677,8 +677,9 @@ export type AgentProvider = Readonly<{
   check(): void | Promise<void>;
   /** Handles the current attention state directly; absent opens DialogBody. */
   attentionAction?: (() => void) | undefined;
-  /** Provider-owned recovery/progress controls and optional saved defaults. */
-  DialogBody: ComponentType<{ onClose(): void }>;
+  /** Provider-owned recovery/progress controls and optional saved defaults,
+   * from the type's `present`. */
+  DialogBody?: ComponentType<{ onClose(): void }>;
   /** Compact device default picker; persistence remains provider-owned. */
   DefaultControl?: ComponentType<{ onConfigure(): void }>;
 }>;
@@ -810,7 +811,60 @@ export type AgentType<Config = unknown> = {
   /** Makes the type hosted: its provider runs each agent, so it has no `run`,
    * `models` or `timeoutMs`, and its agents have no attention. */
   remote?: RemoteAgentType;
+  /** Handles for the type's own UI, given to its plugin's `present`. Each is
+   * JSON, a store (`snapshot` and `subscribe`) or a call returning a promise,
+   * so that agents can later run in another page than their UI. */
+  expose?: unknown;
 };
+/** What an agent type shows, from its plugin's UI entry (`present`); the
+ * rest of the type comes from its agent entry (`register`). */
+export type AgentPresentation<Config = unknown> = Pick<
+  AgentType<Config>,
+  | "icon"
+  | "Peek"
+  | "Create"
+  | "CreateModel"
+  | "tabs"
+  | "importShared"
+  | "exportShared"
+> &
+  Readonly<{
+    provider?: Pick<AgentProvider, "DialogBody" | "DefaultControl">;
+  }>;
+const PRESENTED = [
+  "icon",
+  "Peek",
+  "Create",
+  "CreateModel",
+  "tabs",
+  "importShared",
+  "exportShared",
+] as const;
+/** The type as its readers see it: `type` with what `present` shows. */
+export function presented<Config>(
+  type: AgentType<Config>,
+  shown: AgentPresentation<Config>,
+): AgentType<Config> {
+  const merged: AgentType<Config> = { ...type };
+  for (const field of PRESENTED)
+    if (shown[field] !== undefined)
+      Object.assign(merged, { [field]: shown[field] });
+  if (type.provider) {
+    // Keep getters, such as `attentionAction`, live.
+    const provider = Object.defineProperties(
+      {},
+      Object.getOwnPropertyDescriptors(type.provider),
+    ) as AgentProvider;
+    if (shown.provider?.DialogBody)
+      Object.assign(provider, { DialogBody: shown.provider.DialogBody });
+    if (shown.provider?.DefaultControl)
+      Object.assign(provider, {
+        DefaultControl: shown.provider.DefaultControl,
+      });
+    merged.provider = provider;
+  }
+  return merged;
+}
 /** A hosted type's provider: it holds each agent's key and runs it. The app
  * calls these in order to create one (`provision`, then `activate`) and owns
  * the owner's agent list; every step is asked again after a failure, so each
@@ -869,6 +923,17 @@ export type RemoteAgentType = Readonly<{
   ): Promise<void>;
 }>;
 export type RegisteredAgentType = Contribution<AgentType>;
+type Presentation = Readonly<{
+  id: string;
+  present(exposed: unknown): AgentPresentation;
+}>;
+type SourcePresented = Readonly<{
+  id: string;
+  present(
+    watch: import("./attention").SourceWatch,
+    title: string,
+  ): import("./attention-sources").SourcePresentation;
+}>;
 export type RetypePreview = Readonly<{
   /** Destination settings after applying the target type's migration policy. */
   config: unknown;
@@ -1027,7 +1092,22 @@ export type Agents = {
     watch: import("./attention").SourceWatch,
     title: string,
   ): import("./attention-sources").SourcePresentation | undefined;
+  /** Supplies how this plugin's attention source `sourceId` shows its
+   * watches, from its UI entry. */
+  presentSource(
+    sourceId: string,
+    present: (
+      watch: import("./attention").SourceWatch,
+      title: string,
+    ) => import("./attention-sources").SourcePresentation,
+  ): void;
   register<Config>(type: AgentType<Config>): void;
+  /** Supplies what this plugin's type `typeId` shows, from its UI entry.
+   * `present` gets the type's `expose`. */
+  present<Exposed = unknown, Config = unknown>(
+    typeId: string,
+    present: (exposed: Exposed) => AgentPresentation<Config>,
+  ): void;
   types(): readonly RegisteredAgentType[];
   /** Adds a tab to the settings of every agent running on this device,
    * whatever its type, after Activity. It shows while the plugin is on. */
@@ -1499,6 +1579,19 @@ export class AgentsService extends Service implements Agents {
   private readonly contributions;
   private readonly tabContributions;
   private readonly attentionControls;
+
+  private readonly presentations;
+  private readonly sourcePresentations;
+  /** Each registered type with what it shows, worked out once per pair. */
+  private readonly presentedTypes = new WeakMap<
+    RegisteredAgentType,
+    Readonly<{ from: Presentation; type: RegisteredAgentType }>
+  >();
+  private merged: Readonly<{
+    types: readonly RegisteredAgentType[];
+    shown: readonly Contribution<Presentation>[];
+    result: readonly RegisteredAgentType[];
+  }> = { types: [], shown: [], result: [] };
   private readonly addedTools;
   /** Every added tool's name, its plugin active or still starting. */
   private readonly toolNames = new Set<string>();
@@ -1613,6 +1706,9 @@ export class AgentsService extends Service implements Agents {
     this.hookContributions = createAgentHooks(ctx);
     this.tabContributions = createContributions<AgentAddedTab>(ctx);
     this.attentionControls = createContributions<{ id: string }>(ctx);
+
+    this.presentations = createContributions<Presentation>(ctx);
+    this.sourcePresentations = createContributions<SourcePresented>(ctx);
     this.addedTools = createContributions<AddedTool & { id: string }>(ctx);
     this.attentionSources = createContributions<AttentionProducer>(ctx);
     // Each changes the copy at once and logs a failed save itself.
@@ -1947,6 +2043,10 @@ export class AgentsService extends Service implements Agents {
           this.update();
           this.notify();
         }),
+        this.presentations.subscribe(() => {
+          this.update();
+          this.notify();
+        }),
         // A new state object, so views reading `addedTabs()` render again.
         this.tabContributions.subscribe(() => {
           this.state = Object.freeze({ ...this.state });
@@ -2040,7 +2140,49 @@ export class AgentsService extends Service implements Agents {
       );
     this.contributions.register(this.ctx, type as unknown as AgentType);
   }
-  types = () => this.contributions.snapshot();
+  present<Exposed, Config>(
+    typeId: string,
+    present: (exposed: Exposed) => AgentPresentation<Config>,
+  ) {
+    if (typeof present !== "function")
+      throw new Error("present needs a function");
+    this.presentations.register(this.ctx, {
+      id: typeId,
+      present: present as Presentation["present"],
+    });
+  }
+  presentSource(sourceId: string, present: SourcePresented["present"]) {
+    if (typeof present !== "function")
+      throw new Error("presentSource needs a function");
+    this.sourcePresentations.register(this.ctx, { id: sourceId, present });
+  }
+  types = () => {
+    const types = this.contributions.snapshot();
+    const shown = this.presentations.snapshot();
+    if (types === this.merged.types && shown === this.merged.shown)
+      return this.merged.result;
+    const result = Object.freeze(
+      types.map((type) => {
+        const from = shown.find((entry) => entry.key === type.key);
+        if (!from) return type;
+        const known = this.presentedTypes.get(type);
+        if (known?.from === from) return known.type;
+        let merged = type;
+        try {
+          merged = Object.freeze(
+            presented(type, from.present(type.expose)),
+          ) as RegisteredAgentType;
+        } catch (error) {
+          // Its agents still run; only what the type shows is missing.
+          console.error(`Agent type ${type.key} could not be shown`, error);
+        }
+        this.presentedTypes.set(type, { from, type: merged });
+        return merged;
+      }),
+    );
+    this.merged = { types, shown, result };
+    return result;
+  };
   registerTab(tab: AgentAddedTab) {
     if (
       !/^[a-z0-9][a-z0-9._-]*$/.test(tab.id ?? "") ||
@@ -2092,7 +2234,6 @@ export class AgentsService extends Service implements Agents {
       !plugin ||
       !/^[a-z0-9][a-z0-9._-]*$/.test(source.id) ||
       typeof source.run !== "function" ||
-      (source.present !== undefined && typeof source.present !== "function") ||
       (source.description !== undefined &&
         (typeof source.description !== "string" ||
           !source.description.trim())) ||
@@ -2289,8 +2430,13 @@ export class AgentsService extends Service implements Agents {
     const source = this.attentionSources
       .snapshot()
       .find((source) => this.attentionProvider(source) === watch.provider);
+    const shown =
+      source &&
+      this.sourcePresentations
+        .snapshot()
+        .find((entry) => entry.key === source.key);
     try {
-      return source?.present?.(watch, title);
+      return shown?.present(watch, title);
     } catch (error) {
       // One plugin's mistake leaves its watches plain, not the page broken.
       console.warn(
diff --git a/src/features/panels/service.test.tsx b/src/features/panels/service.test.tsx
index 5a5fb41b2..51c366b63 100644
--- a/src/features/panels/service.test.tsx
+++ b/src/features/panels/service.test.tsx
@@ -1,4 +1,4 @@
-import { expect, it } from "vitest";
+import { expect, it, vi } from "vitest";
 import { Context } from "@deepseek-ai/cordis";
 import { PluginRuntime } from "../../plugins/runtime";
 import { PagesService } from "../pages/service";
@@ -37,9 +37,10 @@ it("independently unloads panels without removing the page or shared data", asyn
   // Channels adds agent teams; GitHub registers tools and an Attention source.
   root.provide("agents", {
     subscribe: () => () => {},
-    snapshot: () => undefined,
+    snapshot: () => ({ agents: [], running: [], interrupted: [] }),
     addTool: () => {},
     addAttentionSource: () => {},
+    presentSource: () => {},
   });
   root.provide("communityReader", {
     subscribe: () => () => {},
@@ -54,6 +55,13 @@ it("independently unloads panels without removing the page or shared data", asyn
   });
   // GitHub reads through gh where the host can run it; here it cannot.
   root.provide("host", {});
+  // GitHub's agent entry keeps where its pull request watches have read to.
+  const stored = new Map<string, string>();
+  vi.stubGlobal("localStorage", {
+    getItem: (key: string) => stored.get(key) ?? null,
+    setItem: (key: string, value: string) => stored.set(key, value),
+    removeItem: (key: string) => stored.delete(key),
+  });
   provideNavigation(root);
   const relay = provideRelay(root);
   const desired = (ids: string[]) => ids.map(plugin);
@@ -95,6 +103,7 @@ it("independently unloads panels without removing the page or shared data", asyn
   } finally {
     await runtime.dispose();
     await root.fiber.dispose();
+    vi.unstubAllGlobals();
   }
 });
 
diff --git a/src/plugins/api.ts b/src/plugins/api.ts
index c96d156eb..21d3d7244 100644
--- a/src/plugins/api.ts
+++ b/src/plugins/api.ts
@@ -67,6 +67,13 @@ export type PluginModule = {
   // Cordis starts apply only when these services are available.
   inject?: Inject;
   apply: (ctx: Context) => void | Promise<void>;
+  /** What agents need while they run: agent types' runtimes, tools, wakes and
+   * Attention sources. It starts with `apply`, under the same plugin identity,
+   * with its own dependencies, so it can later run apart from the UI page. */
+  agent?: Readonly<{
+    inject?: Inject;
+    apply: (ctx: Context) => void | Promise<void>;
+  }>;
 };
 
 // Installation identity follows child Cordis scopes so services can own contributions.
diff --git a/src/plugins/modules.ts b/src/plugins/modules.ts
index 2f7a63eb1..b3363e8ad 100644
--- a/src/plugins/modules.ts
+++ b/src/plugins/modules.ts
@@ -30,9 +30,12 @@ export function createModuleLoader(
       }
       if (!module || typeof module !== "object")
         throw new Error("Invalid plugin module");
-      if ("apply" in module && typeof module.apply === "function")
-        return module as PluginModule;
-      throw new Error("Plugin must export apply(ctx)");
+      if (!("apply" in module) || typeof module.apply !== "function")
+        throw new Error("Plugin must export apply(ctx)");
+      const { agent } = module as { agent?: { apply?: unknown } | null };
+      if (agent !== undefined && typeof agent?.apply !== "function")
+        throw new Error("Plugin agent must have apply(ctx)");
+      return module as PluginModule;
     })();
     modules.set(key, promise);
     void promise.catch(() => {
diff --git a/src/plugins/runtime.test.mjs b/src/plugins/runtime.test.mjs
index 6f6c83ec3..8a58b9cfc 100644
--- a/src/plugins/runtime.test.mjs
+++ b/src/plugins/runtime.test.mjs
@@ -125,6 +125,59 @@ test("startup is not over while the plugin settings are being read", async () =>
   }
 });
 
+test("an agent entry has its own dependencies and the plugin waits for both parts", async () => {
+  const stopped = [];
+  const h = harness(async () => ({
+    apply(ctx) {
+      ctx.pages.register({ id: "main", title: "Main", component: Page });
+      ctx.effect(() => () => stopped.push("ui"));
+    },
+    agent: {
+      inject: ["connection"],
+      apply(ctx) {
+        assert.equal(ctx.pluginOwner.id, "example.page");
+        ctx.effect(() => () => stopped.push("agent"));
+      },
+    },
+  }));
+  try {
+    h.runtime.reconcile(desired([plugin()]));
+    await settle();
+    assert.equal(h.states["example.page"].status, "starting");
+    assert.deepEqual(h.pages.snapshot(), []);
+    h.root.provide("connection", {});
+    await h.wait((s) => s["example.page"]?.status === "active");
+    assert.equal(h.pages.snapshot().length, 1);
+    h.runtime.reconcile([]);
+    await settle();
+    assert.deepEqual(stopped.sort(), ["agent", "ui"]);
+  } finally {
+    await h.dispose();
+  }
+});
+
+test("a failed agent entry fails its plugin and stops its other part", async () => {
+  const h = harness(async () => ({
+    apply(ctx) {
+      ctx.pages.register({ id: "main", title: "Main", component: Page });
+    },
+    agent: {
+      apply() {
+        throw new Error("Agent part failed");
+      },
+    },
+  }));
+  try {
+    h.runtime.reconcile(desired([plugin()]));
+    await h.wait((s) => s["example.page"]?.status === "failed");
+    assert.match(h.states["example.page"].error, /Agent part failed/);
+    await settle();
+    assert.deepEqual(h.pages.snapshot(), []);
+  } finally {
+    await h.dispose();
+  }
+});
+
 test("missing dependencies time out and cannot activate late", async () => {
   vi.useFakeTimers({ toFake: ["setTimeout", "clearTimeout"] });
   let starts = 0;
diff --git a/src/plugins/runtime.ts b/src/plugins/runtime.ts
index dc1e0a04f..7a20e2fe5 100644
--- a/src/plugins/runtime.ts
+++ b/src/plugins/runtime.ts
@@ -14,7 +14,8 @@ type Entry = {
   plugin: PluginInfo;
   cancelled: boolean;
   failed: boolean;
-  fiber?: Fiber;
+  /** The plugin's own fiber, then its agent entry's, when it has one. */
+  fibers: Fiber[];
   unwatch?: () => void;
   stopped?: Promise<void>;
   predecessor: Promise<void>;
@@ -103,6 +104,7 @@ export class PluginRuntime {
         plugin,
         cancelled: false,
         failed: false,
+        fibers: [],
         predecessor: previous ? this.stop(previous) : Promise.resolve(),
       };
       this.entries.set(id, entry);
@@ -158,32 +160,40 @@ export class PluginRuntime {
           ]),
         }),
       });
-      const fiber = scope.plugin({
-        name: entry.plugin.manifest.id,
-        inject: module.inject ?? [],
-        apply: (ctx: Context) => module.apply(ctx),
-      });
-      entry.fiber = fiber;
-      this.watch(entry, fiber);
+      const id = entry.plugin.manifest.id;
+      // Both parts run in this page for now; the plugin is active once both are.
+      const parts = [
+        { name: id, inject: module.inject, apply: module.apply },
+        ...(module.agent ? [{ name: `${id}/agent`, ...module.agent }] : []),
+      ];
+      entry.fibers = parts.map(({ name, inject, apply }) =>
+        scope.plugin({
+          name,
+          inject: inject ?? [],
+          apply: (ctx: Context) => apply(ctx),
+        }),
+      );
+      this.watch(entry, entry.fibers);
     } catch (reason) {
       this.fail(entry, reason);
     }
   }
 
-  private watch(entry: Entry, fiber: Fiber) {
+  private watch(entry: Entry, fibers: readonly Fiber[]) {
     let timer: ReturnType<typeof setTimeout> | undefined;
     const refresh = () => {
       if (entry.cancelled || entry.failed) return;
-      if (fiber.state === cordisState.active) {
-        clearTimeout(timer);
-        timer = undefined;
-        this.update(entry, "active", null);
-      } else if (fiber.state === cordisState.failed) {
+      const failed = fibers.find((fiber) => fiber.state === cordisState.failed);
+      if (failed) {
         // await() retrieves the startup error, but does not wait for missing
         // dependencies. Only the ACTIVE state means contributions are ready.
-        void fiber.await().catch((reason) => this.fail(entry, reason));
-      } else if (fiber.state === cordisState.disposed) {
+        void failed.await().catch((reason) => this.fail(entry, reason));
+      } else if (fibers.some((fiber) => fiber.state === cordisState.disposed)) {
         this.fail(entry, new Error("Plugin was disposed"));
+      } else if (fibers.every((fiber) => fiber.state === cordisState.active)) {
+        clearTimeout(timer);
+        timer = undefined;
+        this.update(entry, "active", null);
       } else {
         this.update(entry, "starting", null);
         timer ??= setTimeout(
@@ -194,7 +204,7 @@ export class PluginRuntime {
     };
     const unsubscribe = this.root.on("internal/status", (changed) => {
       // ctx.plugin() returns a wrapper; events carry the underlying fiber.
-      if (changed.ctx === fiber.ctx) refresh();
+      if (fibers.some((fiber) => changed.ctx === fiber.ctx)) refresh();
     });
     entry.unwatch = () => {
       clearTimeout(timer);
@@ -210,8 +220,10 @@ export class PluginRuntime {
     this.update(entry, "failed", String(reason));
     // Failure stays visible until an explicit retry. Retain the cleanup barrier
     // so replacement also waits for disposal started by a timeout or error.
-    if (entry.fiber) {
-      entry.stopped ??= entry.fiber.dispose();
+    if (entry.fibers.length) {
+      entry.stopped ??= Promise.all(
+        entry.fibers.map((fiber) => fiber.dispose()),
+      ).then(() => {});
       void entry.stopped.catch(() => {});
     }
   }
@@ -221,7 +233,7 @@ export class PluginRuntime {
     entry.unwatch?.();
     entry.stopped ??= Promise.all([
       entry.predecessor,
-      entry.fiber?.dispose(),
+      ...entry.fibers.map((fiber) => fiber.dispose()),
     ]).then(() => {});
     return entry.stopped;
   }