diff --git a/docs/plugin-architecture.md b/docs/plugin-architecture.md
index c7d2b32e89..8ba9eb02d0 100644
--- a/docs/plugin-architecture.md
+++ b/docs/plugin-architecture.md
@@ -253,6 +253,12 @@ 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.
 
+The type's functions of config alone (`defaults`, `importShared`, `adopt`,
+`carry`, `describeMigration`, `migrationWarning` and `summary`) go to both
+calls. The service needs them to create and retype agents, and screens call
+them while rendering. `retypePreview` computes a type change's preview from
+them, so a screen can show it where the service does not run.
+
 A plugin, bundled or installed, can add a tool to every agent session in the
 app with `ctx.agents.addTool({ name, description, inputSchema, call })`. `call`
 gets the agent's Buzz client and where it is working, so the tool acts as the
diff --git a/src/bundled/claude-code/index.ts b/src/bundled/claude-code/index.ts
index 00ec7e50a0..a1ed09c6a3 100644
--- a/src/bundled/claude-code/index.ts
+++ b/src/bundled/claude-code/index.ts
@@ -5,6 +5,7 @@ import { repositoriesContext } from "../../features/communities/repositories";
 import { isTauri } from "@tauri-apps/api/core";
 import { pubkeyOf } from "../../features/agents/membership";
 import { ownerReads } from "../../features/agents/reads";
+import type { AgentTypeConfig } from "../../features/agents/service";
 import type { PluginModule } from "../../plugins/api";
 import { ClaudeLogoIcon } from "../../shared/design-system/icons";
 import { claudeRun, TYPE_ID } from "./run";
@@ -25,6 +26,38 @@ 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];
 
+/** The type's pure config functions: the service needs them to create and
+ * retype agents, and screens to show them. */
+const typeConfig = {
+  defaults: () => ({ config: DEFAULT_CONFIG }),
+  adopt: (carry, saved) => ({
+    ...saved,
+    instructions: carry.instructions ?? saved.instructions,
+    workspace: carry.workspace ?? saved.workspace,
+  }),
+  carry: (saved) => {
+    const { instructions, workspace } = config(saved);
+    return {
+      ...(instructions.trim() && { instructions }),
+      ...(workspace !== DEFAULT_CONFIG.workspace && { workspace }),
+    };
+  },
+  describeMigration: (saved) => {
+    const { model, effort, scope } = config(saved);
+    return [
+      { id: "model", label: "Model", isOverride: Boolean(model.trim()) },
+      { id: "thinking", label: "Thinking", isOverride: Boolean(effort) },
+      {
+        id: "sessions",
+        label: "Sessions",
+        isOverride: scope !== DEFAULT_CONFIG.scope,
+        unchangedKey: scope,
+      },
+    ];
+  },
+  summary: (agent) => config(agent.config).model || "Claude",
+} satisfies AgentTypeConfig<Config>;
+
 export const inject = ["agents"];
 export const apply: PluginModule["apply"] = (ctx) => {
   if (!supported()) return;
@@ -38,6 +71,7 @@ export const apply: PluginModule["apply"] = (ctx) => {
       ActivityTab,
     } = createTabs(exposed);
     return {
+      ...typeConfig,
       icon: ClaudeLogoIcon,
       Create,
       CreateModel,
@@ -122,38 +156,12 @@ function applyAgent(ctx: Parameters<PluginModule["apply"]>[0]) {
     title: "Claude",
     description:
       "Claude on this computer. Each thread it is mentioned in is one continuing session.",
-    defaults: () => ({ config: DEFAULT_CONFIG }),
+    ...typeConfig,
     expose: {
       setup,
       defaults: providerDefaults,
       runtime,
     } satisfies ClaudeExposed,
-    adopt: (carry, saved) => ({
-      ...saved,
-      instructions: carry.instructions ?? saved.instructions,
-      workspace: carry.workspace ?? saved.workspace,
-    }),
-    carry: (saved) => {
-      const { instructions, workspace } = config(saved);
-      return {
-        ...(instructions.trim() && { instructions }),
-        ...(workspace !== DEFAULT_CONFIG.workspace && { workspace }),
-      };
-    },
-    describeMigration: (saved) => {
-      const { model, effort, scope } = config(saved);
-      return [
-        { id: "model", label: "Model", isOverride: Boolean(model.trim()) },
-        { id: "thinking", label: "Thinking", isOverride: Boolean(effort) },
-        {
-          id: "sessions",
-          label: "Sessions",
-          isOverride: scope !== DEFAULT_CONFIG.scope,
-          unchangedKey: scope,
-        },
-      ];
-    },
-    summary: (agent) => config(agent.config).model || "Claude",
     ...(spawn &&
       readFile && {
         usage: (agent, { since, signal }) =>
diff --git a/src/bundled/codex/index.ts b/src/bundled/codex/index.ts
index 4db1e8585f..8045d405e4 100644
--- a/src/bundled/codex/index.ts
+++ b/src/bundled/codex/index.ts
@@ -2,6 +2,7 @@ import { repositoriesContext } from "../../features/communities/repositories";
 import { isTauri } from "@tauri-apps/api/core";
 import { pubkeyOf } from "../../features/agents/membership";
 import { ownerReads } from "../../features/agents/reads";
+import type { AgentTypeConfig } from "../../features/agents/service";
 import type { PluginModule } from "../../plugins/api";
 import { CodexLogoIcon } from "../../shared/design-system/icons";
 import { type Config, config, defaults, validWorkspace } from "./config";
@@ -24,6 +25,52 @@ type CodexExposed = Readonly<{
   setup: Parameters<typeof createTabs>[3];
 }>;
 
+/** The type's pure config functions: the service needs them to create and
+ * retype agents, and screens to show them. */
+const typeConfig = {
+  defaults: () => ({ config: { ...defaults } }),
+  importShared: (source) =>
+    source.runtime === "codex" &&
+    (!source.provider || source.provider === "openai")
+      ? { ...defaults, model: source.model }
+      : undefined,
+  adopt: (carry, saved) => ({
+    ...saved,
+    instructions: carry.instructions ?? saved.instructions,
+    // Codex runs only in an absolute or home workspace.
+    workspace:
+      carry.workspace && validWorkspace(carry.workspace)
+        ? carry.workspace
+        : saved.workspace,
+  }),
+  carry: (saved) => {
+    const { instructions, workspace } = config(saved);
+    return {
+      ...(instructions.trim() && { instructions }),
+      ...(workspace !== defaults.workspace && { workspace }),
+    };
+  },
+  describeMigration: (saved) => {
+    const { model, effort, scope } = config(saved);
+    return [
+      { id: "model", label: "Model", isOverride: Boolean(model.trim()) },
+      {
+        id: "thinking",
+        label: "Thinking",
+        isOverride: Boolean(effort),
+      },
+      {
+        id: "sessions",
+        label: "Sessions",
+        isOverride: scope !== defaults.scope,
+        unchangedKey: scope,
+      },
+    ];
+  },
+  migrationWarning: "Any commands Codex left running will stop.",
+  summary: (agent) => config(agent.config).model || "Codex",
+} satisfies AgentTypeConfig<Config>;
+
 export const inject = ["agents"];
 export const apply: PluginModule["apply"] = (ctx) => {
   if (!supported()) return;
@@ -39,6 +86,7 @@ export const apply: PluginModule["apply"] = (ctx) => {
         ActivityTab,
       } = createTabs(provider, runtime, transcript, setup);
       return {
+        ...typeConfig,
         icon: CodexLogoIcon,
         Create,
         CreateModel,
@@ -147,53 +195,13 @@ function applyAgent(ctx: Parameters<PluginModule["apply"]>[0]) {
     title: "Codex",
     description:
       "Codex on this computer, using its native coding tools and your account.",
-    defaults: () => ({ config: { ...defaults } }),
+    ...typeConfig,
     expose: {
       provider: providerController,
       runtime,
       transcript: transcripts(start, runtime),
       setup,
     } satisfies CodexExposed,
-    importShared: (source) =>
-      source.runtime === "codex" &&
-      (!source.provider || source.provider === "openai")
-        ? { ...defaults, model: source.model }
-        : undefined,
-    adopt: (carry, saved) => ({
-      ...saved,
-      instructions: carry.instructions ?? saved.instructions,
-      // Codex runs only in an absolute or home workspace.
-      workspace:
-        carry.workspace && validWorkspace(carry.workspace)
-          ? carry.workspace
-          : saved.workspace,
-    }),
-    carry: (saved) => {
-      const { instructions, workspace } = config(saved);
-      return {
-        ...(instructions.trim() && { instructions }),
-        ...(workspace !== defaults.workspace && { workspace }),
-      };
-    },
-    describeMigration: (saved) => {
-      const { model, effort, scope } = config(saved);
-      return [
-        { id: "model", label: "Model", isOverride: Boolean(model.trim()) },
-        {
-          id: "thinking",
-          label: "Thinking",
-          isOverride: Boolean(effort),
-        },
-        {
-          id: "sessions",
-          label: "Sessions",
-          isOverride: scope !== defaults.scope,
-          unchangedKey: scope,
-        },
-      ];
-    },
-    migrationWarning: "Any commands Codex left running will stop.",
-    summary: (agent) => config(agent.config).model || "Codex",
     ...(spawn &&
       readFile && {
         usage: (agent, { since, signal }) =>
diff --git a/src/bundled/goose/index.ts b/src/bundled/goose/index.ts
index 55f7008cb0..1585942e55 100644
--- a/src/bundled/goose/index.ts
+++ b/src/bundled/goose/index.ts
@@ -4,6 +4,7 @@ import { repositoriesContext } from "../../features/communities/repositories";
 // in it; goose answers with the in-process Buzz tools, served to it over
 // loopback HTTP MCP.
 import { isTauri } from "@tauri-apps/api/core";
+import type { AgentTypeConfig } from "../../features/agents/service";
 import type { PluginModule } from "../../plugins/api";
 import { GooseLogoIcon } from "../../shared/design-system/icons";
 import { type Config, config, DEFAULT_CONFIG, GooseRuntime } from "./runtime";
@@ -18,6 +19,36 @@ export const TYPE_ID = "goose";
 /** What the type's UI reaches of its runtime. */
 type GooseExposed = Parameters<typeof createTabs>[0];
 
+/** The type's pure config functions: the service needs them to create and
+ * retype agents, and screens to show them. */
+const typeConfig = {
+  defaults: () => ({ config: DEFAULT_CONFIG }),
+  importShared: (source) =>
+    source.runtime === "goose" || source.runtime === "goose-ai"
+      ? {
+          ...DEFAULT_CONFIG,
+          model: source.model,
+          provider: source.provider ?? "",
+        }
+      : undefined,
+  adopt: (carry, saved) => ({
+    ...saved,
+    instructions: carry.instructions ?? saved.instructions,
+    workspace: carry.workspace ?? saved.workspace,
+  }),
+  carry: (saved) => {
+    const { instructions, workspace } = config(saved);
+    return {
+      ...(instructions.trim() && { instructions }),
+      ...(workspace !== DEFAULT_CONFIG.workspace && { workspace }),
+    };
+  },
+  summary: (agent) => {
+    const { model, provider } = config(agent.config);
+    return [provider, model].filter(Boolean).join(" · ") || "Goose";
+  },
+} satisfies AgentTypeConfig<Config>;
+
 export const inject = ["agents"];
 export const apply: PluginModule["apply"] = (ctx) => {
   // Only the desktop app can start `goose-acp`; no unusable type elsewhere.
@@ -32,6 +63,7 @@ export const apply: PluginModule["apply"] = (ctx) => {
       ProviderDialogBody,
     } = createTabs(exposed);
     return {
+      ...typeConfig,
       icon: GooseLogoIcon,
       Create,
       CreateModel,
@@ -100,37 +132,13 @@ function applyAgent(ctx: Parameters<PluginModule["apply"]>[0]) {
     title: "Goose",
     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,
+    ...typeConfig,
     expose: { setup, runtime, history } satisfies GooseExposed,
     provider: {
       snapshot: setup.snapshot,
       subscribe: setup.subscribe,
       check: setup.check,
     },
-    adopt: (carry, saved) => ({
-      ...saved,
-      instructions: carry.instructions ?? saved.instructions,
-      workspace: carry.workspace ?? saved.workspace,
-    }),
-    carry: (saved) => {
-      const { instructions, workspace } = config(saved);
-      return {
-        ...(instructions.trim() && { instructions }),
-        ...(workspace !== DEFAULT_CONFIG.workspace && { workspace }),
-      };
-    },
-    summary: (agent) => {
-      const { model, provider } = config(agent.config);
-      return [provider, model].filter(Boolean).join(" · ") || "Goose";
-    },
     sessions: {
       list: (key) => {
         const live = runtime.sessions(key);
diff --git a/src/bundled/pi/index.ts b/src/bundled/pi/index.ts
index b816450be9..6ff9492f2a 100644
--- a/src/bundled/pi/index.ts
+++ b/src/bundled/pi/index.ts
@@ -6,6 +6,7 @@ import { isTauri } from "@tauri-apps/api/core";
 import { pubkeyOf } from "../../features/agents/membership";
 import { ownerReads } from "../../features/agents/reads";
 import { repositoriesContext } from "../../features/communities/repositories";
+import type { AgentTypeConfig } from "../../features/agents/service";
 import type { PluginModule } from "../../plugins/api";
 import { PiLogoIcon } from "../../shared/design-system/icons";
 import { type Config, config, DEFAULT_CONFIG, PiRuntime } from "./runtime";
@@ -19,6 +20,28 @@ const HANDOVER_MS = 2 * 60_000;
 /** What the type's UI reaches of its runtime. */
 type PiExposed = Parameters<typeof createTabs>[0];
 
+/** The type's pure config functions: the service needs them to create and
+ * retype agents, and screens to show them. */
+const typeConfig = {
+  defaults: () => ({ config: DEFAULT_CONFIG }),
+  adopt: (carry, saved) => ({
+    ...saved,
+    instructions: carry.instructions ?? saved.instructions,
+    workspace: carry.workspace ?? saved.workspace,
+  }),
+  carry: (saved) => {
+    const { instructions, workspace } = config(saved);
+    return {
+      ...(instructions.trim() && { instructions }),
+      ...(workspace !== DEFAULT_CONFIG.workspace && { workspace }),
+    };
+  },
+  summary: (agent) => {
+    const { model, provider } = config(agent.config);
+    return [provider, model].filter(Boolean).join(" · ") || "Pi";
+  },
+} satisfies AgentTypeConfig<Config>;
+
 export const inject = ["agents"];
 export const apply: PluginModule["apply"] = (ctx) => {
   // Only the desktop app can start the Pi host; no unusable type elsewhere.
@@ -27,6 +50,7 @@ export const apply: PluginModule["apply"] = (ctx) => {
     const { ActivityTab, Create, CreateModel, SettingsTab } =
       createTabs(exposed);
     return {
+      ...typeConfig,
       icon: PiLogoIcon,
       Create,
       CreateModel,
@@ -85,24 +109,8 @@ function applyAgent(ctx: Parameters<PluginModule["apply"]>[0]) {
     title: "Pi",
     description:
       "Pi on this computer, with any provider Pi supports. Each thread it is mentioned in is one continuing conversation.",
-    defaults: () => ({ config: DEFAULT_CONFIG }),
+    ...typeConfig,
     expose: { setup: runtime.setup, runtime } satisfies PiExposed,
-    adopt: (carry, saved) => ({
-      ...saved,
-      instructions: carry.instructions ?? saved.instructions,
-      workspace: carry.workspace ?? saved.workspace,
-    }),
-    carry: (saved) => {
-      const { instructions, workspace } = config(saved);
-      return {
-        ...(instructions.trim() && { instructions }),
-        ...(workspace !== DEFAULT_CONFIG.workspace && { workspace }),
-      };
-    },
-    summary: (agent) => {
-      const { model, provider } = config(agent.config);
-      return [provider, model].filter(Boolean).join(" · ") || "Pi";
-    },
     ...(host.spawn && {
       usage: (agent, { since, signal }) =>
         runtime.usage(agent.key, since, signal),
diff --git a/src/features/agents/service.test.ts b/src/features/agents/service.test.ts
index c607a2eb3f..66b8b87630 100644
--- a/src/features/agents/service.test.ts
+++ b/src/features/agents/service.test.ts
@@ -24,8 +24,11 @@ import {
   type Agent,
   AgentsService,
   type AgentType,
+  type Carry,
   type ConfigBinding,
   type Delivery,
+  type RegisteredAgentType,
+  retypePreview,
   type Trigger,
   fromOwner,
   teamPrompt,
@@ -309,6 +312,42 @@ it("shows a type with what its plugin presents, from the handles the type expose
   expect(shown).toHaveBeenCalledOnce();
 });
 
+it("takes a type's config functions from what it presents, for screens where the service does not run", async () => {
+  const { service, plugin } = await setup();
+  const summary = (agent: Agent) => `Shown ${agent.name}`;
+  const config = {
+    defaults: () => ({ config: { model: "m" } }),
+    carry: (saved: unknown): Carry => {
+      const { notes } = saved as { notes?: string };
+      return notes ? { instructions: notes } : {};
+    },
+    adopt: (carry: Carry, saved: unknown) => ({
+      ...(saved as object),
+      notes: carry.instructions,
+    }),
+    summary,
+  };
+  // Here only the screens' side passes them; a type passes them to both.
+  plugin.agents.register({
+    id: "shown",
+    title: "Shown",
+    defaults: config.defaults,
+  });
+  plugin.agents.present("shown", () => config);
+  const type = service.types().find((t) => t.key === "example/shown");
+  expect(type?.summary).toBe(summary);
+  expect(type?.carry).toBe(config.carry);
+  // The preview a screen computes is the service's.
+  expect(
+    retypePreview({ notes: "Keep" }, type, type as RegisteredAgentType),
+  ).toEqual({
+    config: { model: "m", notes: "Keep" },
+    moved: ["instructions"],
+    dropped: [],
+    settings: [],
+  });
+});
+
 it("still runs a type whose present throws", async () => {
   const { service, plugin } = await setup();
   const error = vi.spyOn(console, "error").mockImplementation(() => {});
diff --git a/src/features/agents/service.ts b/src/features/agents/service.ts
index cdfc7005d6..ebb4a1e755 100644
--- a/src/features/agents/service.ts
+++ b/src/features/agents/service.ts
@@ -714,16 +714,42 @@ export type AgentType<Config = unknown> = {
    * so that agents can later run in another page than their UI. */
   expose?: unknown;
 };
+/** A type's functions of config alone. Both its entries pass the same ones,
+ * so screens can call them where the service does not run. */
+export type AgentTypeConfig<Config = unknown> = Pick<
+  AgentType<Config>,
+  | "defaults"
+  | "importShared"
+  | "adopt"
+  | "carry"
+  | "describeMigration"
+  | "migrationWarning"
+  | "summary"
+>;
 /** 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"
 > &
+  Partial<AgentTypeConfig<Config>> &
   Readonly<{
     provider?: Pick<AgentProvider, "DialogBody" | "DefaultControl">;
   }>;
-const PRESENTED = ["icon", "Peek", "Create", "CreateModel", "tabs"] as const;
+const PRESENTED = [
+  "icon",
+  "Peek",
+  "Create",
+  "CreateModel",
+  "tabs",
+  "defaults",
+  "importShared",
+  "adopt",
+  "carry",
+  "describeMigration",
+  "migrationWarning",
+  "summary",
+] as const;
 /** The type as its readers see it: `type` with what `present` shows. */
 export function presented<Config>(
   type: AgentType<Config>,
@@ -822,6 +848,48 @@ export type RetypePreview = Readonly<{
     outcome: "reset" | "dropped";
   }>[];
 }>;
+/** What changing an agent with `config` from `source` to `kind` keeps, moves
+ * and drops. It calls only the types' config functions, so screens can show
+ * it where the service does not run. */
+export function retypePreview(
+  config: unknown,
+  source: Pick<AgentType, "carry" | "describeMigration"> | undefined,
+  kind: Pick<AgentType, "defaults" | "adopt" | "carry" | "describeMigration">,
+): RetypePreview {
+  const carry = source?.carry?.(config) ?? {};
+  const { config: fresh } = kind.defaults();
+  const adopted = kind.adopt ? kind.adopt(carry, fresh) : fresh;
+  const kept = kind.carry?.(adopted) ?? {};
+  const keys = (Object.keys(carry) as (keyof Carry)[]).filter(
+    (key) => carry[key] !== undefined,
+  );
+  const moved = keys.filter((key) => kept[key] === carry[key]);
+  const dropped = keys.filter((key) => kept[key] !== carry[key]);
+  const destinationSettings = new Map(
+    kind.describeMigration?.(adopted).map((setting) => [setting.id, setting]),
+  );
+  const settings =
+    source
+      ?.describeMigration?.(config)
+      .filter((setting) => setting.isOverride)
+      .flatMap((setting) => {
+        const next = destinationSettings.get(setting.id);
+        if (
+          next &&
+          setting.unchangedKey !== undefined &&
+          setting.unchangedKey === next.unchangedKey
+        )
+          return [];
+        return [
+          {
+            id: setting.id,
+            label: setting.label,
+            outcome: next ? ("reset" as const) : ("dropped" as const),
+          },
+        ];
+      }) ?? [];
+  return { config: adopted, moved, dropped, settings };
+}
 /** An unsaved creation request. Only the owner-facing review may approve it. */
 export type AgentCreationRequest = Readonly<{
   id: string;
@@ -3859,48 +3927,8 @@ export class AgentsService extends Service implements Agents {
     kind: RegisteredAgentType,
   ) {
     const record = this.settingsOf(identity);
-    const carry = source?.carry?.(record.config) ?? {};
-    const { config } = kind.defaults();
-    const adopted = kind.adopt ? kind.adopt(carry, config) : config;
-    const kept = kind.carry?.(adopted) ?? {};
-    const keys = (Object.keys(carry) as (keyof Carry)[]).filter(
-      (key) => carry[key] !== undefined,
-    );
-    const moved = keys.filter((key) => kept[key] === carry[key]);
-    const dropped = keys.filter((key) => kept[key] !== carry[key]);
-    const destinationSettings = new Map(
-      kind.describeMigration?.(adopted).map((setting) => [setting.id, setting]),
-    );
-    const settings =
-      source
-        ?.describeMigration?.(record.config)
-        .filter((setting) => setting.isOverride)
-        .flatMap((setting) => {
-          const next = destinationSettings.get(setting.id);
-          if (
-            next &&
-            setting.unchangedKey !== undefined &&
-            setting.unchangedKey === next.unchangedKey
-          )
-            return [];
-          return [
-            {
-              id: setting.id,
-              label: setting.label,
-              outcome: next ? ("reset" as const) : ("dropped" as const),
-            },
-          ];
-        }) ?? [];
-    return {
-      record,
-      adopted,
-      preview: {
-        config: adopted,
-        moved,
-        dropped,
-        settings,
-      },
-    };
+    const preview = retypePreview(record.config, source, kind);
+    return { record, adopted: preview.config, preview };
   }
   private view(identity: Member, record: AgentRecord): Agent {
     return Object.freeze({