diff --git a/packages/app/src/hooks/use-agent-input-draft-core.ts b/packages/app/src/hooks/use-agent-input-draft-core.ts
new file mode 100644
index 000000000..f6a6d8e1a
--- /dev/null
+++ b/packages/app/src/hooks/use-agent-input-draft-core.ts
@@ -0,0 +1,174 @@
+import type { UserComposerAttachment } from "@/attachments/types";
+import type { DraftAgentStatusBarProps } from "@/components/agent-status-bar";
+import type { DraftCommandConfig } from "@/hooks/use-agent-commands-query";
+import type { UseAgentFormStateResult } from "@/hooks/use-agent-form-state";
+import type { AgentModelDefinition, AgentProvider } from "@server/server/agent/agent-sdk-types";
+
+export interface DraftStorage {
+  getItem(key: string): Promise<string | null>;
+  setItem(key: string, value: string): Promise<void>;
+  removeItem(key: string): Promise<void>;
+}
+
+export interface StoredDraft {
+  text: string;
+  attachments: UserComposerAttachment[];
+  cwd: string;
+}
+
+export interface AgentInputDraftCore {
+  load(initialCwd?: string): Promise<StoredDraft | null>;
+  save(draft: StoredDraft): Promise<void>;
+  clear(): Promise<void>;
+}
+
+export function createAgentInputDraftCore(input: {
+  storage: DraftStorage;
+  storageKey: string;
+}): AgentInputDraftCore {
+  return {
+    async load(initialCwd?: string) {
+      const json = await input.storage.getItem(input.storageKey);
+      if (!json) return null;
+      try {
+        const parsed = JSON.parse(json) as Record<string, unknown>;
+        return {
+          text: typeof parsed.text === "string" ? parsed.text : "",
+          attachments: Array.isArray(parsed.attachments)
+            ? (parsed.attachments as UserComposerAttachment[])
+            : [],
+          cwd: typeof parsed.cwd === "string" ? parsed.cwd : (initialCwd ?? ""),
+        };
+      } catch {
+        return null;
+      }
+    },
+    async save(draft) {
+      await input.storage.setItem(input.storageKey, JSON.stringify(draft));
+    },
+    async clear() {
+      await input.storage.removeItem(input.storageKey);
+    },
+  };
+}
+
+export interface DraftKeyContext {
+  selectedServerId: string | null;
+}
+
+export type DraftKeyInput = string | ((context: DraftKeyContext) => string);
+
+export function resolveDraftKey(input: {
+  draftKey: DraftKeyInput;
+  selectedServerId: string | null;
+}): string {
+  if (typeof input.draftKey === "function") {
+    return input.draftKey({ selectedServerId: input.selectedServerId });
+  }
+  return input.draftKey;
+}
+
+export function resolveEffectiveComposerModelId(input: {
+  selectedModel: string;
+  availableModels: AgentModelDefinition[];
+}): string {
+  return input.selectedModel.trim();
+}
+
+export function resolveEffectiveComposerThinkingOptionId(input: {
+  selectedThinkingOptionId: string;
+  availableModels: AgentModelDefinition[];
+  effectiveModelId: string;
+}): string {
+  const selectedThinkingOptionId = input.selectedThinkingOptionId.trim();
+  if (selectedThinkingOptionId) {
+    return selectedThinkingOptionId;
+  }
+
+  const selectedModelDefinition =
+    input.availableModels.find((model) => model.id === input.effectiveModelId) ?? null;
+  return selectedModelDefinition?.defaultThinkingOptionId ?? "";
+}
+
+export function buildDraftComposerCommandConfig(input: {
+  provider: AgentProvider | null;
+  cwd: string;
+  modeOptions: DraftAgentStatusBarProps["modeOptions"];
+  selectedMode: string;
+  effectiveModelId: string;
+  effectiveThinkingOptionId: string;
+  featureValues?: Record<string, unknown>;
+}): DraftCommandConfig | undefined {
+  const cwd = input.cwd.trim();
+  if (!input.provider || !cwd) {
+    return undefined;
+  }
+
+  return {
+    provider: input.provider,
+    cwd,
+    ...(input.modeOptions.length > 0 && input.selectedMode !== ""
+      ? { modeId: input.selectedMode }
+      : {}),
+    ...(input.effectiveModelId ? { model: input.effectiveModelId } : {}),
+    ...(input.effectiveThinkingOptionId
+      ? { thinkingOptionId: input.effectiveThinkingOptionId }
+      : {}),
+    ...(input.featureValues ? { featureValues: input.featureValues } : {}),
+  };
+}
+
+export function buildDraftStatusControls(input: {
+  formState: UseAgentFormStateResult;
+  features?: DraftAgentStatusBarProps["features"];
+  onSetFeature?: DraftAgentStatusBarProps["onSetFeature"];
+  onDropdownClose?: DraftAgentStatusBarProps["onDropdownClose"];
+}): DraftAgentStatusBarProps {
+  const { formState, features, onSetFeature, onDropdownClose } = input;
+  return {
+    providerDefinitions: formState.providerDefinitions,
+    selectedProvider: formState.selectedProvider,
+    onSelectProvider: formState.setProviderFromUser,
+    modeOptions: formState.modeOptions,
+    selectedMode: formState.selectedMode,
+    onSelectMode: formState.setModeFromUser,
+    models: formState.availableModels,
+    selectedModel: formState.selectedModel,
+    onSelectModel: formState.setModelFromUser,
+    isModelLoading: formState.isModelLoading,
+    allProviderModels: formState.allProviderModels,
+    isAllModelsLoading: formState.isAllModelsLoading,
+    onSelectProviderAndModel: formState.setProviderAndModelFromUser,
+    thinkingOptions: formState.availableThinkingOptions,
+    selectedThinkingOptionId: formState.selectedThinkingOptionId,
+    onSelectThinkingOption: formState.setThinkingOptionFromUser,
+    features,
+    onSetFeature,
+    onDropdownClose,
+    onModelSelectorOpen: formState.refetchProviderModelsIfStale,
+  };
+}
+
+export function hasDraftContent(input: {
+  text: string;
+  attachments: UserComposerAttachment[];
+  cwd: string;
+}): boolean {
+  return (
+    input.text.trim().length > 0 || input.attachments.length > 0 || input.cwd.trim().length > 0
+  );
+}
+
+export function areAttachmentsEqual(input: {
+  left: UserComposerAttachment[];
+  right: UserComposerAttachment[];
+}): boolean {
+  if (input.left.length !== input.right.length) {
+    return false;
+  }
+
+  return input.left.every((attachment, index) => {
+    const other = input.right[index];
+    return JSON.stringify(attachment) === JSON.stringify(other);
+  });
+}
diff --git a/packages/app/src/hooks/use-agent-input-draft.test.ts b/packages/app/src/hooks/use-agent-input-draft.test.ts
index b766b0ffd..b373626fb 100644
--- a/packages/app/src/hooks/use-agent-input-draft.test.ts
+++ b/packages/app/src/hooks/use-agent-input-draft.test.ts
@@ -1,194 +1,188 @@
-import { beforeAll, describe, expect, it, vi } from "vitest";
+import { describe, expect, it } from "vitest";
+import {
+  buildDraftComposerCommandConfig,
+  createAgentInputDraftCore,
+  resolveDraftKey,
+  resolveEffectiveComposerModelId,
+  resolveEffectiveComposerThinkingOptionId,
+} from "./use-agent-input-draft-core";
 
-vi.mock("@react-native-async-storage/async-storage", () => ({
-  default: {
-    getItem: async () => null,
-    setItem: async () => undefined,
-    removeItem: async () => undefined,
-  },
-}));
-
-vi.mock("@/attachments/service", () => ({
-  garbageCollectAttachments: async () => undefined,
-}));
-
-vi.mock("./use-agent-form-state", () => ({
-  useAgentFormState: () => ({
-    selectedServerId: "host-1",
-    setSelectedServerId: () => undefined,
-    setSelectedServerIdFromUser: () => undefined,
-    selectedProvider: "codex",
-    setProviderFromUser: () => undefined,
-    selectedMode: "auto",
-    setModeFromUser: () => undefined,
-    selectedModel: "",
-    setModelFromUser: () => undefined,
-    selectedThinkingOptionId: "",
-    setThinkingOptionFromUser: () => undefined,
-    workingDir: "/repo",
-    setWorkingDir: () => undefined,
-    setWorkingDirFromUser: () => undefined,
-    providerDefinitions: [{ id: "codex", label: "Codex", modes: [{ id: "auto", label: "Auto" }] }],
-    providerDefinitionMap: new Map(),
-    agentDefinition: undefined,
-    modeOptions: [{ id: "auto", label: "Auto" }],
-    availableModels: [],
-    allProviderModels: new Map(),
-    isAllModelsLoading: false,
-    availableThinkingOptions: [],
-    isModelLoading: false,
-    modelError: null,
-    refreshProviderModels: () => undefined,
-    setProviderAndModelFromUser: () => undefined,
-    workingDirIsEmpty: false,
-    persistFormPreferences: async () => undefined,
-  }),
-}));
-
-let __private__: typeof import("./use-agent-input-draft").__private__;
-
-beforeAll(async () => {
-  const storage = new Map<string, string>();
-  Object.defineProperty(globalThis, "window", {
-    value: {
-      localStorage: {
-        getItem: (key: string) => storage.get(key) ?? null,
-        setItem: (key: string, value: string) => {
-          storage.set(key, value);
-        },
-        removeItem: (key: string) => {
-          storage.delete(key);
-        },
-      },
+function makeStorage() {
+  const map = new Map<string, string>();
+  return {
+    getItem: async (key: string) => map.get(key) ?? null,
+    setItem: async (key: string, value: string) => {
+      map.set(key, value);
     },
-    configurable: true,
+    removeItem: async (key: string) => {
+      map.delete(key);
+    },
+  };
+}
+
+describe("resolveDraftKey", () => {
+  it("returns a string draft key unchanged", () => {
+    expect(
+      resolveDraftKey({
+        draftKey: "draft:key",
+        selectedServerId: "host-1",
+      }),
+    ).toBe("draft:key");
   });
 
-  ({ __private__ } = await import("./use-agent-input-draft"));
+  it("resolves a computed draft key from the selected server", () => {
+    expect(
+      resolveDraftKey({
+        draftKey: ({ selectedServerId }) => `draft:${selectedServerId ?? "none"}`,
+        selectedServerId: "host-1",
+      }),
+    ).toBe("draft:host-1");
+  });
 });
 
-describe("useAgentInputDraft", () => {
-  describe("__private__.resolveDraftKey", () => {
-    it("returns an object draft key string unchanged", () => {
-      expect(
-        __private__.resolveDraftKey({
-          draftKey: "draft:key",
-          selectedServerId: "host-1",
-        }),
-      ).toBe("draft:key");
-    });
-
-    it("resolves a computed draft key from the selected server", () => {
-      expect(
-        __private__.resolveDraftKey({
-          draftKey: ({ selectedServerId }) => `draft:${selectedServerId ?? "none"}`,
-          selectedServerId: "host-1",
-        }),
-      ).toBe("draft:host-1");
-    });
+describe("resolveEffectiveComposerModelId", () => {
+  it("returns the selected model trimmed", () => {
+    expect(
+      resolveEffectiveComposerModelId({
+        selectedModel: "  gpt-5.4-mini  ",
+        availableModels: [],
+      }),
+    ).toBe("gpt-5.4-mini");
   });
 
-  describe("__private__.resolveEffectiveComposerModelId", () => {
-    const models = [
-      {
-        provider: "codex",
-        id: "gpt-5.4",
-        label: "gpt-5.4",
-        isDefault: true,
-      },
-      {
-        provider: "codex",
-        id: "gpt-5.4-mini",
-        label: "gpt-5.4-mini",
-      },
-    ];
+  it("returns empty string when no model selected", () => {
+    expect(
+      resolveEffectiveComposerModelId({
+        selectedModel: "",
+        availableModels: [],
+      }),
+    ).toBe("");
+  });
+});
 
-    it("prefers the selected model when present", () => {
-      expect(
-        __private__.resolveEffectiveComposerModelId({
-          selectedModel: "gpt-5.4-mini",
-          availableModels: models,
-        }),
-      ).toBe("gpt-5.4-mini");
-    });
+describe("resolveEffectiveComposerThinkingOptionId", () => {
+  const models = [
+    {
+      provider: "codex",
+      id: "gpt-5.4",
+      label: "gpt-5.4",
+      isDefault: true,
+      defaultThinkingOptionId: "high",
+      thinkingOptions: [
+        { id: "medium", label: "Medium" },
+        { id: "high", label: "High", isDefault: true },
+      ],
+    },
+  ];
 
-    it("returns empty string when no model selected", () => {
-      expect(
-        __private__.resolveEffectiveComposerModelId({
-          selectedModel: "",
-          availableModels: models,
-        }),
-      ).toBe("");
-    });
+  it("prefers the selected thinking option when present", () => {
+    expect(
+      resolveEffectiveComposerThinkingOptionId({
+        selectedThinkingOptionId: "medium",
+        availableModels: models,
+        effectiveModelId: "gpt-5.4",
+      }),
+    ).toBe("medium");
   });
 
-  describe("__private__.resolveEffectiveComposerThinkingOptionId", () => {
-    const models = [
-      {
+  it("falls back to the model default thinking option", () => {
+    expect(
+      resolveEffectiveComposerThinkingOptionId({
+        selectedThinkingOptionId: "",
+        availableModels: models,
+        effectiveModelId: "gpt-5.4",
+      }),
+    ).toBe("high");
+  });
+});
+
+describe("buildDraftComposerCommandConfig", () => {
+  it("returns undefined when cwd is empty", () => {
+    expect(
+      buildDraftComposerCommandConfig({
         provider: "codex",
-        id: "gpt-5.4",
-        label: "gpt-5.4",
-        isDefault: true,
-        defaultThinkingOptionId: "high",
-        thinkingOptions: [
-          { id: "medium", label: "Medium" },
-          { id: "high", label: "High", isDefault: true },
-        ],
-      },
-    ];
-
-    it("prefers the selected thinking option when present", () => {
-      expect(
-        __private__.resolveEffectiveComposerThinkingOptionId({
-          selectedThinkingOptionId: "medium",
-          availableModels: models,
-          effectiveModelId: "gpt-5.4",
-        }),
-      ).toBe("medium");
-    });
-
-    it("falls back to the model default thinking option", () => {
-      expect(
-        __private__.resolveEffectiveComposerThinkingOptionId({
-          selectedThinkingOptionId: "",
-          availableModels: models,
-          effectiveModelId: "gpt-5.4",
-        }),
-      ).toBe("high");
-    });
+        cwd: "  ",
+        modeOptions: [],
+        selectedMode: "",
+        effectiveModelId: "gpt-5.4",
+        effectiveThinkingOptionId: "high",
+      }),
+    ).toBeUndefined();
   });
 
-  describe("__private__.buildDraftComposerCommandConfig", () => {
-    it("returns undefined when cwd is empty", () => {
-      expect(
-        __private__.buildDraftComposerCommandConfig({
-          provider: "codex",
-          cwd: "  ",
-          modeOptions: [],
-          selectedMode: "",
-          effectiveModelId: "gpt-5.4",
-          effectiveThinkingOptionId: "high",
-        }),
-      ).toBeUndefined();
-    });
-
-    it("builds the draft command config from derived composer state", () => {
-      expect(
-        __private__.buildDraftComposerCommandConfig({
-          provider: "codex",
-          cwd: "/repo",
-          modeOptions: [{ id: "auto", label: "Auto" }],
-          selectedMode: "auto",
-          effectiveModelId: "gpt-5.4",
-          effectiveThinkingOptionId: "high",
-        }),
-      ).toEqual({
+  it("builds the draft command config from derived composer state", () => {
+    expect(
+      buildDraftComposerCommandConfig({
         provider: "codex",
         cwd: "/repo",
-        modeId: "auto",
-        model: "gpt-5.4",
-        thinkingOptionId: "high",
-      });
+        modeOptions: [{ id: "auto", label: "Auto" }],
+        selectedMode: "auto",
+        effectiveModelId: "gpt-5.4",
+        effectiveThinkingOptionId: "high",
+      }),
+    ).toEqual({
+      provider: "codex",
+      cwd: "/repo",
+      modeId: "auto",
+      model: "gpt-5.4",
+      thinkingOptionId: "high",
     });
   });
 });
+
+describe("createAgentInputDraftCore", () => {
+  it("load returns null when nothing has been saved", async () => {
+    const core = createAgentInputDraftCore({ storage: makeStorage(), storageKey: "test" });
+    expect(await core.load()).toBeNull();
+  });
+
+  it("load returns the draft that was saved", async () => {
+    const core = createAgentInputDraftCore({ storage: makeStorage(), storageKey: "test" });
+    await core.save({ text: "hello world", attachments: [], cwd: "/repo" });
+    expect(await core.load()).toEqual({ text: "hello world", attachments: [], cwd: "/repo" });
+  });
+
+  it("clear removes the persisted draft", async () => {
+    const core = createAgentInputDraftCore({ storage: makeStorage(), storageKey: "test" });
+    await core.save({ text: "hello", attachments: [], cwd: "/repo" });
+    await core.clear();
+    expect(await core.load()).toBeNull();
+  });
+
+  it("load seeds cwd from initialCwd when cwd is absent from stored data", async () => {
+    const storage = makeStorage();
+    await storage.setItem("test", JSON.stringify({ text: "hello", attachments: [] }));
+
+    const core = createAgentInputDraftCore({ storage, storageKey: "test" });
+    const draft = await core.load("/initial");
+    expect(draft?.cwd).toBe("/initial");
+  });
+
+  it("round-trips attachments unchanged", async () => {
+    const attachment = {
+      kind: "github_issue" as const,
+      item: {
+        kind: "issue" as const,
+        number: 42,
+        title: "Unify attachments",
+        url: "https://github.com/example/repo/issues/42",
+        state: "open" as const,
+        body: "body",
+        labels: ["composer"],
+      },
+    };
+    const core = createAgentInputDraftCore({ storage: makeStorage(), storageKey: "test" });
+    await core.save({ text: "", attachments: [attachment], cwd: "/repo" });
+    const draft = await core.load();
+    expect(draft?.attachments).toEqual([attachment]);
+  });
+
+  it("isolated keys do not share state", async () => {
+    const storage = makeStorage();
+    const a = createAgentInputDraftCore({ storage, storageKey: "key-a" });
+    const b = createAgentInputDraftCore({ storage, storageKey: "key-b" });
+    await a.save({ text: "from a", attachments: [], cwd: "" });
+    expect(await b.load()).toBeNull();
+    expect(await a.load()).toMatchObject({ text: "from a" });
+  });
+});
diff --git a/packages/app/src/hooks/use-agent-input-draft.ts b/packages/app/src/hooks/use-agent-input-draft.ts
index 0fab4135b..d1b0c1ef9 100644
--- a/packages/app/src/hooks/use-agent-input-draft.ts
+++ b/packages/app/src/hooks/use-agent-input-draft.ts
@@ -8,9 +8,17 @@ import {
   type UseAgentFormStateResult,
 } from "@/hooks/use-agent-form-state";
 import { useDraftAgentFeatures } from "@/hooks/use-draft-agent-features";
+import {
+  areAttachmentsEqual,
+  buildDraftComposerCommandConfig,
+  buildDraftStatusControls,
+  hasDraftContent,
+  resolveDraftKey,
+  resolveEffectiveComposerModelId,
+  resolveEffectiveComposerThinkingOptionId,
+  type DraftKeyInput,
+} from "@/hooks/use-agent-input-draft-core";
 import { useDraftStore } from "@/stores/draft-store";
-import type { AgentModelDefinition } from "@server/server/agent/agent-sdk-types";
-import type { AgentProvider } from "@server/server/agent/agent-sdk-types";
 
 type AttachmentUpdater =
   | UserComposerAttachment[]
@@ -24,12 +32,6 @@ interface AgentInputDraftComposerOptions {
   lockedWorkingDir?: string;
 }
 
-interface DraftKeyContext {
-  selectedServerId: string | null;
-}
-
-type DraftKeyInput = string | ((context: DraftKeyContext) => string);
-
 interface UseAgentInputDraftInput {
   draftKey: DraftKeyInput;
   initialCwd?: string;
@@ -57,121 +59,6 @@ interface AgentInputDraft {
   composerState: DraftComposerState | null;
 }
 
-function hasDraftContent(input: {
-  text: string;
-  attachments: UserComposerAttachment[];
-  cwd: string;
-}): boolean {
-  return (
-    input.text.trim().length > 0 || input.attachments.length > 0 || input.cwd.trim().length > 0
-  );
-}
-
-function areAttachmentsEqual(input: {
-  left: UserComposerAttachment[];
-  right: UserComposerAttachment[];
-}): boolean {
-  if (input.left.length !== input.right.length) {
-    return false;
-  }
-
-  return input.left.every((attachment, index) => {
-    const other = input.right[index];
-    return JSON.stringify(attachment) === JSON.stringify(other);
-  });
-}
-
-function resolveDraftKey(input: {
-  draftKey: DraftKeyInput;
-  selectedServerId: string | null;
-}): string {
-  if (typeof input.draftKey === "function") {
-    return input.draftKey({ selectedServerId: input.selectedServerId });
-  }
-  return input.draftKey;
-}
-
-function resolveEffectiveComposerModelId(input: {
-  selectedModel: string;
-  availableModels: AgentModelDefinition[];
-}): string {
-  return input.selectedModel.trim();
-}
-
-function resolveEffectiveComposerThinkingOptionId(input: {
-  selectedThinkingOptionId: string;
-  availableModels: AgentModelDefinition[];
-  effectiveModelId: string;
-}): string {
-  const selectedThinkingOptionId = input.selectedThinkingOptionId.trim();
-  if (selectedThinkingOptionId) {
-    return selectedThinkingOptionId;
-  }
-
-  const selectedModelDefinition =
-    input.availableModels.find((model) => model.id === input.effectiveModelId) ?? null;
-  return selectedModelDefinition?.defaultThinkingOptionId ?? "";
-}
-
-function buildDraftComposerCommandConfig(input: {
-  provider: AgentProvider | null;
-  cwd: string;
-  modeOptions: DraftAgentStatusBarProps["modeOptions"];
-  selectedMode: string;
-  effectiveModelId: string;
-  effectiveThinkingOptionId: string;
-  featureValues?: Record<string, unknown>;
-}): DraftCommandConfig | undefined {
-  const cwd = input.cwd.trim();
-  if (!input.provider || !cwd) {
-    return undefined;
-  }
-
-  return {
-    provider: input.provider,
-    cwd,
-    ...(input.modeOptions.length > 0 && input.selectedMode !== ""
-      ? { modeId: input.selectedMode }
-      : {}),
-    ...(input.effectiveModelId ? { model: input.effectiveModelId } : {}),
-    ...(input.effectiveThinkingOptionId
-      ? { thinkingOptionId: input.effectiveThinkingOptionId }
-      : {}),
-    ...(input.featureValues ? { featureValues: input.featureValues } : {}),
-  };
-}
-
-function buildDraftStatusControls(input: {
-  formState: UseAgentFormStateResult;
-  features?: DraftAgentStatusBarProps["features"];
-  onSetFeature?: DraftAgentStatusBarProps["onSetFeature"];
-  onDropdownClose?: DraftAgentStatusBarProps["onDropdownClose"];
-}): DraftAgentStatusBarProps {
-  const { formState, features, onSetFeature, onDropdownClose } = input;
-  return {
-    providerDefinitions: formState.providerDefinitions,
-    selectedProvider: formState.selectedProvider,
-    onSelectProvider: formState.setProviderFromUser,
-    modeOptions: formState.modeOptions,
-    selectedMode: formState.selectedMode,
-    onSelectMode: formState.setModeFromUser,
-    models: formState.availableModels,
-    selectedModel: formState.selectedModel,
-    onSelectModel: formState.setModelFromUser,
-    isModelLoading: formState.isModelLoading,
-    allProviderModels: formState.allProviderModels,
-    isAllModelsLoading: formState.isAllModelsLoading,
-    onSelectProviderAndModel: formState.setProviderAndModelFromUser,
-    thinkingOptions: formState.availableThinkingOptions,
-    selectedThinkingOptionId: formState.selectedThinkingOptionId,
-    onSelectThinkingOption: formState.setThinkingOptionFromUser,
-    features,
-    onSetFeature,
-    onDropdownClose,
-    onModelSelectorOpen: formState.refetchProviderModelsIfStale,
-  };
-}
-
 export function useAgentInputDraft(input: UseAgentInputDraftInput): AgentInputDraft {
   const composerOptions = input.composer ?? null;
   const formState = useAgentFormState({