diff --git a/src/browser/components/ChatInput/useCreationWorkspace.test.tsx b/src/browser/components/ChatInput/useCreationWorkspace.test.tsx
new file mode 100644
index 000000000..10ca8f982
--- /dev/null
+++ b/src/browser/components/ChatInput/useCreationWorkspace.test.tsx
@@ -0,0 +1,401 @@
+import type { DraftWorkspaceSettings } from "@/browser/hooks/useDraftWorkspaceSettings";
+import { getModeKey, getProjectScopeId, getThinkingLevelKey } from "@/common/constants/storage";
+import type { SendMessageError } from "@/common/types/errors";
+import type { BranchListResult, IPCApi, SendMessageOptions } from "@/common/types/ipc";
+import type { RuntimeMode } from "@/common/types/runtime";
+import type { FrontendWorkspaceMetadata } from "@/common/types/workspace";
+import { act, cleanup, render, waitFor } from "@testing-library/react";
+import { afterEach, beforeEach, describe, expect, mock, test } from "bun:test";
+import { GlobalWindow } from "happy-dom";
+import React from "react";
+
+const readPersistedStateCalls: Array<[string, unknown]> = [];
+let persistedPreferences: Record<string, unknown> = {};
+const readPersistedStateMock = mock((key: string, defaultValue: unknown) => {
+  readPersistedStateCalls.push([key, defaultValue]);
+  if (Object.prototype.hasOwnProperty.call(persistedPreferences, key)) {
+    return persistedPreferences[key];
+  }
+  return defaultValue;
+});
+
+const updatePersistedStateCalls: Array<[string, unknown]> = [];
+const updatePersistedStateMock = mock((key: string, value: unknown) => {
+  updatePersistedStateCalls.push([key, value]);
+});
+
+void mock.module("@/browser/hooks/usePersistedState", () => ({
+  readPersistedState: readPersistedStateMock,
+  updatePersistedState: updatePersistedStateMock,
+}));
+
+interface DraftSettingsInvocation {
+  projectPath: string;
+  branches: string[];
+  recommendedTrunk: string | null;
+}
+let draftSettingsInvocations: DraftSettingsInvocation[] = [];
+let draftSettingsState: DraftSettingsHarness;
+const useDraftWorkspaceSettingsMock = mock(
+  (projectPath: string, branches: string[], recommendedTrunk: string | null) => {
+    draftSettingsInvocations.push({ projectPath, branches, recommendedTrunk });
+    if (!draftSettingsState) {
+      throw new Error("Draft settings state not initialized");
+    }
+    return draftSettingsState.snapshot();
+  }
+);
+
+void mock.module("@/browser/hooks/useDraftWorkspaceSettings", () => ({
+  useDraftWorkspaceSettings: useDraftWorkspaceSettingsMock,
+}));
+
+let currentSendOptions: SendMessageOptions;
+const useSendMessageOptionsMock = mock(() => currentSendOptions);
+
+type WorkspaceSendMessage = IPCApi["workspace"]["sendMessage"];
+type WorkspaceSendMessageParams = Parameters<WorkspaceSendMessage>;
+void mock.module("@/browser/hooks/useSendMessageOptions", () => ({
+  useSendMessageOptions: useSendMessageOptionsMock,
+}));
+
+const TEST_PROJECT_PATH = "/projects/demo";
+const TEST_WORKSPACE_ID = "ws-created";
+const TEST_METADATA: FrontendWorkspaceMetadata = {
+  id: TEST_WORKSPACE_ID,
+  name: "demo-branch",
+  projectName: "Demo",
+  projectPath: TEST_PROJECT_PATH,
+  namedWorkspacePath: "/worktrees/demo/demo-branch",
+  runtimeConfig: { type: "local", srcBaseDir: "/home/user/.mux/src" },
+  createdAt: "2025-01-01T00:00:00.000Z",
+};
+
+import { useCreationWorkspace } from "./useCreationWorkspace";
+
+describe("useCreationWorkspace", () => {
+  beforeEach(() => {
+    persistedPreferences = {};
+    readPersistedStateCalls.length = 0;
+    updatePersistedStateCalls.length = 0;
+    draftSettingsInvocations = [];
+    draftSettingsState = createDraftSettingsHarness();
+    currentSendOptions = {
+      model: "gpt-4",
+      thinkingLevel: "medium",
+      mode: "exec",
+    } satisfies SendMessageOptions;
+  });
+
+  afterEach(() => {
+    cleanup();
+    // Reset global window/document/localStorage between tests
+    // @ts-expect-error - test cleanup
+    globalThis.window = undefined;
+    // @ts-expect-error - test cleanup
+    globalThis.document = undefined;
+    // @ts-expect-error - test cleanup
+    globalThis.localStorage = undefined;
+  });
+
+  test("loads branches when projectPath is provided", async () => {
+    const listBranchesMock = mock(
+      (): Promise<BranchListResult> =>
+        Promise.resolve({
+          branches: ["main", "dev"],
+          recommendedTrunk: "dev",
+        })
+    );
+    const { projectsApi } = setupWindow({ listBranches: listBranchesMock });
+    const onWorkspaceCreated = mock((metadata: FrontendWorkspaceMetadata) => metadata);
+
+    const getHook = renderUseCreationWorkspace({
+      projectPath: TEST_PROJECT_PATH,
+      onWorkspaceCreated,
+    });
+
+    await waitFor(() => expect(projectsApi.listBranches.mock.calls.length).toBe(1));
+    expect(projectsApi.listBranches.mock.calls[0][0]).toBe(TEST_PROJECT_PATH);
+
+    await waitFor(() => expect(getHook().branches).toEqual(["main", "dev"]));
+    expect(draftSettingsInvocations[0]).toEqual({
+      projectPath: TEST_PROJECT_PATH,
+      branches: [],
+      recommendedTrunk: null,
+    });
+    expect(draftSettingsInvocations.at(-1)).toEqual({
+      projectPath: TEST_PROJECT_PATH,
+      branches: ["main", "dev"],
+      recommendedTrunk: "dev",
+    });
+    expect(getHook().trunkBranch).toBe(draftSettingsState.state.trunkBranch);
+  });
+
+  test("does not load branches when projectPath is empty", async () => {
+    const listBranchesMock = mock(
+      (): Promise<BranchListResult> =>
+        Promise.resolve({
+          branches: ["main"],
+          recommendedTrunk: "main",
+        })
+    );
+    setupWindow({ listBranches: listBranchesMock });
+    const onWorkspaceCreated = mock((metadata: FrontendWorkspaceMetadata) => metadata);
+
+    const getHook = renderUseCreationWorkspace({
+      projectPath: "",
+      onWorkspaceCreated,
+    });
+
+    await waitFor(() => expect(draftSettingsInvocations.length).toBeGreaterThan(0));
+    expect(listBranchesMock.mock.calls.length).toBe(0);
+    expect(getHook().branches).toEqual([]);
+  });
+
+  test("handleSend sends message and syncs preferences on success", async () => {
+    const listBranchesMock = mock(
+      (): Promise<BranchListResult> =>
+        Promise.resolve({
+          branches: ["main"],
+          recommendedTrunk: "main",
+        })
+    );
+    const sendMessageMock = mock<WorkspaceSendMessage>((..._args: WorkspaceSendMessageParams) =>
+      Promise.resolve({
+        success: true as const,
+        workspaceId: TEST_WORKSPACE_ID,
+        metadata: TEST_METADATA,
+      })
+    );
+    const { workspaceApi } = setupWindow({
+      listBranches: listBranchesMock,
+      sendMessage: sendMessageMock,
+    });
+
+    persistedPreferences[getModeKey(getProjectScopeId(TEST_PROJECT_PATH))] = "plan";
+    persistedPreferences[getThinkingLevelKey(getProjectScopeId(TEST_PROJECT_PATH))] = "high";
+
+    draftSettingsState = createDraftSettingsHarness({
+      runtimeMode: "ssh",
+      sshHost: "example.com",
+      runtimeString: "ssh example.com",
+      trunkBranch: "dev",
+    });
+    const onWorkspaceCreated = mock((metadata: FrontendWorkspaceMetadata) => metadata);
+
+    const getHook = renderUseCreationWorkspace({
+      projectPath: TEST_PROJECT_PATH,
+      onWorkspaceCreated,
+    });
+
+    await waitFor(() => expect(getHook().branches).toEqual(["main"]));
+
+    await act(async () => {
+      await getHook().handleSend("launch workspace");
+    });
+
+    expect(workspaceApi.sendMessage.mock.calls.length).toBe(1);
+    const [workspaceId, message, options] = workspaceApi.sendMessage.mock.calls[0];
+    expect(workspaceId).toBeNull();
+    expect(message).toBe("launch workspace");
+    expect(options?.projectPath).toBe(TEST_PROJECT_PATH);
+    expect(options?.trunkBranch).toBe("dev");
+    expect(options?.model).toBe("gpt-4");
+    expect(options?.mode).toBe("exec");
+    expect(options?.thinkingLevel).toBe("medium");
+    expect(options?.runtimeConfig).toEqual({
+      type: "ssh",
+      host: "example.com",
+      srcBaseDir: "~/mux",
+    });
+
+    await waitFor(() => expect(onWorkspaceCreated.mock.calls.length).toBe(1));
+    expect(onWorkspaceCreated.mock.calls[0][0]).toEqual(TEST_METADATA);
+
+    const projectModeKey = getModeKey(getProjectScopeId(TEST_PROJECT_PATH));
+    const projectThinkingKey = getThinkingLevelKey(getProjectScopeId(TEST_PROJECT_PATH));
+    expect(readPersistedStateCalls).toContainEqual([projectModeKey, null]);
+    expect(readPersistedStateCalls).toContainEqual([projectThinkingKey, null]);
+
+    const modeKey = getModeKey(TEST_WORKSPACE_ID);
+    const thinkingKey = getThinkingLevelKey(TEST_WORKSPACE_ID);
+    expect(updatePersistedStateCalls).toContainEqual([modeKey, "plan"]);
+    expect(updatePersistedStateCalls).toContainEqual([thinkingKey, "high"]);
+  });
+
+  test("handleSend surfaces backend errors and resets state", async () => {
+    const sendMessageMock = mock<WorkspaceSendMessage>((..._args: WorkspaceSendMessageParams) =>
+      Promise.resolve({
+        success: false as const,
+        error: { type: "unknown", raw: "backend exploded" } satisfies SendMessageError,
+      })
+    );
+    setupWindow({ sendMessage: sendMessageMock });
+    draftSettingsState = createDraftSettingsHarness({ trunkBranch: "dev" });
+    const onWorkspaceCreated = mock((metadata: FrontendWorkspaceMetadata) => metadata);
+
+    const getHook = renderUseCreationWorkspace({
+      projectPath: TEST_PROJECT_PATH,
+      onWorkspaceCreated,
+    });
+
+    await act(async () => {
+      await getHook().handleSend("make workspace");
+    });
+
+    expect(sendMessageMock.mock.calls.length).toBe(1);
+    expect(onWorkspaceCreated.mock.calls.length).toBe(0);
+    await waitFor(() => expect(getHook().error).toBe("backend exploded"));
+    await waitFor(() => expect(getHook().isSending).toBe(false));
+    expect(updatePersistedStateCalls).toEqual([]);
+  });
+});
+
+type DraftSettingsHarness = ReturnType<typeof createDraftSettingsHarness>;
+
+function createDraftSettingsHarness(
+  initial?: Partial<{
+    runtimeMode: RuntimeMode;
+    sshHost: string;
+    trunkBranch: string;
+    runtimeString?: string | undefined;
+  }>
+) {
+  const state = {
+    runtimeMode: initial?.runtimeMode ?? ("local" as RuntimeMode),
+    sshHost: initial?.sshHost ?? "",
+    trunkBranch: initial?.trunkBranch ?? "main",
+    runtimeString: initial?.runtimeString,
+  } satisfies {
+    runtimeMode: RuntimeMode;
+    sshHost: string;
+    trunkBranch: string;
+    runtimeString: string | undefined;
+  };
+
+  const setRuntimeOptions = mock((mode: RuntimeMode, host: string) => {
+    state.runtimeMode = mode;
+    state.sshHost = host;
+    const trimmedHost = host.trim();
+    state.runtimeString = mode === "ssh" ? (trimmedHost ? `ssh ${trimmedHost}` : "ssh") : undefined;
+  });
+
+  const setTrunkBranch = mock((branch: string) => {
+    state.trunkBranch = branch;
+  });
+
+  const getRuntimeString = mock(() => state.runtimeString);
+
+  return {
+    state,
+    setRuntimeOptions,
+    setTrunkBranch,
+    getRuntimeString,
+    snapshot(): {
+      settings: DraftWorkspaceSettings;
+      setRuntimeOptions: typeof setRuntimeOptions;
+      setTrunkBranch: typeof setTrunkBranch;
+      getRuntimeString: typeof getRuntimeString;
+    } {
+      const settings: DraftWorkspaceSettings = {
+        model: "gpt-4",
+        thinkingLevel: "medium",
+        mode: "exec",
+        use1M: false,
+        runtimeMode: state.runtimeMode,
+        sshHost: state.sshHost,
+        trunkBranch: state.trunkBranch,
+      };
+      return {
+        settings,
+        setRuntimeOptions,
+        setTrunkBranch,
+        getRuntimeString,
+      };
+    },
+  };
+}
+
+interface SetupWindowOptions {
+  listBranches?: ReturnType<typeof mock<(projectPath: string) => Promise<BranchListResult>>>;
+  sendMessage?: ReturnType<
+    typeof mock<
+      (
+        workspaceId: string | null,
+        message: string,
+        options?: Parameters<typeof window.api.workspace.sendMessage>[2]
+      ) => ReturnType<typeof window.api.workspace.sendMessage>
+    >
+  >;
+}
+
+function setupWindow(options: SetupWindowOptions = {}) {
+  const windowInstance = new GlobalWindow();
+  const listBranches =
+    options.listBranches ??
+    mock((): Promise<BranchListResult> => Promise.resolve({ branches: [], recommendedTrunk: "" }));
+  const sendMessage =
+    options.sendMessage ??
+    mock(
+      (
+        _workspaceId: string | null,
+        _message: string,
+        _opts?: Parameters<typeof window.api.workspace.sendMessage>[2]
+      ) =>
+        Promise.resolve({
+          success: true as const,
+          workspaceId: TEST_WORKSPACE_ID,
+          metadata: TEST_METADATA,
+        })
+    );
+
+  globalThis.window = windowInstance as unknown as typeof globalThis.window;
+  const windowWithApi = globalThis.window as typeof globalThis.window & { api: IPCApi };
+  windowWithApi.api = {
+    projects: {
+      listBranches,
+    },
+    workspace: {
+      sendMessage,
+    },
+    platform: "test",
+    versions: {
+      node: "0",
+      chrome: "0",
+      electron: "0",
+    },
+  } as unknown as typeof windowWithApi.api;
+
+  globalThis.document = windowWithApi.document;
+  globalThis.localStorage = windowWithApi.localStorage;
+
+  return {
+    projectsApi: { listBranches },
+    workspaceApi: { sendMessage },
+  };
+}
+
+interface HookOptions {
+  projectPath: string;
+  onWorkspaceCreated: (metadata: FrontendWorkspaceMetadata) => void;
+}
+
+function renderUseCreationWorkspace(options: HookOptions) {
+  const resultRef: {
+    current: ReturnType<typeof useCreationWorkspace> | null;
+  } = { current: null };
+
+  function Harness(props: HookOptions) {
+    resultRef.current = useCreationWorkspace(props);
+    return null;
+  }
+
+  render(<Harness {...options} />);
+
+  return () => {
+    if (!resultRef.current) {
+      throw new Error("Hook result not initialized");
+    }
+    return resultRef.current;
+  };
+}