diff --git a/ui/src/ui/chat/session-controls.test.ts b/ui/src/ui/chat/session-controls.test.ts
new file mode 100644
index 00000000000..fc892693e3d
--- /dev/null
+++ b/ui/src/ui/chat/session-controls.test.ts
@@ -0,0 +1,276 @@
+/* @vitest-environment jsdom */
+
+import { render } from "lit";
+import { describe, expect, it, vi } from "vitest";
+import type { AppViewState } from "../app-view-state.ts";
+import {
+  createModelCatalog,
+  createSessionsListResult,
+  DEFAULT_CHAT_MODEL_CATALOG,
+} from "../chat-model.test-helpers.ts";
+import type { GatewayBrowserClient } from "../gateway.ts";
+import type { ModelCatalogEntry } from "../types.ts";
+import { renderChatSessionSelect } from "./session-controls.ts";
+
+function createChatHeaderState(
+  overrides: {
+    model?: string | null;
+    modelProvider?: string | null;
+    models?: ModelCatalogEntry[];
+    omitSessionFromList?: boolean;
+  } = {},
+): { state: AppViewState; request: ReturnType<typeof vi.fn> } {
+  let currentModel = overrides.model ?? null;
+  let currentModelProvider = overrides.modelProvider ?? (currentModel ? "openai" : null);
+  const omitSessionFromList = overrides.omitSessionFromList ?? false;
+  const catalog = overrides.models ?? createModelCatalog(...DEFAULT_CHAT_MODEL_CATALOG);
+  const request = vi.fn(async (method: string, params: Record<string, unknown>) => {
+    if (method === "sessions.patch") {
+      const nextModel = (params.model as string | null | undefined) ?? null;
+      if (!nextModel) {
+        currentModel = null;
+        currentModelProvider = null;
+      } else {
+        const normalized = nextModel.trim();
+        const slashIndex = normalized.indexOf("/");
+        if (slashIndex > 0) {
+          currentModelProvider = normalized.slice(0, slashIndex);
+          currentModel = normalized.slice(slashIndex + 1);
+        } else {
+          currentModel = normalized;
+          const matchingProviders = catalog
+            .filter((entry) => entry.id === normalized)
+            .map((entry) => entry.provider)
+            .filter(Boolean);
+          currentModelProvider =
+            matchingProviders.length === 1 ? matchingProviders[0] : currentModelProvider;
+        }
+      }
+      return { ok: true, key: "main" };
+    }
+    if (method === "chat.history") {
+      return { messages: [], thinkingLevel: null };
+    }
+    if (method === "sessions.list") {
+      return createSessionsListResult({
+        model: currentModel,
+        modelProvider: currentModelProvider,
+        omitSessionFromList,
+      });
+    }
+    if (method === "models.list") {
+      return { models: catalog };
+    }
+    if (method === "tools.effective") {
+      return {
+        agentId: "main",
+        profile: "coding",
+        groups: [],
+      };
+    }
+    throw new Error(`Unexpected request: ${method}`);
+  });
+  const state = {
+    sessionKey: "main",
+    connected: true,
+    sessionsHideCron: true,
+    sessionsResult: createSessionsListResult({
+      model: currentModel,
+      modelProvider: currentModelProvider,
+      omitSessionFromList,
+    }),
+    chatModelOverrides: {},
+    chatModelCatalog: catalog,
+    chatModelsLoading: false,
+    client: { request } as unknown as GatewayBrowserClient,
+    settings: {
+      gatewayUrl: "",
+      token: "",
+      locale: "en",
+      sessionKey: "main",
+      lastActiveSessionKey: "main",
+      theme: "claw",
+      themeMode: "dark",
+      splitRatio: 0.6,
+      navCollapsed: false,
+      navGroupsCollapsed: {},
+      borderRadius: 50,
+      chatFocusMode: false,
+      chatShowThinking: false,
+    },
+    chatMessage: "",
+    chatStream: null,
+    chatStreamStartedAt: null,
+    chatRunId: null,
+    chatQueue: [],
+    chatMessages: [],
+    chatLoading: false,
+    chatThinkingLevel: null,
+    lastError: null,
+    chatAvatarUrl: null,
+    basePath: "",
+    hello: null,
+    agentsList: null,
+    agentsPanel: "overview",
+    agentsSelectedId: null,
+    toolsEffectiveLoading: false,
+    toolsEffectiveLoadingKey: null,
+    toolsEffectiveResultKey: null,
+    toolsEffectiveError: null,
+    toolsEffectiveResult: null,
+    applySettings(next: AppViewState["settings"]) {
+      state.settings = next;
+    },
+    loadAssistantIdentity: vi.fn(),
+    resetToolStream: vi.fn(),
+    resetChatScroll: vi.fn(),
+  } as unknown as AppViewState & {
+    client: GatewayBrowserClient;
+    settings: AppViewState["settings"];
+  };
+  return { state, request };
+}
+
+function flushTasks() {
+  return new Promise<void>((resolve) => queueMicrotask(resolve));
+}
+
+describe("chat session controls", () => {
+  it("patches the current session model from the chat header picker", async () => {
+    vi.stubGlobal(
+      "fetch",
+      vi.fn().mockResolvedValue({
+        ok: false,
+      } satisfies Partial<Response>),
+    );
+    const { state, request } = createChatHeaderState();
+    const container = document.createElement("div");
+    render(renderChatSessionSelect(state), container);
+
+    const modelSelect = container.querySelector<HTMLSelectElement>(
+      'select[data-chat-model-select="true"]',
+    );
+    expect(modelSelect).not.toBeNull();
+    expect(modelSelect?.value).toBe("");
+
+    modelSelect!.value = "openai/gpt-5-mini";
+    modelSelect!.dispatchEvent(new Event("change", { bubbles: true }));
+    await flushTasks();
+
+    expect(request).toHaveBeenCalledWith("sessions.patch", {
+      key: "main",
+      model: "openai/gpt-5-mini",
+    });
+    expect(request).not.toHaveBeenCalledWith("chat.history", expect.anything());
+    expect(state.sessionsResult?.sessions[0]?.model).toBe("gpt-5-mini");
+    expect(state.sessionsResult?.sessions[0]?.modelProvider).toBe("openai");
+    vi.unstubAllGlobals();
+  });
+
+  it("reloads effective tools after a chat-header model switch for the active tools panel", async () => {
+    vi.stubGlobal(
+      "fetch",
+      vi.fn().mockResolvedValue({
+        ok: false,
+      } satisfies Partial<Response>),
+    );
+    const { state, request } = createChatHeaderState();
+    state.agentsPanel = "tools";
+    state.agentsSelectedId = "main";
+    state.toolsEffectiveResultKey = "main:main";
+    state.toolsEffectiveResult = {
+      agentId: "main",
+      profile: "coding",
+      groups: [],
+    };
+    const container = document.createElement("div");
+    render(renderChatSessionSelect(state), container);
+
+    const modelSelect = container.querySelector<HTMLSelectElement>(
+      'select[data-chat-model-select="true"]',
+    );
+    expect(modelSelect).not.toBeNull();
+
+    modelSelect!.value = "openai/gpt-5-mini";
+    modelSelect!.dispatchEvent(new Event("change", { bubbles: true }));
+    await flushTasks();
+
+    expect(request).toHaveBeenCalledWith("tools.effective", {
+      agentId: "main",
+      sessionKey: "main",
+    });
+    expect(state.toolsEffectiveResultKey).toBe("main:main:model=openai/gpt-5-mini");
+    vi.unstubAllGlobals();
+  });
+
+  it("clears the session model override back to the default model", async () => {
+    vi.stubGlobal(
+      "fetch",
+      vi.fn().mockResolvedValue({
+        ok: false,
+      } satisfies Partial<Response>),
+    );
+    const { state, request } = createChatHeaderState({ model: "gpt-5-mini" });
+    const container = document.createElement("div");
+    render(renderChatSessionSelect(state), container);
+
+    const modelSelect = container.querySelector<HTMLSelectElement>(
+      'select[data-chat-model-select="true"]',
+    );
+    expect(modelSelect).not.toBeNull();
+    expect(modelSelect?.value).toBe("openai/gpt-5-mini");
+
+    modelSelect!.value = "";
+    modelSelect!.dispatchEvent(new Event("change", { bubbles: true }));
+    await flushTasks();
+
+    expect(request).toHaveBeenCalledWith("sessions.patch", {
+      key: "main",
+      model: null,
+    });
+    expect(state.sessionsResult?.sessions[0]?.model).toBeUndefined();
+    vi.unstubAllGlobals();
+  });
+
+  it("disables the chat header model picker while a run is active", () => {
+    const { state } = createChatHeaderState();
+    state.chatRunId = "run-123";
+    state.chatStream = "Working";
+    const container = document.createElement("div");
+    render(renderChatSessionSelect(state), container);
+
+    const modelSelect = container.querySelector<HTMLSelectElement>(
+      'select[data-chat-model-select="true"]',
+    );
+    expect(modelSelect).not.toBeNull();
+    expect(modelSelect?.disabled).toBe(true);
+  });
+
+  it("keeps the selected model visible when the active session is absent from sessions.list", async () => {
+    vi.stubGlobal(
+      "fetch",
+      vi.fn().mockResolvedValue({
+        ok: false,
+      } satisfies Partial<Response>),
+    );
+    const { state } = createChatHeaderState({ omitSessionFromList: true });
+    const container = document.createElement("div");
+    render(renderChatSessionSelect(state), container);
+
+    const modelSelect = container.querySelector<HTMLSelectElement>(
+      'select[data-chat-model-select="true"]',
+    );
+    expect(modelSelect).not.toBeNull();
+
+    modelSelect!.value = "openai/gpt-5-mini";
+    modelSelect!.dispatchEvent(new Event("change", { bubbles: true }));
+    await flushTasks();
+    render(renderChatSessionSelect(state), container);
+
+    const rerendered = container.querySelector<HTMLSelectElement>(
+      'select[data-chat-model-select="true"]',
+    );
+    expect(rerendered?.value).toBe("openai/gpt-5-mini");
+    vi.unstubAllGlobals();
+  });
+});
diff --git a/ui/src/ui/views/chat.test.ts b/ui/src/ui/views/chat.test.ts
index 376d520f957..800717dc5cc 100644
--- a/ui/src/ui/views/chat.test.ts
+++ b/ui/src/ui/views/chat.test.ts
@@ -3,17 +3,8 @@
 import { render } from "lit";
 import { describe, expect, it, vi } from "vitest";
 import { getSafeLocalStorage } from "../../local-storage.ts";
-import type { AppViewState } from "../app-view-state.ts";
-import {
-  createModelCatalog,
-  createSessionsListResult,
-  DEFAULT_CHAT_MODEL_CATALOG,
-} from "../chat-model.test-helpers.ts";
 import { resetAssistantAttachmentAvailabilityCacheForTest } from "../chat/grouped-render.ts";
 import { normalizeMessage } from "../chat/message-normalizer.ts";
-import { renderChatSessionSelect } from "../chat/session-controls.ts";
-import type { GatewayBrowserClient } from "../gateway.ts";
-import type { ModelCatalogEntry } from "../types.ts";
 import type { SessionsListResult } from "../types.ts";
 import { renderChat, type ChatProps } from "./chat.ts";
 
@@ -27,125 +18,6 @@ function createSessions(): SessionsListResult {
   };
 }
 
-function createChatHeaderState(
-  overrides: {
-    model?: string | null;
-    modelProvider?: string | null;
-    models?: ModelCatalogEntry[];
-    omitSessionFromList?: boolean;
-  } = {},
-): { state: AppViewState; request: ReturnType<typeof vi.fn> } {
-  let currentModel = overrides.model ?? null;
-  let currentModelProvider = overrides.modelProvider ?? (currentModel ? "openai" : null);
-  const omitSessionFromList = overrides.omitSessionFromList ?? false;
-  const catalog = overrides.models ?? createModelCatalog(...DEFAULT_CHAT_MODEL_CATALOG);
-  const request = vi.fn(async (method: string, params: Record<string, unknown>) => {
-    if (method === "sessions.patch") {
-      const nextModel = (params.model as string | null | undefined) ?? null;
-      if (!nextModel) {
-        currentModel = null;
-        currentModelProvider = null;
-      } else {
-        const normalized = nextModel.trim();
-        const slashIndex = normalized.indexOf("/");
-        if (slashIndex > 0) {
-          currentModelProvider = normalized.slice(0, slashIndex);
-          currentModel = normalized.slice(slashIndex + 1);
-        } else {
-          currentModel = normalized;
-          const matchingProviders = catalog
-            .filter((entry) => entry.id === normalized)
-            .map((entry) => entry.provider)
-            .filter(Boolean);
-          currentModelProvider =
-            matchingProviders.length === 1 ? matchingProviders[0] : currentModelProvider;
-        }
-      }
-      return { ok: true, key: "main" };
-    }
-    if (method === "chat.history") {
-      return { messages: [], thinkingLevel: null };
-    }
-    if (method === "sessions.list") {
-      return createSessionsListResult({
-        model: currentModel,
-        modelProvider: currentModelProvider,
-        omitSessionFromList,
-      });
-    }
-    if (method === "models.list") {
-      return { models: catalog };
-    }
-    if (method === "tools.effective") {
-      return {
-        agentId: "main",
-        profile: "coding",
-        groups: [],
-      };
-    }
-    throw new Error(`Unexpected request: ${method}`);
-  });
-  const state = {
-    sessionKey: "main",
-    connected: true,
-    sessionsHideCron: true,
-    sessionsResult: createSessionsListResult({
-      model: currentModel,
-      modelProvider: currentModelProvider,
-      omitSessionFromList,
-    }),
-    chatModelOverrides: {},
-    chatModelCatalog: catalog,
-    chatModelsLoading: false,
-    client: { request } as unknown as GatewayBrowserClient,
-    settings: {
-      gatewayUrl: "",
-      token: "",
-      locale: "en",
-      sessionKey: "main",
-      lastActiveSessionKey: "main",
-      theme: "claw",
-      themeMode: "dark",
-      splitRatio: 0.6,
-      navCollapsed: false,
-      navGroupsCollapsed: {},
-      borderRadius: 50,
-      chatFocusMode: false,
-      chatShowThinking: false,
-    },
-    chatMessage: "",
-    chatStream: null,
-    chatStreamStartedAt: null,
-    chatRunId: null,
-    chatQueue: [],
-    chatMessages: [],
-    chatLoading: false,
-    chatThinkingLevel: null,
-    lastError: null,
-    chatAvatarUrl: null,
-    basePath: "",
-    hello: null,
-    agentsList: null,
-    agentsPanel: "overview",
-    agentsSelectedId: null,
-    toolsEffectiveLoading: false,
-    toolsEffectiveLoadingKey: null,
-    toolsEffectiveResultKey: null,
-    toolsEffectiveError: null,
-    toolsEffectiveResult: null,
-    applySettings(next: AppViewState["settings"]) {
-      state.settings = next;
-    },
-    loadAssistantIdentity: vi.fn(),
-    resetToolStream: vi.fn(),
-    resetChatScroll: vi.fn(),
-  } as unknown as AppViewState & {
-    client: GatewayBrowserClient;
-    settings: AppViewState["settings"];
-  };
-  return { state, request };
-}
-
 function flushTasks() {
   return new Promise<void>((resolve) => queueMicrotask(resolve));
 }
@@ -808,144 +680,6 @@ describe("chat view", () => {
     expect(confirm?.classList.contains("chat-delete-confirm--right")).toBe(true);
   });
 
-  it("patches the current session model from the chat header picker", async () => {
-    vi.stubGlobal(
-      "fetch",
-      vi.fn().mockResolvedValue({
-        ok: false,
-      } satisfies Partial<Response>),
-    );
-    const { state, request } = createChatHeaderState();
-    const container = document.createElement("div");
-    render(renderChatSessionSelect(state), container);
-
-    const modelSelect = container.querySelector<HTMLSelectElement>(
-      'select[data-chat-model-select="true"]',
-    );
-    expect(modelSelect).not.toBeNull();
-    expect(modelSelect?.value).toBe("");
-
-    modelSelect!.value = "openai/gpt-5-mini";
-    modelSelect!.dispatchEvent(new Event("change", { bubbles: true }));
-    await flushTasks();
-
-    expect(request).toHaveBeenCalledWith("sessions.patch", {
-      key: "main",
-      model: "openai/gpt-5-mini",
-    });
-    expect(request).not.toHaveBeenCalledWith("chat.history", expect.anything());
-    expect(state.sessionsResult?.sessions[0]?.model).toBe("gpt-5-mini");
-    expect(state.sessionsResult?.sessions[0]?.modelProvider).toBe("openai");
-    vi.unstubAllGlobals();
-  });
-
-  it("reloads effective tools after a chat-header model switch for the active tools panel", async () => {
-    vi.stubGlobal(
-      "fetch",
-      vi.fn().mockResolvedValue({
-        ok: false,
-      } satisfies Partial<Response>),
-    );
-    const { state, request } = createChatHeaderState();
-    state.agentsPanel = "tools";
-    state.agentsSelectedId = "main";
-    state.toolsEffectiveResultKey = "main:main";
-    state.toolsEffectiveResult = {
-      agentId: "main",
-      profile: "coding",
-      groups: [],
-    };
-    const container = document.createElement("div");
-    render(renderChatSessionSelect(state), container);
-
-    const modelSelect = container.querySelector<HTMLSelectElement>(
-      'select[data-chat-model-select="true"]',
-    );
-    expect(modelSelect).not.toBeNull();
-
-    modelSelect!.value = "openai/gpt-5-mini";
-    modelSelect!.dispatchEvent(new Event("change", { bubbles: true }));
-    await flushTasks();
-
-    expect(request).toHaveBeenCalledWith("tools.effective", {
-      agentId: "main",
-      sessionKey: "main",
-    });
-    expect(state.toolsEffectiveResultKey).toBe("main:main:model=openai/gpt-5-mini");
-    vi.unstubAllGlobals();
-  });
-
-  it("clears the session model override back to the default model", async () => {
-    vi.stubGlobal(
-      "fetch",
-      vi.fn().mockResolvedValue({
-        ok: false,
-      } satisfies Partial<Response>),
-    );
-    const { state, request } = createChatHeaderState({ model: "gpt-5-mini" });
-    const container = document.createElement("div");
-    render(renderChatSessionSelect(state), container);
-
-    const modelSelect = container.querySelector<HTMLSelectElement>(
-      'select[data-chat-model-select="true"]',
-    );
-    expect(modelSelect).not.toBeNull();
-    expect(modelSelect?.value).toBe("openai/gpt-5-mini");
-
-    modelSelect!.value = "";
-    modelSelect!.dispatchEvent(new Event("change", { bubbles: true }));
-    await flushTasks();
-
-    expect(request).toHaveBeenCalledWith("sessions.patch", {
-      key: "main",
-      model: null,
-    });
-    expect(state.sessionsResult?.sessions[0]?.model).toBeUndefined();
-    vi.unstubAllGlobals();
-  });
-
-  it("disables the chat header model picker while a run is active", () => {
-    const { state } = createChatHeaderState();
-    state.chatRunId = "run-123";
-    state.chatStream = "Working";
-    const container = document.createElement("div");
-    render(renderChatSessionSelect(state), container);
-
-    const modelSelect = container.querySelector<HTMLSelectElement>(
-      'select[data-chat-model-select="true"]',
-    );
-    expect(modelSelect).not.toBeNull();
-    expect(modelSelect?.disabled).toBe(true);
-  });
-
-  it("keeps the selected model visible when the active session is absent from sessions.list", async () => {
-    vi.stubGlobal(
-      "fetch",
-      vi.fn().mockResolvedValue({
-        ok: false,
-      } satisfies Partial<Response>),
-    );
-    const { state } = createChatHeaderState({ omitSessionFromList: true });
-    const container = document.createElement("div");
-    render(renderChatSessionSelect(state), container);
-
-    const modelSelect = container.querySelector<HTMLSelectElement>(
-      'select[data-chat-model-select="true"]',
-    );
-    expect(modelSelect).not.toBeNull();
-
-    modelSelect!.value = "openai/gpt-5-mini";
-    modelSelect!.dispatchEvent(new Event("change", { bubbles: true }));
-    await flushTasks();
-    render(renderChatSessionSelect(state), container);
-
-    const rerendered = container.querySelector<HTMLSelectElement>(
-      'select[data-chat-model-select="true"]',
-    );
-    expect(rerendered?.value).toBe("openai/gpt-5-mini");
-    vi.unstubAllGlobals();
-  });
-
   it("keeps tool cards collapsed by default and expands them inline on demand", async () => {
     const container = document.createElement("div");
     const props = createProps({