diff --git a/src/features/chat/view-model.ts b/src/features/chat/view-model.ts
index 5f8c72c0..c3326e00 100644
--- a/src/features/chat/view-model.ts
+++ b/src/features/chat/view-model.ts
@@ -1,4 +1,5 @@
 import type { Thread } from "../../generated/app-server/v2/Thread";
+import type { ReasoningEffort } from "../../generated/app-server/ReasoningEffort";
 import type { RuntimeSnapshot } from "../../runtime/state";
 import {
   autoReviewActive,
@@ -11,6 +12,7 @@ import {
   supportedReasoningEfforts,
 } from "../../runtime/state";
 import { readRuntimeConfig } from "../../runtime/config";
+import { sortedAvailableModels } from "../../runtime/model";
 import { compactContextLabel } from "../../runtime/settings";
 import { contextSummary, effectiveConfigSections, rateLimitSummary } from "../../runtime/view";
 import { getThreadTitle } from "../../domain/threads/model";
@@ -43,6 +45,13 @@ export interface ConnectionDiagnosticsModelInput {
   configuredCommand: string;
 }
 
+export interface RuntimeToolbarChoicesInput {
+  state: ChatState;
+  snapshot: RuntimeSnapshot;
+  setRequestedModel: (model: string | null) => void;
+  setRequestedReasoningEffort: (effort: ReasoningEffort | null) => void;
+}
+
 export function runtimeSnapshotForChatState({ state }: RuntimeSnapshotInput): RuntimeSnapshot {
   return {
     effectiveConfig: state.effectiveConfig,
@@ -66,6 +75,37 @@ export function runtimeSnapshotForChatState({ state }: RuntimeSnapshotInput): Ru
   };
 }
 
+export function runtimeToolbarChoices(input: RuntimeToolbarChoicesInput): Pick<ToolbarViewModel, "modelChoices" | "effortChoices"> {
+  const config = readRuntimeConfig(input.state.effectiveConfig);
+  const activeModel = currentModel(input.snapshot, config);
+  const models = sortedAvailableModels(input.state.availableModels);
+  const modelChoices: ToolbarChoice[] = models.slice(0, 12).map((model) => ({
+    label: model.model,
+    selected: activeModel === model.model,
+    onClick: () => {
+      input.setRequestedModel(model.model);
+    },
+  }));
+  if (models.length === 0) {
+    modelChoices.push({
+      label: "No model list available.",
+      disabled: true,
+      onClick: () => undefined,
+    });
+  }
+
+  const activeEffort = currentReasoningEffort(input.snapshot, config);
+  const effortChoices: ToolbarChoice[] = supportedReasoningEfforts(input.snapshot).map((effort) => ({
+    label: effort,
+    selected: activeEffort === effort,
+    onClick: () => {
+      input.setRequestedReasoningEffort(effort);
+    },
+  }));
+
+  return { modelChoices, effortChoices };
+}
+
 export function toolbarViewModel(input: ToolbarViewModelInput): ToolbarViewModel {
   const { state, snapshot } = input;
   const config = readRuntimeConfig(state.effectiveConfig);
diff --git a/src/features/chat/view.ts b/src/features/chat/view.ts
index 99d9357f..d7bb8696 100644
--- a/src/features/chat/view.ts
+++ b/src/features/chat/view.ts
@@ -17,9 +17,7 @@ import type { ThreadResumeResponse } from "../../generated/app-server/v2/ThreadR
 import type { UserInput } from "../../generated/app-server/v2/UserInput";
 import { collaborationModeLabel as formatCollaborationModeLabel } from "../../runtime/collaboration-mode";
 import { ChatController } from "./chat-controller";
-import { currentModel, currentReasoningEffort, supportedReasoningEfforts, type RuntimeSnapshot } from "../../runtime/state";
-import { readRuntimeConfig } from "../../runtime/config";
-import { sortedAvailableModels } from "../../runtime/model";
+import { currentModel, type RuntimeSnapshot } from "../../runtime/state";
 import { executeSlashCommand as runSlashCommand, type SlashCommandExecutionResult } from "./slash-commands";
 import type { ThreadReferenceInput } from "./slash-commands";
 import { mcpStatusLines } from "./mcp-status";
@@ -48,7 +46,7 @@ import {
   type ReferencedThreadDisplay,
 } from "../../domain/threads/reference";
 import { pendingRequestMessageNode } from "./ui/pending-request-message";
-import { renderToolbar, type ToolbarChoice, type ToolbarViewModel } from "./ui/toolbar";
+import { renderToolbar, type ToolbarViewModel } from "./ui/toolbar";
 import { renderChatPanelShell, unmountChatPanelShell } from "./ui/shell";
 import type { ChatTurnDiffViewState } from "./ui/turn-diff";
 import { ChatMessageRenderer, type ChatMessageScrollIntent } from "./chat-message-renderer";
@@ -62,6 +60,7 @@ import {
   connectionDiagnosticsModel,
   effortStatusLines as buildEffortStatusLines,
   modelStatusLines as buildModelStatusLines,
+  runtimeToolbarChoices,
   runtimeSnapshotForChatState,
   statusSummaryLines as buildStatusSummaryLines,
   toolbarViewModel as buildToolbarViewModel,
@@ -1168,8 +1167,12 @@ export class CodexChatView extends ItemView {
       configuredCommand: this.plugin.settings.codexPath,
       archiveConfirmThreadId: this.archiveConfirmThreadId,
       archiveExportEnabled: this.plugin.settings.archiveExportEnabled,
-      modelChoices: this.modelToolbarChoices(),
-      effortChoices: this.effortToolbarChoices(),
+      ...runtimeToolbarChoices({
+        state: this.state,
+        snapshot: this.runtimeSnapshot(),
+        setRequestedModel: (model) => void this.setRequestedModelFromUi(model),
+        setRequestedReasoningEffort: (effort) => void this.setRequestedReasoningEffortFromUi(effort),
+      }),
       renameState: (threadId) => this.threadRename.editState(threadId),
     });
   }
@@ -1195,39 +1198,6 @@ export class CodexChatView extends ItemView {
     }
   }
 
-  private modelToolbarChoices(): ToolbarChoice[] {
-    const snapshot = this.runtimeSnapshot();
-    const config = readRuntimeConfig(this.state.effectiveConfig);
-    const activeModel = currentModel(snapshot, config);
-    const models = sortedAvailableModels(this.state.availableModels);
-    const choices: ToolbarChoice[] = [
-      ...models.slice(0, 12).map((model) => ({
-        label: model.model,
-        selected: activeModel === model.model,
-        onClick: () => void this.setRequestedModelFromUi(model.model),
-      })),
-    ];
-    if (models.length === 0) {
-      choices.push({
-        label: "No model list available.",
-        disabled: true,
-        onClick: () => undefined,
-      });
-    }
-    return choices;
-  }
-
-  private effortToolbarChoices(): ToolbarChoice[] {
-    const snapshot = this.runtimeSnapshot();
-    const config = readRuntimeConfig(this.state.effectiveConfig);
-    const activeEffort = currentReasoningEffort(snapshot, config);
-    return supportedReasoningEfforts(snapshot).map((effort) => ({
-      label: effort,
-      selected: activeEffort === effort,
-      onClick: () => void this.setRequestedReasoningEffortFromUi(effort),
-    }));
-  }
-
   private toggleHistoryPanel(): void {
     this.dispatch({ type: "ui/panel-set", panel: "history", toggle: true });
     this.scheduleRender();
diff --git a/tests/features/chat/view-model.test.ts b/tests/features/chat/view-model.test.ts
index 046a02b0..5f0ded79 100644
--- a/tests/features/chat/view-model.test.ts
+++ b/tests/features/chat/view-model.test.ts
@@ -4,6 +4,7 @@ import { createAppServerDiagnostics } from "../../../src/app-server/compatibilit
 import { createChatState } from "../../../src/features/chat/chat-state";
 import {
   effortStatusLines,
+  runtimeToolbarChoices,
   modelStatusLines,
   runtimeSnapshotForChatState,
   statusSummaryLines,
@@ -63,6 +64,36 @@ describe("chat view model", () => {
     expect(modelStatusLines(state, snapshot, "Default")).toContain("Mode: Default");
     expect(effortStatusLines(state, snapshot)).toContain("Supported: high");
   });
+
+  it("builds runtime toolbar choices from immutable chat state snapshots", () => {
+    const state = createChatState();
+    state.effectiveConfig = effectiveConfigFixture({ model: "gpt-5.5", model_reasoning_effort: "high" });
+    state.availableModels = [modelFixture("gpt-5.5"), modelFixture("gpt-5-mini")];
+    const selectedModels: (string | null)[] = [];
+    const selectedEfforts: string[] = [];
+
+    const choices = runtimeToolbarChoices({
+      state,
+      snapshot: runtimeSnapshotForChatState({ state }),
+      setRequestedModel: (model) => {
+        selectedModels.push(model);
+      },
+      setRequestedReasoningEffort: (effort) => {
+        if (effort) selectedEfforts.push(effort);
+      },
+    });
+
+    expect(choices.modelChoices).toMatchObject([
+      { label: "gpt-5-mini", selected: false },
+      { label: "gpt-5.5", selected: true },
+    ]);
+    expect(choices.effortChoices).toMatchObject([{ label: "high", selected: true }]);
+
+    choices.modelChoices[0]?.onClick();
+    choices.effortChoices[0]?.onClick();
+    expect(selectedModels).toEqual(["gpt-5-mini"]);
+    expect(selectedEfforts).toEqual(["high"]);
+  });
 });
 
 function effectiveConfigFixture(config: Record<string, unknown>): ConfigReadResponse {