fix(control-ui): persist Set Default agent through config save

ui/src/ui/app-render.ts

@@ -53,6 +53,7 @@ import {
   resetToolsEffectiveState,
   refreshVisibleToolsEffectiveForCurrentSession,
   saveAgentsConfig,
+  setDefaultAgent,
 } from "./controllers/agents.ts";
 import { setAssistantAvatarOverride } from "./controllers/assistant-identity.ts";
 import { loadChannels } from "./controllers/channels.ts";
@@ -66,7 +67,6 @@ import {
   resetConfigPendingChanges,
   runUpdate,
   saveConfig,
-  stageDefaultAgentConfigEntry,
   stageConfigPreset,
   updateConfigRawValue,
   updateConfigFormValue,
@@ -3480,7 +3480,7 @@ export function renderApp(state: AppViewState) {
                   updateConfigFormValue(state, basePathResult, { primary, fallbacks: normalized });
                 },
                 onSetDefault: (agentId) => {
-                  stageDefaultAgentConfigEntry(state, agentId);
+                  void setDefaultAgent(state, agentId);
                 },
               }),
             )

ui/src/ui/controllers/agents.test.ts

@@ -1,6 +1,12 @@
 // Control UI tests cover agents behavior.
 import { describe, expect, it, vi } from "vitest";
-import { loadAgents, loadToolsCatalog, loadToolsEffective, saveAgentsConfig } from "./agents.ts";
+import {
+  loadAgents,
+  loadToolsCatalog,
+  loadToolsEffective,
+  saveAgentsConfig,
+  setDefaultAgent,
+} from "./agents.ts";
 import type { AgentsConfigSaveState, AgentsState } from "./agents.ts";
 
 type TestRequest = (method: string, payload?: unknown) => Promise<unknown>;
@@ -430,3 +436,72 @@ describe("saveAgentsConfig", () => {
     expect(state.agentsSelectedId).toBe("main");
   });
 });
+
+describe("setDefaultAgent", () => {
+  it("stages the canonical default flag and persists it through config.set", async () => {
+    const { state, request } = createSaveState();
+    state.configForm = { agents: { list: [{ id: "main" }, { id: "kimi" }] } };
+    state.configFormOriginal = { agents: { list: [{ id: "main" }, { id: "kimi" }] } };
+    state.configFormDirty = false;
+    request
+      .mockResolvedValueOnce(undefined)
+      .mockResolvedValueOnce({
+        hash: "hash-2",
+        raw: '{"agents":{"list":[{"id":"main"},{"id":"kimi","default":true}]}}',
+        config: { agents: { list: [{ id: "main" }, { id: "kimi", default: true }] } },
+        valid: true,
+        issues: [],
+      })
+      .mockResolvedValueOnce({
+        defaultId: "kimi",
+        mainKey: "main",
+        scope: "per-sender",
+        agents: [
+          { id: "main", name: "main" },
+          { id: "kimi", name: "kimi" },
+        ],
+      });
+
+    await setDefaultAgent(state, "kimi");
+
+    const [method, params] = requireFirstRequestCall(request);
+    const requestParams = requireRecord(params);
+    expect(method).toBe("config.set");
+    expect(JSON.parse(String(requestParams.raw))).toEqual({
+      agents: { list: [{ id: "main" }, { id: "kimi", default: true }] },
+    });
+  });
+
+  it("does not persist when the agent is absent from the config list", async () => {
+    const { state, request } = createSaveState();
+    state.configForm = { agents: { list: [{ id: "main" }] } };
+
+    await setDefaultAgent(state, "ghost");
+
+    expect(request).not.toHaveBeenCalled();
+  });
+
+  it("does not persist unrelated dirty agent config drafts", async () => {
+    const { state, request } = createSaveState();
+    state.configFormDirty = true;
+    state.configFormOriginal = { agents: { list: [{ id: "main" }, { id: "kimi" }] } };
+    state.configForm = {
+      agents: {
+        list: [{ id: "main", model: "gpt-5.5" }, { id: "kimi" }],
+      },
+    };
+
+    await setDefaultAgent(state, "kimi");
+
+    expect(request).not.toHaveBeenCalled();
+    expect(state.configForm).toEqual({
+      agents: {
+        list: [
+          { id: "main", model: "gpt-5.5" },
+          { id: "kimi", default: true },
+        ],
+      },
+    });
+    expect(state.configFormDirty).toBe(true);
+  });
+});

ui/src/ui/controllers/agents.ts

@@ -13,7 +13,7 @@ import type {
   ToolsCatalogResult,
   ToolsEffectiveResult,
 } from "../types.ts";
-import { saveConfig } from "./config.ts";
+import { saveConfig, stageDefaultAgentConfigEntry } from "./config.ts";
 import type { ConfigState } from "./config.ts";
 import {
   formatMissingOperatorReadScopeMessage,
@@ -246,3 +246,18 @@ export async function saveAgentsConfig(state: AgentsConfigSaveState) {
     state.agentsSelectedId = selectedBefore;
   }
 }
+
+export async function setDefaultAgent(
+  state: AgentsConfigSaveState,
+  agentId: string,
+): Promise<void> {
+  const hadPendingConfigDraft = state.configFormDirty;
+  // Set Default is a one-click action on a clean draft, but saveConfig serializes the
+  // whole form. If other edits were already dirty, keep them staged for the explicit
+  // Save button instead of committing unrelated pending config changes.
+  if (stageDefaultAgentConfigEntry(state, agentId)) {
+    if (!hadPendingConfigDraft && state.configFormDirty) {
+      await saveAgentsConfig(state);
+    }
+  }
+}

ui/src/ui/e2e/agents-set-default-persistence.e2e.test.ts

@@ -0,0 +1,106 @@
+// Control UI tests cover Agents page Set Default persistence behavior.
+import { chromium, type Browser } from "playwright";
+import { afterAll, beforeAll, describe, expect, it } from "vitest";
+import {
+  canRunPlaywrightChromium,
+  installMockGateway,
+  resolvePlaywrightChromiumExecutablePath,
+  startControlUiE2eServer,
+  type ControlUiE2eServer,
+  type MockGatewayRequest,
+} from "../../test-helpers/control-ui-e2e.ts";
+
+const chromiumExecutablePath = resolvePlaywrightChromiumExecutablePath(chromium.executablePath());
+const chromiumAvailable = canRunPlaywrightChromium(chromiumExecutablePath);
+const allowMissingChromium = process.env.OPENCLAW_UI_E2E_ALLOW_MISSING_CHROMIUM === "1";
+const describeControlUiE2e = chromiumAvailable || !allowMissingChromium ? describe : describe.skip;
+
+let browser: Browser;
+let server: ControlUiE2eServer;
+
+function requireRecord(value: unknown): Record<string, unknown> {
+  if (!value || typeof value !== "object" || Array.isArray(value)) {
+    throw new Error("Expected object value");
+  }
+  return value as Record<string, unknown>;
+}
+
+function requestParams(request: MockGatewayRequest): Record<string, unknown> {
+  return requireRecord(request.params);
+}
+
+describeControlUiE2e("Control UI agents Set Default mocked Gateway E2E", () => {
+  beforeAll(async () => {
+    if (!chromiumAvailable) {
+      throw new Error(
+        `Playwright Chromium is not installed or cannot start at ${chromiumExecutablePath}. Run \`pnpm --dir ui exec playwright install --with-deps chromium\`, or set OPENCLAW_UI_E2E_ALLOW_MISSING_CHROMIUM=1 only when intentionally skipping this lane.`,
+      );
+    }
+    server = await startControlUiE2eServer();
+    browser = await chromium.launch({ executablePath: chromiumExecutablePath });
+  });
+
+  afterAll(async () => {
+    await browser?.close();
+    await server?.close();
+  });
+
+  it("persists Set Default through config.set instead of only staging the form draft", async () => {
+    const context = await browser.newContext({
+      locale: "en-US",
+      serviceWorkers: "block",
+      viewport: { height: 900, width: 1280 },
+    });
+    const page = await context.newPage();
+    const gateway = await installMockGateway(page, {
+      assistantName: "Main agent",
+      defaultAgentId: "main",
+      methodResponses: {
+        "agents.list": {
+          agents: [
+            { id: "main", name: "Main agent" },
+            { id: "kimi", name: "Kimi agent" },
+          ],
+          defaultId: "main",
+          mainKey: "main",
+          scope: "agent",
+        },
+        "config.get": {
+          config: { agents: { list: [{ id: "main" }, { id: "kimi" }] } },
+          hash: "hash-1",
+          issues: [],
+          raw: '{"agents":{"list":[{"id":"main"},{"id":"kimi"}]}}',
+          valid: true,
+        },
+        "config.set": {
+          config: { agents: { list: [{ id: "main" }, { id: "kimi", default: true }] } },
+          hash: "hash-2",
+          issues: [],
+          raw: '{"agents":{"list":[{"id":"main"},{"id":"kimi","default":true}]}}',
+          valid: true,
+        },
+      },
+    });
+
+    try {
+      const response = await page.goto(`${server.baseUrl}agents`);
+      expect(response?.status()).toBe(200);
+
+      // selectOption / click auto-wait for the element to be actionable (enabled), so
+      // these implicitly assert the dropdown loaded and Set Default is clickable for a
+      // non-default agent.
+      await page.locator("select.agents-select").selectOption("kimi");
+      await page.getByRole("button", { name: "Set Default", exact: true }).click();
+
+      // The fix routes Set Default through the canonical save path; without it the click
+      // only stages a form draft and never emits config.set, so this request never arrives.
+      const setRequest = await gateway.waitForRequest("config.set");
+      const raw = requestParams(setRequest).raw;
+      expect(JSON.parse(String(raw))).toEqual({
+        agents: { list: [{ id: "main" }, { id: "kimi", default: true }] },
+      });
+    } finally {
+      await context.close();
+    }
+  });
+});