diff --git a/apps/desktop/src/main/acp-host.mjs b/apps/desktop/src/main/acp-host.mjs
index 46b15622..c5c2c818 100644
--- a/apps/desktop/src/main/acp-host.mjs
+++ b/apps/desktop/src/main/acp-host.mjs
@@ -789,7 +789,7 @@ export function createAcpHostRuntime(options = {}) {
             const prepared = id === "piAgent" ? withPiPath(command, resolutionDeps(commandDeps))
               : id === "antigravity" ? withAntigravityMacProxy(command, commandDeps) : command;
             connected = await withHandshakeTimeout((signal) => connect(prepared, `install-${id}`, () => {}, signal), 90_000);
-            return { ...adapterShell(id), state: "available", promptCapabilities: connected.promptCapabilities };
+            return { ...adapterShell(id), state: "available", promptCapabilities: connected.promptCapabilities, authMethods: connected.authMethods };
           } catch (error) {
             return { ...adapterShell(id), ...failureFields(classifyAcpFailure(error)), ...(isAuthRequiredError(error) ? { authMethods: error.authMethods ?? [] } : {}) };
           } finally {
@@ -860,7 +860,7 @@ export function createAcpHostRuntime(options = {}) {
         ...adapterShell(id),
         state: "available",
         promptCapabilities: connected.promptCapabilities,
-        ...((id === "workbuddyCn" || id === "workbuddyIntl") ? { authMethods: connected.authMethods } : {}),
+        authMethods: connected.authMethods,
         ...(resolved.version ? { version: resolved.version, managed: true } : {}),
       };
       latestStatus.set(id, adapter);
@@ -878,7 +878,7 @@ export function createAcpHostRuntime(options = {}) {
       let connected;
       try {
         connected = await withHandshakeTimeout((signal) => connect(resolved.command, `auth-${id}`, () => {}, signal, input.methodId), 5 * 60_000);
-        const adapter = { ...adapterShell(id), state: "available", promptCapabilities: connected.promptCapabilities, ...((id === "workbuddyCn" || id === "workbuddyIntl") ? { authMethods: connected.authMethods } : {}), ...(resolved.version ? { version: resolved.version, managed: true } : {}) };
+        const adapter = { ...adapterShell(id), state: "available", promptCapabilities: connected.promptCapabilities, authMethods: connected.authMethods, ...(resolved.version ? { version: resolved.version, managed: true } : {}) };
         latestStatus.set(id, adapter);
         return adapter;
       } catch (error) {
diff --git a/apps/desktop/src/main/acp-host.test.mjs b/apps/desktop/src/main/acp-host.test.mjs
index a328ac26..acef62d9 100644
--- a/apps/desktop/src/main/acp-host.test.mjs
+++ b/apps/desktop/src/main/acp-host.test.mjs
@@ -68,7 +68,7 @@ const collector = () => {
   };
 };
 
-const fakeAgentSource = ({ reportPath, secretPath, allowImage, allowEmbedded, hold, requireAuth, promptRefusal }) => `#!/usr/bin/env bun
+const fakeAgentSource = ({ reportPath, secretPath, allowImage, allowEmbedded, hold, requireAuth, advertiseAuth, promptRefusal }) => `#!/usr/bin/env bun
 import * as acp from ${JSON.stringify(sdkHref)};
 import { writeFileSync } from "node:fs";
 
@@ -78,6 +78,7 @@ const allowImage = ${allowImage ? "true" : "false"};
 const allowEmbedded = ${allowEmbedded ? "true" : "false"};
 const hold = ${hold ? "true" : "false"};
 const requireAuth = ${requireAuth ? "true" : "false"};
+const advertiseAuth = ${advertiseAuth ? "true" : "false"};
 const promptRefusal = ${promptRefusal ? JSON.stringify(promptRefusal) : "null"};
 let authenticated = false;
 const report = { initialize: null, newSession: null, permission: null, readError: null, readResult: null, prompt: null, authMethod: null };
@@ -119,7 +120,7 @@ acp.agent({ name: "edgeever-fake-agent" })
     return {
       protocolVersion: ctx.params.protocolVersion,
       agentCapabilities: { promptCapabilities: { image: allowImage, embeddedContext: allowEmbedded } },
-      authMethods: requireAuth ? [{ id: "browser", name: "Browser" }] : [],
+      authMethods: requireAuth || advertiseAuth ? [{ id: "browser", name: "Browser" }] : [],
     };
   })
   .onRequest("authenticate", (ctx) => {
@@ -708,6 +709,26 @@ describe("ACP stdio session", () => {
     }
   }, 15_000);
 
+  sessionTest("keeps ACP login methods visible when another agent can already create a session", async () => {
+    const directory = await mkdtemp(path.join(tmpdir(), "edgeever-acp-optional-auth-"));
+    try {
+      const scriptPath = await writeFakeAgent(directory, {
+        reportPath: path.join(directory, "report.json"),
+        secretPath: path.join(directory, "secret.txt"),
+        allowImage: false,
+        allowEmbedded: false,
+        hold: false,
+        advertiseAuth: true,
+      });
+      const runtime = createAcpHostRuntime();
+      const probed = await runtime.probeAdapter({ id: "antigravity", path: scriptPath });
+      expect(probed.state).toBe("available");
+      expect(probed.authMethods).toEqual([{ id: "browser", name: "Browser" }]);
+    } finally {
+      await rm(directory, { recursive: true, force: true });
+    }
+  }, 15_000);
+
   sessionTest("reports a prompt-time authentication refusal instead of an empty reply", async () => {
     const directory = await mkdtemp(path.join(tmpdir(), "edgeever-acp-refusal-"));
     try {
diff --git a/apps/web/src/components/settings/DesktopAcpAgentCard.tsx b/apps/web/src/components/settings/DesktopAcpAgentCard.tsx
index 07c1490b..beea8f6b 100644
--- a/apps/web/src/components/settings/DesktopAcpAgentCard.tsx
+++ b/apps/web/src/components/settings/DesktopAcpAgentCard.tsx
@@ -126,15 +126,15 @@ const DesktopAcpAgentCardBody = ({ bridge }: { bridge: boolean }) => {
     installError,
     state: shown?.state,
   });
-  const hasDetails = Boolean(
-    shown?.state === "not_installed" ||
-    shown?.state === "needs_login" ||
-    (isWorkBuddy && shown?.state === "available" && Boolean(shown.authMethods?.length)) ||
-    shown?.updateError
-  );
   const authMethods = shown?.authMethods?.filter((method) => (
     adapterId === "workbuddyCn" ? method.id !== "external" : adapterId === "workbuddyIntl" ? method.id !== "internal" : true
   )) ?? [];
+  const hasDetails = Boolean(
+    shown?.state === "not_installed" ||
+    shown?.state === "needs_login" ||
+    (shown?.state === "available" && authMethods.length > 0) ||
+    shown?.updateError
+  );
 
   const selectAdapter = (id: DesktopAcpAdapterId) => {
     setAdapterId(id);
@@ -369,7 +369,10 @@ const DesktopAcpAgentCardBody = ({ bridge }: { bridge: boolean }) => {
                   {(shown?.state === "needs_login" || shown?.state === "available") && isWorkBuddy ? (
                     <p className="text-xs leading-relaxed text-slate-600">{t(adapterId === "workbuddyCn" ? "aiAssistant.agentSource.workbuddyCnLoginHint" : "aiAssistant.agentSource.workbuddyIntlLoginHint")}</p>
                   ) : null}
-                  {(shown?.state === "needs_login" || (isWorkBuddy && shown?.state === "available")) && authMethods.length ? (
+                  {shown?.state === "available" && !isWorkBuddy && authMethods.length ? (
+                    <p className="text-xs leading-relaxed text-slate-600">{t("aiAssistant.agentSource.authAvailableHint")}</p>
+                  ) : null}
+                  {(shown?.state === "needs_login" || shown?.state === "available") && authMethods.length ? (
                     <div className="flex flex-wrap gap-2 pt-0.5">
                       {authMethods.map((method) => (
                         <Button key={method.id} type="button" variant="outline" size="sm" className="h-8 bg-card text-xs font-normal" disabled={authenticating} onClick={() => void authenticate(method.id)}>
diff --git a/apps/web/src/lib/desktop-acp.test.mjs b/apps/web/src/lib/desktop-acp.test.mjs
index fcdbe449..b2aa9ed4 100644
--- a/apps/web/src/lib/desktop-acp.test.mjs
+++ b/apps/web/src/lib/desktop-acp.test.mjs
@@ -15,3 +15,9 @@ test("a newly installed managed connector takes priority over an older probe", (
   const previous = { id: "antigravity", label: "Antigravity", state: "failed", version: "1.2.1", managed: true };
   expect(displayedDesktopAcpAdapter({ id: "antigravity", path: "", listed: [current], probed: previous })).toBe(current);
 });
+
+test("a prompt-time login failure takes priority over an earlier successful session probe", () => {
+  const current = { id: "grokBuild", label: "Grok Build", state: "needs_login", authMethods: [{ id: "browser", name: "Browser" }] };
+  const earlierProbe = { id: "grokBuild", label: "Grok Build", state: "available" };
+  expect(displayedDesktopAcpAdapter({ id: "grokBuild", path: "", listed: [current], probed: earlierProbe })).toBe(current);
+});
diff --git a/apps/web/src/lib/desktop-acp.ts b/apps/web/src/lib/desktop-acp.ts
index 4d71e42b..e99aea7b 100644
--- a/apps/web/src/lib/desktop-acp.ts
+++ b/apps/web/src/lib/desktop-acp.ts
@@ -33,6 +33,7 @@ export const displayedDesktopAcpAdapter = ({
   const checked = probed?.id === id ? probed : undefined;
   if (id === "antigravity" && path.trim()) return checked;
   if (current?.state === "installing" || (current?.managed && (!checked?.managed || current.version !== checked.version))) return current;
+  if (current?.state === "needs_login" && checked?.state === "available") return current;
   return checked ?? current;
 };
 
diff --git a/packages/shared/src/i18n/en-US.ts b/packages/shared/src/i18n/en-US.ts
index ea74bb87..6782dc52 100644
--- a/packages/shared/src/i18n/en-US.ts
+++ b/packages/shared/src/i18n/en-US.ts
@@ -1439,11 +1439,12 @@ export const enUS = {
       updateFailed: "Automatic update failed. The previous version remains in use.",
       authenticating: "Signing in…",
       authenticateWith: "Sign in with {{method}}",
+      authAvailableHint: "This agent offers ACP sign-in. If sending a message requires login, complete it here.",
       loginUnavailable: "This ACP connector requires authentication but provides no ACP sign-in method. Authenticate in the agent, then check the connection again.",
       autoUpdated: "Auto-updated",
       probe: "Check connection",
       probing: "Checking…",
-      probeHint: "Opens a temporary session and closes it. Your notes are not sent.",
+      probeHint: "Opens and closes a temporary session without sending your notes. This check does not verify model sign-in.",
       notProbed: "Not checked yet",
       invalidPath: "Enter an absolute path to an executable file.",
       states: {
diff --git a/packages/shared/src/i18n/ja.ts b/packages/shared/src/i18n/ja.ts
index de281301..11dd5647 100644
--- a/packages/shared/src/i18n/ja.ts
+++ b/packages/shared/src/i18n/ja.ts
@@ -1439,11 +1439,12 @@ export const ja = {
       updateFailed: "自動更新に失敗しました。以前のバージョンを継続して使用します。",
       authenticating: "ログイン中…",
       authenticateWith: "{{method}} でログイン",
+      authAvailableHint: "この Agent は ACP ログインに対応しています。メッセージ送信時にログインを求められた場合は、ここで認証してください。",
       loginUnavailable: "この ACP 接続コンポーネントは認証が必要ですが、ACP のログイン方法を提供していません。エージェント側で認証してから再確認してください。",
       autoUpdated: "自動更新",
       probe: "接続を確認",
       probing: "確認中…",
-      probeHint: "一時的なセッションを開いてすぐ閉じます。ノートは送信しません。",
+      probeHint: "一時的なセッションを開いてすぐ閉じます。ノートは送信されず、モデルへのログイン状態も確認しません。",
       notProbed: "未確認",
       invalidPath: "実行ファイルの絶対パスを入力してください。",
       states: {
diff --git a/packages/shared/src/i18n/zh-CN.ts b/packages/shared/src/i18n/zh-CN.ts
index d82d7093..6873f8c3 100644
--- a/packages/shared/src/i18n/zh-CN.ts
+++ b/packages/shared/src/i18n/zh-CN.ts
@@ -1439,11 +1439,12 @@ export const zhCN = {
       updateFailed: "自动更新失败，正在继续使用原版本。",
       authenticating: "正在登录…",
       authenticateWith: "使用 {{method}} 登录",
+      authAvailableHint: "此 Agent 提供 ACP 登录方式。若发消息时提示需要登录，可在这里完成认证。",
       loginUnavailable: "这个 ACP 连接组件要求认证，但没有提供 ACP 登录入口。请在对应代理中完成认证后重试连接。",
       autoUpdated: "自动更新",
       probe: "检查连接",
       probing: "正在检查…",
-      probeHint: "会临时建立会话并立即关闭，不会发送你的笔记。",
+      probeHint: "会临时建立会话并立即关闭，不会发送你的笔记；此检查不验证模型请求是否已登录。",
       notProbed: "尚未检查",
       invalidPath: "请填写可执行文件的绝对路径。",
       states: {