fix(frontend): route agent checks to gateway (#1572)

* fix(frontend): route agent checks to gateway

* fix(frontend): proxy langgraph requests locally

* fix(frontend): keep zh-CN text readable

* fix(frontend): add exact local api rewrites

* fix(frontend): support docker-safe internal rewrites

* Update frontend/src/core/agents/api.ts

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

---------

Co-authored-by: Willem Jiang <willem.jiang@gmail.com>
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

frontend/src/app/workspace/agents/new/page.tsx

@@ -16,7 +16,11 @@ import { ArtifactsProvider } from "@/components/workspace/artifacts";
 import { MessageList } from "@/components/workspace/messages";
 import { ThreadContext } from "@/components/workspace/messages/context";
 import type { Agent } from "@/core/agents";
-import { checkAgentName, getAgent } from "@/core/agents/api";
+import {
+  AgentNameCheckError,
+  checkAgentName,
+  getAgent,
+} from "@/core/agents/api";
 import { useI18n } from "@/core/i18n/hooks";
 import { useThreadStream } from "@/core/threads/hooks";
 import { uuid } from "@/core/utils/uuid";
@@ -76,8 +80,16 @@ export default function NewAgentPage() {
         setNameError(t.agents.nameStepAlreadyExistsError);
         return;
       }
-    } catch {
-      setNameError(t.agents.nameStepCheckError);
+    } catch (error) {
+      if (error instanceof AgentNameCheckError) {
+        setNameError(
+          error.reason === "backend_unreachable"
+            ? t.agents.nameStepCheckError
+            : error.message,
+        );
+      } else {
+        setNameError(t.agents.nameStepCheckError);
+      }
       return;
     } finally {
       setIsCheckingName(false);

frontend/src/core/agents/api.ts

@@ -2,6 +2,18 @@ import { getBackendBaseURL } from "@/core/config";
 
 import type { Agent, CreateAgentRequest, UpdateAgentRequest } from "./types";
 
+const BACKEND_UNAVAILABLE_STATUSES = new Set([502, 503, 504]);
+
+export class AgentNameCheckError extends Error {
+  constructor(
+    message: string,
+    public readonly reason: "backend_unreachable" | "request_failed",
+  ) {
+    super(message);
+    this.name = "AgentNameCheckError";
+  }
+}
+
 export async function listAgents(): Promise<Agent[]> {
   const res = await fetch(`${getBackendBaseURL()}/api/agents`);
   if (!res.ok) throw new Error(`Failed to load agents: ${res.statusText}`);
@@ -54,13 +66,29 @@ export async function deleteAgent(name: string): Promise<void> {
 export async function checkAgentName(
   name: string,
 ): Promise<{ available: boolean; name: string }> {
-  const res = await fetch(
-    `${getBackendBaseURL()}/api/agents/check?name=${encodeURIComponent(name)}`,
-  );
+  let res: Response;
+  try {
+    res = await fetch(
+      `${getBackendBaseURL()}/api/agents/check?name=${encodeURIComponent(name)}`,
+    );
+  } catch {
+    throw new AgentNameCheckError(
+      "Could not reach the DeerFlow backend.",
+      "backend_unreachable",
+    );
+  }
+
   if (!res.ok) {
     const err = (await res.json().catch(() => ({}))) as { detail?: string };
-    throw new Error(
+    if (BACKEND_UNAVAILABLE_STATUSES.has(res.status)) {
+      throw new AgentNameCheckError(
+        "Could not reach the DeerFlow backend.",
+        "backend_unreachable",
+      );
+    }
+    throw new AgentNameCheckError(
       err.detail ?? `Failed to check agent name: ${res.statusText}`,
+      "request_failed",
     );
   }
   return res.json() as Promise<{ available: boolean; name: string }>;

frontend/src/core/i18n/locales/en-US.ts

@@ -194,7 +194,8 @@ export const enUS: Translations = {
     nameStepInvalidError:
       "Invalid name — use only letters, digits, and hyphens",
     nameStepAlreadyExistsError: "An agent with this name already exists",
-    nameStepCheckError: "Could not verify name availability — please try again",
+    nameStepCheckError:
+      "Could not reach the DeerFlow backend to verify name availability. Start the backend or set NEXT_PUBLIC_BACKEND_BASE_URL, then try again.",
     nameStepBootstrapMessage:
       "The new custom agent name is {name}. Let's bootstrap it's **SOUL**.",
     agentCreated: "Agent created!",

frontend/src/core/i18n/locales/zh-CN.ts

@@ -183,7 +183,8 @@ export const zhCN: Translations = {
     nameStepContinue: "继续",
     nameStepInvalidError: "名称无效，只允许字母、数字和连字符",
     nameStepAlreadyExistsError: "已存在同名智能体",
-    nameStepCheckError: "无法验证名称可用性，请稍后重试",
+    nameStepCheckError:
+      "无法连接 DeerFlow 后端来验证名称是否可用。请先启动后端，或配置 NEXT_PUBLIC_BACKEND_BASE_URL，然后再重试。",
     nameStepBootstrapMessage:
       "新智能体的名称是 {name}，现在开始为它生成 **SOUL**。",
     agentCreated: "智能体已创建！",