refactor(agents): share the agent-host tool set and keep connection errors English

- AGENT_HOST_TOOL_NAMES in tool-names.ts is now the single list that
  config.ts declares as coreTools and ToolRegistry.isToolDisabled lets
  through, so the declared and runnable sets cannot drift apart.
- The agent-host connection route's eleven error strings were Chinese
  and reached clients verbatim via { error: error.message }. They are
  now English, matching the convention #12854 set for wire reasons
  (review-bot residual 1).

packages/cli/src/config/config.ts

@@ -31,6 +31,7 @@ import {
   type LspClient,
   type ToolName,
   type ToolInvocationGuard,
+  AGENT_HOST_TOOL_NAMES,
   ToolNames,
   NativeLspClient,
   createDebugLogger,
@@ -2873,11 +2874,7 @@ export async function loadCliConfig(
   };
 
   if (agentHostReadOnly) {
-    configParams.coreTools = [
-      ToolNames.READ_FILE,
-      ToolNames.GREP,
-      ToolNames.LS,
-    ];
+    configParams.coreTools = [...AGENT_HOST_TOOL_NAMES];
     configParams.disableAllHooks = true;
     configParams.mcpServers = {};
     configParams.topTierMcpServers = undefined;

packages/cli/src/serve/routes/agent-host-connection.ts

@@ -5,7 +5,7 @@ import { isLoopbackBind } from '../loopback-binds.js';
 import type { WorkspaceRuntime } from '../workspace-registry.js';
 
 function serverUrl(value: unknown, allowHttp: boolean): string {
-  if (typeof value !== 'string') throw new Error('请填写服务地址。');
+  if (typeof value !== 'string') throw new Error('A server URL is required.');
   const url = new URL(value);
   if (
     url.username ||
@@ -19,7 +19,7 @@ function serverUrl(value: unknown, allowHttp: boolean): string {
       ))
   ) {
     throw new Error(
-      '请使用 HTTPS；可信演示网络可显式允许 HTTP。地址不能包含凭证或查询参数。',
+      'Use HTTPS; HTTP is allowed only when explicitly enabled for a trusted network. The URL must not contain credentials, a query, or a fragment.',
     );
   }
   return url.toString().replace(/\/+$/, '');
@@ -82,7 +82,7 @@ export function registerAgentHostConnectionRoutes(
         !input.enrollmentToken ||
         input.provider !== 'qwen'
       ) {
-        throw new Error('接入参数不完整。');
+        throw new Error('Missing connection parameters.');
       }
       if (!isCurrent(req, res, runtime)) return;
       const { startAgentHostConnection } = await import(
@@ -106,7 +106,9 @@ export function registerAgentHostConnectionRoutes(
     } catch (error) {
       res
         .status(400)
-        .json({ error: error instanceof Error ? error.message : '接入失败。' });
+        .json({
+          error: error instanceof Error ? error.message : 'Connection failed.',
+        });
     }
   });
 
@@ -130,7 +132,9 @@ export function registerAgentHostConnectionRoutes(
         !input.remoteToken.trim() ||
         input.provider !== 'qwen'
       )
-        throw new Error('请填写远程服务凭证、远程执行目录和执行程序。');
+        throw new Error(
+          'Remote server credential, remote workspace, and provider are required.',
+        );
       const endpoint = `${remote}/workspaces/${encodeURIComponent(input.remoteCwd)}/agent/hosts`;
       const request = async (path: string, body?: unknown) => {
         const response = await fetch(`${endpoint}${path}`, {
@@ -145,13 +149,15 @@ export function registerAgentHostConnectionRoutes(
         });
         if (response.status === 404)
           throw new Error(
-            '远程服务不支持在线主机接入，或执行目录未注册。请升级并启用协作功能，确认远程工作区后重试。',
+            'The remote server does not support Agent Host enrollment, or the workspace is not registered. Upgrade it, enable agent collaboration, confirm the remote workspace, and retry.',
           );
         if (response.status === 401 || response.status === 403)
-          throw new Error('远程凭证无效，或远程项目尚未授权。');
+          throw new Error(
+            'The remote credential is invalid, or the remote workspace is not authorized.',
+          );
         if (!response.ok)
           throw new Error(
-            `远程接入失败（${response.status}），请检查远程服务日志及协调端回连地址。`,
+            `Remote connection failed (${response.status}). Check the remote server log and the coordinator callback URL.`,
           );
         return (await response.json()) as {
           protocol?: number;
@@ -164,7 +170,9 @@ export function registerAgentHostConnectionRoutes(
         service.protocol !== 1 ||
         !service.providers?.includes(input.provider)
       )
-        throw new Error('远程服务不支持所选执行程序或接入协议。');
+        throw new Error(
+          'The remote server does not support the selected provider or connection protocol.',
+        );
       if (!isCurrent(req, res, runtime)) return;
       // The enrollment token below crosses both legs; mirror the Host's
       // warning on this side, which is the one holding the secret.
@@ -182,11 +190,15 @@ export function registerAgentHostConnectionRoutes(
         allowHttp: input.allowHttp === true,
       });
       if (!isCurrent(req, res, runtime)) return;
-      if (!result.connected) throw new Error('远程服务未确认接入。');
+      if (!result.connected)
+        throw new Error('The remote server did not confirm the connection.');
       res.json(result);
     } catch (error) {
       res.status(400).json({
-        error: error instanceof Error ? error.message : '无法连接远程服务。',
+        error:
+          error instanceof Error
+            ? error.message
+            : 'Cannot reach the remote server.',
       });
     }
   });

packages/core/src/tools/tool-names.ts

@@ -100,6 +100,17 @@ export const ToolNames = {
   THREAD_READ: 'thread_read',
 } as const;
 
+/**
+ * The only tools an agent-host session declares and runs. The Host is
+ * read-only and auto-rejects permission prompts, so anything outside this
+ * set would be advertised to the model yet fail every invocation.
+ */
+export const AGENT_HOST_TOOL_NAMES: readonly string[] = [
+  ToolNames.READ_FILE,
+  ToolNames.GREP,
+  ToolNames.LS,
+];
+
 /**
  * Tool display name constants to avoid circular dependencies.
  * These constants are used across multiple files and should be kept in sync

packages/core/src/tools/tool-registry.ts

@@ -22,7 +22,7 @@ import { McpClientManager } from './mcp-client-manager.js';
 import { DiscoveredMCPTool } from './mcp-tool.js';
 import { parse } from 'shell-quote';
 import { ToolErrorType } from './tool-error.js';
-import { ToolNames } from './tool-names.js';
+import { AGENT_HOST_TOOL_NAMES, ToolNames } from './tool-names.js';
 import { safeJsonStringify } from '../utils/safeJsonStringify.js';
 import type { EventEmitter } from 'node:events';
 import { createDebugLogger } from '../utils/debugLogger.js';
@@ -325,9 +325,7 @@ export class ToolRegistry {
   ): boolean {
     if (
       this.config.getSessionSourceType?.() === 'agent-host' &&
-      name !== ToolNames.READ_FILE &&
-      name !== ToolNames.GREP &&
-      name !== ToolNames.LS
+      !AGENT_HOST_TOOL_NAMES.includes(name)
     ) {
       return true;
     }