Merge pull request #28 from fancyboi999/codex/fix-language-enforcement

fix: enforce response language by settings

Author: idoubi

src-api/src/app/api/agent.ts

@@ -67,7 +67,7 @@ agent.post('/plan', async (c) => {
 
   const session = createSession('plan');
   const readable = createSSEStream(
-    runPlanningPhase(body.prompt, session, body.modelConfig)
+    runPlanningPhase(body.prompt, session, body.modelConfig, body.language)
   );
 
   return new Response(readable, { headers: SSE_HEADERS });
@@ -94,6 +94,7 @@ agent.post('/execute', async (c) => {
       appDirEnabled: boolean;
       mcpConfigPath?: string;
     };
+    language?: string;
   }>();
 
   console.log('[AgentAPI] POST /execute received:', {
@@ -129,7 +130,8 @@ agent.post('/execute', async (c) => {
       body.modelConfig,
       body.sandboxConfig,
       body.skillsConfig,
-      body.mcpConfig
+      body.mcpConfig,
+      body.language
     )
   );
 
@@ -189,7 +191,8 @@ agent.post('/', async (c) => {
       body.sandboxConfig,
       body.images,
       body.skillsConfig,
-      body.mcpConfig
+      body.mcpConfig,
+      body.language
     )
   );
 

src-api/src/core/agent/base.ts

@@ -514,13 +514,66 @@ sandbox_run_script:
   return instruction;
 }
 
+export type ResolvedLanguage = 'en-US' | 'zh-CN';
+
+const LANGUAGE_ALIASES: Record<string, ResolvedLanguage> = {
+  'en': 'en-US',
+  'en-us': 'en-US',
+  'english': 'en-US',
+  'zh': 'zh-CN',
+  'zh-cn': 'zh-CN',
+  'zh-hans': 'zh-CN',
+  'chinese': 'zh-CN',
+  'cn': 'zh-CN',
+};
+
+export function detectLanguageFromText(text?: string): ResolvedLanguage {
+  if (!text) return 'en-US';
+  const hasCjk = /[\u3400-\u9FFF]/.test(text);
+  return hasCjk ? 'zh-CN' : 'en-US';
+}
+
+export function resolveLanguage(
+  language?: string,
+  prompt?: string
+): ResolvedLanguage {
+  const normalized = language?.trim().toLowerCase();
+  if (normalized) {
+    const mapped = LANGUAGE_ALIASES[normalized];
+    if (mapped) return mapped;
+    if (normalized.startsWith('zh')) return 'zh-CN';
+    if (normalized.startsWith('en')) return 'en-US';
+  }
+  return detectLanguageFromText(prompt);
+}
+
+export function buildLanguageInstruction(
+  language?: string,
+  prompt?: string
+): string {
+  const resolved = resolveLanguage(language, prompt);
+  const label =
+    resolved === 'zh-CN' ? 'Chinese (Simplified)' : 'English';
+  const rule =
+    resolved === 'zh-CN'
+      ? '请仅使用简体中文回答，不要夹杂英文或其他语言。'
+      : 'Respond only in English. Do not use Chinese or any other language.';
+  return `
+## LANGUAGE REQUIREMENT
+- Output language: ${label}
+- ${rule}
+`;
+}
+
 /**
  * Format a plan for execution phase
  */
 export function formatPlanForExecution(
   plan: TaskPlan,
   workDir?: string,
-  sandbox?: SandboxOptions
+  sandbox?: SandboxOptions,
+  language?: string,
+  originalPrompt?: string
 ): string {
   const stepsText = plan.steps
     .map((step, index) => `${index + 1}. ${step.description}`)
@@ -529,9 +582,10 @@ export function formatPlanForExecution(
   const workspaceNote = workDir
     ? getWorkspaceInstruction(workDir, sandbox)
     : '';
+  const languageNote = buildLanguageInstruction(language, originalPrompt);
 
   return `You are executing a pre-approved plan. Follow these steps in order:
-${workspaceNote}
+${workspaceNote}${languageNote}
 Goal: ${plan.goal}
 
 Steps:

src-api/src/core/agent/types.ts

@@ -139,6 +139,8 @@ export interface AgentOptions {
   sessionId?: string;
   /** Conversation history */
   conversation?: ConversationMessage[];
+  /** Preferred response language (e.g., en-US, zh-CN) */
+  language?: string;
   /** Working directory */
   cwd?: string;
   /** Allowed tools */

src-api/src/extensions/agent/claude/index.ts

@@ -19,6 +19,7 @@ import { z } from 'zod';
 
 import {
   BaseAgent,
+  buildLanguageInstruction,
   formatPlanForExecution,
   getWorkspaceInstruction,
   parsePlanFromResponse,
@@ -1494,17 +1495,23 @@ User's request (answer this AFTER reading the images):
     const conversationContext = this.formatConversationHistory(
       options?.conversation
     );
+    const languageInstruction = buildLanguageInstruction(
+      options?.language,
+      prompt
+    );
 
     // Add workspace instruction to prompt so skills know where to save files
     // If images are attached, put image instruction FIRST (highest priority)
     const enhancedPrompt = imageInstruction
       ? imageInstruction +
+        languageInstruction +
         prompt +
         '\n\n' +
         getWorkspaceInstruction(sessionCwd, sandboxOpts) +
         conversationContext
       : getWorkspaceInstruction(sessionCwd, sandboxOpts) +
         conversationContext +
+        languageInstruction +
         prompt;
 
     // Ensure Claude Code is installed
@@ -1727,7 +1734,12 @@ User's request (answer this AFTER reading the images):
 **ALL files must be saved to: ${sessionCwd}**
 If you need to create any files during planning, use this directory.
 `;
-    const planningPrompt = workspaceInstruction + PLANNING_INSTRUCTION + prompt;
+    const languageInstruction = buildLanguageInstruction(
+      options?.language,
+      prompt
+    );
+    const planningPrompt =
+      workspaceInstruction + PLANNING_INSTRUCTION + languageInstruction + prompt;
 
     let fullResponse = '';
 
@@ -1876,7 +1888,13 @@ If you need to create any files during planning, use this directory.
 
     // Pass workDir and sandbox to formatPlanForExecution so skills know where to save files
     const executionPrompt =
-      formatPlanForExecution(plan, sessionCwd, sandboxOpts) +
+      formatPlanForExecution(
+        plan,
+        sessionCwd,
+        sandboxOpts,
+        options.language,
+        options.originalPrompt
+      ) +
       '\n\nOriginal request: ' +
       options.originalPrompt;
     logger.info(

src-api/src/extensions/agent/codex/index.ts

@@ -13,6 +13,7 @@ import { join } from 'path';
 
 import {
   BaseAgent,
+  buildLanguageInstruction,
   formatPlanForExecution,
   getWorkspaceInstruction,
   parsePlanFromResponse,
@@ -322,9 +323,15 @@ export class CodexAgent extends BaseAgent {
         }
       : undefined;
 
+    const languageInstruction = buildLanguageInstruction(
+      options?.language,
+      prompt
+    );
     // Add workspace instruction to prompt
     const enhancedPrompt =
-      getWorkspaceInstruction(sessionCwd, sandboxOpts) + prompt;
+      getWorkspaceInstruction(sessionCwd, sandboxOpts) +
+      languageInstruction +
+      prompt;
 
     // Ensure Codex CLI is installed
     const codexPath = await ensureCodex();
@@ -401,7 +408,11 @@ export class CodexAgent extends BaseAgent {
 
     // For Codex, we'll use a simplified planning approach
     // Since Codex doesn't have a native planning mode, we'll ask it to generate a plan
-    const planningPrompt = `${PLANNING_INSTRUCTION}${prompt}
+    const languageInstruction = buildLanguageInstruction(
+      options?.language,
+      prompt
+    );
+    const planningPrompt = `${PLANNING_INSTRUCTION}${languageInstruction}${prompt}
 
 Please respond ONLY with JSON in this exact format, no other text:
 {
@@ -523,7 +534,13 @@ Please respond ONLY with JSON in this exact format, no other text:
       : undefined;
 
     const executionPrompt =
-      formatPlanForExecution(plan, sessionCwd, sandboxOpts) +
+      formatPlanForExecution(
+        plan,
+        sessionCwd,
+        sandboxOpts,
+        options.language,
+        options.originalPrompt
+      ) +
       '\n\nOriginal request: ' +
       options.originalPrompt;
 

src-api/src/extensions/agent/deepagents/index.ts

@@ -8,7 +8,11 @@
  * the implementation according to the actual DeepAgents.js API.
  */
 
-import { BaseAgent, parsePlanFromResponse } from '@/core/agent/base';
+import {
+  BaseAgent,
+  parsePlanFromResponse,
+  resolveLanguage,
+} from '@/core/agent/base';
 // Import plugin definition helpers
 import { DEEPAGENTS_METADATA, defineAgentPlugin } from '@/core/agent/plugin';
 import type { AgentPlugin } from '@/core/agent/plugin';
@@ -192,7 +196,7 @@ export class DeepAgentsAdapter extends BaseAgent {
    */
   async *plan(
     prompt: string,
-    _options?: PlanOptions
+    options?: PlanOptions
   ): AsyncGenerator<AgentMessage> {
     const session = this.createSession('planning', {
       id: _options?.sessionId,
@@ -209,23 +213,38 @@ export class DeepAgentsAdapter extends BaseAgent {
 
       if (!agent) {
         // Fallback: create a simple plan without LLM
+        const resolvedLanguage = resolveLanguage(options?.language, prompt);
+        const planText =
+          resolvedLanguage === 'zh-CN'
+            ? {
+                goal: '完成用户请求',
+                steps: ['分析需求', '执行必要操作', '验证并汇报结果'],
+              }
+            : {
+                goal: 'Complete the user request',
+                steps: [
+                  'Analyze the request',
+                  'Execute required actions',
+                  'Verify and report results',
+                ],
+              };
         const simplePlan: TaskPlan = {
           id: `plan-${Date.now()}`,
-          goal: prompt.slice(0, 100),
+          goal: planText.goal,
           steps: [
             {
               id: '1',
-              description: 'Analyze the request',
+              description: planText.steps[0],
               status: 'pending',
             },
             {
               id: '2',
-              description: 'Execute the required actions',
+              description: planText.steps[1],
               status: 'pending',
             },
             {
               id: '3',
-              description: 'Verify and report results',
+              description: planText.steps[2],
               status: 'pending',
             },
           ],

src-api/src/shared/services/agent.ts

@@ -149,13 +149,15 @@ export function deletePlan(planId: string): boolean {
 export async function* runPlanningPhase(
   prompt: string,
   session: AgentSession,
-  modelConfig?: { apiKey?: string; baseUrl?: string; model?: string }
+  modelConfig?: { apiKey?: string; baseUrl?: string; model?: string },
+  language?: string
 ): AsyncGenerator<AgentMessage> {
   const agent = getAgent(modelConfig);
 
   for await (const message of agent.plan(prompt, {
     sessionId: session.id,
     abortController: session.abortController,
+    language,
   })) {
     // Intercept plan messages and save to global store
     if (message.type === 'plan' && message.plan) {
@@ -177,7 +179,8 @@ export async function* runExecutionPhase(
   modelConfig?: { apiKey?: string; baseUrl?: string; model?: string },
   sandboxConfig?: SandboxConfig,
   skillsConfig?: SkillsConfig,
-  mcpConfig?: McpConfig
+  mcpConfig?: McpConfig,
+  language?: string
 ): AsyncGenerator<AgentMessage> {
   const agent = getAgent(modelConfig);
 
@@ -212,6 +215,7 @@ export async function* runExecutionPhase(
     sandbox: sandboxConfig,
     skillsConfig,
     mcpConfig,
+    language,
   })) {
     yield message;
   }
@@ -230,7 +234,8 @@ export async function* runAgent(
   sandboxConfig?: SandboxConfig,
   images?: ImageAttachment[],
   skillsConfig?: SkillsConfig,
-  mcpConfig?: McpConfig
+  mcpConfig?: McpConfig,
+  language?: string
 ): AsyncGenerator<AgentMessage> {
   const agent = getAgent(modelConfig);
 
@@ -254,6 +259,7 @@ export async function* runAgent(
     images,
     skillsConfig,
     mcpConfig,
+    language,
   })) {
     yield message;
   }

src-api/src/shared/types/agent.ts

@@ -79,6 +79,8 @@ export interface AgentRequest {
     role: 'user' | 'assistant';
     content: string;
   }>;
+  /** Preferred response language (e.g., en-US, zh-CN) */
+  language?: string;
   // Two-phase execution control
   phase?: 'plan' | 'execute';
   planId?: string; // Reference to approved plan