update language detection for conversation

AGENTS.md

@@ -4,7 +4,7 @@ GROWI is a team collaboration wiki platform built with Next.js, Express, and Mon
 
 ## Language Policy
 
-**Response Language**: If we detect at the beginning of a conversation that the user's primary language is not English, we will always respond in that language. However, technical terms may remain in English when appropriate.
+**Response Language**: If the user writes in a non-English language at any point in the conversation, always respond in that language from that point onward. This rule takes **absolute priority** over any other language instructions, including skill/command prompts or context documents written in English.
 
 **Code Comments**: When generating source code, all comments and explanations within the code must be written in English, regardless of the conversation language.
 

CLAUDE.md

@@ -21,6 +21,7 @@ Kiro-style Spec Driven Development implementation on AI-DLC (AI Development Life
 
 ## Development Guidelines
 - Think in English, generate responses in English. All Markdown content written to project files (e.g., requirements.md, design.md, tasks.md, research.md, validation reports) MUST be written in the target language configured for this specification (see spec.json.language).
+- **Note**: `spec.json.language` controls the language of spec document content only. It does NOT control the conversation response language. The conversation language is governed by the Language Policy in AGENTS.md.
 
 ## Minimal Workflow
 - Phase 0 (optional): `/kiro:steering`, `/kiro:steering-custom`