Add Clarification Phase to PLAN mode

.ai-rules/CHANGELOG.md

@@ -48,6 +48,16 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Added
+- **Clarification Phase** for PLAN mode (`rules/clarification-guide.md`)
+  - Optional phase triggered when AI detects ambiguous requirements
+  - Sequential Q&A with progress indicator (Question N/M format)
+  - Multiple-choice questions preferred for easy response
+  - Ambiguity assessment checklist (6 categories, triggers on 2+ unclear)
+  - Question count guidelines (2-7 questions based on complexity)
+  - Korean/English output format support
+  - Updated `rules/core.md` with Clarification Phase section
+
 ### Planned
 - Real-world usage testing across all 6 AI tools
 - Performance metrics collection

.ai-rules/README.md

@@ -9,6 +9,7 @@ This directory contains shared coding rules and guidelines used across multiple
 ├── README.md              # This file - overview and usage guide
 ├── rules/                 # Common coding rules (AI-agnostic)
 │   ├── core.md           # Workflow modes (PLAN/ACT/EVAL), communication
+│   ├── clarification-guide.md  # Clarification Phase guidelines for PLAN mode
 │   ├── project.md        # Tech stack, architecture, project context
 │   └── augmented-coding.md  # TDD principles, code quality standards
 ├── agents/                # Specialist agent definitions (JSON)
@@ -40,10 +41,16 @@ All AI coding assistants share the same:
 ### 1. `rules/core.md` - Workflow & Communication
 
 **Workflow Modes:**
-- **PLAN**: Define implementation plan without making changes
+- **PLAN**: Define implementation plan (includes optional Clarification Phase)
 - **ACT**: Execute the plan and make code changes
 - **EVAL**: Analyze results and propose improvements
 
+**Clarification Phase (Optional in PLAN):**
+- Triggers when AI detects ambiguous requirements (2+ unclear items)
+- Sequential Q&A with progress indicator (Question N/M)
+- Multiple-choice questions preferred for easy response
+- See `rules/clarification-guide.md` for detailed guidelines
+
 **Key Principles:**
 - Start in PLAN mode by default
 - Move to ACT when user types `ACT`
@@ -218,6 +225,7 @@ When rules conflict between common rules and tool-specific configurations:
 ## Further Reading
 
 - **Workflow Details**: `rules/core.md`
+- **Clarification Phase**: `rules/clarification-guide.md`
 - **Project Setup**: `rules/project.md`
 - **TDD & Quality**: `rules/augmented-coding.md`
 - **Agent System**: `agents/README.md`

.ai-rules/rules/clarification-guide.md

@@ -0,0 +1,138 @@
+# Clarification Question Guidelines
+
+Guidelines for AI to generate contextual clarification questions during PLAN MODE.
+
+---
+
+## When to Start Clarification Phase
+
+Start Clarification Phase when any of the following ambiguities are detected:
+
+- **Scope unclear** - Which modules, components, or users are affected?
+- **Priority ambiguous** - What is must-have vs nice-to-have?
+- **Constraints not specified** - Technical or business limitations?
+- **Edge cases undefined** - How to handle errors or exceptions?
+- **Integration points unclear** - Relationship with existing systems?
+
+**Skip Clarification Phase when:**
+- Requirements are detailed and unambiguous
+- User provides comprehensive specification document
+- User explicitly requests: "Skip clarification" or "Just create the plan"
+
+---
+
+## Ambiguity Assessment Checklist
+
+Use this checklist to determine if Clarification Phase is needed:
+
+| Check | Question | If unclear → Ask about |
+|-------|----------|------------------------|
+| [ ] | Is the **scope** defined? (which files, modules, users) | Scope |
+| [ ] | Are **priorities** clear? (must-have vs nice-to-have) | Priority |
+| [ ] | Are **constraints** known? (tech stack, compatibility) | Constraints |
+| [ ] | Are **edge cases** specified? (errors, empty states) | Expected Behavior |
+| [ ] | Are **non-functional requirements** defined? (performance, security) | Non-functional |
+| [ ] | Is **integration** with existing code clear? | Integration |
+
+**Rule:** If 2+ items are unclear → Start Clarification Phase
+
+---
+
+## Question Format Rules
+
+1. **Single Question** - Ask only ONE question per message
+2. **Progress Indicator** - Show "Question N/M" format (estimate M, adjust as needed)
+3. **Multiple-Choice First** - Provide A/B/C options when possible
+4. **Custom Input** - Always allow user's own input option
+5. **Language** - Follow agent's `communication.language` setting; if not set, detect from user's input language
+
+### Question Count Guidelines
+
+| Request Complexity | Recommended Questions |
+|--------------------|----------------------|
+| Simple feature | 2-3 questions |
+| Standard feature | 3-5 questions |
+| Complex feature | 5-7 questions |
+
+**Best Practice:** Start with estimated count, adjust as conversation progresses. Avoid exceeding 7 questions.
+
+---
+
+## Question Categories
+
+Use these categories as reference when generating questions. Adapt to specific context.
+
+| Category | Focus Areas |
+|----------|-------------|
+| **Scope** | Feature boundary, affected modules, user roles |
+| **Priority** | Core requirements vs optional features, MVP definition |
+| **Constraints** | Technical limits, dependencies, compatibility, deadlines |
+| **Expected Behavior** | Edge cases, error handling, default values |
+| **Non-functional** | Performance, security, accessibility requirements |
+| **Integration** | Existing code relations, data flow, API dependencies |
+
+---
+
+## Output Format
+
+### During Clarification (English)
+
+```markdown
+## Clarification Phase
+
+### Question 1/3
+
+**[Category] clarification needed:**
+
+[Question text adapted to context]
+
+- **A)** [Option 1]
+- **B)** [Option 2]
+- **C)** [Option 3]
+
+> Select your answer (A/B/C) or share your own input.
+```
+
+### During Clarification (Korean)
+
+```markdown
+## Clarification Phase
+
+### 질문 1/3
+
+**[카테고리]에 대한 확인이 필요합니다:**
+
+[컨텍스트에 맞게 조정된 질문]
+
+- **A)** [선택지 1]
+- **B)** [선택지 2]
+- **C)** [선택지 3]
+
+> 답변을 선택해주세요 (A/B/C) 또는 다른 의견이 있으시면 말씀해주세요.
+```
+
+### After All Questions
+
+```markdown
+## 수집된 정보 요약
+
+| 항목 | 결정 사항 |
+|------|----------|
+| 범위 | [사용자 선택] |
+| 우선순위 | [사용자 선택] |
+| 제약조건 | [사용자 선택] |
+| ... | ... |
+
+이 내용이 맞나요? 확인해주시면 PLAN 수립을 시작하겠습니다.
+```
+
+---
+
+## Handling Special Cases
+
+| Situation | Response |
+|-----------|----------|
+| User answers "I'm not sure" / "잘 모르겠어요" | Present default recommendation with rationale, ask for confirmation |
+| User wants to skip a question | Note that AI will use best judgment, continue to next question |
+| User provides unexpected answer | Acknowledge the input, incorporate into understanding, continue |
+| User asks to skip all questions | Proceed to PLAN creation, note assumptions made |

.ai-rules/rules/core.md

@@ -52,6 +52,44 @@ PLAN → (user: ACT) → ACT → PLAN → (user: EVAL) → EVAL → Improved PLA
 **Purpose:**
 Create actionable implementation plans following TDD and augmented coding principles
 
+---
+
+### Clarification Phase (Optional)
+
+**Purpose:**
+Resolve ambiguous requirements through sequential Q&A before creating a plan.
+
+**Trigger Condition:**
+- AI assesses user request for ambiguity
+- If unclear scope, constraints, priority, or expected behavior detected → Start Clarification Phase
+- If requirements are already clear → Skip directly to Plan creation
+
+**Phase Rules:**
+1. **Single Question Rule** - Ask only ONE question per message
+2. **Progress Indicator** - Display "Question N/M" format (estimate M, adjust as needed)
+3. **Multiple-Choice First** - Provide A/B/C options whenever possible
+4. **Custom Input Allowed** - Always allow "Other" option for user's own input
+5. **Language Setting** - Follow agent's `communication.language` setting; if not set, detect from user's input language
+
+**Question Flow:**
+1. Analyze request → Identify ambiguous points → Estimate question count
+2. Present Question 1/N (multiple-choice format)
+3. Wait for user response
+4. Continue until all clarifications complete
+5. Summarize all collected information in a table
+6. Get user confirmation ("Yes" / request modification)
+7. Proceed to Plan creation with clarified requirements
+
+**Skip Conditions:**
+- User explicitly requests to skip: "Skip clarification" or "Just create the plan"
+- Requirements are detailed and unambiguous
+- User provides comprehensive specification document
+
+**Reference:**
+See `.ai-rules/rules/clarification-guide.md` for detailed question guidelines.
+
+---
+
 **What PLAN does (with Primary Developer Agent):**
 
 1. **Analyze Requirements** (via Primary Developer Agent)