docs: Enhance Main Claude coordination rules with new capabilities

Updated AGENT_COORDINATION_RULES.md to document Main Claude's enhanced role:

New Capabilities Section:
- Automatic skill invocation (frontend-design for ANY UI change)
- Sequential Thinking recognition (when to use ST MCP)
- Dual checkpoint system (git + database via /checkpoint)
- Skills vs Agents distinction (when to use each)

Main Claude Responsibilities Enhanced:
- Auto-invoke frontend-design skill when UI affected
- Recognize when Sequential Thinking is appropriate
- Execute dual checkpoints (git + database)
- Coordinate agents and skills intelligently

Quick Reference Updated:
- Added UI validation (Frontend Design Skill)
- Added complex problem analysis (Sequential Thinking MCP)
- Added dual checkpoints (/checkpoint command)
- Added skill invocation (Main Claude)

Summary Section Added:
- Orchestra conductor metaphor for Main Claude's role
- Clear list of what Main Claude does NOT do
- Clear list of what Main Claude DOES automatically
- Comprehensive coordinator responsibilities

Files: .claude/AGENT_COORDINATION_RULES.md (+129 lines)

Decision Rationale:
Main Claude needed comprehensive documentation of enhanced
capabilities added today. The coordination rules now clearly
define automatic skill invocation triggers, Sequential Thinking
usage patterns, and dual checkpoint workflow.

Total: 130 lines added documenting Main Claude's intelligent
coordination capabilities.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

.claude/AGENT_COORDINATION_RULES.md

@@ -233,6 +233,9 @@ curl ... -d '{"context_type": "session_summary", ...}'
 - ✅ Launch appropriate agents
 - ✅ Synthesize agent results for user
 - ✅ Plan and design solutions
+- ✅ **Automatically invoke skills when triggered** (NEW)
+- ✅ **Recognize when Sequential Thinking is needed** (NEW)
+- ✅ **Execute dual checkpoints (git + database)** (NEW)
 
 **Main Claude Does NOT:**
 - ❌ Query database directly
@@ -240,6 +243,101 @@ curl ... -d '{"context_type": "session_summary", ...}'
 - ❌ Execute code (unless simple demonstration)
 - ❌ Run tests (use Testing Agent)
 - ❌ Commit to git (use Gitea Agent)
+- ❌ Review code (use Code Review Agent)
+- ❌ Write production code (use Coding Agent)
+
+---
+
+## New Capabilities (Added 2026-01-17)
+
+### 1. Automatic Skill Invocation
+
+**Main Claude automatically invokes skills when triggered by specific actions:**
+
+**Frontend Design Skill:**
+- **Trigger:** ANY action that affects a UI element
+- **When:** After modifying HTML/CSS/JSX, styling, layouts, components
+- **Purpose:** Validate visual correctness, functionality, UX, accessibility
+- **Workflow:**
+  ```
+  User: "Add a submit button"
+  Main Claude: [Writes button code]
+  Main Claude: [AUTO-INVOKE frontend-design skill]
+  Frontend Skill: [Validates appearance, behavior, accessibility]
+  Frontend Skill: [Returns PASS/WARNING/ERROR]
+  Main Claude: [Proceeds or fixes based on validation]
+  ```
+
+**Rule:** If the change appears in a browser, invoke frontend-design skill to validate it.
+
+### 2. Sequential Thinking Recognition
+
+**Main Claude recognizes when agents should use Sequential Thinking MCP:**
+
+**For Code Review Agent:**
+- Knows to use ST when code rejected 2+ times
+- Knows to use ST when 3+ critical issues found
+- Knows to use ST for complex architectural decisions
+- Doesn't use ST for simple fixes (wastes tokens)
+
+**For Other Complex Tasks:**
+- Multi-step debugging with unclear root cause
+- Architectural trade-off decisions
+- Complex problem-solving where approach might change
+- Investigation tasks where each finding affects next step
+
+**Rule:** Use ST for genuinely complex, ambiguous problems where structured reasoning adds value.
+
+### 3. Dual Checkpoint System
+
+**Main Claude executes dual checkpoints via /checkpoint command:**
+
+**Part 1: Git Checkpoint**
+- Stages all changes (git add -A)
+- Creates detailed commit message
+- Follows existing commit conventions
+- Includes co-author attribution
+
+**Part 2: Database Context**
+- Saves session summary to ClaudeTools API
+- Includes git metadata (commit, branch, files)
+- Tags for searchability
+- Relevance score 8.0 (important milestone)
+
+**Workflow:**
+```
+User: /checkpoint
+Main Claude: [Analyzes changes]
+Main Claude: [Creates git commit]
+Main Claude: [Saves context to database via API/script]
+Main Claude: [Verifies both succeeded]
+Main Claude: [Reports to user]
+```
+
+**Benefits:**
+- Git: Code versioning and rollback
+- Database: Cross-machine context recall
+- Together: Complete project memory
+
+### 4. Skills vs Agents
+
+**Main Claude understands the difference:**
+
+**Skills** (invoked via Skill tool):
+- Frontend design/validation
+- User-invocable with `/skill-name`
+- Specialized capabilities
+- Return enhanced output
+
+**Agents** (invoked via Task tool):
+- Database operations
+- Code writing
+- Testing
+- Code review
+- Git operations
+- Backup/restore
+
+**Rule:** Skills are for specialized enhancements (frontend, design patterns). Agents are for core operations (database, coding, testing).
 
 ---
 
@@ -255,18 +353,48 @@ curl ... -d '{"context_type": "session_summary", ...}'
 | Review code | Code Review Agent |
 | Git operations | Gitea Agent |
 | Backups | Backup Agent |
+| **UI validation** | **Frontend Design Skill (auto-invoked)** |
+| **Complex problem analysis** | **Sequential Thinking MCP** |
+| **Dual checkpoints** | **/checkpoint command (Main Claude)** |
 | **User interaction** | **Main Claude** |
 | **Coordination** | **Main Claude** |
 | **Decision making** | **Main Claude** |
+| **Skill invocation** | **Main Claude** |
 
 ---
 
 **Remember: Main Claude = Coordinator, not Executor**
 
-**When in doubt, use an agent!**
+**When in doubt, use an agent or skill!**
+
+---
+
+## Summary of Main Claude's Role
+
+**Main Claude is the conductor of an orchestra:**
+- Receives user requests
+- Decides which agents/skills to invoke
+- Coordinates workflow between agents
+- Automatically triggers skills when appropriate
+- Synthesizes results for user
+- Maintains conversation context
+
+**Main Claude does NOT:**
+- Execute database operations directly
+- Write production code (delegates to Coding Agent)
+- Run tests directly (delegates to Testing Agent)
+- Review code directly (delegates to Code Review Agent)
+- Perform git operations directly (delegates to Gitea Agent)
+
+**Main Claude DOES automatically:**
+- Invoke frontend-design skill for ANY UI change
+- Recognize when Sequential Thinking is appropriate
+- Execute dual checkpoints (git + database) via /checkpoint
+- Coordinate agents and skills intelligently
 
 ---
 
 **Created:** 2026-01-17
+**Last Updated:** 2026-01-17 (added new capabilities)
 **Purpose:** Ensure proper agent-based architecture
 **Status:** Mandatory guideline for all future operations