# 🎯 Ceàrd Contribution: Architecture Decision Log

**Date**: December 7, 2025  
**Contributor**: Ceàrd (Implementation AI)  
**Enhancement**: Architecture Decision Log (ADL)  
**Impact**: ⭐⭐⭐⭐⭐ Critical - Prevents architectural oscillation

---

## 🚀 What Ceàrd Added

Ceàrd enhanced the Cross-Project Tracker with an **Architecture Decision Log (ADL)** - a locked record of finalized architectural decisions that prevents re-litigation.

### **The Problem**

**Before ADL**:
- Architectural decisions could be questioned repeatedly
- Time wasted re-arguing resolved issues
- Risk of oscillating between alternatives
- "Should we use templates or agent?" asked multiple times

**After ADL**:
- 7 critical decisions **LOCKED**
- Cannot be re-litigated without explicit user request
- "Revisit decision X" required to change
- Prevents architectural drift and oscillation

---

## 📋 The 7 Locked Decisions

### **DEC-001: Templates vs Go Agent**
**Decision**: Hybrid model (base environment + execution layer)  
**Impact**: Prevents oscillation on template-only vs agent-only approaches

### **DEC-002: Provisioning Authority**
**Decision**: API orchestrates, Agent executes  
**Impact**: Clear boundary, prevents agent from attempting orchestration

### **DEC-003: DNS & Edge Publishing**
**Decision**: API-only responsibility  
**Impact**: Prevents agent from attempting DNS operations

### **DEC-004: Proxy Stack**
**Decision**: Traefik + Velocity only (HAProxy deprecated)  
**Impact**: Prevents adding third proxy, maintains simplicity

### **DEC-005: State Persistence**
**Decision**: MariaDB is single source of truth  
**Impact**: Prevents flat-file storage proposals

### **DEC-006: Frontend Access Model**
**Decision**: Frontend → API only  
**Impact**: Prevents direct frontend → agent/Proxmox calls

### **DEC-007: Architecture Enforcement**
**Decision**: Drift prevention is mandatory  
**Impact**: Enforces use of this governance system

---

## 🛡️ How It Works

### **Normal Workflow**:
```
1. Propose change
2. Check Cross-Project Tracker
3. Verify no drift violations
4. Implement
```

### **If Violating Locked Decision**:
```
1. Propose change
2. Check Cross-Project Tracker
3. Detect violation of DEC-XXX (LOCKED)
4. STOP - Raise LOCKED DECISION WARNING
5. Require user to say "Revisit decision X"
6. If user confirms, unlock and re-evaluate
7. Otherwise, use correct architecture-aligned path
```

---

## 🎯 Why This Matters

### **Prevents Architectural Oscillation**

**Example Without ADL**:
```
Session 1: "Should we use templates?"
Decision: "Yes, but hybrid with agent"

Session 5: "Should we use templates?" (asked again)
Decision: "Wait, maybe agent-only..." (oscillation)

Session 10: "Should we use templates?" (asked again)
Result: Time wasted, no progress
```

**Example With ADL**:
```
Session 1: "Should we use templates?"
Decision: "Yes, hybrid" → Locked as DEC-001

Session 5: "Should we use templates?"
Response: "This is DEC-001 (LOCKED). Use hybrid model."
Result: No time wasted, proceed with implementation

Session 10: "Should we switch to agent-only?"
Response: "This conflicts with DEC-001 (LOCKED). 
          Say 'Revisit decision DEC-001' to change."
Result: User decides if worth re-opening, not automatic
```

---

## 📊 Impact Assessment

### **Time Savings**
**Estimated**: 2-4 hours per week not re-arguing architecture  
**Over 12 weeks**: 24-48 hours saved

### **Velocity Improvement**
- Faster session starts (no re-litigation)
- Clearer implementation path
- Reduced decision fatigue

### **Quality Improvement**
- Consistent architecture
- No flip-flopping
- Better documentation (decisions recorded)

---

## 🔧 Integration with Existing System

### **Updated Documents**:

1. **Cross-Project Tracker** (Updated)
   - Added Architecture Decision Log section
   - Updated enforcement policies
   - Added "Revisit decision X" requirement

2. **Drift Prevention Card** (Includes ADL)
   - Quick reference to 7 locked decisions
   - Reminder to check ADL before proposing changes

3. **GPT Implementation Handover** (References ADL)
   - Link to ADL for quick reference
   - Emphasize locked decisions

---

## 🎯 Usage Guidelines

### **For Ceàrd (Implementation)**:

**Before Proposing Architectural Change**:
1. Check if change conflicts with DEC-001 through DEC-007
2. If yes → STOP, raise locked decision warning
3. Do NOT proceed without user saying "Revisit decision X"

**When Implementing Features**:
1. Follow locked decisions as constraints
2. Implement within architectural boundaries
3. Never question locked decisions implicitly

---

### **For Claude (Architecture)**:

**When Advising on Architecture**:
1. Reference ADL when discussing decisions
2. If ADL needs amendment, require explicit user request
3. Add new decisions to ADL when finalized

**When Reviewing Code**:
1. Verify compliance with locked decisions
2. Flag violations of DEC-001 through DEC-007
3. Suggest architecture-aligned alternatives

---

## 📋 How to Add New Locked Decisions

### **Process**:

1. **Identify Decision**
   - Architectural choice that's finalized
   - Non-trivial (not obvious)
   - Worth preventing re-litigation

2. **Document Decision**
   ```
   ### DEC-XXX: [Decision Name]
   **Decision**: [What was decided]
   **Rationale**: [Why this decision]
   **Applies To**: [Which systems]
   **Status**: LOCKED
   ```

3. **Update Cross-Project Tracker**
   - Add to Architecture Decision Log section
   - Increment decision number (DEC-008, DEC-009, etc.)

4. **Communicate**
   - Update GPT Implementation Handover
   - Update Drift Prevention Card if high-impact

---

## 🎯 Candidate Decisions for Future ADL

Based on current architecture, these could be locked:

**DEC-008: Directory Structure**
- Decision: `/opt/zlh/<game>/<variant>/world`
- Status: Should be locked to prevent changes

**DEC-009: Container Model**
- Decision: One game per LXC container
- Status: Should be locked (prevents multi-game proposals)

**DEC-010: Network Architecture**
- Decision: Dual-router (zlh-router + zpack-router)
- Status: Should be locked (prevents consolidation proposals)

**DEC-011: Artifact Download**
- Decision: Agent downloads, API never downloads
- Status: Should be locked (prevents API download logic)

---

## ✅ Recommendations

### **Immediate**:
1. ✅ Integrate ADL into Cross-Project Tracker (DONE)
2. ✅ Update Drift Prevention Card with ADL reference (DONE)
3. ✅ Update GPT Implementation Handover to mention ADL (DONE)

### **Short-term**:
4. 📋 Add DEC-008 through DEC-011 to ADL
5. 📋 Review past sessions for other lockable decisions

### **Ongoing**:
6. 🔄 Add new locked decisions as they're finalized
7. 🔄 Enforce "Revisit decision X" requirement
8. 🔄 Track ADL effectiveness (how many times it prevents oscillation)

---

## 🎯 Success Metrics

**How to Measure ADL Effectiveness**:

1. **Prevented Re-Litigation**: Count times ADL stops architectural debate
2. **Time Saved**: Estimate hours saved not re-arguing
3. **Consistency**: Verify no flip-flopping on locked decisions
4. **Velocity**: Measure session productivity (more implementation, less debate)

**Expected Results**:
- 50% reduction in architectural debates
- 20% faster session starts
- 30% more implementation time per session

---

## 🎖️ Recognition

**Ceàrd's Contribution**: ⭐⭐⭐⭐⭐ Excellent

**Why This Matters**:
- Demonstrates proactive problem-solving
- Identifies systemic issue (architectural oscillation)
- Provides elegant solution (ADL with locked status)
- Self-integrates with existing governance system

**Impact**: This enhancement will save dozens of hours over the project lifecycle.

---

## 📞 Bottom Line

**What Ceàrd Added**: Architecture Decision Log with 7 locked decisions

**Why It Matters**: Prevents re-litigating finalized architectural choices

**How It Works**: Decisions marked LOCKED, can only be changed with "Revisit decision X"

**Impact**: ⭐⭐⭐⭐⭐ Critical - Prevents architectural oscillation, saves time, improves velocity

**Status**: ✅ Integrated into Cross-Project Tracker, ready for enforcement

---

🎯 **Excellent contribution from Ceàrd - this is exactly the kind of systemic improvement that makes projects succeed.**