# Phase 4: Observability & Tracing - Implementation Summary

**Version**: 1.5.0  
**Date**: January 25, 2026  
**Status**: COMPLETE

---

## Overview

Phase 4 implements comprehensive observability and tracing for SkillFoundry Framework, providing full visibility into agent activities, decisions, metrics, and performance.

---

## ✅ Completed Features

### 1. Observability Infrastructure

#### Observability Manager (`observability/observability-manager.js`)
- ✅ **Unified Interface**: Single entry point for all observability operations
- ✅ **Singleton Pattern**: Global access to observability features
- ✅ **Automatic Integration**: Combines trace logging, metrics collection, and auditing
- ✅ **Metrics Persistence**: Automatic saving every 10 actions

#### Trace Logger (`observability/trace-logger.js`)
- ✅ **Structured Logging**: JSONL format for efficient storage and parsing
- ✅ **Session Management**: Unique session IDs for each execution
- ✅ **Distributed Tracing**: Trace IDs and span IDs for request correlation
- ✅ **Span Hierarchy**: Parent-child span relationships
- ✅ **Decision Logging**: Separate decision log for key decisions
- ✅ **Trace Retrieval**: Get session traces by date

#### Metrics Collector (`observability/metrics-collector.js`)
- ✅ **Token Tracking**: Total tokens, by agent, by action
- ✅ **Latency Measurement**: Average latency, by agent, by action
- ✅ **Error Tracking**: Error counts, rates, by agent, by type, by action
- ✅ **Action Counting**: Total actions, by agent, by status
- ✅ **Session Tracking**: Unique session counting
- ✅ **Metrics Summary**: Comprehensive summary with averages and rates
- ✅ **Persistence**: Save/load metrics from JSON file

#### Audit Logger (`observability/audit-logger.js`)
- ✅ **Story Completion**: Track story completion events
- ✅ **Security Events**: Log security-related events with severity
- ✅ **Decisions**: Log agent decisions with context
- ✅ **File Operations**: Track file create/update/delete/read operations
- ✅ **Agent Actions**: Log all agent actions with results
- ✅ **Audit Trail**: Retrieve and search audit logs

---

### 2. Trace Viewer

#### Trace Viewer Server (`observability/trace-viewer-server.js`)
- ✅ **Express.js Server**: RESTful API for trace data
- ✅ **Session Listing**: List all sessions for a given date
- ✅ **Trace Retrieval**: Get full trace for a session
- ✅ **Metrics API**: Get metrics summary
- ✅ **Audit API**: Get audit trail by category
- ✅ **Health Endpoint**: Server health check

#### Trace Viewer Client (`logs/dashboards/trace-viewer.html`)
- ✅ **Web Interface**: Modern dark theme UI
- ✅ **Timeline View**: Visual timeline of agent activities
- ✅ **Metrics Dashboard**: Summary cards with key metrics
- ✅ **Session Selection**: Date and session filtering
- ✅ **Trace Details**: Expandable trace entry details
- ✅ **Error Highlighting**: Visual distinction for errors

---

## 📊 Architecture

```
observability/
├── observability-manager.js    # Unified interface
├── trace-logger.js              # Trace logging
├── metrics-collector.js         # Metrics collection
├── audit-logger.js              # Audit logging
├── trace-viewer-server.js       # Web server
└── package.json                 # Dependencies

logs/
├── traces/
│   ├── 2026-01-25/
│   │   ├── session-abc123.jsonl
│   │   └── decisions.jsonl
│   └── metrics.json
├── audit/
│   ├── story-completion.jsonl
│   ├── security-events.jsonl
│   ├── decisions.jsonl
│   ├── file-operations.jsonl
│   └── agent-actions.jsonl
└── dashboards/
    └── trace-viewer.html
```

---

## 🎯 Key Features

### Trace Entry Format
```json
{
  "timestamp": "2026-01-25T12:34:56Z",
  "session_id": "session-123",
  "trace_id": "trace-xyz",
  "span_id": "span-001",
  "agent": "coder",
  "action": "implement_endpoint",
  "input": {...},
  "output": {...},
  "metrics": {
    "tokens_used": 2340,
    "latency_ms": 1250
  },
  "reflection": {
    "self_score": 8
  },
  "status": "success"
}
```

### Metrics Summary
- Total tokens used
- Average latency per agent
- Error rates
- Action counts by status
- Session counts

### Audit Trail
- Story completions
- Security events
- Decisions
- File operations
- Agent actions

---

## 📦 Usage

### In Agent Code

```javascript
import { getObservabilityManager } from './observability/observability-manager.js';

const obs = getObservabilityManager();
await obs.initialize();

// Start action
const spanId = await obs.startAction('coder', 'implement_endpoint', {
  story_id: 'STORY-003',
  endpoint: '/api/v1/auth/refresh'
});

try {
  // Execute action
  const result = await implementEndpoint();
  
  // End action with metrics
  await obs.endAction(spanId, result, {
    tokens_used: result.tokensUsed,
    latency_ms: Date.now() - startTime
  }, {
    self_score: 8
  }, 'success');
} catch (error) {
  await obs.endAction(spanId, {}, {}, {}, 'error', error);
}
```

### Start Trace Viewer

```bash
# Linux/Mac
./scripts/start-trace-viewer.sh

# Windows
.\scripts\start-trace-viewer.ps1

# Access at http://localhost:3001
```

---

## 📊 Statistics

### Code Added
- **Observability Infrastructure**: ~800 lines of Node.js code
- **Trace Viewer**: ~200 lines (server + client)
- **Total**: ~1,000 lines of production-ready code

### Files Created
- **Observability**: 5 JavaScript files + package.json
- **Trace Viewer**: 1 HTML file
- **Scripts**: 2 start scripts (bash + PowerShell)
- **Documentation**: 1 implementation guide

---

## 🚀 Benefits

1. **Full Visibility**: See exactly what agents are doing
2. **Performance Tracking**: Identify bottlenecks and slow operations
3. **Debugging**: Trace issues through complete execution flow
4. **Optimization**: Use metrics to improve agent performance
5. **Compliance**: Audit trail for security and compliance
6. **Decision Tracking**: Understand why agents made certain decisions
7. **Error Analysis**: Track error patterns and rates

---

## 🔄 Integration Points

### With Agents
- All agents can use observability manager
- Automatic metrics collection
- Reflection scores included in traces
- Error tracking automatic

### With Dashboard
- Trace viewer can be integrated into main dashboard
- Metrics can be displayed in charts
- Audit trail can be shown in separate view

### With Memory System
- Traces can be stored in memory bank
- Decisions can be linked to memory entries
- Metrics can inform weight adjustments

---

**Completion Date**: January 25, 2026  
**Version**: 1.5.0  
**Status**: ✅ COMPLETE
