Agent Memory System

Overview

agent-memory-system provides persistent memory architecture enabling AI agents to remember across sessions, learn from experience, and build long-term knowledge.

Purpose: Enable true continuous improvement through persistent memory

Pattern: Capabilities-based (4 memory types with independent operations)

Key Innovation: Multi-layered memory architecture (episodic, procedural, semantic, short-term) enabling agents to learn and adapt over time

Core Principles:

1. Episodic Memory - Remember specific past events and decisions
2. Procedural Memory - Learn and improve skills over time
3. Semantic Memory - Build knowledge graphs of facts and relationships
4. Short-Term Memory - Active working context

---

When to Use

Use agent-memory-system when:

• Building agents that learn from experience
• Preserving context across multiple sessions
• Implementing personalization (remember user preferences)
• Creating adaptive systems (improve over time)
• Long-running projects (remember decisions made weeks ago)
• Skill improvement tracking (what works, what doesn't)

---

Prerequisites

Required

• File system access (for file-based memory)
• JSON support (for structured memory storage)

Optional

• Vector database (Pinecone, Weaviate, Chroma) for episodic memory
• Graph database (Neo4j) for semantic memory
• Redis for fast short-term memory

Understanding

• Memory types and when to use each
• Trade-offs (file-based vs. database)

---

Memory Types

Memory Type 1: Episodic Memory

What: Remembers specific past events, decisions, and their outcomes

Use When: Need to recall "What happened last time we tried X?"

Storage: Vector database (similarity search) or timestamped JSON files

Structure:

{
  "episode_id": "ep_20250115_1530",
  "timestamp": "2025-01-15T15:30:00Z",
  "event_type": "implementation",
  "description": "Implemented user authentication with OAuth",
  "context": {
    "objective": "Add OAuth to existing password auth",
    "approach": "Expand-migrate-contract pattern",
    "decisions": [
      {
        "question": "JWT vs Sessions?",
        "choice": "JWT",
        "rationale": "Stateless, scales better"
      }
    ],
    "outcomes": {
      "quality_score": 94,
      "test_coverage": 89,
      "time_actual": "6.5 hours",
      "time_estimated": "5 hours"
    },
    "learnings": [
      "OAuth token refresh needs explicit testing",
      "Expand-migrate-contract took longer than estimated"
    ]
  },
  "tags": ["authentication", "oauth", "implementation"],
  "embedding": [0.123, -0.456, ...] // For similarity search
}

Operations:

1. Store Episode: Save event after completion
2. Recall Similar: Find similar past episodes (vector similarity)
3. Query by Tag: Retrieve all episodes with specific tags
4. Learn from Outcomes: Extract patterns from successful episodes

Queries:

# Find similar past implementations
recall-episode --similar "implementing OAuth" --top 5

# Find all authentication-related episodes
recall-episode --tag authentication

# Learn from failures
recall-episode --filter "quality_score < 80" --analyze

Benefits:

• Avoid repeating mistakes
• Apply successful patterns
• Improve estimation accuracy
• Faster decision-making

Storage:

• Simple: JSON files in .memory/episodic/YYYY-MM-DD/
• Advanced: Vector DB for semantic search

---

Memory Type 2: Procedural Memory

What: Learned skills, successful patterns, automation rules

Use When: "How do we usually do X?" or "What's our standard approach for Y?"

Storage: Structured files or code patterns

Structure:

{
  "skill_id": "implement_authentication",
  "skill_name": "Implementing Authentication Systems",
  "learned_from": [
    "ep_20250115_1530",
    "ep_20250120_1045",
    "ep_20250125_1400"
  ],
  "pattern": {
    "approach": "Expand-migrate-contract",
    "steps": [
      "1. Add new auth alongside existing",
      "2. Dual-write period (both methods work)",
      "3. Migrate users gradually",
      "4. Deprecate old auth"
    ],
    "pitfalls": [
      "Always test token refresh explicitly",
      "Plan for 20% longer than estimated (migrations complex)"
    ],
    "success_criteria": {
      "quality_score": ">= 90",
      "test_coverage": ">= 85",
      "backward_compatible": true
    }
  },
  "usage_count": 3,
  "success_rate": 1.0,
  "avg_quality_score": 93.3,
  "avg_time_hours": 6.2,
  "last_used": "2025-01-25T14:00:00Z"
}

Operations:

1. Extract Pattern: Learn pattern from successful episodes
2. Store Skill: Save learned procedural knowledge
3. Apply Skill: Use learned pattern for new task
4. Improve Skill: Update based on new experiences

Queries:

# Get learned pattern for authentication
get-skill "authentication implementation"

# Find most successful patterns
list-skills --sort-by success_rate --top 10

# Update skill with new learning
update-skill "authentication" --episode ep_20250125_1400

Benefits:

• Codify successful patterns
• Improve patterns over time
• Share knowledge across team
• Faster implementation (apply proven patterns)

Storage: .memory/procedural/skills/

---

Memory Type 3: Semantic Memory

What: Facts, relationships, knowledge graph of concepts

Use When: "What's the relationship between X and Y?" or "What do we know about Z?"

Storage: Graph database (Neo4j) or JSON with relationships

Structure:

{
  "concepts": [
    {
      "id": "oauth",
      "type": "technology",
      "description": "OAuth 2.0 authorization framework",
      "properties": {
        "security_level": "high",
        "complexity": "medium",
        "browser_required": true
      },
      "relationships": [
        {
          "type": "used_by",
          "target": "user_authentication",
          "weight": 0.95
        },
        {
          "type": "requires",
          "target": "jwt",
          "weight": 0.85
        },
        {
          "type": "alternative_to",
          "target": "password_auth",
          "weight": 0.7
        }
      ]
    }
  ],
  "facts": [
    {
      "subject": "oauth",
      "predicate": "supports",
      "object": "multiple_providers",
      "confidence": 1.0,
      "source": "ep_20250115_1530"
    }
  ]
}

Operations:

1. Store Fact: Add new knowledge
2. Query Knowledge: Retrieve facts about concepts
3. Find Relationships: Navigate knowledge graph
4. Infer Knowledge: Deduce new facts from relationships

Queries:

# What do we know about OAuth?
query-knowledge "oauth"

# What are alternatives to password auth?
query-knowledge "password_auth" --relationship alternative_to

# Find all authentication methods
query-knowledge --type authentication_method

Benefits:

• Build institutional knowledge
• Understand concept relationships
• Make informed decisions
• Avoid knowledge loss

Storage:

• Simple: JSON files in .memory/semantic/
• Advanced: Neo4j graph database

---

Memory Type 4: Short-Term Memory

What: Active working context, current session state

Use When: Need to remember within current conversation

Storage: RAM or Redis (fast access)

Structure:

{
  "session_id": "session_20250126_1200",
  "started_at": "2025-01-26T12:00:00Z",
  "current_task": "Implementing user authentication",
  "context": {
    "files_read": [
      "src/auth/login.ts",
      "src/auth/tokens.ts"
    ],
    "decisions_made": [
      {"what": "Use JWT", "why": "Stateless scaling"}
    ],
    "next_steps": [
      "Implement token refresh",
      "Add rate limiting"
    ]
  },
  "temporary_data": {
    "research_findings": "...",
    "plan_summary": "..."
  }
}

Operations:

1. Set Context: Store current working data
2. Get Context: Retrieve active context
3. Update Context: Modify current state
4. Clear Context: Reset working memory

Benefits:

• Fast access to current state
• No context window pollution
• Efficient session management

Storage: File in .memory/short-term/current-session.json

---

Core Operations

Operation 1: Store Memory

Purpose: Save information to appropriate memory type

Process:

// Store episodic memory
await storeMemory({
  type: 'episodic',
  event: {
    description: 'Implemented OAuth authentication',
    decisions: [...],
    outcomes: {...},
    learnings: [...]
  },
  tags: ['authentication', 'oauth', 'implementation']
});

// Store procedural memory (learned pattern)
await storeMemory({
  type: 'procedural',
  skillName: 'Implementing Authentication',
  pattern: {
    approach: 'Expand-migrate-contract',
    steps: [...],
    pitfalls: [...]
  }
});

// Store semantic memory (fact)
await storeMemory({
  type: 'semantic',
  fact: {
    subject: 'oauth',
    predicate: 'requires',
    object: 'jwt',
    confidence: 0.95
  }
});

Outputs:

• Memory persisted to storage
• Indexed for retrieval
• Timestamped

---

Operation 2: Recall Memory

Purpose: Retrieve relevant memories for current task

Process:

// Recall similar episodes
const similarEpisodes = await recallMemory({
  type: 'episodic',
  query: 'implementing authentication',
  limit: 5
});

// Recall learned patterns
const authPattern = await recallMemory({
  type: 'procedural',
  skillName: 'Implementing Authentication'
});

// Query knowledge
const oauthFacts = await recallMemory({
  type: 'semantic',
  concept: 'oauth'
});

Outputs:

• Relevant memories retrieved
• Ranked by relevance/recency
• Ready to inform current decisions

---

Operation 3: Learn from Experience

Purpose: Extract patterns and update procedural memory

Process:

1. Analyze Episodes:

   // Get all authentication implementations
   const authEpisodes = await recallMemory({
     type: 'episodic',
     tags: ['authentication', 'implementation']
   });
   
   // Extract patterns
   const patterns = analyzePatterns(authEpisodes);
   // - Approach used: expand-migrate-contract (3/3 times)
   // - Avg quality score: 93.3
   // - Common pitfall: Token refresh testing (3/3 missed initially)

2. Update Procedural Memory:

   await storeMemory({
     type: 'procedural',
     skillName: 'Implementing Authentication',
     pattern: {
       approach: 'expand-migrate-contract', // Learned from all 3 episodes
       common_pitfall: 'Always test token refresh explicitly', // Learned
       quality_target: '>= 93', // Based on historical avg
       time_estimate: '6-7 hours' // Based on historical data
     },
     learnedFrom: authEpisodes.map(ep => ep.id),
     confidence: 0.95 // High (based on 3 episodes)
   });

Outputs:

• Learned patterns codified
• Procedural memory updated
• Future decisions informed by experience

---

Operation 4: Personalize

Purpose: Adapt to user preferences and patterns

Process:

// Track user preferences
const preferences = await recall Memory({
  type: 'semantic',
  concept: 'user_preferences'
});

// Learn from usage patterns
const userPatterns = {
  preferred_approach: 'TDD', // User always uses TDD
  testing_thoroughness: 'high', // User requests >=95% coverage
  verification_level: 'all_layers', // User runs all 5 layers
  commit_style: 'conventional' // User uses conventional commits
};

// Apply personalization
if (userPatterns.preferred_approach === 'TDD') {
  // Auto-suggest TDD workflow
  // Skip asking "test-first or code-first?"
}

Outputs:

• Personalized recommendations
• Reduced repetitive questions
• Faster workflows

---

Cross-Session Integration

Session Start Integration

Hook: SessionStart hook loads memory

#!/bin/bash
# .claude/hooks/load-memory.sh (SessionStart)

echo "📚 Loading agent memory..."

# Load short-term memory from last session
if [ -f ".memory/short-term/last-session.json" ]; then
  echo "  └─ Previous session context available"
  # Claude can read this file to continue work
fi

# Load recent episodic memories (last 7 days)
RECENT_EPISODES=$(find .memory/episodic/ -name "*.json" -mtime -7 | wc -l)
echo "  └─ Recent episodes: $RECENT_EPISODES"

# Load active skills
LEARNED_SKILLS=$(ls .memory/procedural/skills/ | wc -l)
echo "  └─ Learned skills: $LEARNED_SKILLS"

echo "✅ Memory loaded"

---

Session End Integration

Hook: SessionEnd hook saves memory

#!/bin/bash
# .claude/hooks/save-memory.sh (SessionEnd)

echo "💾 Saving agent memory..."

# Save current session to episodic memory
if [ -f ".memory/short-term/current-session.json" ]; then
  TIMESTAMP=$(date +%Y%m%d_%H%M%S)
  cp .memory/short-term/current-session.json \
     .memory/episodic/$(date +%Y-%m-%d)/session_$TIMESTAMP.json

  echo "  └─ Episode saved"
fi

# Extract learnings if quality was high
# (Automated learning extraction)

echo "✅ Memory saved"

---

Memory Architecture

File-Based Memory (Simple)

Structure:

.memory/
├── episodic/              # Past events
│   ├── 2025-01-15/
│   │   ├── session_153000.json
│   │   └── decision_153045.json
│   └── 2025-01-16/
│       └── session_090000.json
├── procedural/            # Learned skills
│   └── skills/
│       ├── authentication_impl.json
│       ├── testing_pattern.json
│       └── verification_approach.json
├── semantic/              # Knowledge graph
│   ├── concepts.json
│   └── relationships.json
└── short-term/            # Active session
    ├── current-session.json
    └── last-session.json (backup)

Benefits:

• Simple (no database required)
• Version-controllable
• Human-readable
• Easy backup

Limitations:

• No semantic search
• Manual indexing needed
• Slower for large datasets

---

Database-Backed Memory (Advanced)

Episodic (Vector DB):

• Pinecone: Managed, fast, expensive
• Weaviate: Self-hosted, flexible
• Chroma: Lightweight, good for prototypes

Semantic (Graph DB):

• Neo4j: Industry standard
• AgensGraph: PostgreSQL-based
• NetworkX: Python library (simple graphs)

Short-Term (Cache):

• Redis: Fast, ephemeral
• Memcached: Simple caching

Benefits:

• Semantic search (similarity, relationships)
• Fast queries at scale
• Advanced capabilities

Limitations:

• Infrastructure complexity
• Cost (hosted solutions)
• Deployment overhead

---

Integration with Multi-AI Skills

With multi-ai-implementation

Before Implementation (recall relevant patterns):

// Step 1: Explore - Check memory for similar implementations
const similarWork = await recallMemory({
  type: 'episodic',
  query: currentObjective,
  limit: 3
});

// Apply learnings
if (similarWork.length > 0) {
  console.log("📚 Found similar past work:");
  similarWork.forEach(episode => {
    console.log(`  - ${episode.description}`);
    console.log(`    Quality: ${episode.outcomes.quality_score}`);
    console.log(`    Learnings: ${episode.learnings.join(', ')}`);
  });
}

// Step 2: Plan - Use learned patterns
const authPattern = await recallMemory({
  type: 'procedural',
  skillName: 'Implementing Authentication'
});

if (authPattern) {
  console.log("📖 Applying learned pattern:");
  console.log(`  Approach: ${authPattern.pattern.approach}`);
  console.log(`  Estimated time: ${authPattern.avg_time_hours} hours`);
}

After Implementation (save episode):

// Step 6: Commit - Save to episodic memory
await storeMemory({
  type: 'episodic',
  event: {
    description: 'Implemented user authentication',
    decisions: capturedDuringImplementation,
    outcomes: {
      quality_score: 94,
      test_coverage: 89,
      time_actual: 6.5,
      time_estimated: 5
    },
    learnings: [
      'Token refresh needs explicit testing',
      'Estimation was 30% low'
    ]
  }
});

// Extract and update patterns
await learnFromExperience(['authentication', 'implementation']);

---

With multi-ai-planning

Before Planning:

// Recall similar plans
const similarPlans = await recallMemory({
  type: 'episodic',
  query: 'plan for ' + objective,
  filter: 'event_type == "planning"'
});

// Check quality of past plans
if (similarPlans.length > 0) {
  const avgQuality = average(similarPlans.map(p => p.outcomes.quality_score));
  console.log(`📊 Past similar plans averaged ${avgQuality}/100`);
}

After Planning:

// Save plan to memory
await storeMemory({
  type: 'episodic',
  event: {
    event_type: 'planning',
    description: 'Planned OAuth implementation',
    context: {
      tasks: planGenerated.tasks.length,
      quality_score: planGenerated.quality_score,
      estimated_hours: planGenerated.metadata.estimated_total_hours
    }
  }
});

---

With multi-ai-verification

Before Verification:

// Recall common issues for this type of code
const commonIssues = await recallMemory({
  type: 'semantic',
  concept: 'authentication',
  relationship: 'common_issues'
});

// Focus verification on known problem areas
verificationFocus = commonIssues.map(issue => issue.description);

After Verification:

// Save verification results
await storeMemory({
  type: 'episodic',
  event: {
    event_type: 'verification',
    description: 'Verified OAuth implementation',
    outcomes: {
      quality_score: 92,
      layers_passed: 5,
      issues_found: 3,
      time_minutes: 85
    }
  }
});

// Update semantic memory with new facts
if (issues_found.includes('bcrypt_rounds_low')) {
  await storeMemory({
    type: 'semantic',
    fact: {
      subject: 'bcrypt',
      predicate: 'recommended_rounds',
      object: '12-14',
      confidence: 0.95,
      source: 'verification_20250126'
    }
  });
}

---

Memory Management

Memory Lifecycle

Creation (automatic):

• After every skill completion
• After significant decisions
• On verification completion
• On failure (for learning)

Retention (configurable):

• Episodic: 90 days (can extend for important episodes)
• Procedural: Indefinite (patterns persist)
• Semantic: Indefinite (facts persist)
• Short-term: Until session end + 1 backup

Cleanup (automatic):

• Old episodic memories: archive or delete
• Unused procedural patterns: mark inactive
• Low-confidence facts: deprecate
• Short-term: clear after session end

Memory Consolidation

Nightly Process:

#!/bin/bash
# Run nightly (cron job)

# 1. Consolidate recent episodes into patterns
node .memory/scripts/consolidate-episodes.js --days 7

# 2. Update procedural memory
node .memory/scripts/update-skills.js

# 3. Clean up old short-term memory
find .memory/short-term/ -name "*.json" -mtime +7 -delete

# 4. Archive old episodes
find .memory/episodic/ -name "*.json" -mtime +90 -exec mv {} .memory/archive/ \;

# 5. Update knowledge graph
node .memory/scripts/update-knowledge-graph.js

---

Best Practices

1. Store After Every Significant Event

Don't wait until end of project - save continuously

2. Tag Generously

More tags = better recall ("authentication", "security", "oauth", "implementation")

3. Include Context in Episodes

Store enough context to understand decision later

4. Extract Learnings Explicitly

Don't just store what happened - store what you learned

5. Review Memory Periodically

Monthly review: what patterns emerged, what improved, what to change

6. Share Memory Across Team

Semantic and procedural memory are team assets

---

Appendix A: Memory Integration with Hooks

SessionStart: Load Memory

{
  "event": "SessionStart",
  "description": "Load agent memory on session start",
  "handler": {
    "command": ".claude/hooks/load-memory.sh"
  }
}

SessionEnd: Save Memory

{
  "event": "SessionEnd",
  "description": "Save agent memory on session end",
  "handler": {
    "command": ".claude/hooks/save-memory.sh"
  }
}

PostToolUse: Track Decisions

{
  "event": "PostToolUse",
  "tools": ["Write"],
  "description": "Track significant code changes",
  "handler": {
    "command": ".claude/hooks/track-change.sh \"$FILE\" \"$TOOL\""
  }
}

---

Appendix B: Vector DB Integration

Simple Vector Search (File-Based)

# Calculate similarity using embeddings
from sklearn.metrics.pairwise import cosine_similarity
import numpy as np

# Get embedding for current query
query_embedding = get_embedding(current_objective)

# Load all episode embeddings
episodes = load_all_episodes()

# Calculate similarities
similarities = cosine_similarity(
    [query_embedding],
    [ep['embedding'] for ep in episodes]
)[0]

# Get top 5 most similar
top_indices = np.argsort(similarities)[-5:][::-1]
similar_episodes = [episodes[i] for i in top_indices]

Advanced Vector DB (Pinecone)

import pinecone

# Initialize
pinecone.init(api_key="...", environment="...")
index = pinecone.Index("agent-memory")

# Store episode
index.upsert([
    ("ep_20250115_1530", episode_embedding, episode_metadata)
])

# Recall similar
results = index.query(
    query_embedding,
    top_k=5,
    include_metadata=True
)

similar_episodes = [r['metadata'] for r in results['matches']]

---

Quick Reference

The 4 Memory Types

Type	Storage	Retrieval	Retention	Use For
Episodic	Vector DB or timestamped JSON	Similarity search	90 days	"What happened when we did X?"
Procedural	JSON files	Name/tag lookup	Indefinite	"How do we usually do Y?"
Semantic	Graph DB or JSON	Concept queries	Indefinite	"What do we know about Z?"
Short-Term	RAM/Redis or JSON	Direct access	Session only	"What's the current context?"

Memory Operations

Operation	Purpose	Complexity	Time
Store	Save memory	Low	Instant
Recall	Retrieve memory	Low-Medium	<1s file, <100ms DB
Learn	Extract patterns	Medium	Minutes
Personalize	Adapt to user	Medium	Ongoing

---

agent-memory-system enables persistent memory across sessions, allowing agents to learn from experience, improve over time, and build institutional knowledge - the foundation for truly adaptive AI systems.

For integration examples, see examples/. For database setup, see Appendix B.