Persistent Memory

Core Principle

Memory is context that survives sessions. Use it strategically—store what matters, retrieve efficiently, protect what's private.

When to Use This Skill

• Working on multi-session projects
• Need to recall previous decisions
• Building on past work
• Maintaining project context
• Debugging issues that span sessions
• Onboarding to existing projects

The Iron Law

MEMORY IS NOT FREE. RETRIEVE SELECTIVELY.

Every token of context costs. Don't dump entire history—search and fetch only what's relevant.

Why Persistent Memory?

Benefits:

• Continue where you left off
• Recall past decisions and rationale
• Maintain consistency across sessions
• Build institutional knowledge
• Reduce repetitive explanations
• Track project evolution

Without persistent memory:

• Start fresh every session
• Repeat context explanations
• Forget past decisions
• Lose architectural rationale
• Inconsistent approaches
• No learning from history

Memory Architecture

┌─────────────────────────────────────────────────────────┐
│                    MEMORY SYSTEM                         │
│                                                          │
│  ┌──────────────┐    ┌──────────────┐    ┌───────────┐ │
│  │   Capture    │───▶│    Store     │───▶│  Retrieve │ │
│  │  (Hooks)     │    │  (SQLite +   │    │  (Search) │ │
│  │              │    │   Vectors)   │    │           │ │
│  └──────────────┘    └──────────────┘    └───────────┘ │
│         │                   │                   │       │
│         ▼                   ▼                   ▼       │
│  ┌──────────────┐    ┌──────────────┐    ┌───────────┐ │
│  │ Session      │    │ Observations │    │ Summaries │ │
│  │ Lifecycle    │    │ & Context    │    │ & Answers │ │
│  └──────────────┘    └──────────────┘    └───────────┘ │
└─────────────────────────────────────────────────────────┘

Setup with claude-mem

Installation

# Install the plugin
/plugin marketplace add thedotmack/claude-mem
/plugin install claude-mem

# Restart Claude Code
# Memory automatically starts capturing

Verify Installation

# Check the web UI
open http://localhost:37777

# Memory service should be running on port 37777

Configuration

The plugin captures automatically via lifecycle hooks:

• SessionStart - New session begins
• UserPromptSubmit - User sends message
• PostToolUse - Tool execution complete
• Stop - Task completed
• SessionEnd - Session ends

Memory Best Practices

1. What to Remember

DO store:

• Architectural decisions and rationale
• Project conventions and patterns
• Bug fixes and their root causes
• Configuration choices
• API contracts and schemas
• Team preferences

DON'T store:

• Temporary debugging output
• Sensitive credentials
• Large file contents
• Trivial operations

2. Privacy Controls

Use <private> tags to exclude sensitive content:

Here's the database config:
<private>
DATABASE_URL=postgres://user:password@host:5432/db
API_KEY=sk-secret-key-here
</private>

The schema uses PostgreSQL with these tables...

Content within <private> tags is NOT stored in memory.

3. Efficient Retrieval

Memory retrieval uses a three-layer workflow:

Layer 1: Search Index
  └── Quick keyword/semantic match
  └── Returns: observation IDs + snippets
  └── Cost: ~100 tokens

Layer 2: Timeline Context
  └── Fetch surrounding observations
  └── Returns: chronological context
  └── Cost: ~500 tokens

Layer 3: Full Details
  └── Fetch complete observations
  └── Returns: full content
  └── Cost: varies (can be large)

Best practice: Start with Layer 1, only go deeper if needed.

4. Querying Memory

# Good queries (specific)
"How did we implement authentication?"
"What was the decision on database schema?"
"Why did we choose React over Vue?"

# Poor queries (too broad)
"What did we do?"
"Show me everything"
"All past work"

5. Memory Hygiene

Periodically review and clean:

# Access web UI to browse memory
open http://localhost:37777

# Review recent sessions
# Delete irrelevant observations
# Check storage usage

Integration Patterns

Pattern 1: Session Continuity

# At session start
"Check memory for our previous work on the authentication feature.
What was our approach and what's left to do?"

# Memory retrieves relevant context automatically

Pattern 2: Decision Recall

# When making architectural decisions
"Search memory for past discussions about state management.
What approaches did we consider and why did we choose Redux?"

Pattern 3: Bug Investigation

# When debugging recurring issues
"Search memory for similar errors we've seen before.
How did we fix the authentication timeout issue last time?"

Pattern 4: Onboarding Context

# When starting on existing project
"Retrieve memory summaries for this project.
What are the key architectural decisions and conventions?"

Memory-Aware Workflow

Starting a Session

1. Claude automatically loads relevant memory
2. Review injected context (check token cost)
3. Ask clarifying questions if context seems incomplete
4. Proceed with task

During Work

1. Important decisions → explicitly note rationale
2. Sensitive data → use <private> tags
3. Complex solutions → document approach
4. Errors fixed → note root cause

Ending a Session

1. Summarize what was accomplished
2. Note any pending work
3. Document blockers or questions
4. Memory auto-captures on session end

Token Efficiency

Understanding Costs

The web UI shows token costs for context injection:

Context Type	Typical Tokens	When to Use
Session summary	100-300	Always (automatic)
Search results	200-500	Specific queries
Full observation	500-2000	Deep dive needed
Timeline context	300-800	Understanding sequence

Optimization Strategies

1. Use specific queries
   ❌ "What do you know?"
   ✅ "What's our API rate limiting strategy?"

2. Progressive disclosure
   - Start with summaries
   - Drill down only if needed
   - Don't fetch everything

3. Prune irrelevant results
   - Skip old/outdated context
   - Focus on recent sessions
   - Filter by relevance

Troubleshooting

Memory Not Capturing

# Check if service is running
curl http://localhost:37777/health

# Verify plugin is installed
/plugin list

# Reinstall if needed
/plugin uninstall claude-mem
/plugin install claude-mem

Search Not Finding Results

1. Try different keywords
2. Use semantic queries (describe what you mean)
3. Check date range
4. Verify content wasn't marked <private>

High Token Usage

1. Review what's being injected
2. Use more specific queries
3. Disable automatic context for trivial tasks
4. Clean old irrelevant observations

Common Mistakes

Mistake	Impact	Fix
Storing secrets	Security risk	Use <private> tags
Retrieving everything	Token explosion	Query specifically
Ignoring memory	Repeated work	Check memory first
No privacy tags	Credentials exposed	Tag sensitive content
Stale memory	Wrong context	Periodically clean

Integration with Other Skills

Use with:

• rag-architecture - Memory as knowledge source
• agentic-design - Long-term agent memory
• llm-integration - Context management
• subagent-driven-development - Cross-task context

Enhances:

• brainstorming - Recall past ideas
• code-review - Remember past issues
• writing-plans - Build on previous plans

Checklist

Before relying on memory:

• Plugin installed and running
• Web UI accessible at localhost:37777
• Privacy tags used for sensitive data
• Token costs understood
• Retrieval queries specific

During sessions:

• Important decisions documented
• Rationale captured
• Sensitive content tagged private
• Context retrieved efficiently

Authority

Based on:

• claude-mem plugin by @thedotmack
• Vector database best practices
• Information retrieval research
• Context window optimization patterns

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Bottom Line: Memory extends context across sessions. Store decisions, protect secrets, retrieve selectively. Every token costs—be strategic about what you recall.