30 Days of Stress Testing an AI Agent Memory System
30 Days of Stress Testing an AI Agent Memory System
Thirty days of stress testing your own memory system reveals uncomfortable truths about what agents actually remember and what they quietly forget.
The Experiment
We ran an AI agent with persistent memory for 30 consecutive days, logging every memory write, every retrieval, and every case where the agent should have remembered something but did not. The goal was simple: find out where memory breaks.
What We Found
Retention Rates Drop Fast
- Day 1-7: 94% recall accuracy on stored memories
- Day 8-14: 78% recall accuracy
- Day 15-21: 61% recall accuracy
- Day 22-30: 52% recall accuracy
The drop is not because memories were deleted. They were still stored. The problem is retrieval - as the memory store grows, the agent struggles to find the right memory at the right time.
What Persists Well
- User preferences (formatting, tone, tool choices) - these get reinforced constantly
- Error patterns (things that failed before) - negative memories stick
- Workflow sequences (step-by-step procedures) - structured memories retrieve well
What Decays
- One-off context (why a specific decision was made on day 3) - gone by day 15
- Nuanced preferences (not just "use dark mode" but "use dark mode except in presentations") - the nuance fades
- Cross-domain connections (linking a coding pattern to a business decision) - too abstract to retrieve reliably
Fixes That Helped
- Aggressive summarization - compress old memories into summaries weekly
- Tagging with retrieval cues - add explicit tags that match how the agent will search later
- Decay scoring - rank memories by recency and frequency of access
- Periodic reinforcement - re-state important memories in the system prompt
Memory is not a solved problem. But understanding where it breaks is the first step to building agents that actually learn over time.
- Ebbinghaus Decay Curve for Agent Memory
- AI Agent Memory Triage - Retention and Decay
- Long-Term Memory Separates Toy from Useful Agents
Fazm is an open source macOS AI agent. Open source on GitHub.