Context Windows Aren't Memory: Why AI Agents Need Real Recall

Chroma's July 2025 study of 18 frontier models found performance degrades as context windows fill, even before hitting limits. Mem0's 2026 benchmarks show retrieval-based memory achieves 91.6% accuracy on LoCoMo using under 7,000 tokens vs. 500,000 for full-context stuffing, with 91% lower latency. The article argues developers should build external memory systems instead of relying solely on context windows.