HeurChain is memory infrastructure for AI agents — not a wrapper, not a prompt trick. Agents connect via MCP and get a persistent, structured memory store that survives across sessions, models, and machines. Memory is organized in three tiers (ops/ notes/ self/) with ACT-R cognitive decay. Agents remember what they keep using. They forget what they don't. Hybrid BM25 + vector retrieval via RRF. Sub-200ms P95. MIT licensed. Docker in under 10 minutes.