MuscleMemory is an open-source procedural memory system that watches AI coding agents and captures repeatable, successful workflows as reusable "skills." It records which files were changed, the final passing test command that proves the fix, and contextual warnings for partial matches. A skill is only accepted after two independent successful reproductions and human approval via a dashboard; a single subsequent failure disables the skill and failed attempts are stored as "watch out" notes. The system is local by default (SQLite and a small on-device model) with an option for PostgreSQL + pgvector for teams, and integrates with Codex, Claude Code, Cursor, CleanSlate, an MCP API and Python/TypeScript SDKs.
Benchmarks show concrete gains: in controlled Codex sessions MuscleMemory reduced input tokens by 25.5%, tool calls by 30.4% and elapsed time by 28.2% while preserving successful outcomes; other runs reported up to 43.5% token reduction. Installation is straightforward (pipx install, init, start, connect) and a dashboard lets maintainers inspect, approve, export (SKILL.md) and manage skills. Command normalization, bounded file checks and strict trust rules prevent unsafe replay. The project is Apache‑2.0 licensed, tested but early-stage, and notes limits such as benchmark scope and untested cross-repository recall.
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