Mnemos: an MCP server for persistent Claude Code memory

Claude Code forgets everything between sessions, forcing you to re-explain conventions, corrections, and context every time. Mnemos (GitHub) is an MCP server that fixes that by storing and replaying persistent memory across sessions.

How it works

• On session start, it pushes a ranked context block (conventions, corrections, skills, hot files, recent session summaries) into Claude's prompt.
• Records corrections as tried / wrong_because / fix. Three corrections on the same topic auto-promote into a reusable skill with When this applies / Avoid / Do sections — deterministic pattern mining, no LLM in the loop.
• Bi-temporal store: facts carry valid/invalid timestamps, so "we used to use X, now Y" works without stale context.
• Compaction recovery: one tool call restores the goal and key decisions after Claude Code compacts mid-session.
• Prompt-injection scanner at write boundary (instruction overrides, zero-width unicode, MCP spoofing).
• Retrospective replay: regenerate any past session as markdown with everything learned since layered in, paste it back to Claude, ask "what would I do differently now."

Stack & install

• Single static Go binary, 15 MB. No Python, no Docker, no vector DB, no CGO.
• SQLite + FTS5 retrieval, optional cosine similarity if Ollama is running.
• Install (MIT, free, no paid tier):

curl -fsSL https://raw.githubusercontent.com/polyxmedia/mnemos/main/scripts/install.sh | bash
mnemos init

• mnemos init auto-wires Claude Code, Claude Desktop, Cursor, Windsurf, and Codex CLI. Restart your agent and mnemos_* tools show up.

Who it's for

Developers using Claude Code who are tired of re-teaching conventions every session and want reproducible, token-free memory.