Memory MCP

Persistent memory and full-text session search for AI coding assistants, exposed as an MCP server.

The problem

AI coding assistants forget everything between sessions. Architecture decisions, user preferences, project context, what you debugged last Tuesday -- gone. You re-explain the same things constantly.

Memory MCP fixes this with two capabilities:

1. Explicit memory -- save notes, decisions, patterns, and preferences that persist across sessions. Your assistant remembers what you told it.
2. Session search -- full-text search across your entire conversation history. Find that thing you discussed three weeks ago without scrolling through logs.

No database servers. No background processes. No cloud. One SQLite file on your machine.

Supported session sources

Source	Location	Format
Claude Code	~/.claude/projects/	JSONL (streamed content blocks)
Claude Code history	~/.claude/history.jsonl	JSONL (survives session file pruning)
OpenCode	~/.local/share/opencode/opencode.db	SQLite (sessions, messages, parts tables)
Oh My Pi	~/.omp/agent/sessions/	JSONL (event-per-line)

Adding a new source requires one parser file and a registry entry. See Adding a new source.

Installation

Requires Python 3.11+ with SQLite FTS5 support (included in standard Python builds).

pip install -e .

Or run directly with uv (no install needed):

uv run --directory /path/to/memory_mcp python -m memory_mcp

MCP configuration

Add to your MCP client config (e.g., ~/.claude/mcp.json or project-level .mcp.json):

With pip install:

{
  "mcpServers": {
    "memory": {
      "command": "memory-mcp"
    }
  }
}

With uv (no install):

{
  "mcpServers": {
    "memory": {
      "command": "uv",
      "args": ["run", "--directory", "/path/to/memory_mcp", "python", "-m", "memory_mcp"]
    }
  }
}

Tools

Memory (explicit knowledge store)

Tool	Description
save_memory	Persist a note with optional tags and context. Survives across all future sessions.
search_memory	Full-text search across saved memories. Keyword-based, ranked by relevance.
list_memories	Browse recent memories, optionally filtered by tag.
delete_memory	Remove a memory by ID.

Sessions (historical conversation search)

Tool	Description
list_sessions	Browse past sessions. Filter by source (claude_code, omp) or project path.
get_session	Retrieve the full conversation from a specific session.
search_sessions	Full-text search across all session messages, thinking blocks, and tool usage.
refresh_sessions	Re-scan session directories and index new or changed files.

How it works

On startup, Memory MCP scans configured session directories and indexes every conversation into a local SQLite database with FTS5 full-text search indexes. Subsequent startups skip files whose mtime hasn't changed.

• Database location: ~/.memory_mcp/memory.db (override with MEMORY_MCP_DB env var)
• Session sources: auto-detected from standard locations (extend with MEMORY_MCP_SOURCES env var, format: type:path;type:path)
• Indexing: incremental by file mtime, parallelized across 8 threads
• Search: FTS5 with BM25 ranking, prefix matching, phrase support

Adding a new session source

1. Create memory_mcp/parsers/your_source.py implementing the SessionParser protocol:
   • source_type: str attribute
   • parse_file(path: str) -> ParsedSession | None method
2. Register it in memory_mcp/parsers/__init__.py
3. Add directory detection in memory_mcp/config.py

See parsers/claude_code.py or parsers/omp.py for examples.

Testing

python tests/test_e2e.py

The end-to-end test starts the MCP server as a subprocess, exercises all 8 tools over the stdio protocol, and asserts tool responses. Uses a throwaway database so your real data is untouched.

Architecture

memory_mcp/
  server.py        # FastMCP entry point, lifespan manages DB + startup scan
  config.py        # Auto-detects session dirs, DB path
  db.py            # SQLite + FTS5 schema, all queries, sync triggers
  scanner.py       # Walks session dirs, dispatches to parsers, parallel indexing
  parsers/
    base.py        # ParsedSession / ParsedMessage dataclasses, SessionParser protocol
    claude_code.py # Claude Code JSONL parser (merges streamed assistant blocks)
    claude_history.py # Claude Code history.jsonl parser (one file, many sessions)
    omp.py         # OMP JSONL parser
    opencode.py    # OpenCode SQLite parser (reads DB directly, read-only)
  tools/
    memory.py      # save_memory, search_memory, list_memories, delete_memory
    sessions.py    # list_sessions, get_session, search_sessions, refresh_sessions

License

MIT