Longmem

Cross-project memory for AI coding assistants.
Stop solving the same problems twice.

Your AI solves the same bug in a different project six months later. Writes the same boilerplate. Explains the same pattern. You already knew the answer.

longmem gives your AI a persistent memory that works across every project and every session. Before reasoning from scratch, it searches what you've already solved. After something works, it saves it. The longer you use it, the less you repeat yourself.

You describe a problem
        │
        ▼
  search_similar()
  ┌─────────────────────────────────────────────────────┐
  │  1. pre-filter by category (ci_cd / auth / db / …)  │
  │  2. semantic search  (Ollama or OpenAI embeddings)   │
  │  3. keyword search   (SQLite FTS5 exact match)       │
  │  4. merge + rank results                             │
  └─────────────────────────────────────────────────────┘
        │                          │
   score ≥ 85%               score < 85%
        │                          │
        ▼                          ▼
  cached solution           AI reasons from scratch
  + edge cases                      │
  + team knowledge               "it works"
  (any project)                     │
                                    ▼
                          confirm_solution()
                          saved once — surfaces
                          from every future project

Why longmem

Quickstart

1. Install

pipx install longmem

2. Setup — checks Ollama, pulls the embedding model, writes your IDE config

longmem init

3. Activate in each project — copies the rules file that tells the AI how to use memory

cd your-project
longmem install

4. Restart your IDE. Memory tools are now active on every chat.

Need Ollama? Install from ollama.com, then ollama pull nomic-embed-text. Or use OpenAI — see Configuration.

How it works

longmem is an MCP server. Your IDE starts it on demand. Two rules drive the workflow:

Rule 1 — search first. Before the AI reasons about any bug or question, it calls search_similar. If a match is found (cosine similarity ≥ 85%), the cached solution is returned with any edge-case notes. Below the threshold, the AI solves normally.

Rule 2 — save on success. When you confirm something works, the AI calls confirm_solution. One parameter — just the solution text. Problem metadata is auto-filled from the earlier search.

The rules file (longmem.mdc for Cursor, CLAUDE.md for Claude Code) wires this up automatically. No manual prompting.

AI forgot to save? Run longmem review — an interactive CLI to save any solution in 30 seconds.

Cold start — getting value from day one

longmem is most useful once it has entries. The fastest way to seed it:

Option 1 — review as you go. After every solved problem this week, run longmem review and describe what you fixed. Ten entries is enough to feel the difference.

Option 2 — team import. If a teammate already has entries, they export and you import:

# teammate
longmem export team_knowledge.json

# you
longmem import team_knowledge.json

Option 3 — shared DB. Set db_path (or db_uri for S3/cloud) to the same location for the whole team. Every save is instantly available to everyone.

CLI

longmem with no arguments starts the MCP server (used by your IDE).

Configuration

Config lives at ~/.longmem/config.toml. All fields are optional — defaults work with a local Ollama instance.

Switch to OpenAI embeddings

embedder       = "openai"
openai_model   = "text-embedding-3-small"
openai_api_key = "sk-..."   # or set OPENAI_API_KEY

Install the extra: pip install 'longmem[openai]'

Team shared database

Point every team member's config at the same path:

# NFS / shared drive
db_path = "/mnt/shared/longmem/db"

Or use cloud storage:

# S3 (uses AWS env vars)
db_uri = "s3://my-bucket/longmem"

# LanceDB Cloud
db_uri = "db://my-org/my-db"
lancedb_api_key = "ldb_..."   # or set LANCEDB_API_KEY

No shared mount? Use longmem export / longmem import to distribute a snapshot.

Team knowledge base

Save facts that are true across your whole stack under project="shared" so they surface from any repo:

save_solution(
  problem="why oauth2-proxy uses port 4181 not default 4180",
  solution="General: 4180 is the oauth2-proxy default. 4181 means something else already occupies 4180.\n\nThis team's setup: Sinfonia always runs on 4180. Every other project uses 4181+ by convention.",
  project="shared",
  category="networking",
  tags=["oauth2-proxy", "ports", "nginx"]
)

search_similar searches all projects — a shared entry surfaces automatically from any repo without needing search_by_project.

Three-layer solution format — write solutions so they work for anyone who finds them:

Tuning

similarity_threshold = 0.85   # minimum score to surface a cached result (default 0.85)
duplicate_threshold  = 0.95   # minimum score to block a save as a near-duplicate (default 0.95)

MCP tools

The server exposes 11 tools. The two you interact with most:

• search_similar — semantic + keyword hybrid search. Returns ranked matches with similarity scores, edge cases, and a keyword_match flag when the hit came from exact text rather than vector similarity.
• confirm_solution — saves a solution with one parameter. Problem metadata auto-filled from the preceding search.

Full list: save_solution, correct_solution, enrich_solution, add_edge_case, search_by_project, delete_solution, rebuild_index, list_recent, stats.

Call rebuild_index once you reach 256+ entries to compact the database and build the ANN index for faster search.

Category reference

Categories pre-filter before vector search — keeps retrieval fast at any scale.