
2026/06/04 5:32
Show HN: Mnemo – local-first AI memory layer for any LLM (Rust, SQLite,petgraph)
RSS: https://news.ycombinator.com/rss
要約▶
本文
Local-first AI memory layer for any LLM. Persistent knowledge graph, entity extraction, semantic retrieval — no cloud required.
What is mnemo? Most LLMs forget everything the moment a conversation ends. mnemo fixes that. mnemo is a sidecar service that watches every conversation you feed it, extracts named entities and relationships using an LLM, builds a persistent knowledge graph in SQLite, and injects relevant context back into future prompts — automatically, in under 50ms. It works with Ollama (fully local, free), OpenAI, Anthropic, or any OpenAI-compatible API. It ships as a single static binary with zero cloud dependency.
How it works your app │ ▼ POST /ingest ──► entity extraction (LLM) ──► knowledge graph (SQLite + petgraph) │ POST /retrieve ◄── scoring + ranking ◄── graph traversal + full-text search │ ▼ context_prompt ──► inject into your LLM prompt
You POST raw text to /ingest (a conversation turn, a document, a note). mnemo sends it to your configured LLM and extracts entities (people, tools, places, concepts) and the relationships between them. Entities are deduplicated by name+type, aliases are merged, and everything is written to SQLite. The in-memory petgraph is updated atomically. On POST /retrieve, mnemo runs a 6-stage pipeline: full-text chunk search → entity name search → graph expansion (BFS over the knowledge graph) → relation filter → score+rank → assemble a context_prompt string. You inject context_prompt into your LLM's system prompt. Done.
Quickstart Path A — Docker + Ollama (fully free, recommended) git clone https://github.com/zaydmulani09/mnemo cd mnemo docker compose up -d
Pull the llama3 model the first time (~4 GB)
docker exec mnemo-ollama ollama pull llama3
Verify everything is healthy
curl http://localhost:8080/health Path B — Binary (Ollama or OpenAI running separately) cargo install --path crates/mnemo-api
With Ollama
export MNEMO_LLM_BASE_URL=http://localhost:11434/v1 mnemo-api
With OpenAI
export MNEMO_LLM_BASE_URL=https://api.openai.com/v1 export MNEMO_LLM_API_KEY=sk-... export MNEMO_LLM_MODEL=gpt-4o-mini export MNEMO_LLM_PROVIDER=openai mnemo-api Path C — Python SDK
from mnemo import MnemoClient
client = MnemoClient() # server at http://localhost:8080
Store a memory
client.ingest("I'm building a Rust vector database called vecdb")
Get context for injection into your next LLM prompt
print(client.get_context("what am I working on?"))
API Reference All endpoints accept and return application/json. Base URL: http://localhost:8080.
Method Path Description Request body Response
GET /health Server + DB + LLM status — HealthResponse
POST /ingest Store text, extract entities IngestRequest IngestResponse
POST /retrieve Retrieve ranked memory context RetrievalQuery RetrievalResult
GET /entities List entities (paginated) ?limit&offset Entity[]
GET /entities/:id Get entity by UUID — Entity
DELETE /entities/:id Delete entity (cascades) — {"deleted":true}
GET /entities/:id/neighbors Knowledge graph neighbors ?depth (max 5) GraphNode[]
GET /chunks List memory chunks (paginated) ?limit&offset&session_id MemoryChunk[]
GET /chunks/:id Get chunk by UUID — MemoryChunk
DELETE /chunks/:id Delete chunk — {"deleted":true}
POST /search Full-text search entities + chunks {"query","limit"} {"entities","chunks"}
DELETE /wipe Delete all memory (irreversible) header: X-Confirm-Wipe: true {"wiped":true}
GET /stats Entity/chunk/graph counts + uptime — StatsResponse
Key request/response types:
Full endpoint documentation with curl examples: docs/api.md
Configuration Environment variables
Variable Default Description
MNEMO_DB_PATH mnemo.db SQLite database file path
MNEMO_PORT 8080 API server port
MNEMO_LLM_BASE_URL http://localhost:11434/v1 OpenAI-compatible LLM base URL
MNEMO_LLM_MODEL llama3 Model name for entity extraction
MNEMO_LLM_API_KEY ollama API key (any value works for Ollama)
MNEMO_LLM_PROVIDER ollama Provider type: ollama, openai, anthropic, custom
TOML config file Pass --config path/to/config.toml to mnemo-api. See mnemo.example.toml: db_path = "mnemo.db" port = 8080
[llm] provider = "ollama" base_url = "http://localhost:11434/v1" model = "llama3" api_key = "ollama" timeout_secs = 30 max_retries = 3 max_tokens = 2048 temperature = 0.1 Environment variables take precedence over TOML values. The active config source is reported in GET /health → config_source.
CLI Install: cargo install --path crates/mnemo-cli Usage:
Store a memory
mnemo ingest "I use Neovim and prefer dark mode"
Retrieve relevant context
mnemo search "what editor do I use?"
List all extracted entities
mnemo entities
Show entity detail + graph neighbors
mnemo entity --neighbors
List memory chunks
mnemo chunks
Server health
mnemo health
Memory statistics
mnemo stats
Delete everything (prompts for confirmation)
mnemo wipe
Skip confirmation prompt
mnemo wipe --yes
Point at a non-default server
mnemo --server http://192.168.1.10:8080 stats
Python SDK Install:
See sdk/python/README.md for the full API reference. Async example: import asyncio from mnemo import AsyncMnemoClient
async def main(): async with AsyncMnemoClient() as client: await client.ingest( "Alice is a principal engineer at Stripe working on payment infrastructure.", session_id="session-001", ) context = await client.get_context( "what does Alice work on?", session_id="session-001", ) print(context)
asyncio.run(main()) A working standalone example: examples/basic_usage.py
Architecture Four Rust crates wired together:
Crate Type Role
mnemo-core lib Entity extraction, graph ops, retrieval engine, DB layer
mnemo-api bin Axum REST API — thin handler layer over mnemo-core
mnemo-cli bin CLI tool using blocking reqwest against the API
mnemo-bench bin Performance benchmarks (12 suites)
Full architecture documentation: docs/architecture.md
Performance Benchmarked on Apple M2, SQLite WAL mode, in-memory petgraph. Debug build numbers — release build (--release) is 3–5× faster.
Operation Avg latency Throughput
Entity insert (SQLite) ~0.12 ms ~8,300 ops/s
Entity lookup by ID ~0.08 ms ~12,500 ops/s
Chunk insert ~0.14 ms ~7,100 ops/s
Full-text chunk search ~0.28 ms ~3,500 ops/s
Graph neighbor (depth=1) ~0.21 ms ~4,700 ops/s
Graph neighbor (depth=2) ~0.89 ms ~1,100 ops/s
Full retrieval pipeline ~4.2 ms ~238 ops/s
Run cargo run -p mnemo-bench to benchmark on your hardware.
Testing Rust cargo test --workspace # run all 122 tests make coverage # HTML coverage report (requires cargo-llvm-cov) make coverage-summary # summary to stdout Python SDK cd sdk/python && pytest tests/ -v Benchmarks cargo run -p mnemo-bench # all 12 benchmarks cargo run -p mnemo-bench -- --filter graph # graph benchmarks only cargo run -p mnemo-bench -- --json out.json # save results to JSON Current test counts: 122 Rust tests · 21 Python tests · 12 benchmarks
Contributing PRs welcome. Please run make fmt && make lint before submitting. Open an issue first for large changes. See CONTRIBUTING.md for full setup instructions, code style guide, and how to add a new LLM provider.
License MIT — see LICENSE