A single Rust binary that gives AI agents durable cross-session memory as an MCP-native server — one binary, one SQLite file, no Docker, Postgres, or cloud. Exposes 55 MCP tools spanning entity CRUD, hybrid search/RAG, an entity link graph, an immutable journal/audit trail, key-value state with TTL, and a memory lifecycle engine. Ships framework adapters for LangChain, CrewAI, Haystack, Pydantic AI, Google ADK (all on PyPI), plus source-only LangGraph and AutoGen adapters and a web dashboard. Renamed from Mimir (earlier Mneme) on 2026-07-08.
- Storage
- Embedded SQLite with FTS5 for keyword search and stored dense vectors for semantic search; entities are idempotent by (category, key) with prior versions snapshotted into history for bi-temporal time-travel queries. Ebbinghaus decay scores age memories (buffer→working→core promotion, automatic archival, purge+VACUUM); optional transparent AES-256-GCM encryption of entity bodies (FTS index stays plaintext). Bundled quantized all-MiniLM-L6-v2 embeddings are compiled into the binary.
- Retrieval
- Hybrid recall by default: dense vector + FTS5 keyword fused via Reciprocal Rank Fusion, with Porter-stemming query expansion and graceful fallback to keyword search when no embeddings exist. Plus pure semantic search, bi-temporal `as_of` lookups, proactive just-in-time recall, entity-graph traversal, and `mimir_ask` RAG over stored memories via any Ollama/OpenAI-compatible LLM.
- Self-host
- Self-host: trivial
- License
- MIT
- Pricing
- Open-source MIT, free; one-line install of a single ~8MB binary with bundled embeddings (no network, no API key by default). No paid tier. · Free / OSS
- GitHub stars
- 67
- Last release
- 2026-08-26
- Last commit
- 2026-08-31
- First catalogued
- 2026-06-28
Strengths
- Zero-dependency local-first deployment: one Rust binary + one SQLite file, bundled in-process embeddings, fully offline with no API key
- Broad MCP surface (40+ tools): hybrid search/RAG, entity link graph, immutable journal/audit trail, KV state with TTL, and a decay-based memory lifecycle
- Permissive MIT license with security/compliance posture (AES-256-GCM at rest, air-gapped, published SBOM) and five pip-installable adapters (LangChain, CrewAI, Haystack, Pydantic AI, Google ADK)
Watch out
- Deprecated 2026-10-01: the core repo (github.com/Perseus-Computing-LLC/perseus-vault) now 404s and is absent from the org's public repo listing (31 other repos checked, no renamed successor found) — the project has lost its public open-source pathway, the catalog's hard inclusion requirement. The vendor's product site (perseus.observer) still markets Perseus Vault and the adapter repos (langchain-perseus-vault, perseus-vault-haystack, etc.) remain public and were pushed as recently as 2026-09-14, but their own PyPI metadata still points at the now-dead core repo URL — strongly suggesting the engine source was pulled private/closed rather than renamed
- Renamed Mimir → Perseus Vault on 2026-07-08 (earlier name: Mneme); the old GitHub URL 301-redirects and some in-repo integration READMEs still say 'Mimir'. Expect churn in package and repo names
- Very new and low-adoption (39 stars as of 2026-08-01, up from 16 in July; repo created 2026-06); the comparison matrix and 100K-entity stress numbers in the README are self-reported and the project framing is marketing-forward
- Single-vendor (Perseus Computing LLC); long-term maintenance track record is not yet established
- Bundled embedder is a small all-MiniLM-L6-v2 model; higher-quality semantic recall needs an external Ollama/OpenAI embedding endpoint
Best for
- Local-first or air-gapped agents wanting a single-binary, MCP-native memory store with hybrid search, audit trail, and lifecycle decay
How it integrates
Benchmark results
No sourced results yet.
Sources
- Monthly card re-verification — GitHub API returns 404 Not Found for the canonical repo; cross-checked against a full listing of Perseus-Computing-LLC's 31 public repos (orgs/Perseus-Computing-LLC/repos) which contains adapter/demo repos (perseus-vault-demo, perseus-vault-dsh, langchain-perseus-vault, etc.) but no perseus-vault core repo under any obvious name (tried perseus-vault-core, perseus-vault-engine, perseus-memory, perseus-vault-mcp, vault, vault-mcp, mneme — all 404). No 301 redirect observed (curl -IL returns a bare 404, not a redirect), so this is not a simple rename. Deprecating immediately per the status lifecycle's 'repo gone/archived' rule rather than holding in needs-review, since the mandatory open-source pathway (links.github) is now unverifiable (third-party)
- Vendor homepage still markets Perseus Vault as a live product (demo, '99.8% session recall@10' benchmark) with no sunset notice, but the only GitHub link on the page points to the hermes-memconflict report, not the core engine repo (vendor)
- Old product page, still reachable, now serves only a redirect notice: 'Mimir was renamed to Mneme, then to Perseus Vault.' The live page is perseus.observer/vault/ — links.home updated from the former to the latter (vendor)
- Monthly card re-verification — GitHub API repo metadata: 39 stars, license MIT confirmed, archived=false, last commit on the default branch 2026-08-01 (third-party)
- Perseus Vault README (formerly Mimir) — 'Persistent Memory for AI Agents — MCP-Native. Local-First. Zero Dependencies.'; version badge 2.17.0; 55 MCP tools; LangGraph/CrewAI/AutoGen integration badges (vendor)
- GitHub API repo metadata — 16 stars, MIT, pushed 2026-07-09, latest release v2.19.1 (2026-07-07). The old Perseus-Computing-LLC/mimir path 301-redirects here (third-party)
- PyPI — langchain-perseus-vault 0.1.0, 'memory for LangChain … backed by Perseus Vault (formerly "Mimir"/"Mneme")'. Sibling packages: crewai-perseus-vault 0.1.0, perseus-vault-haystack 0.1.0, pydantic-ai-perseus-vault 0.1.0, adk-perseus-vault-memory 0.3.0 (third-party)
- perseus-vault integrations/langgraph/README.md — 'Install from source (not yet published to PyPI)'; integrations/autogen uses `pip install -e`. LangGraph and AutoGen remain source-only (vendor)
- GitHub license API — confirms MIT; repo not archived (checked v2.21.0, pushed 2026-07-23) (third-party)
- Perseus Vault README (v2.20.2) — 55+ MCP tools, MIT license, no pricing/paid tier; langgraph-perseus-vault and autogen-perseus-vault still absent from PyPI (vendor)
- Monthly card re-verification — still deprecated: the repo now returns 404 (deleted or made private), a step beyond the dormancy that originally triggered deprecation. githubStars left at its last-known value (67) since the API can no longer confirm it. (third-party)
Last verified 2026-11-01 · updated by refresh-framework-cards