Mimir

Persistent memory for AI agents. Structured entity model. SQLite + FTS5 + hybrid vector search. MCP-native. Fully local.

What is Mimir?

Mimir is a lightweight MCP JSON-RPC 2.0 stdio server that gives AI agents durable memory across sessions. Agents store structured entities, journal their decisions, manage transient state, generate embeddings, query with hybrid search, and ingest external data — all through 30 MCP tools.

It uses SQLite with FTS5 + dense vector search across three tables: entities (structured, idempotent), journal (append-only event log), and state (key-value with TTL). Optional Ollama integration enables RAG (mimir_ask) and embedding generation (mimir_embed). A built-in web dashboard provides visual exploration.

Works with any MCP host: Claude Desktop, Cursor, OpenClaw, Hermes Agent, Perseus, etc.

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Quick Start

# Build from source
git clone https://github.com/Perseus-Computing-LLC/mimir.git
cd mimir
cargo build --release

# Linux/macOS: use cargo install to avoid macOS security kill (Killed: 9)
cargo install --path .

# Or copy manually (Linux only — macOS will kill the unsigned binary)
cp target/release/mimir ~/.local/bin/

# Or download the binary
curl -sSL https://github.com/Perseus-Computing-LLC/mimir/releases/download/v1.0.0/mimir-v1.0.0-linux-x86_64 -o mimir
chmod +x mimir && mv mimir ~/.local/bin/

Requirements: Rust 1.70+ (stable), a C compiler (rusqlite bundles SQLite).

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Install

Mimir is a standalone Rust binary — no Python client needed. Download the latest release:

# Linux x86_64
curl -fsSL https://github.com/Perseus-Computing-LLC/mimir/releases/latest/download/mimir-x86_64-unknown-linux-gnu -o mimir
chmod +x mimir
sudo mv mimir /usr/local/bin/

# macOS (Apple Silicon)
curl -fsSL https://github.com/Perseus-Computing-LLC/mimir/releases/latest/download/mimir-aarch64-apple-darwin -o mimir
chmod +x mimir
sudo mv mimir /usr/local/bin/

# Or build from source
cargo build --release
./target/release/mimir --db ./memory.db

Quickstart

# Start the server
./mimir serve --db memory.db

# Remember a fact via the HTTP API
curl -s -X POST http://localhost:8787/mcp \
  -H 'Content-Type: application/json' \
  -d '{"jsonrpc":"2.0","id":1,"method":"tools/call","params":{"name":"mimir_remember","arguments":{"category":"demo","key":"hello","body_json":"{\"text\":\"Hello world — my first persistent memory!\"}"}}}'

# Recall it
curl -s -X POST http://localhost:8787/mcp \
  -H 'Content-Type: application/json' \
  -d '{"jsonrpc":"2.0","id":1,"method":"tools/call","params":{"name":"mimir_recall","arguments":{"query":"first memory"}}}'

Why Mimir vs Alternatives

	Mimir	Mem0	Letta	Zep
Deployment	Single binary	Cloud + self-host	Docker/Postgres	Docker/Postgres
Dependencies	None (SQLite embedded)	Python + vector DB	Postgres + Python	Postgres + Go
Encryption	AES-256-GCM ✅	❌	❌	❌
Hybrid Search	BM25 + Dense + RRF	Vector only	Vector only	Vector + Graph
MCP Tools	23	5	8	0
Offline/Local	✅ Fully local	Cloud-dependent	Docker needed	Docker needed
License	MIT	Apache 2.0	Apache 2.0	Apache 2.0

Mimir is for teams that want production memory without infrastructure — no Postgres, no Docker, no cloud services. Just one binary.

Features

Hybrid Search

• FTS5 keyword search with LIKE fallback and stemming expansion
• Dense vector search via cosine similarity on stored embeddings
• Reciprocal Rank Fusion (RRF) — combine keyword + vector results
• Query expansion — Porter stemming variants for broader recall

RAG & Embeddings

• mimir_ask — natural language Q&A over stored memories via Ollama
• mimir_embed — generate and store dense vectors via Ollama /api/embed
• Supports single-entity and batch-category embedding

Encryption

• AES-256-GCM transparent encryption for entity body_json
• Opt-in via --encryption-key flag
• mimir keygen subcommand for key generation
• FTS5 index stays plaintext for search

Web Dashboard

• Built-in Axum HTTP server (mimir serve --web --port 8767)
• Dark-themed dashboard with search, entity table, vis.js graph, timeline
• Default bind: 127.0.0.1 (use --web-bind 0.0.0.0 to expose)
• Separate SQLite connection in WAL mode for concurrent reads

External Connectors

• GitHub issues connector — ingest issues/PRs by repo, rate-limit aware
• File watcher — scan directories for .md/.txt/.json files with content-hash dedup
• mimir_ingest — trigger connector syncs, dry-run preview
• YAML-based connector config via --connectors-config

Data Lifecycle

• mimir_prune — bulk archive by category, decay threshold, or age
• Ebbinghaus decay with retrieval boosts and configurable archiving
• Near-duplicate detection via trigram similarity
• Vault export/import — markdown files with YAML frontmatter

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MCP Tools (30 tools)

Entity tools

Tool	Description
mimir_remember	Store/update entity. Idempotent by (category, key).
mimir_recall	Search with FTS5/dense/hybrid modes, filters, stemming expansion.
mimir_recall_when	Proactive just-in-time recall: surface entities whose recall_when triggers match a given context.
mimir_get_entity	Fetch one entity by ID with full body_json (e.g. to read a result truncated by preview_cap).
mimir_forget	Soft-delete (archived=1).
mimir_link	Create relationship links between entities.
mimir_unlink	Remove entity links.

Search & RAG

Tool	Description
mimir_ask	RAG: recall context, query Ollama, return grounded answer with sources.
mimir_embed	Generate dense vectors via Ollama /api/embed. Single or batch.
mimir_ingest	Trigger connector syncs (GitHub, file watcher).

Journal tools

Tool	Description
mimir_journal	Append journal event with evaluated/acted/forward structure.
mimir_timeline	Query journal by time range with optional filters.

State tools

Tool	Description
mimir_state_set	Set key-value state with optional TTL.
mimir_state_get	Get state value. Returns null if expired/missing.
mimir_state_delete	Delete state entry.
mimir_state_list	List state keys, optionally filtered by prefix.

Management

Tool	Description
mimir_health	Server and DB health check.
mimir_stats	Full DB statistics across all tables.
mimir_compact	Archive entities below decay threshold (supports dry-run).
mimir_migrate	Migrate v0.1.x DB to v0.2.0 schema.
mimir_context	Pre-formatted markdown context for session injection.
mimir_workspace_list	List all distinct entity categories.
mimir_prune	Bulk archive by category, decay, or age.
mimir_cohere	Autonomous coherence pass: promote buffer→working, apply decay, auto-link related entities, archive stale.

Graph & analysis

Tool	Description
mimir_traverse	Walk entity link graph up to configurable depth.
mimir_score	Assign quality score (0.0-1.0).
mimir_conflicts	Detect near-duplicate entities via trigram similarity.
mimir_decay	Recalculate Ebbinghaus decay scores.

Vault

Tool	Description
mimir_vault_export	Export entities to .md files with YAML frontmatter.
mimir_vault_import	Import from .md vault directory (idempotent).

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CLI

mimir serve --db /data/mimir.db
mimir serve --web --port 8767 --encryption-key ~/.mimir/secret.key
mimir serve --llm-endpoint http://localhost:11434/api/generate --llm-model llama3
mimir serve --connectors-config ~/.mimir/connectors.yaml
mimir keygen --key-file ~/.mimir/secret.key
mimir migrate --from old.db --to new.db

Flags

Flag	Description
--db	SQLite database path (default: ~/.mimir/data/mimir.db)
--web	Start web dashboard
--port	Dashboard port (default: 8767)
--web-bind	Dashboard bind address (default: 127.0.0.1)
--encryption-key	AES-256-GCM key file path
--llm-endpoint	Ollama API endpoint for mimir_ask and mimir_embed
--llm-model	Ollama model name (default: llama3)
--connectors-config	Path to connectors.yaml

MCP Configuration

{
  "mcpServers": {
    "mimir": {
      "command": "mimir",
      "args": ["--db", "/home/YOU/.mimir/data/mimir.db"]
    }
  }
}

Perseus

mimir:
  enabled: true
  transport: "stdio"
  command: ["mimir", "--db", "~/.mimir/data/mimir.db"]
  timeout_s: 30.0
  merge_strategy: "local_first"
  fallback_to_local: true
  context_categories: ["decision", "architecture", "convention"]
  context_limit: 10

---

Connector Config

connectors:
  github:
    enabled: true
    token: "${GITHUB_TOKEN}"
    repos:
      - Perseus-Computing-LLC/mimir
      - Perseus-Computing-LLC/perseus
    days_past: 90
    max_items_per_repo: 500
  file_watcher:
    enabled: true
    paths:
      - ~/Documents/notes
      - ~/projects
    extensions:
      - .md
      - .txt
    debounce_ms: 1500

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Key Properties

• 30 MCP tools — full CRUD, search, RAG, embeddings, connectors, lifecycle
• Hybrid search — FTS5 + dense vectors + RRF fusion
• Encryption at rest — AES-256-GCM, opt-in, transparent
• Web dashboard — built-in, browser-based, dark theme
• Zero runtime deps — static binary with bundled SQLite
• No LLM required — core operations work offline; Ollama optional for RAG/embeddings
• Single-file database — easy backup, copy, inspect
• Fully offline — no telemetry, no API calls, no network by default

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License

MIT — see LICENSE.