mnemo-mcp 2.3.0b19

Open-source MCP Server for persistent AI memory with embedded sync

Mnemo MCP Server

mcp-name: io.github.n24q02m/mnemo-mcp

Persistent AI memory with hybrid search and embedded sync. Open, free, unlimited.

Sister projects from n24q02m (click to expand)

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Table of contents

• Roadmap
• Features
• Quick install
• Configuration
• Comparison vs. peers
• Status
• Documentation
• Tools
• Security
• Build from Source
• Trust Model
• License

Roadmap

All three phases below have shipped. The temporal knowledge graph (Phase 3) is the current major line (v2.x).

Phase	Version	Status	Highlights
Phase 1	v1.x	Shipped	Typed memory(action="capture") (6 context_types + dedup) -- RRF (k=60) hybrid fusion + cross-encoder rerank + temporal decay -- importance x recency archive policy + restore -- Alembic migrations -- multi-provider LLM dispatch -- plugin trinity (recall-context + memory-commit skills, SessionStart + opt-in PostToolUse hooks)
Phase 2	v1.x	Shipped	LLM-driven compression of older memories + Passport sync (encrypted import/export bundle for cross-machine bootstrap) -- AES-256-GCM + Argon2id, S3 / R2 / B2 / MinIO + GDrive backends, delta-sync with LWW per row
Phase 3	v2.x	Shipped (BREAKING)	Temporal knowledge graph -- bitemporal valid_from / valid_to columns -- entity resolution via embedding KNN -- entity_search / entity_graph / history actions -- KG-aware passport bundle sections -- KG_AUTO_ENABLED opt-in auto-extract on capture

Features

• Hybrid retrieval -- FTS5 + sqlite-vec, fused via Reciprocal Rank Fusion (k=60), then re-ranked by a configurable rerank chain (RERANK_MODELS, order = litellm fallback; empty -> local qwen3-reranker) with temporal decay and importance boost
• Typed capture -- memory(action="capture") with 6 context_types (conversation/fact/preference/skill/task/decision), embedding-based dedup, and a configurable LLM chain (LLM_MODELS, order = litellm fallback)
• Knowledge graph -- Automatic entity extraction and relation tracking; top results boosted by graph proximity
• Importance scoring + archive policy -- LLM-scored 0.0-1.0 importance; soft-archive when recency_factor * (1 - importance) > 1.0; restore action available
• Auto-archive trigger -- Background sweep every Nth capture (default 100) -- no cron required
• STM-to-LTM consolidation -- LLM summarization of related memories in a category
• Duplicate detection -- Warns before adding semantically similar memories
• Zero config -- Built-in local Qwen3 ONNX embedding + reranking, no API keys needed. Optional cloud providers (Jina AI, Gemini, OpenAI, Cohere)
• Multi-machine sync -- JSONL-based merge sync via Google Drive (bundled Desktop OAuth public client)
• Plugin trinity -- Ships /recall-context + /memory-commit skills and SessionStart + opt-in PostToolUse hooks (see docs/ARCHITECTURE.md)
• Proactive memory -- Tool descriptions and skills guide AI to save preferences, decisions, facts at the right moment
• LLM compression -- Per-turn compression via the multi-provider dispatcher targets ~3x token reduction at >=0.90 fact retention; graceful skip when no provider configured (see docs/compression.md)
• Encrypted passport sync -- AES-256-GCM bundles + Argon2id KDF, S3 (R2 / B2 / MinIO) and Google Drive backends, delta-sync with last-write-wins per row (see docs/passport.md). Bootstrap via the passport-bootstrap skill.
• Temporal knowledge graph -- Bitemporal columns (valid_from / valid_to / superseded_by) on every memory + entity-resolution dedup (embedding KNN at default 0.85 cosine threshold) + audit trail (memory_audit table with prev/new state hashes) + new actions (entity_search / entity_graph / history) + opt-in KG_AUTO_ENABLED auto-extract on capture. BREAKING for clients that called memory.get expecting historical-inclusive results: pass as_of for time-travel; default now filters to current-state (valid_to IS NULL).

Quick install

# Method 1 (default): plugin install via Claude Code
/plugin marketplace add n24q02m/claude-plugins
/plugin install mnemo-mcp@n24q02m-plugins

# Method 1 (CLI): direct uvx invocation (zero config -- runs on the built-in local model)
claude mcp add mnemo -- uvx mnemo-mcp

# Method 3 (HTTP / multi-device / multi-user)
docker run -d --name mnemo-mcp-http -p 8085:8080 \
  -v mnemo-data:/data -e MCP_TRANSPORT=http \
  -e PUBLIC_URL=https://mnemo.example.com \
  n24q02m/mnemo-mcp:latest

No API keys are required: with no provider keys set, mnemo runs fully offline on the bundled local Qwen3 ONNX embedding + reranker. Add cloud provider keys only to switch embedding / rerank / LLM onto a hosted model (see Configuration).

Full setup matrices live at the canonical docs site mcp.n24q02m.com/servers/mnemo-mcp/setup/ and the paste-to-agent snippet at claude-plugins/plugins/mnemo-mcp/setup-with-agent.md.

Configuration

All settings are plain environment variables (no prefix). Everything is optional -- mnemo runs zero-config on the local model. The most common knobs:

Model selection (per-task chains)

Embedding, reranking, and LLM features each take an ordered, comma-separated chain of provider/model entries (tried in order, litellm fallback). Leave a chain empty to use the bundled local model (embedding / rerank) or to disable the feature (LLM).

Env var	Default	Purpose
EMBEDDING_MODELS	(empty -> local Qwen3 ONNX)	Embedding chain, e.g. jina_ai/jina-embeddings-v5-text-small,gemini/gemini-embedding-001
RERANK_MODELS	(empty -> local Qwen3 cross-encoder)	Rerank chain, e.g. jina_ai/jina-reranker-v3,cohere/rerank-v3.5
LLM_MODELS	(built-in cloud chain)	LLM chain for graph extraction / importance / compression; empty disables those features
EMBEDDING_DIMS	768	Embedding dimensions (0 = auto-detect)

Provider is inferred from the model prefix; supply each provider's key via the litellm <PROVIDER>_API_KEY convention:

model prefix	key env var	get it at
jina_ai/	JINA_AI_API_KEY	jina.ai/api-dashboard
gemini/	GEMINI_API_KEY	aistudio.google.com/apikey
openai/ (or bare)	OPENAI_API_KEY	platform.openai.com/api-keys
cohere/	COHERE_API_KEY	dashboard.cohere.com/api-keys

Any other litellm provider works via env passthrough; see https://docs.litellm.ai/docs/providers/<provider> for its <PROVIDER>_API_KEY name. Custom OpenAI-compatible endpoints (SSRF-guarded): LLM_API_BASE, EMBEDDING_API_BASE, RERANK_API_BASE.

Changing the embedding model changes the vector space. A safe-by-default guard blocks boot on mismatch; set REINDEX_ON_MODEL_CHANGE=true to re-embed.

Storage, sync, retrieval, and archive

Env var	Default	Purpose
DB_PATH	~/.mnemo-mcp/memories.db	SQLite database path (also accepts MNEMO_DB_PATH)
SYNC_ENABLED	true	Enable Google Drive multi-machine sync
GOOGLE_DRIVE_CLIENT_ID	(none)	OAuth client ID required for sync
SYNC_FOLDER	mnemo-mcp	Google Drive folder name
SYNC_INTERVAL	300	Auto-sync interval in seconds (0 = manual only)
RERANK_ENABLED	true	Enable reranking of fused results
RERANK_TOP_N	10	Number of reranked results to keep
ARCHIVE_ENABLED	true	Enable importance x recency soft-archive sweeps
ARCHIVE_AFTER_DAYS	90	Age before a memory is eligible for archive
DEDUP_THRESHOLD	0.9	Similarity above which a new memory is a duplicate
RECENCY_HALF_LIFE_DAYS	7	Half-life for temporal decay scoring
KG_AUTO_ENABLED	false	Auto-extract entities + relations on capture
LOG_LEVEL	INFO	Log verbosity

Manual config example

{
  "mcpServers": {
    "mnemo": {
      "command": "uvx",
      "args": ["mnemo-mcp"],
      "env": {
        "EMBEDDING_MODELS": "jina_ai/jina-embeddings-v5-text-small,gemini/gemini-embedding-001",
        "RERANK_MODELS": "jina_ai/jina-reranker-v3",
        "LLM_MODELS": "gemini/gemini-3-flash-preview",
        "JINA_AI_API_KEY": "jina_xxx",
        "GEMINI_API_KEY": "AIza_xxx"
      }
    }
  }
}

Comparison vs. peers

Feature	mnemo-mcp	Mem0	Letta	OpenMemory
Hybrid retrieval (FTS + vec)	yes (FTS5 + sqlite-vec + RRF)	yes	partial	yes
Cross-encoder rerank chain	yes (qwen3 local + Jina + Cohere)	partial (Cohere only)	no	no
Temporal decay scoring	yes (exp half-life)	no	no	no
Importance boost in rank	yes (LLM 0.0-1.0)	no	no	no
Soft-archive + restore policy	yes (importance x recency)	no	no	no
Self-hostable (single SQLite file)	yes (zero ext deps)	partial (cloud-first)	yes (Postgres)	yes (Postgres + Qdrant)
Multi-provider LLM dispatch	yes (LLM_MODELS chain, any litellm provider)	partial	yes	partial
Plugin trinity (skills + hooks)	yes (recall-context + memory-commit)	n/a	n/a	n/a
Multi-machine sync	yes (GDrive bundled OAuth)	yes (cloud)	n/a	n/a
E2E-encrypted passport sync	yes (AES-256-GCM + Argon2id, S3 + GDrive)	no	no	no
LLM compression on capture	yes (multi-provider, ~3x at >=0.90 retention)	no	no	no
Backend-pluggable sync architecture	yes (S3 / R2 / B2 / MinIO + GDrive)	no	no	no
Bitemporal valid_from / valid_to queries	yes (as_of time-travel)	no	partial (events only)	no
Entity resolution via embedding KNN	yes (cosine threshold tunable)	no	no	no
Audit trail with state hashes	yes (memory_audit table)	no	no	no

Status

2026-05-02 -- Architecture stabilization update

Past months saw significant churn around credential handling and the daemon-bridge auto-spawn pattern. This caused multi-process races, browser tab spam, and inconsistent setup UX across plugins. The architecture is now stable: 2 clean modes (stdio + HTTP), no daemon-bridge layer, no auto-spawn from stdio.

Apologies for the instability period. If you encountered issues with prior versions, please update to the latest release and follow the current setup docs -- most prior workarounds are no longer needed.

Related plugins from the same author:

• wet-mcp -- Web search + content extraction
• imagine-mcp -- Image/video understanding + generation
• better-notion-mcp -- Notion API
• better-email-mcp -- Email management
• better-telegram-mcp -- Telegram
• better-godot-mcp -- Godot Engine
• better-code-review-graph -- Code review knowledge graph

All plugins share the same architecture -- install once, learn pattern transfers.

Documentation

Full docs at mcp.n24q02m.com/servers/mnemo-mcp/setup/:

• Setup -- install methods for Claude Code, Codex, Gemini CLI, Cursor, Windsurf, mcp.json
• Modes overview -- stdio / local-relay / remote-relay / remote-oauth
• Multi-user setup -- per-JWT-sub credential model

In-repo references:

• docs/ARCHITECTURE.md -- storage layout, embedding / rerank dispatch, knowledge graph, plugin trinity
• docs/compression.md -- LLM compression pipeline
• docs/passport.md -- encrypted passport sync (S3 / GDrive backends)
• docs/BENCHMARKS.md -- retrieval quality + latency metrics

Install with AI agent -- paste this to your AI coding agent:

Install MCP server mnemo-mcp following the steps at https://raw.githubusercontent.com/n24q02m/claude-plugins/main/plugins/mnemo-mcp/setup-with-agent.md

Tools

15 MCP tools, 17 memory actions. The memory surface is exposed both as 11 specialized single-purpose tools and a legacy memory dispatcher (same actions), plus config, help, and config__open_relay:

Tool	Actions	Description
add_memory, search_memory, list_memories, update_memory, delete_memory, export_memories, import_memories, memory_stats, restore_memory, archived_memories, consolidate_memories	(one action each)	Specialized single-purpose memory tools -- the recommended surface
memory (legacy dispatcher)	add, capture, search, list, update, delete, export, import, stats, restore, archived, archive_now, consolidate, compress, entity_search, entity_graph, history	Core CRUD + typed capture (6 context_types) + hybrid search (RRF + rerank + temporal decay) + import/export + soft-archive + restore + on-demand archive sweep + LLM consolidation + LLM compression + temporal KG (entity search / graph / history)
config	status, sync, set, warmup, setup_sync, setup_status, setup_start, setup_skip, setup_reset, setup_complete, setup_relay, sync_now, export_passport, import_passport	Server status, trigger sync, update settings, pre-download embedding model, authenticate sync provider, manage HTTP setup form lifecycle, passport export/import
help	topic="memory" or topic="config"	Full documentation for any tool
config__open_relay	(HTTP relay mode)	Open the zero-config relay setup form (registered via mcp-core)

Plugin trinity (Claude Code marketplace install):

Component	Trigger	Purpose
mnemo:recall-context skill	session start, before significant decisions, "what do I know about X?"	Pulls cwd / topic-relevant memories with context_type filtering
mnemo:memory-commit skill	"remember this" / "save this" / "ghi nho" / "luu lai"	Typed manual capture with context_type decision tree
mnemo:knowledge-audit skill	periodic / "audit memory"	Find duplicates, contradictions, stale entries; consolidate
mnemo:session-handoff skill	end of session	Capture decisions / preferences / corrections / conventions / open questions
SessionStart hook	every session init	Non-blocking nudge to invoke recall-context
PostToolUse hook (opt-in)	CAPTURE_AUTO_ENABLED=true	Hint memory-commit after Write/Edit of CLAUDE.md / AGENTS.md / ARCHITECTURE.md / docs/*.md

MCP Resources

URI	Description
mnemo://stats	Database statistics and server status

MCP Prompts

Prompt	Parameters	Description
save_summary	summary	Generate prompt to save a conversation summary as memory
recall_context	topic	Generate prompt to recall relevant memories about a topic

Security

• Graceful fallbacks -- Cloud → Local embedding, no cross-mode fallback
• Sync token security -- OAuth tokens stored at ~/.mnemo-mcp/tokens/ with 600 permissions
• Input validation -- Sync provider, folder, remote validated against allowlists
• Error sanitization -- No credentials in error messages

Build from Source

git clone https://github.com/n24q02m/mnemo-mcp.git
cd mnemo-mcp
uv sync
uv run mnemo-mcp

Trust Model

This plugin implements TC-Local (machine-bound, single trust principal). The mode/storage/encryption breakdown below is the full classification.

Mode	Credentials	Memory data	Who can read your data?
stdio (default)	Read from environment variables (no credential file written)	Local SQLite at ~/.mnemo-mcp/memories.db	Only your OS user
HTTP self-host (single user)	Encrypted config.enc under ~/.mnemo-mcp/	Local SQLite (same host)	Only you (admin = user)
HTTP multi-user remote (PUBLIC_URL)	Per-JWT-sub store at subs/<sub>/config.json	Per-sub isolated rows	Only the authenticated user (per-sub isolation)

Passport sync bundles are always end-to-end encrypted (AES-256-GCM + Argon2id); backends never see plaintext.

License

MIT -- See LICENSE.