🧠 Mnemo Agent Memory

A Lightweight, High-Precision, Zero-Token-Waste Memory Engine, Knowledge Graph, and Portable Notes System Built Exclusively for AI Coding Agents via MCP.

📖 Table of Contents

• The Core Problem (Why Mnemo Exists)

• Key Architectural Pillars

• System Architecture

• Core Features & Capabilities

• MCP Tools Reference

• CLI Usage & Commands

• Portable Memory Bundles (Team Collaboration)

• Configuration & Environment Variables

• Project ID Auto-Locking Mechanism

• License

Related MCP server: memento

🎯 The Core Problem (Why Mnemo Exists)

As AI coding agents (such as Google Antigravity, Claude, Cursor, and OpenCode) work on complex codebases, they encounter three fundamental limitations:

1. Context Window Contamination & Token Waste:
   Traditional agent workflows perform heavy file dumps or forced multi-turn memory searches. This floods the model's context window with irrelevant lines, depletes API context budgets rapidly, and causes context drift.

2. Heavy External Database Overhead:
   Existing agent memory frameworks rely heavily on external vector database services or C++ native binaries (PostgreSQL/pgvector, Pinecone, sqlite3 native builds). In modern agent environments, managing external databases creates complex setup hurdles and cross-platform compilation failures.

3. Team Context Disconnection:
   When multiple developers work on the same repository, historical decisions made by one AI agent session are lost to teammates, forcing each developer's AI agent to re-learn architecture from scratch.

Mnemo solves all three problems at the root. It provides a 100% pure Node.js memory engine operating over the Model Context Protocol (MCP), enforces a Zero-Token-Waste Protocol, auto-locks project identity, mirrors all memories into Markdown notes, and supports portable team memory bundles for instant team collaboration.

⚡ Key Architectural Pillars

1. 🛡️ Zero-Token-Waste Protocol

Mnemo injects relevant past architectural context directly into agent prompts via <MNEMO_CONTEXT> without forcing redundant tool-call turns. Search payloads are ultra-compact (over 90% size reduction), allowing agents to freely use native search tools (grep_search, view_file) at maximum speed.

2. 👥 Portable Team Memory Bundles

Mnemo allows developers to export the entire project memory (notes, index, and Knowledge Graph) into a single portable .json bundle file (mnemo export-memory). Teammates can import this bundle (mnemo import-memory), automatically building local vector embeddings so their AI agent instantly shares the same project context.

3. 🔒 Auto-Lock Project ID

To eliminate storage drift, Mnemo automatically persists a mnemo.json file in the workspace root during its first normalization step. Once generated, the Project ID is permanently locked, ensuring absolute memory consistency across developer sessions, folder renames, or structural refactors.

4. 🕸️ Embedded Knowledge Graph & Local ONNX Embeddings

Mnemo maintains a directed persistent Knowledge Graph tracking relationships between concepts, code entities, decision logs, and file structures. Local embeddings are computed via @xenova/transformers (all-MiniLM-L6-v2 ONNX) 100% locally without external API keys, featuring automatic idle RAM unloading.

5. 🧹 Multi-Agent Auto-Cleanup

Uninstalling Mnemo (npm uninstall -g mnemo-agent-memory or mnemo remove) automatically triggers lifecycle hooks that clean injected agent rules (GEMINI.md, AGENTS.md, CLAUDE.md, .cursorrules, .windsurfrules) and remove registered MCP servers across all supported agents.

🏗️ System Architecture

flowchart TD
    subgraph Client ["AI Agent / IDE Environment"]
        Agent["AI Coding Agent (Antigravity / Claude / Cursor / OpenCode)"]
    end

    subgraph MCP ["Model Context Protocol Interface"]
        Server["Mnemo MCP Server (stdio / HTTP)"]
    end

    subgraph Core ["Mnemo Engine Core (Pure Node.js)"]
        Store["Index & Memory Store"]
        Vec["Local ONNX Embeddings (all-MiniLM-L6-v2)"]
        Graph["Knowledge Graph Engine (Nodes & Edges)"]
        Bundle["Portable Memory Bundle (Export / Import)"]
        Lock["Project ID Auto-Lock (mnemo.json)"]
    end

    subgraph Storage ["Local Filesystem (~/.mnemo/projects/)"]
        NotesDir["notes/ (*.md)"]
        GraphDir["graph/ (graph.json)"]
        VectorsDir["vectors/ (*.bin)"]
        ObsidianVault["Obsidian Vault Mirror"]
    end

    Agent <-->|"MCP Tools (memory_recall, memory_save, file_info)"| Server
    Server --> Core
    Core --> Storage
    NotesDir <-->|"Two-way Sync"| ObsidianVault

🚀 Core Features & Capabilities

• Hybrid Vector + Keyword Search: Powered by @xenova/transformers (running all-MiniLM-L6-v2 locally via ONNX without Python) combined with BM25 keyword matching and Reciprocal Rank Fusion (RRF).

• Smart Memory Auto-Injection: Automatically computes memory similarity and injects relevant context into agent prompts within a configurable token budget.

• AST Skeleton Extraction: file_info parses file structures and outputs function symbols with line coordinates, enabling precise code inspection.

• Portable Memory Bundles: Export and import complete memory snapshots (notes, index, graph) into a single portable .json file for team sharing.

• Obsidian Mirroring: Seamless two-way sync with an Obsidian-compatible vault directory (notes_export / notes_import).

• Web Dashboard: Interactive web interface (default port 3112) to visualize knowledge graphs, view memories, and manage project notes.

🔧 MCP Tools Reference

When running as an MCP Server, Mnemo exposes the following 14 tools to the AI Agent:

💻 CLI Usage & Commands

Mnemo comes with a powerful CLI executable (mnemo).

# View CLI Help
mnemo --help

# Export project memory bundle for team sharing
mnemo export-memory mnemo-bundle.json

# Import project memory bundle from teammate
mnemo import-memory mnemo-bundle.json

# Export & sync notes to Obsidian vault
mnemo notes-export

# Import & re-index notes/*.md files
mnemo notes-import

# Knowledge Graph Operations
mnemo graph init          # Initialize graph for current workspace
mnemo graph --extend      # Extract and extend new graph entities
mnemo graph query <name>  # Search specific entity relations
mnemo graph prune         # Clean up stale/archived graph nodes

# Agent Connection & Cleanup
mnemo connect agy        # Connect Mnemo MCP to Google Antigravity
mnemo remove             # Clean up agent rules, MCP registrations, and skills

📦 Portable Memory Bundles (Team Collaboration)

Sharing project memory with teammates is simple:

1. Export Memory:

   mnemo export-memory team-memory.json

2. Share File: Commit team-memory.json to your repository or send it to your teammate.

3. Import Memory:

   mnemo import-memory team-memory.json

   Your teammate's Mnemo engine will reconstruct notes, index, Knowledge Graph, and automatically compute local vector embeddings so their AI agent instantly shares the exact same project context.

⚙️ Configuration & Environment Variables

Mnemo can be configured globally via ~/.mnemo/config.json or overridden per-session using Environment Variables (MNEMO_*):

🔒 Project ID Auto-Locking Mechanism

To guarantee 100% session consistency, Mnemo uses a 3-tier deterministic resolution strategy:

1. mnemo.json (Priority 1): Reads name or projectId from workspace root.

2. package.json (Priority 2): Reads name if mnemo.json does not exist yet.

3. Folder Slug Fallback (Priority 3): Uses the last two path segments of the workspace folder.

The Auto-Lock Feature: Upon first run, if mnemo.json is missing, Mnemo calculates the target ID and immediately writes a locked mnemo.json file into the root folder. This prevents Project ID shifts even if package.json is added later or the folder is relocated.

📄 License

Distributed under the MIT License. See LICENSE for details.