n2n-memory

Project-local memory MCP server for AI coding agents.

中文版

Context as code. Memory as asset.

n2n-memory is an open-source, local-first Model Context Protocol (MCP) memory server for AI coding assistants. It prevents cross-project memory pollution by storing durable project knowledge in .mcp/memory.json and active task context in .mcp/context.json inside each repository.

What Is n2n-memory?

n2n-memory gives AI coding tools a project-local knowledge graph they can read and update through MCP. It is designed for developers and teams who use AI assistants across multiple repositories and want memory that is local, auditable, Git-friendly, and not mixed with unrelated projects.

TL;DR

• Install: npx -y @datafrog-io/n2n-memory
• Protocol: Model Context Protocol (MCP), stdio transport
• Storage: .mcp/memory.json for durable memory, .mcp/context.json for active task state
• Best for: AI coding assistant memory, project architecture notes, shared team context
• Not for: cloud sync, global personal memory, source code indexing, or vector database replacement

🌟 Key Highlights

• Project-Level Physical Isolation: Memory and active context are stored under [Project Root]/.mcp/.
• Git-Friendly: JSON data is automatically sorted by key to generate clean and readable git diff.
• Dual-Buffer State: Durable graph knowledge lives in memory.json; high-frequency task state lives in context.json.
• Tool Agnostic: Uses the .mcp naming convention, not tied to any specific AI brand or IDE plugin.
• Assets for Your Code: Memory stays with your code; team members can share AI's understanding of the architecture by simply pulling the repository.
• Universal Compatibility: Works with MCP-enabled clients and AI coding tools that support stdio MCP servers.
• Privacy-First: Built with security by design, keeping your data local and isolated.

Use Cases

• Restore project context at the start of an AI coding session.
• Preserve architecture decisions, implementation notes, known pitfalls, and active task state.
• Share durable project memory with teammates through Git.
• Keep memory isolated per repository when working across many client, product, or open-source projects.
• Query a local project knowledge graph without adding a database or cloud service.

How It Compares

🚀 Quick Start

1. Installation & Config (IDE / Claude Desktop)

The easiest way to use this is via npx:

Claude Desktop

File Path: %APPDATA%\Claude\claude_desktop_config.json

{
  "mcpServers": {
    "n2n-memory": {
      "command": "npx",
      "args": ["-y", "@datafrog-io/n2n-memory"]
    }
  }
}

Cursor / VSCode (MCP Plugin)

Add in the MCP settings panel:

• Name: n2n-memory
• Type: command
• Command: npx -y @datafrog-io/n2n-memory

2. Usage Guide

This service is path-driven. AI assistants should pay attention to:

1. Absolute Project Root: When calling any n2n_* tool, provide the absolute path of the current project root or workspace top-level directory (projectPath).
2. Initialization Handshake: If .mcp does not exist yet, call the tool again with confirmNewProjectRoot set to the detected root returned by the server.
3. Auto Storage: Durable memory is saved to [ProjectPath]/.mcp/memory.json; active task context is saved to [ProjectPath]/.mcp/context.json.
4. Collaboration: Commit .mcp/memory.json when the knowledge graph should be shared with the team. Commit context.json only if your workflow wants active task state shared.

Recommended .gitignore policy for teams that want to share durable memory:

.mcp/context.json
!.mcp/
!.mcp/memory.json

If your project memory may contain private implementation details, keep the whole .mcp/ directory ignored.

Available Tools:

• n2n_add_entities: Create new entities.
• n2n_add_observations: Append observations or facts.
• n2n_create_relations: Establish connections between existing entities.
• n2n_read_graph: Read project memory and active context (Supports summaryMode and pagination).
• n2n_get_graph_summary: Quickly fetch a lightweight index of all entities (Supports pagination).
• n2n_update_context: Update current task status and next steps.
• n2n_search: Search the graph via keyword or fuzzy matching (Supports pagination).
• n2n_delete_entities: Remove entities and their attached relations.
• n2n_delete_observations: Remove specific observations from entities.
• n2n_delete_relations: Remove specific relations.
• n2n_open_nodes: Retrieve specific entities by name.
• n2n_export_markdown: Export the graph to a Markdown file inside the project root.

Safety Notes:

• Existing but unreadable JSON files are treated as data integrity errors, not as empty memory.
• Export paths must be relative and must stay inside the project root.
• Relations that point to missing entities are rejected.
• Generic README-only folders are not treated as project roots; use a real project marker such as .git, package.json, or language-specific build files.
• Full local paths are hidden from server logs by default. Set N2N_LOG_LEVEL=debug when diagnosing path issues.

🗺️ Future Roadmap

• Semantic Search: Integration of minimalist Vector Embeddings for fuzzy memory retrieval.
• Ontology Enforcement: Optional schema for relation type consistency.
• Time Travel: Versioned snapshots for memory rollback.

FAQ

Is n2n-memory a vector database?

No. n2n-memory stores a deterministic JSON knowledge graph. Semantic search may be added later, but the core design is structured, Git-friendly project memory.

Should I commit .mcp/memory.json?

Commit .mcp/memory.json when the knowledge graph is useful to your team. Keep it ignored if it may contain private implementation details. context.json is active task state and is often better left uncommitted.

Does n2n-memory send data to the cloud?

No. n2n-memory is a local MCP server. It reads and writes files under your project directory.

How is this different from global memory?

Global memory follows the assistant or user across contexts. n2n-memory follows the repository, so unrelated projects do not contaminate each other's memory.

Does it work with Claude Desktop, Cursor, and VS Code?

Yes, when the client supports stdio MCP servers. The README includes Claude Desktop and Cursor / VS Code MCP configuration examples.

📖 Related Docs

• Design Solution: Why project-level isolation?
• API Reference: Tool descriptions and schema.
• Development: How to build, test and extend.
• Changelog: Version history and incident recovery.
• llms.txt: Short AI-readable project summary for coding agents and answer engines.

📄 License

This project is licensed under the MIT License.

Built by N2NS Lab, the open-source lab from Datafrog, focused on practical AI developer tools.