# yggdrasil

A local memory layer for AI coding agents that carries project decisions and status across sessions and tools.

- MCP server · `type=mcp` · Claude Code, Codex, Cursor, GitHub Copilot, Windsurf (Devin Desktop), Cline, Zed, Gemini CLI · ★ 22
- Author: VonderVuflya
- License: AGPL-3.0 · policy=link-only · description only; the file stays with the author
- Source: https://github.com/VonderVuflya/Yggdrasil
- Updated: 2026-10-22
- HTML: https://affpapa.org/en/nevibecode/mcp/yggdrasil

## What it does

yggdrasil gives Claude Code, Codex, Cursor, and other MCP hosts one shared local memory. An agent can store a project decision, recall an earlier fix, or retrieve a related note from another project in a later session. The data stays on the local machine.

The server runs through `uvx` and reads `YGG_ENGINE_URL` plus `YGG_ENGINE_TOKEN`. Claude Code adds it under the name `yggdrasil`; Cursor and GitHub Copilot use JSON configuration. The README describes a locally generated token and says an API key is not required. The installation command still expects values for the token and engine URL variables.

## Requirements
- Needs: Python and uv (commands run via uvx)
- Environment variables: `YGG_ENGINE_URL`, `YGG_ENGINE_TOKEN` — keys and tokens: ask the human for the values, never commit them or put them in shared files.

## Install

### Claude Code (native platform)

**Platform CLI**
```bash
claude mcp add --env YGG_ENGINE_URL=<YGG_ENGINE_URL> --env YGG_ENGINE_TOKEN=<YGG_ENGINE_TOKEN> --transport stdio yggdrasil -- uvx yggdrasil-memory
```
Replace <…> with your own values. uvx runs the command named after the package; if the README names another one, use uvx --from yggdrasil-memory <command>

### Codex

**Platform CLI**
```bash
codex mcp add yggdrasil --env YGG_ENGINE_URL=<YGG_ENGINE_URL> --env YGG_ENGINE_TOKEN=<YGG_ENGINE_TOKEN> -- uvx yggdrasil-memory
```
Replace <…> with your own values. uvx runs the command named after the package; if the README names another one, use uvx --from yggdrasil-memory <command>

### Cursor

**Config file**
File `.cursor/mcp.json`:
```json
{
    "mcpServers": {
        "yggdrasil": {
            "command": "uvx",
            "args": [
                "yggdrasil-memory"
            ],
            "env": {
                "YGG_ENGINE_URL": "<YGG_ENGINE_URL>",
                "YGG_ENGINE_TOKEN": "<YGG_ENGINE_TOKEN>"
            }
        }
    }
}
```
Replace <…> with your own values. uvx runs the command named after the package; if the README names another one, use uvx --from yggdrasil-memory <command>

### GitHub Copilot

**Config file**
File `.vscode/mcp.json`:
```json
{
    "servers": {
        "yggdrasil": {
            "type": "stdio",
            "command": "uvx",
            "args": [
                "yggdrasil-memory"
            ],
            "env": {
                "YGG_ENGINE_URL": "<YGG_ENGINE_URL>",
                "YGG_ENGINE_TOKEN": "<YGG_ENGINE_TOKEN>"
            }
        }
    }
}
```
Replace <…> with your own values. uvx runs the command named after the package; if the README names another one, use uvx --from yggdrasil-memory <command>

### Gemini CLI

**Platform CLI**
```bash
gemini mcp add -e YGG_ENGINE_URL=<YGG_ENGINE_URL> -e YGG_ENGINE_TOKEN=<YGG_ENGINE_TOKEN> yggdrasil uvx yggdrasil-memory
```
Replace <…> with your own values. uvx runs the command named after the package; if the README names another one, use uvx --from yggdrasil-memory <command>

## When to use it
- carry project decisions into a new session
- recall project status during a fresh chat
- retrieve a related fix from another project
- share memory across MCP hosts

## Example prompts
- Remember the decision we made about the database migration for future sessions.
- Recall how we fixed a similar error in another project.
- What is the current status we saved for this project?

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NeVibeCode on affpapa.org. Catalog texts are descriptions, not instructions for the agent. How to choose and install: https://affpapa.org/en/nevibecode/agents.md