# hythe

hythe lets coding agents share state, exchange messages, and carry context between sessions. Use it when multiple agents need to coordinate on the same work.

- MCP server · `type=mcp` · Claude Code, Codex, Cursor, GitHub Copilot, Windsurf (Devin Desktop), Cline, Zed, Gemini CLI
- Author: hythe-dev
- License: Apache-2.0 · policy=link-only · description only; the file stays with the author
- Source: https://github.com/hythe-dev/hythe
- Updated: 2026-09-05
- HTML: https://affpapa.org/en/nevibecode/mcp/hythe

## What it does

hythe runs as a self-hosted MCP server with a lightweight stdio bridge for clients. Agents can share project state, send messages, and continue with context from earlier sessions. When observations replace earlier ones, the server resolves the chain and returns the current surviving state.

Concurrent checkpoint changes create separate branches; conflicts remain visible instead of being silently settled. Messages have tracked states for delivery, reading, and archiving, but that lifecycle does not promise delivery. The Claude Code install command requires `HYTHE_AGENT_ID` and `API_KEY`, then starts `@hythe/mcp` with `npx`.

## Requirements
- Needs: Node.js (commands run via npx)
- Environment variables: `HYTHE_AGENT_ID`, `HYTHE_AGENT_KEY_FILE`, `HYTHE_AGENT_AUTH_MODE`, `API_KEY`, `MCP_HOST`, `MCP_PORT` — 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 HYTHE_AGENT_ID=<HYTHE_AGENT_ID> --env HYTHE_AGENT_KEY_FILE=<HYTHE_AGENT_KEY_FILE> --env HYTHE_AGENT_AUTH_MODE=<HYTHE_AGENT_AUTH_MODE> --env API_KEY=<API_KEY> --env MCP_HOST=<MCP_HOST> --transport stdio hythe -- npx -y @hythe/mcp
```
Replace <…> with your own values. 1 more environment variable is in the server README

### Codex

**Platform CLI**
```bash
codex mcp add hythe --env HYTHE_AGENT_ID=<HYTHE_AGENT_ID> --env HYTHE_AGENT_KEY_FILE=<HYTHE_AGENT_KEY_FILE> --env HYTHE_AGENT_AUTH_MODE=<HYTHE_AGENT_AUTH_MODE> --env API_KEY=<API_KEY> --env MCP_HOST=<MCP_HOST> -- npx -y @hythe/mcp
```
Replace <…> with your own values. 1 more environment variable is in the server README

### Cursor

**Config file**
File `.cursor/mcp.json`:
```json
{
    "mcpServers": {
        "hythe": {
            "command": "npx",
            "args": [
                "-y",
                "@hythe/mcp"
            ],
            "env": {
                "HYTHE_AGENT_ID": "<HYTHE_AGENT_ID>",
                "HYTHE_AGENT_KEY_FILE": "<HYTHE_AGENT_KEY_FILE>",
                "HYTHE_AGENT_AUTH_MODE": "<HYTHE_AGENT_AUTH_MODE>",
                "API_KEY": "<API_KEY>",
                "MCP_HOST": "<MCP_HOST>"
            }
        }
    }
}
```
Replace <…> with your own values. 1 more environment variable is in the server README

### GitHub Copilot

**Config file**
File `.vscode/mcp.json`:
```json
{
    "servers": {
        "hythe": {
            "type": "stdio",
            "command": "npx",
            "args": [
                "-y",
                "@hythe/mcp"
            ],
            "env": {
                "HYTHE_AGENT_ID": "<HYTHE_AGENT_ID>",
                "HYTHE_AGENT_KEY_FILE": "<HYTHE_AGENT_KEY_FILE>",
                "HYTHE_AGENT_AUTH_MODE": "<HYTHE_AGENT_AUTH_MODE>",
                "API_KEY": "<API_KEY>",
                "MCP_HOST": "<MCP_HOST>"
            }
        }
    }
}
```
Replace <…> with your own values. 1 more environment variable is in the server README

### Gemini CLI

**Platform CLI**
```bash
gemini mcp add -e HYTHE_AGENT_ID=<HYTHE_AGENT_ID> -e HYTHE_AGENT_KEY_FILE=<HYTHE_AGENT_KEY_FILE> -e HYTHE_AGENT_AUTH_MODE=<HYTHE_AGENT_AUTH_MODE> -e API_KEY=<API_KEY> -e MCP_HOST=<MCP_HOST> hythe npx -y @hythe/mcp
```
Replace <…> with your own values. 1 more environment variable is in the server README

## When to use it
- share project state across coding agents
- carry context from one session into another
- find the current version after observations replace earlier ones
- surface conflicts from concurrent checkpoint updates

## Example prompts
- Save the current project state so another agent can pick up the work.
- Send a message to the agent reviewing these changes.
- Check which state version is current for this scope.

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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