# MCP Standalone — ChatGPT VPS Tools

Standalone MCP server for ChatGPT (and Claude/Cursor) — exposes VPS tools via **OAuth 2.1 + PKCE S256**, **long-horizon** ready with `exec_start/poll`.

Forked pattern from `mso/lib/mcp` — no Next.js, no database, just Fastify + `~/.mcp-standalone/mcp.json` (sha256 only, atomic 0600).

## Features

- **OAuth 2.1 PKCE S256** only (`plain` rejected), `code_verifier` 43-128, `isAllowedRedirect` https-only, `timingSafeEqual`
- **Discovery:** `/.well-known/oauth-authorization-server` (RFC 8414) + `/.well-known/oauth-protected-resource` (RFC 9728) + `/.well-known/openid-configuration` fallback + `/.well-known/oauth-protected-resource/mcp` variants
- **DCR:** `POST /oauth/register` (RFC 7591) → `201` with `client_id`, `grant_types`, etc.
- **Tools (16):** `fs_list, fs_read, fs_search, fs_usage, sys_stats, sys_processes` (read) + `fs_write, fs_mkdir, fs_delete, fs_move, fs_copy` (write) + `exec_run, exec_start, exec_status, exec_output, exec_wait` (exec, long-horizon)
- **Long-horizon:** `exec_start` returns `<500ms` `{job_id, pid}`, poll `exec_status/output/wait` until `completed` — never `exec_run` for >30s tasks
- **Jail:** `MCP_FS_READ_ROOTS / WRITE_ROOTS` (realpath), denylist `~/.ssh`, `~/.mcp-standalone`, `~/.mso`, etc., catastrophic filter (`rm -rf /`, fork bomb → 126)

## Quick Start

```bash
cp .env.example .env  # fill MCP_SESSION_SECRET (openssl rand -hex 32), MCP_LOGIN_PASSWORD, etc.
npm install
npm start  # or systemd: mcp-standalone.service → :8790
```

`.env`:
```
PORT=8790
HOST=127.0.0.1
MCP_BASE_URL=https://mcp.brain.biz.id
MCP_SESSION_SECRET=...
MCP_LOGIN_PASSWORD=...
MCP_FS_READ_ROOTS=~:~/projects:~/bridgemind:~/HERMES-OC
MCP_FS_WRITE_ROOTS=~:~/projects:~/bridgemind:~/HERMES-OC
MCP_MAX_SCOPE=exec
OAUTH_CLIENT_ID=chatgpt-mcp-xxxx  # optional, empty = allow DCR any
MCP_STORE=~/.mcp-standalone/mcp.json
```

## Cloudflare Tunnel

```yaml
# ~/.cloudflared/config.yml
- hostname: mcp.brain.biz.id
  service: http://localhost:8790
```
```bash
cloudflared tunnel route dns gendis-shine mcp.brain.biz.id
sudo systemctl restart cloudflared-tunnel
```

## ChatGPT Connectors

- MCP Server URL: `https://mcp.brain.biz.id/mcp`
- Auth: OAuth → `https://mcp.brain.biz.id/oauth/authorize` + `https://mcp.brain.biz.id/oauth/token`
- Client ID: `chatgpt-mcp-...` or leave empty for DCR
- Scope: `exec`

Verify:
```bash
curl https://mcp.brain.biz.id/.well-known/oauth-authorization-server | jq
curl https://mcp.brain.biz.id/health
```

## Systemd

```bash
sudo cp mcp-standalone.service /etc/systemd/system/
sudo systemctl enable --now mcp-standalone
```

## License

MIT