pty-mcp
An MCP (Model Context Protocol) server that gives AI agents interactive terminal sessions — local shells, SSH, serial ports, and persistent remote sessions that survive disconnects.
Built for sysadmins and network engineers who want AI to help with real server and device management, not just code generation.
Why
AI agents run commands in non-interactive shells. They can't:
- SSH into a server and interact with running processes
- Connect to routers or switches via serial console
- Monitor logs and react when a specific event occurs
- Keep session state across multiple commands
- Wait for a server to reboot and detect when it's back up
pty-mcp solves all of these by providing real PTY sessions over MCP.
Without pty-mcp, AI agents resort to sleep 30 && check_status loops — burning CPU cycles and API calls waiting for things to happen. With wait_for, the agent blocks server-side until the event occurs. Less polling, less energy, better for polar bears. 🐻❄️
Use Cases
Server administration
# Reboot a server and wait until it's back online
create_local_session("ping myserver")
read_output(wait_for: "bytes from", timeout: 300)
→ blocks until server responds after reboot (~80s, one tool call)
Network device management
# Connect to a router via serial console
create_serial_session(port: "/dev/ttyUSB0", baud: 9600)
send_input("show interfaces status")
read_output(wait_for: "\\$")
Log monitoring and alerting
# Watch logs and act when something happens
create_ssh_session(host: "prod", user: "admin")
send_input("tail -f /var/log/app.log")
read_output(wait_for: "ERROR|CRITICAL", timeout: 3600)
→ returns the error line + context when it appears
Long-running tasks that survive disconnects
create_ssh_session(host: "server", user: "admin", persistent: true)
send_input("apt upgrade -y")
detach_session() → close Claude Code, task continues
# Reconnect later to check result
Features
| Feature | Description |
|---|
| Local terminal | Interactive bash/python/node sessions on local machine |
| SSH sessions | Connect to remote hosts with key/password auth, SSH config support |
| Serial port | Connect to devices via serial (IoT, embedded, network gear) |
| Persistent sessions | Sessions survive SSH disconnects via ai-tmux daemon |
| Attach/Detach | Detach from a running session, reconnect later |
| Control keys | Send ctrl+c, ctrl+d, arrow keys, tab, escape |
| Settle detection | Waits for output to settle before returning (smart timeout) |
| Pattern matching | wait_for blocks until a regex pattern appears in output (v0.2.0) |
| Bounded memory | Ring buffer prevents OOM on long-running sessions (v0.2.0) |
| Audit log | Optional voluntary operation log — record send_input commands to a collector for review and traceability (v0.8.0) |
Architecture
┌─────────────────────────────────────────────────────┐
│ AI Agent (Claude Code, etc.) │
│ │
│ MCP Tools: create_local_session, send_input, │
│ send_control, read_output, close_session │
└──────────────────────┬──────────────────────────────┘
│ JSON-RPC stdio
┌──────────────────────┴──────────────────────────────┐
│ pty-mcp (MCP Server) │
│ │
│ Session Manager │
│ ├── LocalSession (local PTY via creack/pty) │
│ ├── SSHSession (remote PTY via x/crypto/ssh) │
│ ├── SerialSession (serial port via go.bug.st) │
│ └── RemoteSession (persistent via ai-tmux) │
└─────────────────────────────────────────────────────┘
Persistent mode (ai-tmux):
pty-mcp ──SSH──▶ ai-tmux client ──Unix socket──▶ ai-tmux server (daemon)
├── PTY: bash
├── PTY: ssh admin@router
└── PTY: tail -f /var/log/syslog
Quick Start
Claude Code Plugin (recommended)
Installs the binary automatically and registers the MCP server:
claude plugin marketplace add raychao-oao/pty-mcp
claude plugin install pty-mcp@pty-mcp
Restart Claude Code — the binary downloads automatically on session start, then restart once more to activate it. No manual claude mcp add needed.
Updating:
claude plugin marketplace update pty-mcp
claude plugin update pty-mcp@pty-mcp
