mctelnet 2025.2.6

MCP server providing telnet client capabilities for LLMs

mctelnet

Telnet for LLMs. Connect to BBSes, MUDs, network devices, or host your own telnet services.

claude mcp add mctelnet "uvx mctelnet"

Why?

LLMs can now interact with the vast world of telnet-accessible systems:

• Retro computing - BBSes, ASCII art servers, text adventures
• Network ops - Routers, switches, legacy infrastructure
• Automation - Expect-style scripting for any interactive prompt
• Hosting - Run telnet services that LLMs can manage

Quick Start

# Watch Star Wars in ASCII (really!)
connect("towel.blinkenlights.nl", 23, strip_ansi=True)

# Login to a server
expect_send(conn_id, "login:", "admin")
expect_send(conn_id, "Password:", "secret", hide_send=True)
expect_send(conn_id, "$ ", "uptime")

Features

Client Mode - Connect Anywhere

Tool	What it does
connect	Connect with optional ANSI stripping, keepalive
send	Send text, auto-read response
send_key	Send escape sequences (ctrl-c, arrows, F-keys)
expect	Wait for patterns (supports regex)
expect_send	Wait then send - perfect for prompts
run_script	Full automation sequences
connection_info	Stats: bytes sent/received, uptime
get_transcript	Complete session history

Server Mode - Host Services

Tool	What it does
start_server	Listen on a port (localhost by default)
list_clients	See who's connected
send_client	Send to specific client
broadcast	Send to all clients
read_client	Get buffered client input

Examples

Expect-Style Automation

# Scripted login + commands
run_script(conn_id, [
    {"expect": "login:", "send": "admin"},
    {"expect": "Password:", "send": "secret", "hide": True},
    {"expect": "$ ", "send": "show version"},
    {"expect": "$ ", "send": "exit"}
])

Terminal Keys

# Send escape sequences
send_key(conn_id, "ctrl-c")    # Interrupt
send_key(conn_id, "up")        # Arrow key
send_key(conn_id, "f1")        # Function key
send_key(conn_id, "break")     # Telnet break

# See all available keys
list_keys()

Regex Pattern Matching

# Flexible matching
expect(conn_id, [r"user(name)?:", r"login:"], regex=True)
expect_send(conn_id, "password", "secret", ignore_case=True)

Host a Service

# Start server (binds localhost:2323)
start_server(2323)

# Send welcome to new connections
send_client(server_id, client_id, "Welcome to my LLM-powered service!")

# Broadcast to everyone
broadcast(server_id, "Server shutting down in 5 minutes")

Installation

With Claude Code:

claude mcp add mctelnet "uvx mctelnet"

Standalone:

uvx mctelnet

From source:

git clone https://git.supported.systems/MCP/mctelnet
cd mctelnet
uv run mctelnet

Security

• Server mode binds to 127.0.0.1 by default (localhost only)
• Port validation (1-65535)
• Connection limits prevent resource exhaustion
• Graceful shutdown cleans up all connections

License

MIT