create_sessionLABSCO SUMMARY
An agent can hold a REPL open instead of cramming everything into one command.
State is the whole point: a variable set on one call is still there on the next, which is what makes a remote Rails console or a long Python session workable through a model. The browser view means you can watch what it is doing rather than infer it.
What it is
A session manager for interactive REPLs and shells. A session survives between calls, so state built up inside it stays there, and each session gets a browser URL that streams its terminal output live over WebSocket.
What you get
- Sessions created from a preset — Python, IPython, Node.js, Ruby pry or irb, bash, zsh — or from a custom configuration with your own setup commands and environment
- Input sent to a live session, optionally waiting for the prompt to return
- Sessions listed, inspected and destroyed, and the available presets listed
- Signals sent to a running session
- A browser URL per session, streaming the terminal live, with a display name in the tab title
- Assistance when a command times out, and prompt patterns learned within a session
Requirements
Node.js and npx — the package installs on demand. It starts a web UI on a local port, moving up to the next free one if that one is taken. The REPLs run on the machine hosting the server, so they reach whatever that machine reaches.
Setup effort
One command — npx -y repl-mcp@latest
USE CASES
01
Exploring data step by step instead of in one command
Open a session, then send lines into it one at a time — each builds on the state the last one left.
02
Keeping a console open across a long debugging session
List the sessions still running, check what state one is in, and carry on typing into it rather than starting again.
03
Watching what the agent is typing
Take the browser URL the session returns and open it, so the terminal is visible live rather than summarised back to you.
04
Interrupting something that has run away
Send a signal to the session and check its state, instead of killing the whole server and losing everything else in it.
05
Starting from the right interpreter
Read the available presets and pick the one that matches — or pass a custom configuration with the setup commands you need.
06
Cleaning up when the work is done
List what is still open and destroy the sessions you are finished with, so nothing is left holding a shell.
10 tools
Listed in project docs. Your client may show a different list.
send_input_to_sessionlist_repl_sessionsget_session_detailsdestroy_repl_sessionlist_repl_configurationssend_signal_to_sessionset_session_readywait_for_sessionmark_session_failedBEFORE YOU INSTALL
What to know first
Tools you get
10 tools named in the project's documentation.
Requires
npx on PATH
INSTALLATION
Connect your client
Server setup
TERMINAL
npx -y repl-mcp@latestMCP Clients
VS Code
VS CODE · JSON
{
"servers": {
"repl-mcp": {
"command": "npx",
"args": [
"-y",
"repl-mcp@latest"
]
}
}
}Claude Code
CLAUDE CODE · TERMINAL
claude mcp add repl-mcp -- npx -y repl-mcp@latestCursor
CURSOR · URL
https://cursor.com/install-mcp?name=repl-mcp&config=eyJjb21tYW5kIjoibnB4IiwiYXJncyI6WyIteSIsInJlcGwtbWNwQGxhdGVzdCJdfQo=
