Repl MCP Server

Universal REPL session manager MCP server

Local serverstdioPython

What is the Repl MCP MCP server?

Repl MCP MCP server exists for a simple reason — assistants are far more useful when they can act on Repl MCP directly instead of describing what you should do. Universal REPL session manager MCP server.

What you get

A simple MCP server for managing REPL sessions. Provides basic tools to create and execute commands in various REPLs and shells, with an integrated Web UI for browser-based session monitoring.

What the assistant can call

Once Repl MCP is connected, these are the calls the assistant has available:

  • create_session — Create a new REPL session with preset or custom configuration. Use displayName to set a custom name that appears in the browser tab title. Returns a
  • send_input_to_session — The send_input_to_session tool exposed by this server
  • list_repl_sessions — List all active REPL sessions. Each session includes a webUrl for browser access
  • get_session_details — Get detailed information about a specific session. Includes webUrl for browser access
  • destroy_repl_session — The destroy_repl_session tool exposed by this server
  • list_repl_configurations — The list_repl_configurations tool exposed by this server
  • send_signal_to_session — Send a signal (like Ctrl+C, Ctrl+Z) to interrupt or control a REPL session process
  • set_session_ready — Mark a session as ready with a specific prompt pattern. Used during session recovery
  • wait_for_session — The wait_for_session tool exposed by this server
  • mark_session_failed — The mark_session_failed tool exposed by this server
  • Building — The Building tool exposed by this server
  • Windows — The Windows tool exposed by this server

Configuration and credentials

You will need one environment variable: SESSION_ID. Keep credentials in your client's env block or a secrets manager rather than in a file you might commit.

Setting it up

Installation goes through your MCP client rather than a global install: point it at repl-mcp on npm and it is fetched when the client starts. The copy-paste blocks for Claude Desktop, Claude Code and Cursor are further down this page.

Choosing this one

Among the browser automation options, the useful question is rarely "what can it do" but "what does it cost you to run" — permissions, credentials, and how much of your context its toolset consumes. Repl MCP's toolset — create_session, send_input_to_session, list_repl_sessions and 9 more — is a fair guide to whether it matches your workflow. It is maintained by takafu; worth a glance at recent repository activity before you build anything load-bearing on it.

SyncDev reviews every entry in this directory against the project's own documentation before publishing, and revisits them as servers change.

Before you rely on it

  • It runs with your machine's permissions. That is convenient and also the reason to think about what you point it at before you approve a tool call.
  • With 12 tools registered it takes up a noticeable share of the context window; turn it off in projects that never touch Repl MCP.
  • MCP clients confirm each tool call by default. Leave that on until you have watched what the repl mcp mcp server does with a few real requests.

Available tools

ToolWhat it does
create_sessionCreate a new REPL session with preset or custom configuration. Use displayName to set a custom name that appears in the browser tab title. Returns a webUrl that can be opened in a browser to monitor the session via Web U
send_input_to_sessionThe send_input_to_session tool exposed by this server.
list_repl_sessionsList all active REPL sessions. Each session includes a webUrl for browser access.
get_session_detailsGet detailed information about a specific session. Includes webUrl for browser access.
destroy_repl_sessionThe destroy_repl_session tool exposed by this server.
list_repl_configurationsThe list_repl_configurations tool exposed by this server.
send_signal_to_sessionSend a signal (like Ctrl+C, Ctrl+Z) to interrupt or control a REPL session process.
set_session_readyMark a session as ready with a specific prompt pattern. Used during session recovery.
wait_for_sessionThe wait_for_session tool exposed by this server.
mark_session_failedThe mark_session_failed tool exposed by this server.
BuildingThe Building tool exposed by this server.
WindowsThe Windows tool exposed by this server.

How to install the Repl MCP MCP server

{
  "mcpServers": {
    "repl": {
      "command": "npx",
      "args": ["-y", "repl-mcp"],
      "env": {
        "SESSION_ID": "your-value"
      }
    }
  }
}

Add to claude_desktop_config.json, then restart Claude Desktop.

Configuration

VariableDescriptionRequired
SESSION_IDConfiguration value read at startup.Optional

Example prompts to try

  • Use Repl MCP to create session.
  • Use Repl MCP to send input to session.
  • Use Repl MCP to list repl sessions.

Frequently asked questions

It connects Repl MCP to MCP-compatible AI assistants such as Claude and Cursor, exposing 12 tools (create_session, send_input_to_session, list_repl_sessions, and more) that the assistant can call on your behalf. Instead of copying data back and forth by hand, the assistant works with Repl MCP directly.