Mcp Rpn

io.github.daedalusPublished by GitHub account daedalusv0.1.1Updated Oct 24, 2026

MCP server that exposes an RPN calculator

VerifiedSTDIODesktop onlyDeveloper Tools

Overview

AI-generated overview

A local MCP server that gives an assistant an RPN (Reverse Polish Notation) calculator with an evaluate tool and a stack-clearing tool.

What you can do
Evaluate RPN expressions with arithmetic operators such as add, subtract, multiply, divide, power and modulo, optionally showing the stack state after evaluation. Run stack commands such as clear, dup and swap inside expressions. Clear the calculator stack with a dedicated tool.
When to use it
Useful when you want an assistant to do quick arithmetic in Reverse Polish Notation, including stack-based calculations, without leaving the chat. It is a small utility rather than a general math or data tool.
Requirements
Runs locally over stdio; install the mcp-rpn package from PyPI with pip and start it with the mcp-rpn command. No accounts, API keys or environment variables are declared.
Before you install
The README lists the multiply operator as -, the same symbol as subtract, so multiplication may not behave as expected; verify results. It only computes numbers and does not write, send or delete data.

Installation

In SourceWeft

  1. Open Mcp Rpn in the dashboard and add it to a workspace.
  2. Enable the server for the chats that should use its tools.

Desktop only via STDIO. STDIO servers start a local process, so they need the SourceWeft desktop host.

Other MCP clients

Follow the launch instructions in the repository.

README

mcp-rpn

MCP server that exposes an RPN calculator

[PyPI] [Python] [Ruff]

Install

bash
pip install mcp-rpn

Usage

bash
mcp-rpn

The server uses stdio transport for MCP protocol communication.

MCP Tools

evaluate

Evaluate an RPN (Reverse Polish Notation) expression.

json
{  "name": "evaluate",  "arguments": {    "expression": "3 4 +",    "show_stack": true  }}

Operators:

  • + - Add
  • - - Subtract
  • - - Multiply
  • / - Divide
  • ** - Power
  • % - Modulo

Commands:

  • clear - Clear the stack
  • dup - Duplicate top of stack
  • swap - Swap top two elements

Examples:

  • 3 4 + returns 7
  • 10 5 2 + * 2 - returns 32
  • 3 2 / returns 1.5

clear

Clear the calculator stack.

json
{  "name": "clear",  "arguments": {}}

Development

bash
git clone https://github.com/daedalus/mcp-rpn.gitcd mcp-rpnpip install -e ".[test]"
# run testspytest
# formatruff format src/ tests/
# lintruff check src/ tests/
# type checkmypy src/

MCP Registry

mcp-name: io.github.daedalus/mcp-rpn

Source: README.md at commit 03da1d5

Tools

0
SourceWeft has not started this package in its sandbox yet, so its tools are not known.

Version history

1
  1. v0.1.1LatestSep 16, 2026

Score

50% of the applicable checks met

How complete this listing is, computed from the registry entry, the endpoint and public sources. Not a rating of the server and not a statement that it is safe or working today: reachability is a dated check, and no installs or reviews go into the score.

  • Reached in the last 30 days25 pts

    Keep the endpoint answering the MCP handshake; SourceWeft probes it every 30 days.

  • Auth declared10 pts

    Declare the credential headers in the registry entry, or keep the endpoint answering the probe so its auth can be classified.

  • Tools listed15 pts

    Answer tools/list without a credential, or ship a package that starts in a sandbox without one.

  • DescriptionRequired15 pts
  • Logo10 pts
  • Documentation15 pts
  • License10 pts