Summary
Exposes a stateful RPN calculator through MCP with two tools: evaluate and clear. The evaluate tool handles standard arithmetic operators (add, subtract, multiply, divide, power, modulo) plus stack commands like dup, swap, and clear. Stack state persists between calls unless you explicitly clear it. Reach for this when you need Claude to chain multi-step calculations without juggling intermediate results in conversation context. The RPN approach means you can build complex expressions incrementally, useful for financial calculations, unit conversions, or any scenario where you're iteratively computing values. Runs over stdio transport and packages cleanly via pip.
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MCP server that exposes an RPN calculator
Install
pip install mcp-rpn
Usage
mcp-rpn
The server uses stdio transport for MCP protocol communication.
MCP Tools
evaluate
Evaluate an RPN (Reverse Polish Notation) expression.
{
"name": "evaluate",
"arguments": {
"expression": "3 4 +",
"show_stack": true
}
}
Operators:
+- Add-- Subtract-- Multiply/- Divide**- Power%- Modulo
Commands:
clear- Clear the stackdup- Duplicate top of stackswap- Swap top two elements
Examples:
3 4 +returns710 5 2 + * 2 -returns323 2 /returns1.5
clear
Clear the calculator stack.
{
"name": "clear",
"arguments": {}
}
Development
git clone https://github.com/daedalus/mcp-rpn.git
cd mcp-rpn
pip install -e ".[test]"
# run tests
pytest
# format
ruff format src/ tests/
# lint
ruff check src/ tests/
# type check
mypy src/
MCP Registry
mcp-name: io.github.daedalus/mcp-rpn
Featured
Keeps your Mac awake while Claude Code, Codex or Cursor works. Lets it sleep when they are done.
Try free for 7 days →Block distracting apps from your iPhone permanently without a 3rd party app. Free and open source.
Block now (100% free) →Notes, actions and memory. Without a meeting bot. First month 100% off.
Download for free →belt cli automatically finds the best tools and skills for your agent. image, video, music, tts...
one prompt install →Free an open-source skills that make AI coding agents easier to understand, verify, and control.
Download for free →Connect your Claude agent to live crypto prices and trading routes via 1inch
Get the MCP →