calc-mcp — Claude Code MCP server: what it does, how to install
calc-mcp gives AI coding clients local tools for calculations, dates, encoding, hashes, and random values. Use it when repeatable results matter.
claude mcp add calc-mcp -- npx -y @coo-quack/calc-mcpWhat calc-mcp does
calc-mcp exposes 21 MCP tools covering arithmetic, date handling, encoding, hashing, randomness, conversions, and data parsing. The server can evaluate expressions, inspect time zones, create UUIDs, transform colors and units, validate JSON, and parse URLs or JWTs.
Processing stays on the local machine, so the tools do not send data to external services. Setup runs the package with npx, and Node.js is required. Without Node.js, the server will not start.
What it helps with
- check an expression without relying on model arithmetic
- create a random UUID or test password
- convert a date across time zones
- encode, decode, or hash a value
- inspect a URL, JWT, or JSON document
Example prompts for the agent
- Calculate this expression and return the exact result.
- Generate a UUID v7 and a random password for my test data.
- Validate this JSON, decode the JWT, and show its fields.
How to install calc-mcp
Platform CLI
claude mcp add calc-mcp -- npx -y @coo-quack/calc-mcpPlatform CLI
codex mcp add calc-mcp -- npx -y @coo-quack/calc-mcpConfig file
{
"mcpServers": {
"calc-mcp": {
"command": "npx",
"args": [
"-y",
"@coo-quack/calc-mcp"
]
}
}
}Config file
{
"servers": {
"calc-mcp": {
"type": "stdio",
"command": "npx",
"args": [
"-y",
"@coo-quack/calc-mcp"
]
}
}
}Platform CLI
gemini mcp add calc-mcp npx -y @coo-quack/calc-mcpStep by step, with commands for each platform: How to add an MCP server to Claude Code, Codex, Cursor, VS Code, Gemini CLI and more
Questions about calc-mcp
How do I install calc-mcp in Claude Code?
Run claude mcp add calc-mcp -- npx -y @coo-quack/calc-mcp.
What does calc-mcp do?
It adds MCP tools for math, dates, random values, encoding, hashes, conversions, and parsing. The computations run locally.
What does calc-mcp need to run?
Node.js and an MCP client are required. calc-mcp itself does not require an account or API key.
