cal-mcp

# Cal Server [](https://archestra.ai/mcp-catalog/pwh-pwh__cal-mcp) [](https://smithery.ai/server/@pwh-pwh/cal-mcp) <a href="https://glama.ai/mcp/servers/@pwh-pwh/cal-mcp"> <img width="380" height="200" src="https://glama.ai/mcp/servers/@pwh-pwh/cal-mcp/badge" alt="Cal Server MCP server" /> </a> ## Project Introduction `Cal Server` is a simple mathematical expression calculation service built on the `FastMCP` framework, running in the Bun runtime environment. It utilizes the `expr-eval` library to parse and compute mathematical expressions input by users, interacting with the outside world through standard input and output (stdio). This project aims to provide a lightweight and efficient calculation tool that supports basic mathematical operations and built-in constants. ## Features - **Expression Calculation**: Supports user input of mathematical expressions and returns the calculation results. - **Built-in Constants**: - `E`: `Math.E` in the Bun environment. - `PI`: `Math.PI` in the Bun environment. - `true`: Logical true value. - `false`: Logical false value. - **Tool Name**: `cal`. - **Parameters**: Accepts a string type mathematical expression (`exp`). ## Dependencies - `fastmcp`: Used for building MCP services. - `expr-eval`: Used for parsing and calculating mathematical expressions. - `zod`: Used for parameter validation. ## Prerequisites - Ensure that the [Bun](https://bun.sh/) runtime is installed (latest version recommended). ## Installation ### Installing via Smithery To install cal-mcp for Claude Desktop automatically via [Smithery](https://smithery.ai/server/@pwh-pwh/cal-mcp): ```bash npx -y @smithery/cli install @pwh-pwh/cal-mcp --client claude ``` ### MCP Client Configuration ```json "cal-mcp": { "name": "Calculation", "description": "", "isActive": true, "command": "bunx", "args": [ "cal-mcp" ] } ``` ### Manual Installation 1. Clone the project repository: ```bash git clone <repository-url> ``` 2. Navigate to the project directory and install dependencies: ```bash bun install ``` ## Usage 1. Start the service: ```bash bun run index.ts ``` The service will run through standard input and output (stdio). 2. Input a mathematical expression: - Example input: `2 + 3 * PI` - Output: Calculation result (in string format). 3. Supported expression examples: - Basic operations: `2 + 2` → `4` - Using constants: `PI * 2` → `6.283185307179586` - Complex expressions: `E ^ 2 + 1` → `8.38905609893065` ## Notes - The input expression must be a valid mathematical expression; otherwise, it may throw an error. - The service currently only supports interaction via `stdio`. - The project uses the Bun runtime, so ensure commands are compatible with Bun.