Cal Server (cal-mcp) is a simple mathematical expression calculation service built on the FastMCP framework, using the Bun runtime environment. It uses the expr-eval library to parse and evaluate mathematical expressions entered by users, and interacts with the outside world through standard input/output (stdio). This project aims to provide a lightweight and efficient calculation tool that supports basic mathematical operations and built-in constants.
Purpose: Used to calculate mathematical expressions, it can be integrated as an MCP service into environments that support MCP, providing expression evaluation capability.
Main capabilities:
- Expression calculation: Supports users entering 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).
- Parameters: Accepts a string-type mathematical expression (exp).
Dependencies and runtime environment:
- fastmcp: Used to build the MCP service.
- expr-eval: Used to parse and calculate mathematical expressions.
- Ensure that the Bun runtime is installed (the latest version is recommended).
Usage:
- Install via Smithery: Can automatically install cal-mcp for Claude Desktop.
- Manual installation:
- Clone the project repository: git clone <repository URL>
- Enter the project directory and install dependencies: bun install
- Start the service: bun run index.ts, the service will run through standard input/output (stdio).
Input and output examples:
- Input mathematical expression: Example input 2 + 3 * PI, output is the calculation result (in string form).
- Basic operation: 2 + 2 -> 4
- Using constants: PI * 2 -> 6.283185307179586
- Complex expression: E ^ 2 + 1 -> 8.38905609893065
Applicable scenarios: Scenarios that require providing mathematical expression calculation capability in an MCP manner, for example, calling expression evaluation in a client that supports MCP.
Limitations:
- The input expression must be a valid mathematical expression, otherwise an error may be thrown.
- The service currently only supports interaction through stdio.
- The project uses the Bun runtime, so ensure that commands are compatible with Bun.
- Hosted deployment: A hosted deployment is provided on Fronteir AI。
