Calculator Server

What avisangle/calculator-server MCP server does

The avisangle/calculator-server MCP server provides 13 tools for mathematical and quantitative work. Its core operations include arithmetic with multiple operands and selectable decimal precision, scientific functions, expression evaluation, statistical analysis, unit conversion, and financial calculations.

The server also includes specialized operations for statistical summaries, individual percentile calculations, bulk unit conversion, NPV, IRR, loan comparisons, and investment scenario comparisons. Expression evaluation accepts variables, parentheses, mathematical constants such as π and e, and function calls.

Supported conversion categories are length, weight, temperature, volume, and area. Financial operations include simple and compound interest, loan payments, ROI, present and future value, NPV, and IRR.

How it works

The application is written in Go and communicates using the Model Context Protocol. A client can call tools through standard input/output, or connect to the HTTP transport at /mcp. The HTTP mode accepts MCP JSON-RPC requests with POST, establishes an SSE stream with GET, and handles CORS preflight requests with OPTIONS.

HTTP requests use the documented MCP headers, including Accept and MCP-Protocol-Version. The server supports JSON responses and optional Server-Sent Events for streaming responses. Session identifiers are generated for HTTP sessions, and the implementation includes origin validation and security headers for CORS handling.

Calculations use shopspring/decimal for financial precision, gonum.org/v1/gonum for scientific computing, and govaluate for expression parsing. Input validation and detailed errors are part of the request handling behavior.

Setup and configuration

The avisangle/calculator-server MCP server requires Go 1.21 or newer. The documented local workflow is:

1. Obtain the repository and enter its directory.
2. Run make deps to install dependencies.
3. Run make build to create the server binary.
4. Run make run to start it.

The alternative Go workflow initializes or updates the module, builds ./cmd/server, and starts the resulting calculator-server binary with -transport=stdio. For HTTP mode, the documented invocation uses -transport=http -port=8080; the endpoint is then http://localhost:8080/mcp.

No API keys, database connections, or other credentials are described in the provided material. The README does not document integrations with specific MCP desktop or coding clients.

Tools and capabilities

• Perform addition, subtraction, multiplication, and division with multiple operands.
• Evaluate trigonometric, logarithmic, exponential, power, square-root, absolute-value, and factorial functions.
• Evaluate expressions with variables, constants, nested parentheses, and function calls.
• Calculate descriptive statistics, variability measures, and percentiles.
• Convert individual or batches of values across supported unit categories.
• Analyze loans and investments using payment, NPV, IRR, and scenario calculations.

Limitations and notes

The provided material describes the available operations and transports but does not specify all tool argument schemas, default values, numerical edge-case behavior, or the exact HTTP session lifecycle. HTTP clients must follow the documented /mcp endpoint and required MCP headers. The server is intended for mathematical computation; it does not provide general-purpose data storage, external market data, or financial advice.