io.github.cyanheads/calculator-mcp-server
Evaluate, simplify, and differentiate mathematical expressions.
Open source Repository Open in the app JSON README (API)
About
Evaluate, simplify, and differentiate mathematical expressions.
Details
- Kind
- MCP servers
- Topic
- No topic detected
- Publisher
- cyanheads
- Origin
- official
- Category
- ferramentas
- Transport
- http
- Version
- 0.4.1
- Stars
- 1
- Last push
- 2026-08-22T13:52:04Z
- Repository state
- ativo
- Language
- TypeScript
- License
- Apache-2.0
- Added
- 2026-08-29 03:02:38
- Updated
- 2026-08-29 03:02:38
- Origin id
io.github.cyanheads/calculator-mcp-server
README
<div align="center">
<h1>@cyanheads/calculator-mcp-server</h1>
<p><b>Evaluate, simplify, and differentiate mathematical expressions via MCP. STDIO or Streamable HTTP.</b>
<div>1 Tool • 1 Resource</div>
</p>
</div>
<div align="center">
[](./CHANGELOG.md) [](./LICENSE) [](https://github.com/users/cyanheads/packages/container/package/calculator-mcp-server) [](https://modelcontextprotocol.io/) [](https://www.npmjs.com/package/@cyanheads/calculator-mcp-server) [](https://www.typescriptlang.org/) [](https://bun.sh/)
</div>
<div align="center">
[](https://github.com/cyanheads/calculator-mcp-server/releases/latest/download/calculator-mcp-server.mcpb) [](https://cursor.com/en/install-mcp?name=calculator-mcp-server&config=eyJjb21tYW5kIjoibnB4IiwiYXJncyI6WyIteSIsIkBjeWFuaGVhZHMvY2FsY3VsYXRvci1tY3Atc2VydmVyIl19) [](https://vscode.dev/redirect?url=vscode:mcp/install?%7B%22name%22%3A%22calculator-mcp-server%22%2C%22command%22%3A%22npx%22%2C%22args%22%3A%5B%22-y%22%2C%22%40cyanheads%2Fcalculator-mcp-server%22%5D%7D)
[](https://www.npmjs.com/package/@cyanheads/mcp-ts-core)
</div>
<div align="center">
**Public Hosted Server:** [https://calculator.caseyjhand.com/mcp](https://calculator.caseyjhand.com/mcp)
</div>
---
## Tools
One tool for all mathematical operations:
| Tool Name | Description |
|:----------|:------------|
| `calculate` | Evaluate math expressions, simplify algebraic expressions, or compute symbolic derivatives. |
### `calculate`
A single tool covering 100% of the server's purpose. The `operation` parameter defaults to `evaluate`, so the common case is just `{ expression: "..." }`.
- **Evaluate** — arithmetic, trigonometry, logarithms, statistics, matrices, complex numbers, unit conversion, combinatorics
- **Simplify** — reduce algebraic expressions symbolically (e.g., `2x + 3x` -> `5 * x`). Supports algebraic and trigonometric identities
- **Derivative** — compute symbolic derivatives (e.g., `3x^2 + 2x + 1` -> `6 * x + 2`)
- Variable scope via `scope` parameter: `{ "x": 5, "y": 3 }`
- Configurable precision for numeric results
- Blank optional `variable` and `precision` values from form-based MCP clients are treated as omitted
---
## Resources
| URI Pattern | Description |
|:------------|:------------|
| `calculator://help` | Available functions, operators, constants, and syntax reference. |
---
## Features
Built on [`@cyanheads/mcp-ts-core`](https://github.com/cyanheads/mcp-ts-core):
- Declarative tool definitions — single file per tool, framework handles registration and validation
- Unified error handling across all tools
- Structured logging with optional OpenTelemetry tracing
- Runs locally (stdio/HTTP) or in Docker
Calculator-specific:
- Hardened math.js v15 instance — dangerous functions disabled, evaluation sandboxed via `vm.runInNewContext()` with timeout
- No auth required — all operations are read-only and stateless
- Input validation: expression length limits, expression separator rejection (semicolons and newlines), numeric-only scope values
- Result validation: blocked result types (functions, parsers, result sets), configurable max result size
- Scope sanitization: numeric-only values, prototype pollution prevention (blocked `__proto__`, `constructor`, etc.)
---
## Getting Started
### Public Hosted Instance
A public instance is available at `https://calculator.caseyjhand.com/mcp` — no installation required. Point any MCP client at it via Streamable HTTP:
```json
{
"mcpServers": {
"calculator-mcp-server": {
"type": "streamable-http",
"url": "https://calculator.caseyjhand.com/mcp"
}
}
}
```
### Self-Hosted / Local
Add one of the following to your MCP client configuration file:
```json
{
"mcpServers": {
"calculator-mcp-server": {
"type": "stdio",
"command": "bunx",
"args": ["@cyanheads/calculator-mcp-server@latest"]
}
}
}
```
Or with npx (no Bun required):
```json
{
"mcpServers": {
"calculator-mcp-server": {
"type": "stdio",
"command": "npx",
"args": ["-y", "@cyanheads/calculator-mcp-server@latest"]
}
}
}
```
Or with Docker:
```json
{
"mcpServers": {
"calculator-mcp-server": {
"type": "stdio",
"command": "docker",
"args": [
"run", "-i", "--rm",
"-e", "MCP_TRANSPORT_TYPE=stdio",
"ghcr.io/cyanheads/calculator-mcp-server:latest"
]
}
}
}
```
### Prerequisites
- [Bun v1.3.0](https://bun.sh/) or higher
### Installation
1. **Clone the repository:**
```sh
git clone https://github.com/cyanheads/calculator-mcp-server.git
```
2. **Navigate into the directory:**
```sh
cd calculator-mcp-server
```
3. **Install dependencies:**
```sh
bun install
```
---
## Configuration
| Variable | Description | Default |
|:---------|:------------|:--------|
| `CALC_MAX_EXPRESSION_LENGTH` | Maximum allowed expression string length (10–10,000). | `1000` |
| `CALC_EVALUATION_TIMEOUT_MS` | Maximum evaluation time in milliseconds (100–30,000). | `5000` |
| `CALC_MAX_RESULT_LENGTH` | Maximum result string length in characters (1,000–1,000,000). | `100000` |
| `MCP_TRANSPORT_TYPE` | Transport: `stdio` or `http`. | `stdio` |
| `MCP_HTTP_HOST` | Hostname for the HTTP server. | `localhost` |
| `MCP_HTTP_PORT` | Port for HTTP server. | `3010` |
| `MCP_HTTP_ENDPOINT_PATH` | Path for the HTTP MCP endpoint. | `/mcp` |
| `MCP_HTTP_MAX_BODY_BYTES` | Maximum inbound HTTP request size; `0` disables the limit. | `1048576` |
| `MCP_AUTH_MODE` | Auth mode: `none`, `jwt`, or `oauth`. | `none` |
| `MCP_LOG_LEVEL` | Log level (RFC 5424). | `info` |
See [`.env.example`](./.env.example) for optional session, resumability, logging, and telemetry settings.
---
## Running the Server
### Local Development
- **Build and run the production version:**
```sh
bun run build
bun run start:http # or start:stdio
```
- **Run checks and tests:**
```sh
bun run devcheck # Lints, formats, type-checks
bun run test # Runs test suite
```
### Docker
```sh
docker build -t calculator-mcp-server .
docker run -p 3010:3010 calculator-mcp-server
```
The image defaults to Streamable HTTP on port `3010`, stateless sessions, and logs at `/var/log/calculator-mcp-server`.
---
## Project Structure
| Directory | Purpose |
|:----------|:--------|
| `src/mcp-server/tools/` | Tool definitions (`*.tool.ts`). |
| `src/mcp-server/resources/` | Resource definitions (`*.resource.ts`). |
| `src/services/` | Domain service integrations (MathService). |
| `src/config/` | Environment variable parsing and validation with Zod. |
| `docs/` | Generated directory tree. |
---
## Development Guide
See [`AGENTS.md`](./AGENTS.md) or [`CLAUDE.md`](./CLAUDE.md) for development guidelines and architectural rules. The short version:
- Handlers throw, framework catches — no `try/catch` in tool logic
- Use `ctx.log` for logging
- Register new tools and resources in `src/index.ts`
---
## Contributing
Issues and pull requests are welcome. Run checks before submitting:
```sh
bun run devcheck
bun run test
```
---
## License
Apache-2.0 — see [LICENSE](LICENSE) for details.