Metadata-Version: 2.4
Name: calculator-mcp-rubens
Version: 0.0.17
Summary: A calculator MCP server using the FastMCP framework.
License-Expression: MIT
License-File: LICENSE
Keywords: ai,calculator,math,llm,mcp,utility
Author: Rubens Gomes
Author-email: rubens.s.gomes@gmail.com
Maintainer: Rubens Gomes
Maintainer-email: rubens.s.gomes@gmail.com
Requires-Python: >=3.14,<4.0.0
Classifier: Development Status :: 4 - Beta
Classifier: Programming Language :: Python :: 3.14
Requires-Dist: calculator-lib-rubens (>=0.2.0,<1.0.0)
Requires-Dist: cryptography (>=50.0.1,<51.0.0)
Requires-Dist: fastmcp (>=4.0.5,<5.0.0)
Requires-Dist: key-value (>=0.1.2,<1.0.0)
Requires-Dist: py-key-value-aio (>=0.4.6,<1.0.0)
Requires-Dist: pyyaml (>=6.0.3,<7.0.0)
Project-URL: Documentation, https://github.com/rubensgomes-org/calculator-mcp/blob/main/README.md
Project-URL: Homepage, https://github.com/rubensgomes-org/calculator-mcp
Project-URL: Repository, https://github.com/rubensgomes-org/calculator-mcp
Description-Content-Type: text/markdown

[![License: MIT](https://img.shields.io/badge/License-MIT-yellow.svg)](https://github.com/rubensgomes-org/calculator-mcp/blob/main/LICENSE)
[![AI Assisted](https://img.shields.io/badge/AI--Assisted-Development-007ACC)](https://github.com/rubensgomes-org/calculator-mcp/blob/main/AI_DISCLAIMER.md)

# Calculator MCP Server

`calculator-mcp` is a small Streamable HTTP MCP (Model Context Protocol) server
that exposes 16 arithmetic operations as callable tools for an AI LLM (Large
Language Model) to consume. It contains no math of its own — every tool is a
thin synchronous wrapper that logs its arguments and delegates to an
open-source shared math calculator `calculator-lib-rubens` PyPI library
package.

## Features

16 calculator tools available via MCP based on JSON-RPC 2.0 messages:

**Two-operand operations**: `add`, `subtract`, `multiply`, `divide`, `power`,
`nth_root`, `modulo`, `floor_divide`

**Single-operand operations**: `sqrt`, `absolute`, `floor`, `ceil`, `log10`,
`ln`, `exp`

**Rounding**: `round_number` (with configurable decimal places)

## AI Disclaimer

This project includes code and documentation created with the assistance of AI
tools. For details on usage, limits, and review practices, please see the
[AI Disclaimer](https://github.com/rubensgomes-org/calculator-mcp/blob/main/AI_DISCLAIMER.md).

## Prerequisites

- Python 3.14+
- pip 26.2+
- curl 8.7+

## Installation and Usage

### Installation

The `calculator-mcp` can be installed by running
`pip install calculator-mcp-rubens`. 

**IMPORTANT**: release versioning was recently reset to start again at
version 0.0.1. Uninstall any previously installed version first.

- Uninstall any previously installed release:

    ```bash
    pip uninstall calculator-mcp-rubens
    # recommend to purge the cache as well
    pip cache purge
    ```

- To install locally into the user's home environment run command below

    ```bash
    # install "calculator-mcp" and dependencies into user local pip environment
    # NOTE: use --no-cache-dir to avoid issues with earlier version in cache
    pip --no-cache-dir install -U --user calculator-mcp-rubens --verbose
    ```

- Confirm installed version with most recently released GitHub version at
  [calculator-mcp/releases](https://github.com/rubensgomes-org/calculator-mcp/releases)

    ```bash
    # show the installed version of calculator-mcp-rubens
    pip show calculator-mcp-rubens
    ```

### Usage

#### Configuration

The server ships with a default `config.yaml` bundled inside the package. To
override it, set the `CALCULATOR_MCP_CONFIG` environment variable to the
absolute path of your custom configuration file:

```bash
export CALCULATOR_MCP_CONFIG=/path/to/your/config.yaml
```

When `CALCULATOR_MCP_CONFIG` is not set, the bundled default is used
automatically.

The configuration file has three sections. The `logging` section controls Python
logging via `dictConfig`. The default configuration logs `calculator_mcp`
messages at `DEBUG` level to stderr.

```yaml
# =============================================================================
# Server Configuration
# =============================================================================
server:
    # the home page of this project
    homepage: "https://github.com/rubensgomes-org/calculator-mcp"
    # MCP transport: "stdio" or "http"
    # http: for web services using the Streamable HTTP protocol
    transport: "http"
    # Host IP address for the HTTP/MCP server.
    # The "0.0.0.0" is used because this application is meant to run from
    # within a Docker container, which requires the wildcard address or
    # NADDR_ANY to accept HTTP connections
    # from outside the Docker container.
    # Use 127.0.0.1 to restrict the server to localhost only.
    host: "0.0.0.0"
    #host: "127.0.0.1"
    # Port for the HTTP/MCP server, defaults to:
    port: 8080
    #port: 9090
    # timeout in seconds
    timeout: 10
    # Stateless HTTP mode (Modern Era, 2026-07-28 spec): true drops session
    # affinity for single-shot tools/call requests. Ignored for "stdio".
    stateless: false

# =============================================================================
# Client Configuration
# =============================================================================
client:
    # the URL the client should use when the server transport is "http"
    #    is_oauth: false
    #    url: "http://127.0.0.1:8080/mcp"
    is_oauth: true
    url: "https://rubens-calculator-mcp.fastmcp.app/mcp"
    # location to store OAuth token
    token_dir: "~/.fastmcp"
    # fixed port for the OAuth callback server
    callback_port: 10000

# =============================================================================
# Logging Configuration
# =============================================================================
logging:
    version: 1
    disable_existing_loggers: false
    formatters:
        standard:
            format: "%(asctime)s [%(levelname)s] %(name)s: %(message)s"
    handlers:
        console:
            class: logging.StreamHandler
            formatter: standard
            stream: ext://sys.stderr
    loggers:
        calculator_mcp:
            level: DEBUG
            handlers:
                - console
            propagate: false
        # MCP protocol tracing — set to DEBUG to see full JSON-RPC messages
        mcp.client.streamable_http:
            level: INFO
            handlers:
                - console
            propagate: false
        # HTTP request/response summaries — set to DEBUG for detail
        httpx:
            level: DEBUG
            handlers:
                - console
            propagate: false
        # HTTP wire-level tracing (headers, TCP) — set to DEBUG for detail
        httpcore:
            level: INFO
            handlers:
                - console
            propagate: false
        # Server: inbound JSON-RPC — set to DEBUG for parsed requests
        mcp.server.lowlevel.server:
            level: INFO
            handlers:
                - console
            propagate: false
        # Server: StreamableHTTP transport — DEBUG for method-level tracing
        mcp.server.streamable_http:
            level: INFO
            handlers:
                - console
            propagate: false
        # Server: session/transport lifecycle — DEBUG for session details
        mcp.server.streamable_http_manager:
            level: INFO
            handlers:
                - console
            propagate: false
        # Server: HTTP request lines (method, path, status)
        uvicorn.access:
            level: INFO
            handlers:
                - console
            propagate: false
    root:
        level: WARNING
        handlers:
            - console
```

#### Running the MCP Server

- Launch `calculator-mcp` locally with sensible defaults:

    ```bash
    # Launches the Streamable HTTP MCP server locally at:
    # http://0.0.0.0:8080/mcp
    # The "0.0.0.0" is used because this application is meant to run from
    # within a Docker container, which requires the wildcard address, or
    # INADDR_ANY, to accept HTTP connections from outside the container.
    calculator-mcp
    ```

- Health check

    ```bash
    curl -v http://localhost:8080/health
    # Expect: OK
    ```

#### Legacy Era (Pre-July 2026)

The Legacy Era MCP server is based on a stateful session state that requires
a connection setup handshake using `initialize` / `initialized` JSON-RPC
messages.

**NOTE** Change the config.yaml server -- > stateless to `false`.

**1. Initialize MCP session**

The MCP endpoint requires a session, established via initialize first.
Run these in order:

- Store the JSON below in a local file `/tmp/initialize.json`:

    ```bash
    # remove indentation spaces when copying/pasting this command to the shell
    cat > /tmp/initialize.json <<EOF
    {
      "jsonrpc": "2.0",
      "id": 1,
      "method": "initialize",
      "params": {
        "protocolVersion": "2025-06-18",
        "capabilities": {},
        "clientInfo": {
          "name": "curl-test",
          "version": "1.0"
        }
      }
    }
    EOF
    ```

- Initialize the session and grab the `Mcp-Session-Id` from the response
  headers:

    ```bash
    # Look for the "mcp-session-id: <SID>" header in the output
    curl -i http://localhost:8080/mcp \
      -H "Content-Type: application/json" \
      -H "Accept: application/json, text/event-stream" \
      -d @/tmp/initialize.json
    ```

- Send the required `notifications/initialized` notification (use the SID
  obtained above):

    ```bash
    SID="<paste-mcp-session-id-here>"
    # Expect "202 Accepted" response
    curl -v http://localhost:8080/mcp \
      -H "Content-Type: application/json" \
      -H "Accept: application/json, text/event-stream" \
      -H "Mcp-Session-Id: $SID" \
      -d '{"jsonrpc":"2.0","method":"notifications/initialized"}'
    ```

**2. List tools** — `tools/list`

Once you have initialized your MCP session, list all the tools:

```bash
curl -s http://localhost:8080/mcp \
  -H "Content-Type: application/json" \
  -H "Accept: application/json, text/event-stream" \
  -H "Mcp-Session-Id: $SID" \
  -d '{"jsonrpc":"2.0","id":2,"method":"tools/list"}'
```

This returns all 16 tools: add, subtract, multiply, divide, power, nth_root,
modulo, floor_divide, sqrt, absolute, floor, ceil, log10, ln, exp,
round_number.

**3. Call a tool** (e.g. `add`) — `tools/call`

```bash
curl -s http://localhost:8080/mcp \
  -H "Content-Type: application/json" \
  -H "Accept: application/json, text/event-stream" \
  -H "Mcp-Session-Id: $SID" \
  -d '{"jsonrpc":"2.0","id":3,"method":"tools/call","params":
       {"name":"add","arguments":{"a":2,"b":3}}}'
```

**Note**: reuse the same `Mcp-Session-Id` (obtained during initialization)
for every subsequent request — the server ties the session to that ID.

#### Modern Era (2026-07-28 Spec)

The Modern Era MCP server is stateless. Single-shot tools/call, no handshake
needed.

**NOTE** Change the config.yaml server -- > stateless to `true`.

- Tools call to add two number

    ```bash
    curl -i -sS -X POST http://localhost:8080/mcp \
      -H "Content-Type: application/json" \
      -H "Accept: application/json, text/event-stream" \
      -d '{
    "jsonrpc": "2.0",
    "id": 1,
    "method": "tools/call",
    "params": {
      "name": "add",
      "arguments": {"a": 2, "b": 3},
      "_meta": {
        "io.modelcontextprotocol/protocolVersion": "2026-07-28",
        "io.modelcontextprotocol/clientCapabilities": {}
        }
      }
    }'
    ```

## License

The project is licensed under
[MIT License](https://github.com/rubensgomes-org/calculator-mcp/blob/main/LICENSE).

---
Author: [Rubens Gomes](https://rubensgomes.com/)

