python-sdk: Building MCP Servers for LLM Context Provision

The python-sdk provides a Python implementation of the Model Context Protocol (MCP), specifically designed to simplify building MCP servers and clients. With 24,617 GitHub stars, this SDK streamlines the process of standardizing context provision for Large Language Models (LLMs), offering structured ways to expose data and functionality.

Core MCP Server Capabilities

At its heart, the python-sdk empowers developers to expose structured data and functionality to LLMs. This is achieved through three primary primitives:

• Resources: These act like GET endpoints in a REST API, allowing you to expose data to LLMs. Think of them as read-only views into your application's state or external data sources.
• Tools: Similar to POST endpoints, Tools enable LLMs to trigger actions within your server. These are expected to perform computations and can have side effects, allowing LLMs to interact dynamically with your application.
• Prompts: These are reusable templates that help define effective interaction patterns between LLMs and your MCP server. They guide how LLMs should interpret available Resources and Tools.

The SDK's FastMCP server component handles connection management and message routing, providing the backbone for these interactions. It supports standard transports such as stdio and SSE, ensuring broad compatibility.

Streamlined Setup and Development Workflow

Getting started with the python-sdk is straightforward. For dependency management, uv is recommended:

uv add "mcp[cli]"

Alternatively, pip can be used:

pip install mcp

For development, the SDK offers a dedicated mode. You can run your server script and leverage the built-in MCP development tools:

mcp dev server.py

This development environment includes an MCP Inspector, a valuable tool for testing and debugging your server's exposed Resources, Tools, and Prompts.

A key integration point is with Claude Desktop. The SDK provides a command to install your server for use with Claude Desktop, making it easy to wire your custom context and capabilities into the LLM environment:

mcp install server.py

The SDK also provides a client interface for connecting to existing MCP servers, offering flexibility for both server and client-side development. For advanced use cases, a low-level server implementation is available, allowing for deeper customization.

Handling Image Data

Beyond text-based context, the python-sdk includes an Image class specifically for handling image data. This allows developers to integrate visual information into their MCP servers, enabling LLMs to process and respond to image-related context.

References

• python-sdk on GitHub
• Model Context Protocol Documentation
• python-sdk on model-context-protocol.com