SDKs and frameworks
Vendors of libraries and frameworks for building MCP servers and clients. 8 vendors typed here by main layer, each read on its own pages on 5 November 2026 and listed A to Z: FastMCP and FastMCP Gateway, LangChain, Mastra, MCP official SDKs, Pydantic AI, Spring AI, Stainless and xmcp.
Of these, 4 state at least one standard on the pages read, and 8 publish a price for at least one product. Other layers they also cover: host or runtime (1) and gateway or proxy (1).
SDKs and frameworks
| Vendor | What it does for this layer | Pricing | Ora score |
|---|---|---|---|
| FastMCP and FastMCP Gateway | FastMCP is Prefect's open-source Python framework for MCP servers, clients and apps, and FastMCP Gateway is Prefect's commercial service that hosts and governs FastMCP servers from a git push. | open source, Apache-2.0; free start, paid plans as of 2026-11-05 | 63 (C) scanned 2026-09-07 |
| LangChain | LangChain connects its agents to MCP servers through MCPAdapter, built on FastMCP, which discovers a server's tools and adapts them into LangChain tools; the older langchain-mcp-adapters package remains on GitHub. | open source as of 2026-11-05 | 74 (B) scanned 2026-10-17 |
| Mastra | Mastra is an open-source TypeScript agent framework whose @mastra/mcp package provides an MCP client for agents and an MCPServer that exposes Mastra tools and agents to external MCP clients. | open source; monthly plus usage as of 2026-11-05 | 78 (B) scanned 2026-11-01 |
| MCP official SDKs | The Model Context Protocol project publishes ten official SDKs, ranked in three tiers by feature completeness, protocol support and maintenance commitment, for building MCP servers and clients. | open source as of 2026-11-05 | 69 (C) scanned 2026-10-16 |
| Pydantic AI | Pydantic AI is a Python agent framework that connects agents to MCP servers through an MCP capability, runs servers locally by default with an opt-in for model providers' native MCP, and can serve agents as MCP servers. | open source as of 2026-11-05 | 90 (A) scanned 2026-11-04 |
| Spring AI | Spring AI builds on the MCP Java SDK with Spring Boot starters for MCP clients and servers, annotation-based tool handling, and the Spring WebFlux and WebMVC transports. | open source as of 2026-11-05 | 58 (C) scanned 2026-04-24 |
| Stainless | Stainless generates an MCP server from an OpenAPI spec as a subpackage of a generated TypeScript SDK, exposing a code execution tool and a docs search tool instead of one tool per endpoint. | per generator as of 2026-11-05 | 58 (C) scanned 2026-09-10 |
| xmcp | xmcp is a TypeScript framework from basement.studio that registers MCP tools, prompts and resources from project files and ships adapters for Next.js and Express plus auth and payment integrations. | open source as of 2026-11-05 | 57 (C) scanned 2026-09-16 |