Anthropic has acquired Stainless, the company that generates all official SDKs for the Claude API. Founded in 2022, Stainless also produces CLI tools and MCP servers. With this acquisition, Anthropic aims to further expand the connectivity of Claude agents with external data and tools.
Stainless converts API specifications into SDKs in languages including TypeScript, Python, Go, Java, and Kotlin. Hundreds of companies use Stainless to generate their own SDKs, command-line interfaces, and MCP servers, according to Anthropic.
That broad range of languages is necessary to ensure that every generated SDK feels native within its programming language. That was the starting point for Stainless. “I started Stainless because SDKs deserve as much care as the APIs they wrap,” said founder and CEO Alex Rattray. Anthropic was one of his earliest customers.
From SDK generator to part of Anthropic
The acquisition better illustrates how Anthropic aims to shape connectivity. The company developed the Model Context Protocol (MCP), the de facto standard for connecting AI agents to external tools and data. MCP has since become so widespread that OpenAI has also incorporated it into its Agents SDK. Earlier this year, management of MCP was transferred to the Agentic AI Foundation under the Linux Foundation.
In addition to SDKs, Stainless also generates MCP servers, the connectors that link agents to APIs. “Agents are only as useful as what they can connect to,” says Katelyn Lesse, Head of Platform Engineering at Anthropic. “We’re excited to bring the Stainless team into Anthropic to advance Claude’s ability to connect with data and tools.”
Developer experience as a priority
With Stainless on board, Anthropic aims to further refine the developer experience around the Claude Platform. This ranges from model development to the tooling that developers use to integrate Claude into their own systems. The Stainless team will continue doing the same work, according to Rattray, but on the platform where it carries the most weight.