Anthropic acquires Stainless

The frontier of AI is shifting from models that answer to agents that act—and agents are only as capable as the systems they can reach. Today, Anthropic is acquiring Stainless, a leader in SDKs and MCP server tooling, to extend that reach even further.

Founded in 2022, Stainless has powered the generation of every official Anthropic SDK since the earliest days of our API. Hundreds of companies rely on Stainless to generate SDKs, CLIs, and MCP servers—the libraries, command-line tools, and connectors that let developers and agents use an API. Stainless turns an API spec into SDKs across TypeScript, Python, Go, Java, and more. Each one is fast, reliable, and built to feel native in its language.

“Stainless has shaped how developers experience the Claude API since the start, and it’s been great to work with them on that,” said Katelyn Lesse, Head of Platform Engineering at Anthropic. “Agents are only as useful as what they can connect to. We’re excited to bring the Stainless team into Anthropic to advance Claude’s ability to connect to data and tools.”