Anthropic acquires Stainless to boost AI agent connectivity

Anthropic has acquired Stainless, a company that builds software development kits (SDKs) and API tooling. The deal strengthens Anthropic’s push into AI agents that can take actions across different systems, not just answer questions.

Founded in 2022, Stainless has actually powered every official Anthropic SDK since the company’s early API days. The startup helps hundreds of companies generate SDKs, command-line tools, and connectors that let developers and AI agents use APIs. Stainless converts API specifications into working SDKs across multiple programming languages including TypeScript, Python, Go, Java, and Kotlin.

The acquisition signals how AI companies are shifting focus from chatbots to agents that can perform tasks across multiple software platforms. This requires reliable connections to external systems – exactly what Stainless specializes in building. As AI agents become more capable, their usefulness depends heavily on how many different tools and databases they can access.

“Agents are only as useful as what they can connect to,” said 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 to data and tools.”

The move also ties into Anthropic’s Model Context Protocol (MCP), which the company created to make agent connectivity easier. By owning the tooling that generates these connections, Anthropic can better control how developers and agents interact with external systems through Claude.

For Stainless founder and CEO Alex Rattray, the deal lets his team continue their core work while focusing on the platform where it has the most impact. “I started Stainless because SDKs deserve as much care as the APIs they wrap,” Rattray said. “Anthropic was one of the first teams to bet on this with us.”

This acquisition reflects broader industry trends where AI companies are buying specialized tooling firms rather than building everything in-house. It also shows how the next phase of AI development will likely focus on integration and connectivity rather than just making models smarter. The companies that can help AI agents reliably interact with existing software ecosystems may prove just as valuable as those building the underlying AI models.