Anthropic announced on Saturday that it has acquired Stainless, the startup responsible for building software development kits and related tooling since the AI company launched its API. The purchase is intended to reinforce Claude’s connectivity to outside data and applications as Anthropic pivots more of its effort toward AI agents.
Founded in 2022, Stainless develops SDKs, command-line interfaces and Model Context Protocol servers that enable both developers and AI agents to interact with application programming interfaces. The company specializes in converting API specifications into ready-to-use SDKs across a variety of programming languages, including TypeScript, Python, Go, Java and Kotlin, among others. According to information in the announcement, hundreds of companies rely on Stainless to construct their connectivity layers.
Anthropic framed the deal around the practical limits of agent capabilities. In the company’s statement, Katelyn Lesse, Head of Platform Engineering at Anthropic, underscored that the effectiveness of agents depends on the breadth and quality of their integrations.
"We’re excited to bring the Stainless team into Anthropic to advance Claude’s ability to connect to data and tools," Lesse said.
Stainless founder and CEO Alex Rattray commented on the decision to join Anthropic, noting the alignment between the teams and the platform’s early adoption of SDK generation techniques.
"We have been watching what developers have built on Claude over the last few years, which made bringing our teams together an easy decision," Rattray said.
The announcement did not include any financial details about the transaction.
This acquisition brings an established set of SDK-generation capabilities directly into Anthropic, positioning the company to more tightly integrate tool and data connectivity into Claude as it emphasizes agent-based workflows. Beyond the immediate engineering implications, the move highlights Anthropic’s strategy of internalizing tooling used by the developer ecosystem supporting its platform.
While the company framed the acquisition as a step to improve agent connectivity, the public statement leaves certain details unspecified, including the terms of the deal and a timeline for when integrated features might reach developers and agent users.