More than 276,000 KPMG employees will soon have access to Anthropic’s Claude, following a strategic alliance that highlights a growing dependence on the tooling developed by Stainless. Anthropic is acquiring Stainless, the company responsible for generating every official Anthropic SDK since the beginning of its API, and the infrastructure underpinning agent connectivity. This move underscores a shift in artificial intelligence toward agents capable of action, reliant on robust connections to external systems. “Agents are only as useful as what they can connect to,” said Katelyn Lesse, Head of Platform Engineering at Anthropic, as the company integrates Stainless’ Multi-tool Connectivity Platform, created by Anthropic to facilitate this agent-focused strategy, directly into its offerings.
Stainless SDKs and Tooling Power Anthropic’s Claude API
Founded before the launch of Anthropic’s Claude API, Stainless has quietly underpinned the developer experience for the AI model by generating every official software development kit since the beginning; this foundational relationship was only recently made public through Anthropic’s acquisition of the firm. Hundreds of companies, including KPMG, currently utilize Stainless’ tooling to create SDKs, command-line interfaces, and Multi-tool Connectivity Platform servers, essential components for accessing and integrating APIs into their systems. Stainless automates the process of transforming an API specification into SDKs for multiple languages, including TypeScript, Python, Go, and Java, ensuring speed, reliability, and a native feel for each platform. The acquisition highlights Anthropic’s strategic investment in agent-focused AI, demonstrated by the internal creation of the Multi-tool Connectivity Platform, designed specifically to facilitate agent connectivity; this platform is now bolstered by Stainless’ expertise.
Alex Rattray, Founder and CEO of Stainless, stated, “I started Stainless because SDKs deserve as much care as the APIs they wrap,” reflecting a commitment to developer experience that aligns with Anthropic’s goals. This integration of the two teams promises to further advance Claude’s capabilities in connecting to diverse tools and data sources, ultimately expanding the platform’s reach and utility.
MCP Server Development Advances Agent Connectivity for Claude
The current focus on artificial intelligence extends beyond simply generating responses; the emphasis is now on creating agents capable of independent action, a shift demanding robust connectivity infrastructure. Stainless’ technology translates API specifications into software development kits for languages including TypeScript, Python, and Java, ensuring fast and reliable access for developers building upon the Claude platform. Stainless has been instrumental in shaping the developer experience with Claude since the API’s inception. Anthropic didn’t simply acquire external expertise; the company proactively developed its own Multi-tool Connectivity Platform, or MCP, specifically to facilitate agent connections, demonstrating a long-term commitment to this architecture.
Stainless has shaped how developers experience the Claude API since the start, and it’s been great to work with them on that.
Katelyn Lesse, Head of Platform Engineering at Anthropic
