Inside Stainless: The Developer Tools Startup Anthropic Just Bought for $300 Million

If your MCP server has dozens of tools, it's probably built wrong. You need tools that are specific and clear for each use case—but you also can't have too many. This creates an almost impossible tradeoff that most companies don't know how to solve.

That's why we interviewed Alex Rattray, the founder and CEO of Stainless. Stainless builds APIs, SDKs, and MCP servers for companies like OpenAI and Anthropic. Alex has spent years mastering how to make software talk to software, and he came on the show to share what he knows. We get into MCP and the future of the AI-native internet.

[Disclosure: Dan is a small investor in Stainless.]

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Timestamps:

00:01:15 - Introduction

00:05:09 - APIs and MCP, the connectors of the new internet

00:11:00 - Why MCP exists

00:17:15 - Why MCP servers are hard to get right

00:20:24 - Design principles for reliable MCP servers

00:25:06 - Using MCP for business ops at Stainless

00:40:57 - Alex's take on the security model for MCP

00:44:42 - How one-off AI actions become permanent production software

Links to resources mentioned in the episode:

Alex Rattray: Alex Rattray (@RattrayAlex), Alex Rattray

Stainless: https://www.stainless.com/