Anthropic rejected an early sandbox-based agent API design because it delayed initial responses and lost the agent when the sandbox failed.

“And there was a whole product development journey that we went on to get there because our first iteration of an API for agents was just, like, throw cloud code in a sandbox and, like, shove an API on top.”

“And the reason why we didn't launch that as our, like, durable scalable solution is everything that I just said. It was like you've got to boot a sandbox and boot cloud code before you can even get a token back, right?”

“The sandbox dies, and you lose your whole agent, and so reliability wasn't where we wanted it to be. So we architected this way mostly for reliability and latency. But the interesting thing, there's actually a, a...”