devboxes

A devbox is an ephemeral AWS EC2 instance, drawn from a pre-warmed pool so that a coding agent has a complete working environment in about 10 seconds. Alistair Gray, writing about Stripe's Minions, describes them as "cattle, not pets": nothing inside one is meant to outlive the task that created it.

Two notes, from 2026-02-09 and 2026-02-19, come back to devboxes for the same reason. Isolation is what makes unsupervised agents workable at Stripe. A Minion runs inside a devbox that can reach neither production nor user data, so Stripe's engineers removed the confirmation prompts from their custom fork of goose. The safety question was answered by the infrastructure instead of by a human approving each step.

The environment a devbox hands an agent is the one Stripe's human engineers already work in. That equivalence carries Gray's wider argument: the investment Stripe made in tooling, infrastructure and CI for its engineers now pays a second time by serving agents. Between the two notes, the count of agent pull requests merged each week moved from over 1,000 to over 1,300.

What the notes leave unresolved is how much of this transfers. Stripe's version sits on hundreds of millions of lines of Ruby typed with Sorbet, a suite of more than 3 million tests, and Toolshed, an MCP server exposing roughly 500 tools. The 10-second devbox is the cheap part of that stack.