Builderbot is an orchestration layer that coordinates multiple AI agents across our entire codebase. It works inside Slack: anyone can tag @builderbot with a short description of what they need, and it gets to work right there in the thread, whether it’s a bug fix, a migration across services, or a new feature. Multiple team members can collaborate with it in real time, watching it research, plan, and implement while they steer the direction. There's no context switching, the conversation is the development environment.

What makes this different from a coding assistant is scope. Builderbot understands the full context of Block's codebase, every service, every API, every convention, and can contribute to any piece of code at the entire company. An engineer working on Cash App can use it to make a change in a Square service they've never touched, because the system already knows how that service works. It picks up tickets directly from Linear and Jira, creates the branch, writes the code, opens the pull request, watches CI, and iterates based on feedback. Humans step in where humans add the most value.

Builderbot executes over 200,000 operations per day and merges approximately 1,500 pull requests per week, about 15% of all production code changes across Block. What used to take months now takes days.

I'd love to know what this means exactly. Is this a custom tool call? Something less generic than what ships with most harnesses or something more exotic? Otherwise, there wouldn't be much point in calling it out, right?

What makes this different from a coding assistant is scope. Builderbot understands the full context of Block's codebase, every service, every API, every convention, and can contribute to any piece of code at the entire company.