Hundreds of agents build a browser
Cursor ran hundreds of concurrent coding agents, split into planners and workers, on one project for close to a week to build a web browser.
The agents wrote over 1 million lines of code across 1,000 files, and a three-week Solid to React migration reached +266K/-193K edits.
Overview
How it was set up
Planner agents create tasks and spawn sub-planners, workers complete tasks and push to one branch, and a judge agent decides whether to continue. GPT-5.2 models were used.
Worth knowing
The Solid to React migration still needs careful review. Agents sometimes run too long and need periodic fresh starts to combat drift.
A prompt to start from
The source does not show the prompt.
Sources 1
History
- Source published
- 2026-01-14
- Added to Agentic Feats
- 2026-10-13
- Pick
- No
- Markdown copy
- /c/hundreds-of-agents-build-a-browser-cursor.md
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