Browser Use ditches predefined state and actions: raw CDP and existing coding agents win
The bitter lesson of browser agents
Browser Use traces its evolution from a fixed ReAct loop with predefined state and actions to letting models write both observations and actions via raw CDP. Replacing 12 browser tools with browser_exec cut mean token use by 60% for Opus 4.8 and 66% for Kimi K3. The company now reuses proven coding agent harnesses like Pi, Codex, and OpenCode, arguing that exposing the simplest underlying interface and letting the model choose what to see and do is the real bitter lesson.
Browsers, computers, text, music: the same principle applies. As models change, rethink the harness.