Browser tool for agents on Browserless

The browser_use capability gives an agent a browser tool on a Browserless browser. Pages are read as an accessibility tree with element refs, and the agent acts by ref or viewport coordinate, fills forms, finds text and works across tabs. Traffic goes through the Everruns network guard.

On Claude models that support Anthropic’s native browser toolset, the capability uses it directly; set native_tools: false to keep the function tool.

Browser use is experimental and ships behind the browserless_browser_use feature flag.

See Browser use and #4375, #4376.