agent-browser automatically accepts alert and beforeunload dialogs
Introduced 2026-03-30 · score 0.93
HOW TO USE IT
When testing a page that may show JavaScript dialogs, run the browser with agent-browser v0.23.1; `alert` and `beforeunload` dialogs are accepted automatically by default. Disable that behavior with `--no-auto-dialog` or `AGENT_BROWSER_NO_AUTO_DIALOG=1`; `confirm` and `prompt` still need explicit handling.
agent-browser open <url>agent-browser --no-auto-dialog open <url>AGENT_BROWSER_NO_AUTO_DIALOG=1 agent-browser open <url>WHY THIS HELPS
Test a web page that may show JavaScript alert or beforeunload dialogs during browser automation.
BEFORE THIS CHANGE
The v0.23.1 changelog says agent-browser previously hung when native browser dialogs appeared, waiting for manual intervention.
REQUIREMENTS AND LIMITATIONS
- Version: v0.23.1
- --no-auto-dialog: Boolean flag that disables automatic dismissal of `alert` and `beforeunload` dialogs.
- AGENT_BROWSER_NO_AUTO_DIALOG: Environment variable that disables automatic dismissal of `alert` and `beforeunload` dialogs; the documented disabling example sets it to `1`.
- Prerequisite: Install agent-browser. The README recommends `npm install -g agent-browser` and `agent-browser install` to download Chrome the first time.
- `confirm` and `prompt` dialogs still require explicit handling.
FIRST-PARTY EVIDENCE
- https://github.com/vercel-labs/agent-browser/releases/tag/v0.23.1
- https://github.com/vercel-labs/agent-browser/pull/1075
- https://github.com/vercel-labs/agent-browser/blob/v0.23.1/README.md
- https://github.com/vercel-labs/agent-browser/blob/v0.23.1/CHANGELOG.md
Check the installed version and the source before using it. Entry JSON