Troubleshooting

Updated Jul 27, 2026
  • agent-browser not found: Install it with npm install -g agent-browser, run agent-browser install, and confirm agent-browser --version works on PATH. If it cannot be installed, pass --backend playwright and install the needed Playwright browser.
  • Browser download warnings: For local Playwright captures, install the missing system libraries named in the Playwright warning banner, then re-run bunx playwright install ....
  • CDP connection failures: Confirm that agent-browser get cdp-url still returns a live endpoint and that no firewall or provider policy blocks the WebSocket connection.
  • Invalid bridge option combinations: --cdp-url requires --mode cdp and cannot be combined with --browser, because the CDP endpoint already selects the browser. --backend agent-browser requires CDP mode and cannot be combined with --browser. --use-current-page requires the agent-browser backend.
  • Navigation timeouts: Adjust --timeout or use --wait-until load for pages with continuous network chatter.
  • "Event stream closed" on stderr: When agent-browser is starting a cold session, the first open call can race the event-stream handshake and exit non-zero with "Event stream closed" on stderr. css-view automatically retries the open command once. You will see a [agent-browser] Transient open failure detected warning on stderr, followed by [agent-browser] Retry succeeded. if recovery succeeds. If the retry also fails, the second error is reported and css-view exits non-zero. Verify that the agent-browser daemon is running (agent-browser --version) and retry the command.
  • Large pages: Use --max-nodes (walker) or pare down the property list to reduce output size.