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Browser Agent / Observability

Agent cannot see browser state

The agent has a browser process, but the observation channel returns no useful page state.

Error text / 报错原文

  • agent cannot see browser state
  • no snapshot available
  • empty browser snapshot

What it means

The agent has a browser process, but the observation channel returns no useful page state.

Most common causes

  • Accessibility tree unavailable
  • Page is canvas-heavy
  • Tool reads a different tab than the visible one
  • CDP session reset after navigation

Fastest fix

  • Reproduce the smallest failing case outside the agent.
  • Confirm auth, session, and transport before changing app code.
  • Disable unrelated tools or servers and retry once.
  • Capture the exact timestamp, client version, and raw error text.

Safe fix

  • Keep secrets in environment variables or the platform secret store.
  • Use least-privilege scopes and read-only tools by default.
  • Add validation around manifests, schemas, and callback URLs.
  • Document the working local and production configuration.

What not to do

  • Do not paste OAuth tokens or session IDs into public logs.
  • Do not bypass TLS, CSP, or permission prompts as a permanent fix.
  • Do not enable every MCP tool globally just to make one task pass.

Diagnostic commands

node --version
npx @playwright/mcp@latest --help
curl http://127.0.0.1:9222/json/version

Related tools

Related errors

Sources