AI Browser Guard

External automation frameworks (Playwright, Puppeteer, Selenium, Anthropic Computer Use, OpenAI Operator) drive the browser over the Chrome DevTools Protocol with native input. AI Browser Guard detects and alerts on these agents, and its kill switch closes the tab they control, but it does not block their individual actions and cannot see their clicks, typing, or screenshots in the timeline. A browser extension cannot enforce per-action policy against a framework that owns the tab's debugger slot; the only categorical block is a managed-Chrome policy (RemoteDebuggingAllowed=false), and modern Chrome already blocks remote debugging of your default profile by default. The delegation presets and per-action blocking below apply to IN-PAGE / injected automation only, best-effort. If a session report shows few or no actions for an external agent, that means its actions were not observable, not that nothing happened.

FIVE CORE FEATURES

1. Agent Takeover Detection — identifies automation frameworks without requiring agents to self-identify. WebDriver flag detection, CDP connection scanning, behavioral heuristics (click precision, typing cadence, synthetic events), and framework fingerprinting.

2. Emergency Kill Switch — one-click stop. Revokes delegated permissions, dispatches a page-realm stop to in-page automation, and closes the tabs an agent controls (the real interruption of an in-progress action). It does not terminate an external CDP session -- an extension cannot -- and a persistent external driver can reopen a tab. Keyboard shortcut: Ctrl+Shift+K (Cmd+Shift+K on Mac).

3. Delegation Wizard — define what agents can and cannot do before they connect: Read-Only (navigate and read, no clicking or typing), Limited (specific sites you choose, with time limits 15min / 1hr / 4hr), or Full Access (everything allowed, with logging and alerts).

4. Boundary Violation Alerts — when an IN-PAGE agent attempts a scripted navigation, form submission, click, keystroke, new-tab open, or download outside its delegation scope, the action is blocked (best-effort) and you receive a notification showing what was attempted, which rule blocked it, and the option to allow it once. External CDP frameworks drive via native input these alerts cannot see -- for those, rely on detection and the kill switch. (DOM reads, injected scripts, and screenshots are not blocked; use the kill switch to close the agent's tab.)

5. Session Timeline — chronological log of all agent actions: timestamps, action types, target URLs, element selectors, and whether each action was allowed or blocked. Last 5 sessions retained.

PRIVACY

By default, AI Browser Guard makes zero network requests. All detection, delegation, and session tracking runs locally on your device. There is no analytics, no telemetry, and no tracking. Session logs and settings are stored in chrome.storage.local and are deleted when you uninstall.

The extension also offers four optional features that make network requests and are OFF BY DEFAULT. They only act after you explicitly enable them, and each can be turned off again with one click:

• AIM identity lookup and registry trust lookup — when an agent is detected, look up a trust score for that agent type. Only the detected agent type (for example "playwright") is sent. Your URLs and page content are never sent.
• Anonymized contribution — share anonymized detection and behavior summaries (an anonymous token, the detected framework name, and summary counts) to improve community threat intelligence. Prompted once after 5 detections; dismissible.
• Site safety declarations — when an AI agent is detected on a page, request that website's /.well-known/ai-safety.txt, a public file a site may publish to state what it claims about its own content, and show those claims alongside the detection. This is the one feature that contacts the website your agent is on instead of an OpenA2A server. The request is a plain GET for that one fixed filename: no cookies, no page address, no referrer, and nothing about you. It follows no redirects, runs only over HTTPS, and runs only while an agent is detected — never on pages you browse yourself. Results are cached locally for 24 hours; turning the setting off deletes every stored declaration. Declarations are display-only: self-asserted claims the extension does not verify, and they never change what the extension detects, scores, or blocks.

None of these features transmit your URLs, page content, form data, keystrokes, cookies, authentication tokens, or identity. Three of them contact only OpenA2A's own servers (aim.opena2a.org, api.oa2a.org); site safety declarations contacts the website your agent is on, which receives nothing about you but can see that the request was made.

Full privacy policy: https://opena2a.org/aibrowserguard/privacy

PERMISSIONS

AI Browser Guard requests host access to all URLs because AI agents can operate on any website, so the detection content script must run on every page. By default the extension makes no network requests; the only outbound requests are the optional, off-by-default features described under PRIVACY.

ABOUT OPENA2A

AI Browser Guard is built by OpenA2A, an open-source security platform building infrastructure for the AI agent ecosystem. Learn more: https://opena2a.org — Source code: https://github.com/opena2a-org/AI-BrowserGuard

This is a beta release. We are actively improving detection accuracy, adding framework signatures, and expanding delegation controls. Open an issue on GitHub with feedback: https://github.com/opena2a-org/AI-BrowserGuard/issues