Locke Extension by Sonomos

Locke Extension connects supported AI websites, including ChatGPT, Claude, Gemini, Grok and Perplexity, to the Locke desktop app for on-device screening.

For in-scope fetch/XHR requests with a body, it holds the request and transfers the body (including conversation text and supported uploaded files), method, destination, path/query and page-set headers to the local app through native messaging. The app returns a verdict:

• allow: send the held request to the website.
• redact: send the desktop app's rebuilt body to the website.
• block: do not send the request; the page sees a network error.

No clean verdict means an in-scope request is blocked. A user's explicit time-boxed fail-open setting in the desktop app can return an unchecked verdict; the extension reports those sends in its popup.

Content scripts run only on catalog-listed hosts and their matched subdomains/frames, without an all-URLs permission. Screening is further restricted by request-path rules, provider policy and disabled-site settings. Some cross-origin uploads from those pages are also screened. Not every action on a supported site is covered: navigation/address-bar search prompts, WebSockets, worker traffic and unrecognized upload shapes are outside this screening path. See https://github.com/sonomoshq/Locke-Extension/blob/main/HONEST.md.

Scanning happens in the local desktop app. The extension does not send screening copies to a Sonomos cloud service; allowed/redacted page requests still reach the user's chosen website. Browser-added Cookie headers are not captured, but page-set headers may include authentication information. The cross-origin upload screening copy omits presigned URL query credentials.

The extension does not persist request bodies. It stores local settings, disabled-site configuration and a 100-entry diagnostic audit buffer, plus session-only connection/screening state and counters. Diagnostic metadata may include URLs or paths. Local connection requests carry browser/version information. See https://sonomos.ai/locke/privacy/ for local processing and desktop retention.

Requires the Locke desktop app. Without a working connection, in-scope requests are blocked and the toolbar badge shows the connection problem.