Drawbridge Privacy Policy

Effective Date: July 6, 2026

Overview

Drawbridge is an on-device privacy extension for AI chat sites. This privacy policy explains what data we collect, how we use it, and how we protect your information.

        Drawbridge does not collect, transmit, or store any personal data on external servers.
    

Data Processing

All processing happens locally in your browser:

The Rampart PII detection model runs entirely on your device using the extension's offscreen document.
Detected personal information is pseudonymized to placeholder tokens (e.g., [GIVEN_NAME_1]) before any data leaves your browser.
The mapping between real values and placeholder tokens is stored only in memory within the offscreen document and is never persisted to disk.

Permissions

Drawbridge requests the following Chrome permissions:

storage: Used to save your extension settings (e.g., the master toggle, fail-closed preference) locally in your browser.
scripting: Used to inject content scripts that scan the composer and intercept outbound messages on supported sites.
offscreen: Used to host the Rampart model in a dedicated offscreen document where WebGPU/WASM execution is allowed.

Host Permissions

Drawbridge requests access to:

https://claude.ai/* — to scan and protect messages on Claude.ai.
https://huggingface.co/* and https://*.hf.co/* — to download the Rampart model weights from Hugging Face. The model is downloaded once and cached locally. No personal data is sent to Hugging Face.

Data Retention

Settings: Persisted in Chrome's local storage until you uninstall the extension or clear extension data.
Session mappings: Stored only in memory. They are lost when the browser restarts, the extension updates, or the offscreen document is recreated. No real values are ever written to disk.

Third Parties

Hugging Face: The extension downloads the Rampart model weights from Hugging Face. No personal data is sent to Hugging Face.
AI chat sites: Only the pseudonymized placeholder tokens are sent to supported sites. Real values never leave your machine.

Contact

For questions about this privacy policy, please open an issue at https://github.com/sprice/drawbridge.

Changes

We may update this privacy policy from time to time. Changes will be posted to the GitHub repository.