Security.

How Mosaik keeps things safe

Mosaik runs on your computer and talks to the internet on your behalf, so it's built to keep what it touches in its lane. In short:

• Your key. Kept in Windows Credential Manager if you ask Mosaik to remember it, and only in memory if you don't. It's never written to Mosaik's database or log, never put in a problem report, and only ever sent to OpenRouter.
• Web pages. Mosaik fetches only ordinary http and https addresses, never anything on your own network, reads a limited amount of each page, and treats what it finds as information for the model, not instructions.
• Styled answers. The formatting a model adds to an answer is cleaned against a strict list of allowed tags and styles before it's shown. Interactive pieces run in a sealed frame that can't reach Mosaik, your files, your other chats or your key, and can't send data anywhere.
• The Python tool. Model-written Python runs in a separate, locked-down process with a time and memory limit, and no access to files, the network or other programs.
• Updates. The app only accepts installers from Mosaik's own releases on GitHub, checks each one's size and SHA-256 before running it, and never runs a file that doesn't match.
• No tracking. No analytics or telemetry, so there's no stream of usage data to leak.

The installer isn't code-signed yet. Until it is, you can check a download against the SHA-256 on the Download page. Signing is planned.

Reporting a security problem

If you've found a way to get at someone's key, files or data through Mosaik, the website or the update service, please tell us privately first. Write to [email protected] with “Security” in the subject, and include:

• what the problem is and what someone could do with it;
• the steps to reproduce it, and your Mosaik and Windows versions;
• whether you'd like to be credited, and how.

We'll confirm we've got it, keep you posted while it's being fixed, and credit you in the release notes if you'd like. Please don't post details in public until a fix is out, and don't test against other people's data or try to take the website down.

What counts

The Mosaik desktop app, mosaikchat.com and its update and report services. Problems in OpenRouter, a model provider or a search engine belong with them. Prompt injection that only changes what a model says is a known limit of today's models. It counts when it gets a model to reach something it shouldn't, such as your files, your key or another chat.