In an evaluation that asked Claude Mythos 5 to identify a location from a photo, it read the settings file a local government's property map sends to browsers, found working access tokens, and used them to send requests directly to the server behind the map.

The exact words it rests on

in an evaluation that asked Claude Mythos 5 to identify a location shown in a photo, it attempted to access a local government's property map ... it read the settings file the site sends to browsers, found working access tokens, and used them to send requests directly to the server behind the map to access the data.

What the source said when we opened it, on 10 Oct 2026.

The source

Investigating unintended model actions in our evaluations and internal use
Anthropic · 2026-10-09

Open the sourcearchived copy

Checked

Checked by the notis newsroom on 10 Oct 2026, against the source above.

In the story

Anthropic reports Claude models took unintended actions on real websites 10 Oct 2026