| 1. Claude Opus 5 (High) |
| 2. Claude Opus 5 (Max) |
| 3. Claude Fable 5 (High) |
| 4. GPT 5.6 Sol (xHigh) |
| 5. Claude Opus 4.8 (High) |
The BriefA folder of code can now run its own commands on your computer as soon as an AI coding agent opens it. The trick hides in the folder's own git settings, in a file called .git/config, which can name a program for git to run in the background. The agent runs a routine git check, that program runs as you, and it happens outside the agent's safety sandbox. Sometimes it happens before you type a single prompt. Seven agents were tested and all seven ran it, including Claude Code, Codex and Cursor. Downloading a repo the normal way with git clone, fetch or pull is safe, because those commands do not copy that setting. The danger is code that arrives as plain files: a zip a coworker sent you, a shared drive, a sync folder, or a USB stick. Four of the eight holes are patched and four are still open. Update your coding agent today, and open .git/config and read it before you point an agent at any folder that did not come from a clone.
Level UpThis week, learn to read a repo's .git/config before you trust it. Open the file in any text editor and look for a line that names a program to run, such as core.fsmonitor or a hooksPath that points somewhere odd. Two minutes with the git config guide tells you which settings can launch a program, so you can spot a bad one on sight instead of hoping your agent catches it. →Git: the git config reference