Grok Build CLI Silently Uploaded Repos and Git History

Grok Build CLI v0.2.93 uploaded whole tracked repositories to a Google Cloud Storage bucket during ordinary coding sessions, per a Hacker News post from researcher cereblab. The uploads included full Git history.

On a 12GB test repo, cereblab measured 5.1GB of uploads split across 73 chunks, against roughly 192KB of actual model traffic. That's more than 26,000 times as much data leaving the machine as the model itself needed to answer a prompt.

The bucket, named grok-code-session-traces, also received a file the agent had been explicitly instructed not to read. Whatever the Improve the model setting is supposed to gate, it didn't cover that file.

Turning the toggle off didn't help either. The Grok Build server kept returning trace_upload_enabled:true no matter the local setting. Switching the feature off in the CLI had no effect on what actually left the repo.

xAI's fix arrived about a day after the findings went up: a hidden disable_codebase_upload flag, undocumented anywhere. The v0.2.98 changelog doesn't mention it. Cereblab's post doesn't say whether xAI told anyone whose code had already passed through the bucket before that flag existed.

Whether disable_codebase_upload actually blocks the behavior is untested in public. The same mitmproxy setup cereblab used to catch the original uploads would show whether the new flag works.