If you used Grok Build CLI before July 13, 2026, rotate your credentials. All of them. Security researcher cereblab published a wire-level analysis on July 12 showing the tool transmitted 5.10 gigabytes per coding session to a Google Cloud Storage bucket named grok-code-session-traces — against roughly 192 kilobytes of data the model actually needed for the task. That ratio works out to about 27,800 to one.

What was in those 5 gigabytes: the entire repository. Every tracked file. The complete Git history, including secrets that had been committed and deleted months prior. Your .env file with API keys and database passwords. SSH keys. The "Improve the model" privacy toggle did not prevent any of it.

Three days later, on July 15, xAI published the full Grok Build source at github.com/xai-org/grok-build under Apache 2.0. 844,530 lines of Rust. The five upload modules — upload/gcs.rs, upload/trace.rs, upload/manifest.rs, upload/turn.rs, upload/config_files.rs — all came with it. Not removed. Gated by a server-side flag xAI can re-enable without a software update.

Source spread

• cereblab — Wire-level analysis of Grok Build CLI v0.2.93 [skeptic] — Primary evidence. mitmproxy capture of all network traffic from a 12 GB repo test, showing 83 upload responses before stream truncation, and the 192 KB vs 5.10 GiB contrast.
• xAI — Grok Build is Now Open Source [hype] — Official announcement. Claims ZDR was always respected when users disabled upload; no acknowledgment of the privacy toggle failure for non-enterprise users.
• TechTimes — Grok Build Shipped Entire Codebases; Privacy Toggle Did Nothing [skeptic] — Documents the toggle failure, credential types exposed, and the full upload scope.
• Byteiota — Grok Build Is Open Source — But the Upload Code Remains [skeptic] — Confirms the five upload modules in the Apache 2.0 source and explains the server-side flag architecture.
• MLQ News — xAI's Grok Build CLI Caught Uploading Entire Codebases [skeptic] — Secondary coverage confirming credential types and the upload methodology.

Pros & cons

What's true:

• The uploads are currently disabled. xAI turned off default retention on July 12, the same day the analysis dropped.
• The open-source release is genuine: 844,530 lines of Rust you can read, compile, and audit. That's a real transparency move, whatever its timing.
• Per xAI, enterprise customers with Zero Data Retention agreements had their data excluded from uploads. The ZDR contracts appear to have held.
• Elon Musk committed to deletion of previously retained data on July 14. That commitment is on record, which is more than we usually get.

What isn't fixed:

• The upload code is still there. Five modules in the published source, ready to run, waiting on a server-side flag. "Trust the flag" is a different guarantee than "the capability is gone."
• The privacy toggle labeled "Improve the model" failed for non-enterprise users. xAI's ZDR explanation covers enterprise contracts; it doesn't explain why the toggle did nothing for everyone else.
• Deleted secrets from Git history are the dangerous part. If you committed a secret, realized your mistake, and deleted it from tracked files, that commit is still in git log. Grok Build was uploading the full bundle, history included.
• The open-sourcing happened three days after the disclosure. That's responsive, as these things go. But you can't audit what the behavior was before you could see the code.

Samwise's take

Further reading

• cereblab — Wire-level analysis of Grok Build CLI 0.2.93 — primary source; technical; worth reading in full
• xAI — Grok Build is Now Open Source — official announcement with xAI's account of what happened
• TechTimes — Grok Build Shipped Entire Codebases; Privacy Toggle Did Nothing — July 14 coverage with credential type details
• TechTimes — Grok Build Open-Sourced: Code to Exfiltrate Repos Stays In — July 16 follow-up on the upload modules in the open-source release
• Byteiota — Grok Build Is Open Source — But the Upload Code Remains — technical analysis of the server-side flag architecture
• MLQ News — xAI's Grok Build CLI Caught Uploading Entire Codebases — secondary coverage and credential type confirmation