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Elon Musk: SpaceX’s entire corpus of engineering data (excluding ITAR-restricted…

2026-07-21 · 06:00 UTC ·@elonmusk ·0 min read

Brief

Elon Musk said SpaceX will add its massive (non‑ITAR) engineering dataset into supplemental training during the “2T run,” aiming to boost Grok’s engineering performance. Cory Robin reports his team’s side‑by‑side tests since the Grok Build launch led them to drop Claude and, as of Jul 20, adopt Grok Build for heavy aerospace math/science/data while retaining Codex for some tasks.

Why it matters

Elon Musk: SpaceX’s entire corpus of engineering data (excluding ITAR-restricted material) will be added during supplemental training of the “2T run,” which he says will dramatically improve Grok’s engineering capabilities.

Key details

  • Cory Robin (@flycory): After weeks of side-by-side testing since the Grok Build launch, his team removed Claude from workflows; as of Jul 20 they are normalizing on Grok Build for heavy aerospace math/science/data because it gives higher accuracy and requires less hand-holding, though Codex remains useful after six months on it.
Source evidence

SpaceX’s massive corpus of world-class engineering data (excluding material blocked by ITAR) will be added during supplemental training of the 2T run.

This will dramatically improve Grok’s engineering capabilities.

Cory Robin (@flycory)

For the past few wks since Grok Build launch, we've run SxS testing of complex Codex & Grok Build tasks. Eliminated Claude for needy intern BS. Grok Build wins more trust w/ higher accuracy & less hand-holding. Codex remains solid; each has unique strengths. For heavy math/science/data in aerospace, we're normalizing on Grok Build as of Jul 20. Exciting yet nerve-racking shift after 6mo on Codex. Qs on process/A/B testing welcome.

Congratulations to @SpaceXAI and the Build TEAM!

— https://nitter.net/flycory/status/2079287429148938494#m