Breaking

xAI to Publicly Launch Grok 4.5 on July 9, Trained on Cursor Data

July 8, 2026 at 11:25 EDT

Foundation Models
Software Dev & Coding

xAI is set to publicly release its new foundation model "Grok 4.5" on July 9. Confirmed by Elon Musk, the model is built on a new 1.5-trillion-parameter architecture called "V9" and distinguished by supplemental training using developer data from the coding tool Cursor.

July 9, 2026 · xAI / SpaceXAI

Grok 4.5 Goes Public — Built on a 1.5-Trillion-Parameter "V9" Core

xAI's new foundation model launches July 9, distinguished by supplemental training on Cursor developer data. Musk claims Opus-class performance — but independent benchmarks remain unpublished.

1.5T

Parameters in the V9 core (self-reported)

~3×

Larger than current v8-small (~0.5T)

4.5

Succeeds public model Grok 4.3

Scale of the V9 core vs. current model

Roughly 3× the parameter count of v8-small

0.5T

v8-small
(current)

1.5T

V9 core
(Grok 4.5)

The training path — a coding "data flywheel"

STEP 1

V9 initial training (1.5T params)

→

STEP 2

Supplemental: Cursor developer data + SFT / RL

→

STEP 3

Improved "Grok Build" harness for tools & agents

Optimism

Developers see promise in Cursor-derived coding skills — "could be a game changer if it is truly Opus-class." Musk touts it as faster, more token-efficient, and lower cost.

Skepticism

All figures are self-reported; SWE-Bench and MMLU results are unpublished. Past versions drew complaints of hallucination and overly concise replies.

Key timeline & open questions

Jun 28, 2026

Private beta begins internally at SpaceX & Tesla

Jul 9, 2026

Public access via SpaceXAI

Not yet disclosed

Pricing, context window, availability & independent benchmarks

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