No, Grok 2.5 has not been open-sourced. Here's how you can tell

"Companies love to exaggerate about open-sourcing AI. It plays well with people, naive developers get excited, and stock buyers invest more cash in their businesses. There's only one little problem: It's not true. First, Mark Zuckerberg claimed Meta Llama was open source. Now, it's Elon Musk's turn, as he claims that his AI startup , xAI, is open-sourcing Grok 2.5, last year's large language model (LLM)."

"If you improve the code, xAI will be happy to use your changes. Of course, that's true of any open-source project. However, I quote from the : You may not use the Materials, derivatives, or outputs (including generated data) to train, create, or improve any foundational, large language, or general-purpose AI models, except for modifications or fine-tuning of Grok 2 permitted under and in accordance with the terms of this Agreement."

"The xAI Grok 2.5 model, which was our best model last year, is now open source. Grok 3 will be made open source in about 6 months, " . This release comes with the complete model weights. Grok 2 is available to download on Hugging Face ."

xAI released Grok 2.5 model weights while labeling the release as open source. The license explicitly forbids using materials, derivatives, or outputs to train, create, or improve any foundational, large language, or general-purpose AI models, except for permitted modifications or fine-tuning of Grok 2 under the agreement. The source code is not provided and usage restrictions limit reuse, effectively blocking true open-source freedoms. The release functions as promotional open-washing to drive interest and adoption. Other AI projects offer genuinely open access and fewer restrictions for developers and researchers.

Read at ZDNET