Truly open-source models should allow researchers to replicate and interrogate them.Credit: MirageC/Getty Technology giants such as Meta and Microsoft are describing their artificial intelligence (AI) models as ‘open source’ while failing to disclose important information about the underlying technology, say researchers who analysed a host of popular chatbot models.The definition of open source when it comes to AI models is not yet agreed, but advocates say that ’full’ openness boosts science, a...