The two roles
A deployer is anyone who uses an AI system under their own authority in a professional capacity [1]. A provider is anyone who develops an AI system, or has one developed, and places it on the market or puts it into service under their own name or trademark [2]. Putting into service also covers supply for own use [3]: anyone who has an HR tool built and uses it themselves can therefore be a provider.
When a deployer becomes a provider
From 2 December 2027 [6], for high-risk systems a deployer becomes a provider if they put their name or trademark on the system, substantially modify it so that it remains high-risk, or change the intended purpose of an AI system, including a general-purpose AI system, so that it becomes high-risk [4]. If you use a general-purpose chatbot to filter applications or assess candidates, that can be such a change of purpose, because recruitment and selection are listed in Annex III [5].
Why it matters
As the provider of a high-risk system you carry the duties of Article 16 [4]; as a deployer, the lighter duties of Article 26. So record who the provider is, what the intended purpose of the tool is, and whether you deviate from it.