Elon Musk has launched an AI chatbot called Grok on his social media site X, formerly Twitter, but so far it is only available to selected users.
"In some important respects, it is the best that currently exists," he posted on X, before its release.
Mr Musk boasted that Grok "loves sarcasm" and would answer questions with "a little humour".
However, early signs suggest it suffers from problems common to other artificial intelligence tools.
Other models decline to respond to some questions, for example providing criminal advice. But Mr Musk said Grok would answer "spicy questions that are rejected by most other AI systems".
In a demonstration of the new tool, posted by Mr Musk, Grok was asked for a step-by-step guide to making cocaine.
It responded "just a moment while I pull up the recipe... because I'm totally going to help you with that", and listed generalised rather than useable information, combined with sarcastic suggestions, before warning against pursuing the idea.
It struck a gleeful tone in reference to the trial of crypto-entrepreneur Sam Bankman-Fried, but mistakenly suggested it took eight hours for the jury to deliver a guilty verdict, when in fact they returned it in under five.
Generative AI tools like Grok have been widely criticised for including basic errors while sounding highly convincing in their style of writing.
The team behind Grok xAI was launched in July, drawing on talent from other AI research firms. It is a separate company, but closely linked to Mr Musk's other enterprises X and the electric car firm, Tesla.
Earlier this year Mr Musk said he wanted his version of AI to be "a maximum truth-seeking AI that tries to understand the nature of the universe".
Mr Musk said a major advantage of Grok was that it had access to up-to-date information from the X platform, which set it apart from the launch versions of some rivals, although increasingly up-to-date responses are available for paying customers with other AI tools.
Grok is currently in a test or "beta" format but will later be available to paying subscribers of X. Mr Musk said late on Sunday that the chatbot would be "built into the X app and be available as a standalone app".
Last week at the UK's AI summit, Mr Musk conceded there were dangers associated with AI development.
But he has also been a long-standing champion of the technology. He was a co-founder of the firm OpenAI which created ChatGPT, the first AI tool made widely available last year. Microsoft has invested in OpenAI making the tool available on its platform.
Since then Google launched its rival artificial intelligence (AI) model, Bard, and Meta has launched Llama. The tools are designed to use previously ingested information to generate text answers that sound as though a human has written them.
Grok is a term coined by science fiction writer Robert A. Heinlein, in his 1961 novel Stranger in a Strange Land. In it "grokking" was to empathise deeply with others.
However, xAI said Grok was modelled after the Hitchhiker's Guide to the Galaxy, by Douglas Adams, which started as a BBC radio series in the 1980s, but was later remade in print and on film.
xAI said Grok was "intended to answer almost anything and, far harder, even suggest what questions to ask".
Grok was a "very early beta product - the best we could do with two months of training", it added.
BBC