Artificial-intelligence aide handles email, meetings and other things, but its price and limited use have some skeptical

Microsoft’s new artificial-intelligence assistant for its bestselling software has been in the hands of testers for more than six months and their reviews are in: useful, but often doesn’t live up to its price.

The company is hoping for one of its biggest hits in decades with Copilot for Microsoft 365, an AI upgrade that plugs into Word, Outlook and Teams. It uses the same technology as OpenAI’s ChatGPT and can summarize emails, generate text and create documents based on natural language prompts.

Companies involved in testing say their employees have been clamoring to test the tool—at least initially. So far, the shortcomings with software including Excel and PowerPoint and its tendency to make mistakes have given some testers pause about whether, at $30 a head per month, it is worth the price