A developer using Claude Code to build a temperature-monitoring app got an unexpected diagnosis from the AI agent: their Mac was running a hidden cryptocurrency miner. The agent identified the process as xmrig, consuming about 1175% CPU — roughly 12 cores — and pushing the machine to 112 degrees Celsius. The developer, posting as UntilHEX on Reddit, had suspected the Mac was running poorly and was inspired to create the monitor app after noticing the heat.
Claude Code explained that the miner had been added to the Mac's startup items, likely on August 29, and offered to clean it up rather than taking action on its own. It proposed stopping the startup item and the miner, then moving the files to a quarantine folder. The developer accepted, and later reported that the cleanup was effective, with only one file requiring manual removal due to an access issue.
After the AI-assisted cleanup, the developer ran a Malwarebytes scan to verify the machine was clean. The incident highlights how AI coding agents can serve as an unexpected layer of security, catching malware that might otherwise go unnoticed — though in this case, the miner's heavy CPU usage was the clue that something was wrong.