I was using auto mode and asked for some code to be done and Cursor automatically started a subagent in Claude 4.6 and started billing me on my On Demand usage. I never switched to Claude and did not expect this to happen without my knowledge.
Steps to Reproduce
Cursor decided to got to Claude 4.6 by itself. I have no idea what triggered this for a subagent, but it wasn´t me.
Hey, thanks for the report. What you’re describing isn’t intended behavior. In Auto mode, the subagent should inherit Auto, not switch to a specific premium model on its own. This is a known issue we’re tracking, and I can’t share an ETA yet.
Until it’s fixed, here’s what helps avoid those charges:
Turn off Claude 4.6 Sonnet in Settings > Models. Subagent resolution respects the blocked models list, so it won’t get picked.
Set an explicit subagent model (for example Composer) in Settings > Models so the behavior is predictable.
Add a rule/instruction like “subagents must always inherit the parent model”.
If you don’t want any overage charges at all, keep on-demand usage turned off.
About the on-demand charge itself, email [email protected] and the team there can review your specific case.
I’ll post an update here when we have news on the main issue.