tip your hand
tip (one's) hand
To reveal one's intentions, plans, secrets, or resources. An allusion to letting someone else see the cards one is currently holding (one's "hand"). The foreign leader has definitely tipped his hand when it comes to his country's position in the negotiations. Remember not to tip your hand when you go into the meeting.
tip your hand (or mitt)reveal your intentions inadvertently. US informal
This expression is the opposite of keep your cards close to your chest (see card).
1966 Martin Woodhouse Tree Frog We couldn't very well oppose it without tipping our hand.