Truth Serum

You administer a poison to a creature you touched that prevents it from telling lies. The creature touched must make a Constitution saving throw. On a success, nothing happens. On a failure, the creature can't speak a deliberate lie until the power ends.

An affected creature is aware of the power and can thus avoid answering questions to which it would normally respond with a lie. Such a creature can be evasive in its answers as long as it remains within the boundaries of the truth.