### Answer
Based on the available sources, chat pricing is based on message generation rather than session duration. [(1) ](
)
Specifically, if the AI begins speaking with a
custom (static) message, there is no cost—charges only apply when a
Dynamic message is generated. [(2) ](
)
So for an open chat session where no texts are being sent and no dynamic messages are generated, you would not incur charges during that idle time.
For reference, chat pricing starts at
$0.002/message. [(1) ](
)