The Veiled Dragon — Troy Denning

An aspiring Harper agent finds that solving a poisoning -- and impressing her superiors -- is much harder than she imagined
 
The Bedine witch Ruha has left the parched sea of Anauroch on her quest to become a Harper. That quest takes her to Eversult, where she must prove her mettle by discovering who has poisoned Lady Yanseldara. Simple enough -- find the poison and track the poisoner.
 
But when the Cult of the Dragon, a Shou Prince, an oriental merchant, and an ancient dracolich get involved, Ruha's simple task becomes far more complicated. As she soon discovers, life is never simple for a Harper, and poisoners' plots hold more treacherous twists than the tail of a Shou dragon.

The Veiled Dragon is the twelfth book in a series of loosely-connected novels about the Harpers.