Golden Circle Signatory Treaty
In the Jeweled Amber game.
The GCST is the treaty signed between Amber and shadow realms for mutual defense and diplomacy.
Recent politics have been furthering an effort to establish a GC agreement in Halzir, Taxorami. The world does not meet most requirements but Wendel of the Hothouse argues that many places in shadow that want alliances with Amber may not meet the level of government that traditional regions have met.