While the gnomes love their fun and games, the endless intrigue works because of the limits imposed by the Trust. There are only two rules - the national interest comes first, and no crime. The former rule comes in when gnomes try to leverage outside alliances for profit and gain. The second not only means the Trust maintain a monopoly on violence, but also ensures the intricate system of trust and debts in gnomish society continues to function.
The gnomish connection to Thelanis may play some role here, as the particular wording of debts and obligations is of utmost importance, with the letter of the law always coming before the spirit of it. An important part of growing up Zilargo is learning that fine line between creative interpretations of obligations and outright fraud. Furthermore, gnomes still understand that tit invites tat, and joyful fulfillment of obligations engenders bonds of friendship rather than distrust. Deception may be second nature, but friendships and family are treaures.
The Trust are a secret police in the sense that individual members work in secret, rather than their existence is a secret. Uninformed visitors from other lands may be unaware, but anyone with a passing understanding of Zil society knows that ambition is checked by the Trust.
History: Formed over two centuries ago as a way to preserve the scholarly focus of Korranberg college, the Trust today is a multinational intelligence agency that answers only to the Triumvirate. While the majority of the Trust's mission involves domestic affairs, gnome spies dot the five nations. In line with their national character, the gnomes didn't use this for direct military action. However, they were able to leverage their vast pool of intelligence to secede from Breland by declaring an "Alliance". Battered from the lengthy war, the Brelish were unable to devote resources to maintain sovereignty over a province-turned-ally.
Hierarchy: Today, the Trust maintains order through a finely layered set of agents and assets. On a basic level, the Trust rewards snitches and informants, who provide information via dead drops (leaving information in a previously-agreed upon location for the Trust agent to pick up) in exchange for financial compensation. More devoted assets may be asked to perform more complicated or important actions, such as deliver messages, in exchange for greater compensation.
The Trust employs two kinds of agents. Ganos ("eyes") manage webs of assets who provide information that can be transmitted home and processed by analysts and their superiors, who are known as shalons ("minds"). The shalons use this information to deploy the valos ("hands"), the trained thieves and assassins who enforce the law.
The trust has four secret languages, and the typical agent knows two to three, communicating with a given asset using only a single one of them. The Trust heavily "siloes" its operations, which is to say any given agent knows very little about the plans of other agents. The job of the home office is to coordinate agents in a way that avoids revealing their plans any more than necessary.
While ostensibly available to all well-resourced agencies, the Trust leverages "ghost" agents more than any other group. Such "ghost" agents are not incorporeal undead - rather, they are outfitted with a ring of invisibility and ring of sustenance, ensuring that they do not have to reveal themselves until the moment of their choosing. How many of these ghost agents is a mystery - the Brelish King's Dark Lanterns estimate that at least one ghost agent is positioned in each major city of Khorvaire, but the true number is up to the DM.
Methods: A common misconception (that the Trust actively promotes) is that the group is filled with lethal assassins. The truth is they rarely resort to violence, preferring to scare off potential lawbreakers. Masters of poisons, the Trust uses sub-lethal doses to communicate a message to a particularly stubborn target. However, if someone persists despite the warnings, the Trust will act before a crime is actually committed if they believe one will be.
Compared to the Code of Galifar, the Trust's system of law enforcement affords the accused few rights. At the same time, the Trust's consistent anti-corruption efforts, consistent attempts to de-escalate, and the general higher quality of life in Zilargo mean that on a pragmatic level, crime is much less common in the first place.
While working abroad as an intelligence agency rather than domestic law enforcement, the Trust's corliganos ("roving eyes") only take action when absolutely necessary. The Trust prefers to simply accumulate knowledge for use in future conflicts, staying as a "neutral" third party in the cold war the surviving nations are engaged in.