Defines a context entry that is sent with every agent request.

Context entries provide the agent with information about the current application state (e.g., current page, user preferences, selected items). The persistent flag controls whether the context survives component unmounting (default: true).

Related: useAgentContext registers context, frontendContextAtom stores it, ToolContext.frontendContext receives it on the server.

interface ContextDefinition {
    key: string;
    description: string;
    value: unknown;
    persistent?: boolean;
    priority?: number;
}