Module host 

Process-global engine host: the things exactly one of which should exist per process regardless of how many sessions the process serves.

engine::setup::boot used to construct all of this inside the session’s Runtime. It now builds (or reuses) the EngineHost and borrows the process-global parts from it; subagent spawns borrow the same parts instead of rebuilding an HTTP client + registry + token cache per spawn.

Structs

DriverGrantError

(E-P2) Returned by EngineHost::claim_driver when another live session already holds the driver grant for a plugin.

EngineHost

ExtensionsLoadingGuard

See EngineHost::extensions_loading_guard.

HostOpts

HostParts

Everything a Runtime borrows from its host rather than constructing. Cheap to clone (all Arc/handle types).