Local peer communication

Peer communication is off until a plugin acquires a subscription through IPluginHost.Automation.Network.Subscribe. Each client combines its own plugins' requests. Enabling a feature on one client does not enable another client's plugins.

The capabilities are ClientState, Casts, and Commands. SendCommands is a temporary outgoing role; BroadcastCommand acquires it automatically and releases it after acknowledgement or timeout. Sending does not enable command reception. Dispose a subscription when its feature stops. The plugin scope also releases all remaining subscriptions on unload. Older hosts return SupportsSubscriptions = false and a null lease.

One hub per user and data directory starts on demand. It runs independently of the launcher using the installed acdream-headless peer-hub <peer-directory> entry point. Both client executables must be present in the installation. Windows uses a current-user named pipe; Linux and macOS use a Unix-domain socket in a private directory. No TCP listener, peer JSON files, or directory polling are used. The hub exits after its last connection leaves and its 15-second idle period expires.

Clients register their character, world, tags and requested capabilities. Messages are routed only within the same world to subscribed recipients. State is sent only when another participant requests it, and replaces older queued state. Casts and commands retain their order in bounded queues. Incoming commands are submitted on the client's tick thread through the ordinary command entry, with tag filtering and per-recipient stagger. Acknowledgement confirms hub queue acceptance, not execution. Commands are deduplicated, expire after 15 seconds before delivery, and are never replayed after a connection drops. Queue overflow closes the connection and is reported as a gap rather than silently dropping an event.

CaptureClients, CaptureCasts, and CaptureCommands read the local memory cache. IsConnected becomes true after registration and initial peer state are received. Until then, an empty capture must not be interpreted as proof that nobody else is present. Disconnect removes local peers and their cached casts. Connection errors are logged and reconnection uses bounded backoff. Remote imports remain independent of this local transport; a plugin can continue using its existing remote relay.

Validation and performance

The IPC integration tests cover routing, world/tag filtering, stagger, casts, disconnect, duplicate identities, bounds and inactivity without subscribers. Host parity tests drive both hosts through IPluginHost and test local and imported commands and casts. Plugin lifecycle tests check lease release and independent client settings.

For performance, compare identical Release client/plugin versions and launcher profiles, with the same number of characters and feature settings. Measure process CPU seconds over the recorded interval and normalize by elapsed seconds and logical processor count. Record session identity, world state, personal kills and covered seconds. Reject restarts and gaps. Compare subscriptions off, casts on, state on, commands on, and the full combination separately. Feature-off measurements cannot isolate transport savings or establish that combat behaviour is equivalent.

Coordinated contract release

This implementation targets the 0.1.21 contract. Build the client first and pack AcDream.Plugin.Abstractions in Release. Copy that package into each plugin's packages-local folder before restore/build. The package is compile-only; the host supplies the assembly at runtime. Plugin manifests require host 0.1.21. CI downloads the corresponding OpenAC release, so the contract release must exist before the dependent plugin changes can pass remote CI or be published.