feat(plugin): expose synthetic session input (#37212)

packages/core/src/plugin/host.ts

@@ -425,6 +425,7 @@ export const make = Effect.fn("PluginHost.make")(function* (plugin: PluginV2.Int
       get: (input) => runtime.session.get(input.sessionID),
       prompt: runtime.session.prompt,
       command: runtime.session.command,
+      synthetic: runtime.session.synthetic,
       interrupt: (input) => runtime.session.interrupt(input.sessionID),
     },
   } satisfies Plugin.Context

packages/core/src/plugin/promise.ts

@@ -244,6 +244,17 @@ export function fromPromise(plugin: Plugin) {
                   resume: input.resume ?? undefined,
                 }),
               ),
+            synthetic: (input) =>
+              run(
+                host.session.synthetic({
+                  ...input,
+                  sessionID: Session.ID.make(input.sessionID),
+                  id: input.id == null ? undefined : SessionMessage.ID.make(input.id),
+                  description: input.description ?? undefined,
+                  delivery: input.delivery ?? undefined,
+                  resume: input.resume ?? undefined,
+                }),
+              ),
             interrupt: (input) => run(host.session.interrupt({ sessionID: Session.ID.make(input.sessionID) })),
           },
         }