Expose ordinary run execution observations

types.go

@@ -143,6 +143,9 @@ type RunRequest struct {
 	// Negative values are invalid for Prepare, PrepareExecution, and Run.
 	// Injected LLMClient implementations remain single-dispatch.
 	TransientRetries *int
+	// Observer receives metadata about this Run invocation synchronously. It is
+	// excluded from JSON and is not invoked by Prepare or PrepareExecution.
+	Observer ExecutionObserver `json:"-"`
 }
 
 // PreparedRun contains prepared prompt execution state returned by