Capture completed conversation exchanges

internal/usecase/runner.go

@@ -165,7 +165,7 @@ func (r *Runner) Run(ctx context.Context, req domain.RunRequest) (*domain.RunRes
 	}
 	directAPIKey := state.effectiveModel.APIKey
 
-	return r.executePreparedRun(ctx, operation.run, directAPIKey, state.transientRetries, runID, start, func(
+	return r.executePreparedRun(ctx, operation.run, operation.capture, operation.parent, directAPIKey, state.transientRetries, runID, start, func(
 		ctx context.Context,
 		artifact *domain.Artifact,
 		attemptsUsed int,
@@ -185,6 +185,8 @@ type preparedValidationFunc func(
 func (r *Runner) executePreparedRun(
 	ctx context.Context,
 	prepared *domain.PreparedRun,
+	capture bool,
+	parent *domain.Exchange,
 	directAPIKey string,
 	transientRetries uint64,
 	runID string,
@@ -254,8 +256,14 @@ func (r *Runner) executePreparedRun(
 
 	end := time.Now().UTC()
 	executionTarget.APIKey = ""
+	var exchange *domain.Exchange
+	if capture {
+		exchange = domain.CaptureExchange(parent, runID, prepared.Messages[parent.MessageCount():], genResp.Content)
+	}
 
 	return &domain.RunResult{
+		Exchange:             exchange,
+		ParentRunID:          prepared.ParentRunID,
 		RunID:                runID,
 		Artifact:             outputArtifact,
 		RawOutput:            genResp.Content,