diff --git a/cmd/opencodereview/output.go b/cmd/opencodereview/output.go
index d1da56d..b256fb4 100644
--- a/cmd/opencodereview/output.go
+++ b/cmd/opencodereview/output.go
@@ -132,8 +132,32 @@ func buildDiffLines(comment model.LlmComment) []suggestdiff.DiffLine {
 	return suggestdiff.ComputeLineDiff(oldLines, newLines)
 }
 
+type jsonOutput struct {
+	Status   string            `json:"status"`
+	Message  string            `json:"message,omitempty"`
+	Comments []model.LlmComment `json:"comments"`
+}
+
 func outputJSON(comments []model.LlmComment) error {
+	out := jsonOutput{
+		Status:   "success",
+		Comments: comments,
+	}
+	if len(comments) == 0 {
+		out.Message = "No comments generated."
+	}
 	enc := json.NewEncoder(os.Stdout)
 	enc.SetIndent("", "  ")
-	return enc.Encode(comments)
+	return enc.Encode(out)
+}
+
+func outputJSONNoFiles() error {
+	out := jsonOutput{
+		Status:   "skipped",
+		Message:  "No supported files changed.",
+		Comments: []model.LlmComment{},
+	}
+	enc := json.NewEncoder(os.Stdout)
+	enc.SetIndent("", "  ")
+	return enc.Encode(out)
 }
diff --git a/cmd/opencodereview/review_cmd.go b/cmd/opencodereview/review_cmd.go
index 95c8087..8fda2fd 100644
--- a/cmd/opencodereview/review_cmd.go
+++ b/cmd/opencodereview/review_cmd.go
@@ -133,6 +133,11 @@ func runReview(args []string) error {
 		telemetry.RecordCommentsGenerated(ctx, int64(len(comments)))
 	}
 
+	// If no files were reviewed (e.g. workspace has no changes), inform the caller in JSON mode.
+	if opts.outputFormat == "json" && len(comments) == 0 && ag.FilesReviewed() == 0 {
+		return outputJSONNoFiles()
+	}
+
 	telemetry.PrintTraceSummary(ag.FilesReviewed(), int64(len(comments)), ag.TotalInputTokens(), ag.TotalOutputTokens(), ag.TotalTokensUsed(), duration)
 
 	if opts.outputFormat == "json" {
diff --git a/internal/agent/agent.go b/internal/agent/agent.go
index cb5e173..ca42d28 100644
--- a/internal/agent/agent.go
+++ b/internal/agent/agent.go
@@ -189,7 +189,7 @@ func (a *Agent) Run(ctx context.Context) ([]model.LlmComment, error) {
 		fmt.Fprintln(stdout.Writer(), "[ocr] No supported files changed. Skipping review.")
 		telemetry.Event(ctx, "no.files.changed")
 		a.session.Finalize()
-		return nil, nil
+		return []model.LlmComment{}, nil
 	}
 
 	a.currentDate = time.Now().Format("2006-01-02 15:04")