Verify self-contained schema preparation and submission

internal/engine/engine.go

@@ -73,7 +73,7 @@ func (o *Options) SetSchemaFS(fsys fs.FS, root string) error {
 
 // SetSchemaFile selects a single schema file.
 func (o *Options) SetSchemaFile(path string) error {
-	fsys, root, _, err := fileSource(path)
+	fsys, root, err := fileSource(path)
 	if err != nil {
 		return err
 	}
@@ -208,23 +208,23 @@ func validateSourceFS(fsys fs.FS, root string) error {
 	return nil
 }
 
-func fileSource(name string) (fs.FS, string, string, error) {
+func fileSource(name string) (fs.FS, string, error) {
 	if strings.TrimSpace(name) == "" {
-		return nil, "", "", fmt.Errorf("source path is required")
+		return nil, "", fmt.Errorf("source path is required")
 	}
 	directory := filepath.Dir(name)
 	base := filepath.Base(name)
 	if base == "." || base == string(filepath.Separator) {
-		return nil, "", "", fmt.Errorf("source path must name a file")
+		return nil, "", fmt.Errorf("source path must name a file")
 	}
 	info, err := os.Stat(name)
 	if err != nil {
-		return nil, "", "", fmt.Errorf("failed to access source file %q: %w", name, err)
+		return nil, "", fmt.Errorf("failed to access source file %q: %w", name, err)
 	}
 	if info.IsDir() {
-		return nil, "", "", fmt.Errorf("source path %q must be a file", name)
+		return nil, "", fmt.Errorf("source path %q must be a file", name)
 	}
-	return os.DirFS(directory), filepath.ToSlash(base), directory, nil
+	return os.DirFS(directory), filepath.ToSlash(base), nil
 }
 
 func (e *Engine) InspectPrompt(ctx context.Context, id string) (*domain.PromptInspection, error) {