diff --git a/cmd/fn/main.go b/cmd/fn/main.go
index 7a914f6f..63dc6346 100644
--- a/cmd/fn/main.go
+++ b/cmd/fn/main.go
@@ -127,6 +127,9 @@ func cmdIndex() {
 	for _, e := range result.ValidationErrors {
 		fmt.Fprintf(os.Stderr, "  INVALID: %s\n", e)
 	}
+	for _, w := range result.Warnings {
+		fmt.Fprintf(os.Stderr, "  WARN: %s\n", w)
+	}
 	for _, e := range result.Errors {
 		fmt.Fprintf(os.Stderr, "  ERROR: %s\n", e)
 	}
diff --git a/registry/indexer.go b/registry/indexer.go
index fe7d3662..12bddafc 100644
--- a/registry/indexer.go
+++ b/registry/indexer.go
@@ -15,6 +15,7 @@ type IndexResult struct {
 	Apps             int
 	Analysis         int
 	ValidationErrors []string
+	Warnings         []string
 	Errors           []string
 }
 
@@ -202,6 +203,30 @@ func Index(db *DB, root string) (*IndexResult, error) {
 		result.Analysis++
 	}
 
+	// Post-insert: warn about file_path entries that don't exist on disk
+	for _, f := range functions {
+		if f.FilePath != "" {
+			abs := filepath.Join(root, f.FilePath)
+			if _, err := os.Stat(abs); err != nil {
+				result.Warnings = append(result.Warnings, fmt.Sprintf("%s: file_path %q not found", f.ID, f.FilePath))
+			}
+		}
+		if f.TestFilePath != "" {
+			abs := filepath.Join(root, f.TestFilePath)
+			if _, err := os.Stat(abs); err != nil {
+				result.Warnings = append(result.Warnings, fmt.Sprintf("%s: test_file_path %q not found", f.ID, f.TestFilePath))
+			}
+		}
+	}
+	for _, t := range types {
+		if t.FilePath != "" {
+			abs := filepath.Join(root, t.FilePath)
+			if _, err := os.Stat(abs); err != nil {
+				result.Warnings = append(result.Warnings, fmt.Sprintf("%s: file_path %q not found", t.ID, t.FilePath))
+			}
+		}
+	}
+
 	return result, nil
 }