diff --git a/cli/slsa-verifier/verify.go b/cli/slsa-verifier/verify.go
index f41e0ecc..e4316754 100644
--- a/cli/slsa-verifier/verify.go
+++ b/cli/slsa-verifier/verify.go
@@ -72,6 +72,7 @@ func verifyArtifactCmd() *cobra.Command {
 	o.AddFlags(cmd)
 	// --provenance-path must be supplied when verifying an artifact.
 	cmd.MarkFlagRequired("provenance-path")
+	cmd.MarkFlagFilename("provenance-path", verify.CommonFilenameExtensions...)
 	return cmd
 }
 
@@ -137,6 +138,12 @@ func verifyNpmPackageCmd() *cobra.Command {
 			}
 			return nil
 		},
+		ValidArgsFunction: func(cmd *cobra.Command, args []string, toComplete string) ([]string, cobra.ShellCompDirective) {
+			if len(args) != 0 {
+				return nil, cobra.ShellCompDirectiveNoFileComp
+			}
+			return []string{"tgz"}, cobra.ShellCompDirectiveFilterFileExt
+		},
 		Short: "Verifies SLSA provenance for an npm package tarball [experimental]",
 		Run: func(cmd *cobra.Command, args []string) {
 			v := verify.VerifyNpmPackageCommand{
diff --git a/cli/slsa-verifier/verify/options.go b/cli/slsa-verifier/verify/options.go
index ef1cf65c..73f9b9ca 100644
--- a/cli/slsa-verifier/verify/options.go
+++ b/cli/slsa-verifier/verify/options.go
@@ -45,6 +45,8 @@ type VerifyOptions struct {
 
 var _ Interface = (*VerifyOptions)(nil)
 
+var CommonFilenameExtensions = []string{"sigstore", "intoto", "intoto.jsonl", "json"}
+
 // AddFlags implements Interface.
 func (o *VerifyOptions) AddFlags(cmd *cobra.Command) {
 	/* Builder options */
@@ -73,6 +75,7 @@ func (o *VerifyOptions) AddFlags(cmd *cobra.Command) {
 	/* Other options */
 	cmd.Flags().StringVar(&o.ProvenancePath, "provenance-path", "",
 		"path to a provenance file")
+	cmd.MarkFlagFilename("provenance-path", CommonFilenameExtensions...)
 
 	cmd.Flags().StringVar(&o.ProvenanceRepository, "provenance-repository", "",
 		"image repository for provenance with format: <registry>/<repository>")
@@ -123,6 +126,7 @@ func (o *VerifyNpmOptions) AddFlags(cmd *cobra.Command) {
 
 	cmd.Flags().StringVar(&o.AttestationsPath, "attestations-path", "",
 		"path to a file containing the attestations")
+	cmd.MarkFlagFilename("attestations-path", CommonFilenameExtensions...)
 
 	cmd.Flags().StringVar(&o.PackageName, "package-name", "",
 		"the package name")
@@ -164,6 +168,7 @@ func (o *VerifyVSAOptions) AddFlags(cmd *cobra.Command) {
 
 	cmd.Flags().StringVar(&o.AttestationPath, "attestation-path", "",
 		"path to a file containing the attestation")
+	cmd.MarkFlagFilename("attestation-path", CommonFilenameExtensions...)
 
 	cmd.Flags().StringVar(&o.VerifierID, "verifier-id", "",
 		"the unique verifier ID who created the attestation")
@@ -182,6 +187,7 @@ func (o *VerifyVSAOptions) AddFlags(cmd *cobra.Command) {
 
 	cmd.Flags().StringVar(&o.PublicKeyPath, "public-key-path", "",
 		"path to a public key file")
+	cmd.MarkFlagFilename("public-key-path", "pem")
 
 	cmd.Flags().StringVar(&o.PublicKeyID, "public-key-id", "",
 		"[optional] the ID of the public key, defaults to the SHA256 digest of the base64-encoded public key")