diff --git a/src/main.ml b/src/main.ml
index 0fc461f4311bfa5b79f818c9b8f94870d20a1563..68d86548191017ec3e8a397b43e2451e9cd2f327 100644
--- a/src/main.ml
+++ b/src/main.ml
@@ -165,10 +165,9 @@ let verify_cmd =
       let all_provers = Prover.list_available () in
       let doc =
         Fmt.str
-          "Prover to use. Support is provided for the following provers: %s."
-          (Fmt.str "%a"
-             (Fmt.list ~sep:Fmt.comma Fmt.string)
-             (List.map ~f:Prover.to_string all_provers))
+          "Prover to use. Support is provided for the following provers: %a."
+          (Fmt.list ~sep:Fmt.comma Fmt.string)
+          (List.map ~f:Prover.to_string all_provers)
       in
       let provers =
         Arg.enum (List.map ~f:(fun p -> (Prover.to_string p, p)) all_provers)