diff --git a/tools/offline.ml b/tools/offline.ml
index 2f9137e9..c45d7356 100644
--- a/tools/offline.ml
+++ b/tools/offline.ml
@@ -2,24 +2,46 @@ open Cmdliner
 open Cmdliner.Term.Syntax
 open Offline_impl
 
+module Arg = struct
+  include Arg
+
+  let timestamp =
+    Arg.Conv.make ~docv:"timestamp argument" ~parser:Timestamp.of_string
+      ~pp:Timestamp.pp ()
+
+  let relative_time =
+    Arg.Conv.make ~docv:"relative time argument"
+      ~parser:Timestamp.Span.of_string ~pp:Timestamp.Span.pp ()
+
+  let amount =
+    Arg.Conv.make ~docv:"amount argument" ~parser:Amount.of_string ~pp:Amount.pp
+      ()
+end
+
 let default_master_offline_key_file = "data/master_offline_private_key"
+(*
 let default_response_file = "response.json"
 let default_request_file = "request.json"
+*)
 
-(*let to_term_ret = function Error e -> `Error (false, e) | Ok () -> `Ok ()*)
-let to_term_ret = Fun.id
+let master_key =
+  let doc = "Master offline Eddsa private key file." in
+  Arg.(
+    value
+    & opt file default_master_offline_key_file
+    & info [ "master_key_file" ] ~doc)
 
-let timestamp =
-  Arg.Conv.make ~docv:"timestamp argument" ~parser:Timestamp.of_string
-    ~pp:Timestamp.pp ()
+let input =
+  let doc = "input file" in
+  Arg.(required & opt (some file) None & info [ "i"; "input" ] ~doc)
 
-let relative_time =
-  Arg.Conv.make ~docv:"relative time argument" ~parser:Timestamp.Span.of_string
-    ~pp:Timestamp.Span.pp ()
+let output =
+  let doc = "output file" in
+  Arg.(required & opt (some filepath) None & info [ "o"; "output" ] ~doc)
 
-let amount =
-  Arg.Conv.make ~docv:"amount argument" ~parser:Amount.of_string ~pp:Amount.pp
-    ()
+let url =
+  let doc = "url" in
+  Arg.(required & opt (some string) None & info [ "url" ] ~doc)
 
 let setup_cmd =
   let doc = "Generate offline master keys" in
@@ -33,56 +55,31 @@ let setup_cmd =
   Cmd.make (Cmd.info "setup" ~doc)
   @@
   let+ output = output in
-  setup ~output |> to_term_ret
+  setup ~output
 
 let download_cmd =
   let doc = "GET /management/keys/" in
   let man =
     [ `S Manpage.s_description; `P "$(cmd) download /management/keys." ]
   in
-  let output =
-    let doc = "output file" in
-    Arg.(
-      value & opt filepath default_response_file & info [ "o"; "output" ] ~doc)
-  in
   Cmd.make (Cmd.info "download" ~doc ~man)
   @@
   let+ output = output in
-  download ~output |> to_term_ret
+  download ~output
 
 let upload_cmd =
   let doc = "POST input.json data to url (default /management/keys)" in
-  let input =
-    let doc = "input file" in
-    Arg.(value & opt file default_request_file & info [ "i"; "input" ] ~doc)
-  in
-  let url =
-    let doc = "url" in
-    Arg.(value & opt string "/management/keys" & info [ "url" ] ~doc)
-  in
   Cmd.make (Cmd.info "upload" ~doc)
   @@
   let+ input = input and+ url = url in
-  upload ~input ~url |> to_term_ret
-
-let master_key =
-  let doc = "Master offline Eddsa private key file." in
-  Arg.(value & opt file default_master_offline_key_file & info [ "key" ] ~doc)
-
-let input =
-  let doc = "input file" in
-  Arg.(value & opt file default_response_file & info [ "i"; "input" ] ~doc)
-
-let output =
-  let doc = "output file" in
-  Arg.(value & opt filepath default_request_file & info [ "o"; "output" ] ~doc)
+  upload ~input ~url
 
 let sign_cmd =
   let doc = "Sign FutureKeysResponse." in
   Cmd.make (Cmd.info "sign" ~doc)
   @@
   let+ input = input and+ output = output and+ master_key = master_key in
-  sign ~input ~output ~master_key |> to_term_ret
+  sign ~input ~output ~master_key
 
 let revoke_denom_cmd =
   let doc = "Revoke denomination." in
@@ -93,7 +90,7 @@ let revoke_denom_cmd =
   Cmd.make (Cmd.info "revoke-denom" ~doc)
   @@
   let+ output = output and+ master_key = master_key and+ h_denom = h_denom in
-  revoke_denom ~output ~master_key ~h_denom |> to_term_ret
+  revoke_denom ~output ~master_key ~h_denom
 
 let revoke_signkey_cmd =
   let doc = "Revoke signkey." in
@@ -104,7 +101,7 @@ let revoke_signkey_cmd =
   Cmd.make (Cmd.info "revoke-signkey" ~doc)
   @@
   let+ output = output and+ master_key = master_key and+ signkey = signkey in
-  revoke_signkey ~output ~master_key ~signkey |> to_term_ret
+  revoke_signkey ~output ~master_key ~signkey
 
 let global_fees_cmd =
   let doc = "Provides global fee configuration." in
@@ -148,7 +145,6 @@ let global_fees_cmd =
   global_fees ~output ~master_key ~start_date ~end_date ~history_fee
     ~account_fee ~purse_fee ~history_expiration ~purse_account_limit
     ~purse_timeout
-  |> to_term_ret
 
 let cli =
   let info =
diff --git a/tools/offline_impl.ml b/tools/offline_impl.ml
index 2ad704ba..cd4ce9db 100644
--- a/tools/offline_impl.ml
+++ b/tools/offline_impl.ml
@@ -5,6 +5,10 @@ let read_file fname = Bos.OS.File.read (Fpath.v fname) |> unwrap_err_msg
 let write_file fname content =
   Bos.OS.File.write (Fpath.v fname) content |> unwrap_err_msg
 
+let read_master_key_file filename =
+  let* master_key = read_file filename in
+  Crypto.EddsaPrivateKey.of_octets master_key
+
 let base_url = Uri.of_string "http://localhost:3434/"
 let full_url path = Uri.with_path base_url path |> Uri.to_string
 
@@ -40,9 +44,8 @@ let setup ~output =
 
 let sign ~master_key ~input ~output =
   let open Crypto in
+  let* master_key = read_master_key_file master_key in
   let* input = read_file input in
-  let* master_key = read_file master_key in
-  let* master_key = EddsaPrivateKey.of_octets master_key in
   let master_pub = EddsaPrivateKey.pub_of_priv master_key in
   let* future_keys_response = Api.decode Api.FutureKeysResponse.jsont input in
   let* () =
@@ -56,9 +59,7 @@ let sign ~master_key ~input ~output =
   Ok ()
 
 let revoke_denom ~output ~master_key ~h_denom =
-  let open Crypto in
-  let* key = read_file master_key in
-  let* key = EddsaPrivateKey.of_octets key in
+  let* key = read_master_key_file master_key in
   let* h_denom = B32.decode h_denom in
   let h_denom = Bin_type.DenominationHash.of_octets h_denom in
   let denom_revoke = Offline_sig.mk_denom_revoke ~key h_denom in
@@ -68,8 +69,7 @@ let revoke_denom ~output ~master_key ~h_denom =
 
 let revoke_signkey ~output ~master_key ~signkey =
   let open Crypto in
-  let* key = read_file master_key in
-  let* key = EddsaPrivateKey.of_octets key in
+  let* key = read_master_key_file master_key in
   let* signkey = EddsaPublicKey.of_b32 signkey in
   let v = Offline_sig.mk_signkey_revoke ~key signkey in
   let* s = Api.encode Api.SignkeyRevocationSignature.jsont v in
@@ -80,8 +80,7 @@ let global_fees ~output ~master_key ~start_date ~end_date ~history_fee
     ~account_fee ~purse_fee ~history_expiration ~purse_account_limit
     ~purse_timeout =
   let open Crypto in
-  let* key = read_file master_key in
-  let* key = EddsaPrivateKey.of_octets key in
+  let* key = read_master_key_file master_key in
   let* purse_account_limit =
     match
       purse_account_limit >= 0
@@ -124,5 +123,4 @@ let global_fees ~output ~master_key ~start_date ~end_date ~history_fee
       }
   in
   let* s = Api.encode Api.GlobalFees.jsont global_fees in
-  let* () = write_file output s in
-  Ok ()
+  write_file output s