diff --git a/src/proto_alpha/lib_client/managed_contract.ml b/src/proto_alpha/lib_client/managed_contract.ml
index 5d406c1276484f09886e9aa0085023eb0b6364cd..3d5c2c6996a1d25462f1e72ca86173acb9f16378 100644
--- a/src/proto_alpha/lib_client/managed_contract.ml
+++ b/src/proto_alpha/lib_client/managed_contract.ml
@@ -39,13 +39,15 @@ let check_smart_contract (cctxt : #full) opt_res some =
 let get_contract_manager (cctxt : #full) contract =
   let open Micheline in
   let open Michelson_v1_primitives in
-  Client_proto_context.get_storage
-    cctxt
-    ~chain:cctxt#chain
-    ~block:cctxt#block
-    ~unparsing_mode:Optimized
-    contract
-  >>=? fun storage ->
+  let open Lwt_result_syntax in
+  let* storage =
+    Client_proto_context.get_storage
+      cctxt
+      ~chain:cctxt#chain
+      ~block:cctxt#block
+      ~unparsing_mode:Optimized
+      contract
+  in
   check_smart_contract cctxt storage @@ fun storage ->
   match root storage with
   | Prim (_, D_Pair, Bytes (_, bytes) :: _, _) | Bytes (_, bytes) -> (
@@ -81,10 +83,11 @@ let get_contract_manager (cctxt : #full) contract =
         storage
 
 let parse code =
-  Lwt.return
-    ( Micheline_parser.no_parsing_error
-    @@ Michelson_v1_parser.parse_expression code
-    >>? fun exp -> ok @@ Script.lazy_expr Michelson_v1_parser.(exp.expanded) )
+  let open Lwt_result_syntax in
+  let parsed_exp = Michelson_v1_parser.parse_expression code in
+  let*? {expanded; _} = Micheline_parser.no_parsing_error parsed_exp in
+  let la = Script.lazy_expr expanded in
+  return la
 
 let build_lambda_for_set_delegate ~delegate =
   match delegate with
@@ -106,49 +109,56 @@ let build_delegate_operation (cctxt : #full) ~chain ~block ?fee
     contract (* the KT1 to delegate *)
     (delegate : Signature.public_key_hash option) =
   let entrypoint = entrypoint_do in
-  (Michelson_v1_entrypoints.contract_entrypoint_type
-     cctxt
-     ~chain
-     ~block
-     ~contract
-     ~entrypoint
-     ~normalize_types:true
-   >>=? function
-   | Some _ ->
-       (* their is a "do" entrypoint (we could check its type here)*)
-       parse @@ build_lambda_for_set_delegate ~delegate >>=? fun param ->
-       return (param, entrypoint)
-   | None -> (
-       (*  their is no "do" entrypoint trying "set/remove_delegate" *)
-       let entrypoint =
-         match delegate with
-         | Some _ -> entrypoint_set_delegate
-         | None -> entrypoint_remove_delegate
-       in
-       Michelson_v1_entrypoints.contract_entrypoint_type
-         cctxt
-         ~chain
-         ~block
-         ~contract
-         ~entrypoint
-         ~normalize_types:true
-       >>=? function
-       | Some _ ->
-           (*  their is a "set/remove_delegate" entrypoint *)
-           let delegate_data =
-             match delegate with
-             | Some delegate ->
-                 let (`Hex delegate) =
-                   Signature.Public_key_hash.to_hex delegate
-                 in
-                 "0x" ^ delegate
-             | None -> "Unit"
-           in
-           parse delegate_data >>=? fun param -> return (param, entrypoint)
-       | None ->
-           cctxt#error
-             "Cannot find a %%do or %%set_delegate entrypoint in contract@."))
-  >>=? fun (parameters, entrypoint) ->
+  let open Lwt_result_syntax in
+  let* expr_opt =
+    Michelson_v1_entrypoints.contract_entrypoint_type
+      cctxt
+      ~chain
+      ~block
+      ~contract
+      ~entrypoint
+      ~normalize_types:true
+  in
+  let* parameters, entrypoint =
+    match expr_opt with
+    | Some _ ->
+        (* there is a "do" entrypoint (we could check its type here)*)
+        let* param = parse @@ build_lambda_for_set_delegate ~delegate in
+        return (param, entrypoint)
+    | None -> (
+        (*  there is no "do" entrypoint trying "set/remove_delegate" *)
+        let entrypoint =
+          match delegate with
+          | Some _ -> entrypoint_set_delegate
+          | None -> entrypoint_remove_delegate
+        in
+        let* expr_opt =
+          Michelson_v1_entrypoints.contract_entrypoint_type
+            cctxt
+            ~chain
+            ~block
+            ~contract
+            ~entrypoint
+            ~normalize_types:true
+        in
+        match expr_opt with
+        | Some _ ->
+            (*  there is a "set/remove_delegate" entrypoint *)
+            let delegate_data =
+              match delegate with
+              | Some delegate ->
+                  let (`Hex delegate) =
+                    Signature.Public_key_hash.to_hex delegate
+                  in
+                  "0x" ^ delegate
+              | None -> "Unit"
+            in
+            let* param = parse delegate_data in
+            return (param, entrypoint)
+        | None ->
+            cctxt#error
+              "Cannot find a %%do or %%set_delegate entrypoint in contract@.")
+  in
   return
     (Client_proto_context.build_transaction_operation
        ~amount:Tez.zero
@@ -161,27 +171,31 @@ let set_delegate (cctxt : #full) ~chain ~block ?confirmations ?dry_run
     ?verbose_signing ?simulation ?branch ~fee_parameter ?fee ~source ~src_pk
     ~src_sk contract (* the KT1 to delegate *)
     (delegate : Signature.public_key_hash option) =
-  build_delegate_operation cctxt ~chain ~block ?fee contract delegate
-  >>=? fun operation ->
+  let open Lwt_result_syntax in
+  let* operation =
+    build_delegate_operation cctxt ~chain ~block ?fee contract delegate
+  in
   let operation = Annotated_manager_operation.Single_manager operation in
-  Injection.inject_manager_operation
-    cctxt
-    ~chain
-    ~block
-    ?confirmations
-    ?dry_run
-    ?verbose_signing
-    ?simulation
-    ?branch
-    ~source
-    ~fee:(Limit.of_option fee)
-    ~gas_limit:Limit.unknown
-    ~storage_limit:(Limit.known Z.zero)
-    ~src_pk
-    ~src_sk
-    ~fee_parameter
-    operation
-  >>=? return_single_manager_result
+  let* result =
+    Injection.inject_manager_operation
+      cctxt
+      ~chain
+      ~block
+      ?confirmations
+      ?dry_run
+      ?verbose_signing
+      ?simulation
+      ?branch
+      ~source
+      ~fee:(Limit.of_option fee)
+      ~gas_limit:Limit.unknown
+      ~storage_limit:(Limit.known Z.zero)
+      ~src_pk
+      ~src_sk
+      ~fee_parameter
+      operation
+  in
+  return_single_manager_result result
 
 let d_unit =
   Micheline.strip_locations (Prim (0, Michelson_v1_primitives.D_Unit, [], []))
@@ -231,52 +245,60 @@ let build_lambda_for_transfer_to_originated ~destination ~entrypoint ~amount
 let build_transaction_operation (cctxt : #full) ~chain ~block ~contract
     ~(destination : Contract.t) ?(entrypoint = Entrypoint.default) ?arg ~amount
     ?fee ?gas_limit ?storage_limit () =
-  (match destination with
-  | Implicit destination when Entrypoint.is_default entrypoint ->
-      return @@ build_lambda_for_transfer_to_implicit ~destination ~amount
-  | Implicit _ ->
-      cctxt#error
-        "Implicit accounts have no entrypoints. (targeted entrypoint %%%a on \
-         contract %a)"
-        Entrypoint.pp
-        entrypoint
-        Contract.pp
-        destination
-  | Originated destination ->
-      (Michelson_v1_entrypoints.contract_entrypoint_type
-         cctxt
-         ~chain
-         ~block
-         ~contract:destination
-         ~entrypoint
-         ~normalize_types:true
-       >>=? function
-       | None ->
-           cctxt#error
-             "Contract %a has no entrypoint named %a"
-             Contract_hash.pp
-             destination
-             Entrypoint.pp
-             entrypoint
-       | Some parameter_type -> return parameter_type)
-      >>=? fun parameter_type ->
-      (match arg with
-      | Some arg ->
-          Lwt.return @@ Micheline_parser.no_parsing_error
-          @@ Michelson_v1_parser.parse_expression arg
-          >>=? fun {expanded = arg; _} -> return_some arg
-      | None -> return_none)
-      >>=? fun parameter ->
-      let parameter = Option.value ~default:d_unit parameter in
-      return
-      @@ build_lambda_for_transfer_to_originated
-           ~destination
-           ~entrypoint
-           ~amount
-           ~parameter_type
-           ~parameter)
-  >>=? fun lambda ->
-  parse lambda >>=? fun parameters ->
+  let open Lwt_result_syntax in
+  let* lambda =
+    match destination with
+    | Implicit destination when Entrypoint.is_default entrypoint ->
+        return @@ build_lambda_for_transfer_to_implicit ~destination ~amount
+    | Implicit _ ->
+        cctxt#error
+          "Implicit accounts have no entrypoints. (targeted entrypoint %%%a on \
+           contract %a)"
+          Entrypoint.pp
+          entrypoint
+          Contract.pp
+          destination
+    | Originated destination ->
+        let* parameter_type =
+          let* expr_opt =
+            Michelson_v1_entrypoints.contract_entrypoint_type
+              cctxt
+              ~chain
+              ~block
+              ~contract:destination
+              ~entrypoint
+              ~normalize_types:true
+          in
+          match expr_opt with
+          | None ->
+              cctxt#error
+                "Contract %a has no entrypoint named %a"
+                Contract_hash.pp
+                destination
+                Entrypoint.pp
+                entrypoint
+          | Some parameter_type -> return parameter_type
+        in
+        let* parameter =
+          match arg with
+          | Some arg ->
+              let* {expanded = arg; _} =
+                Lwt.return @@ Micheline_parser.no_parsing_error
+                @@ Michelson_v1_parser.parse_expression arg
+              in
+              return_some arg
+          | None -> return_none
+        in
+        let parameter = Option.value ~default:d_unit parameter in
+        return
+        @@ build_lambda_for_transfer_to_originated
+             ~destination
+             ~entrypoint
+             ~amount
+             ~parameter_type
+             ~parameter
+  in
+  let* parameters = parse lambda in
   let entrypoint = entrypoint_do in
   return
     (Client_proto_context.build_transaction_operation
@@ -295,41 +317,44 @@ let transfer (cctxt : #full) ~chain ~block ?confirmations ?dry_run
     (Kind.transaction Kind.manager Injection.result * Contract_hash.t list)
     tzresult
     Lwt.t =
-  build_transaction_operation
-    cctxt
-    ~chain
-    ~block
-    ~contract
-    ~destination
-    ~entrypoint
-    ?arg
-    ~amount
-    ?fee
-    ?gas_limit
-    ?storage_limit
-    ()
-  >>=? fun operation ->
+  let open Lwt_result_syntax in
+  let* operation =
+    build_transaction_operation
+      cctxt
+      ~chain
+      ~block
+      ~contract
+      ~destination
+      ~entrypoint
+      ?arg
+      ~amount
+      ?fee
+      ?gas_limit
+      ?storage_limit
+      ()
+  in
   let operation = Annotated_manager_operation.Single_manager operation in
-  Injection.inject_manager_operation
-    cctxt
-    ~chain
-    ~block
-    ?confirmations
-    ?dry_run
-    ?verbose_signing
-    ?simulation
-    ~force
-    ?branch
-    ~source
-    ~fee:(Limit.of_option fee)
-    ~gas_limit:(Limit.of_option gas_limit)
-    ~storage_limit:(Limit.of_option storage_limit)
-    ?counter
-    ~src_pk
-    ~src_sk
-    ~fee_parameter
-    operation
-  >>=? fun ((_, _, _, result) as res) ->
-  Lwt.return (Injection.originated_contracts ~force result)
-  >>=? fun contracts ->
-  return_single_manager_result res >>=? fun res -> return (res, contracts)
+  let* ((_, _, _, result) as res) =
+    Injection.inject_manager_operation
+      cctxt
+      ~chain
+      ~block
+      ?confirmations
+      ?dry_run
+      ?verbose_signing
+      ?simulation
+      ~force
+      ?branch
+      ~source
+      ~fee:(Limit.of_option fee)
+      ~gas_limit:(Limit.of_option gas_limit)
+      ~storage_limit:(Limit.of_option storage_limit)
+      ?counter
+      ~src_pk
+      ~src_sk
+      ~fee_parameter
+      operation
+  in
+  let*? contracts = Injection.originated_contracts ~force result in
+  let* res = return_single_manager_result res in
+  return (res, contracts)