diff --git a/src/rpc/util.h b/src/rpc/util.h
index 606bc4669..89b2e126e 100644
--- a/src/rpc/util.h
+++ b/src/rpc/util.h
@@ -1,237 +1,246 @@
 // Copyright (c) 2017-2019 The Bitcoin Core developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #ifndef BITCOIN_RPC_UTIL_H
 #define BITCOIN_RPC_UTIL_H
 
 #include <node/transaction.h>
 #include <rpc/protocol.h>
 #include <rpc/request.h>
 #include <script/standard.h> // For CTxDestination
 #include <univalue.h>
 #include <util/check.h>
 
 #include <boost/variant.hpp>
 
 #include <string>
 #include <vector>
 
 class CChainParams;
 class CKeyStore;
 class CPubKey;
 class CScript;
 class UniValue;
 
 /**
  * Wrapper for UniValue::VType, which includes typeAny: used to denote don't
  * care type.
  */
 struct UniValueType {
     UniValueType(UniValue::VType _type) : typeAny(false), type(_type) {}
     UniValueType() : typeAny(true) {}
     bool typeAny;
     UniValue::VType type;
 };
 
 /**
  * Type-check arguments; throws JSONRPCError if wrong type given. Does not check
  * that the right number of arguments are passed, just that any passed are the
  * correct type.
  */
 void RPCTypeCheck(const UniValue &params,
                   const std::list<UniValueType> &typesExpected,
                   bool fAllowNull = false);
 
 /**
  * Type-check one argument; throws JSONRPCError if wrong type given.
  */
 void RPCTypeCheckArgument(const UniValue &value,
                           const UniValueType &typeExpected);
 
 /**
  * Check for expected keys/value types in an Object.
  */
 void RPCTypeCheckObj(const UniValue &o,
                      const std::map<std::string, UniValueType> &typesExpected,
                      bool fAllowNull = false, bool fStrict = false);
 
 /**
  * Utilities: convert hex-encoded values (throws error if not hex).
  */
 extern uint256 ParseHashV(const UniValue &v, std::string strName);
 extern uint256 ParseHashO(const UniValue &o, std::string strKey);
 extern std::vector<uint8_t> ParseHexV(const UniValue &v, std::string strName);
 extern std::vector<uint8_t> ParseHexO(const UniValue &o, std::string strKey);
 
 extern Amount AmountFromValue(const UniValue &value);
 extern std::string HelpExampleCli(const std::string &methodname,
                                   const std::string &args);
 extern std::string HelpExampleRpc(const std::string &methodname,
                                   const std::string &args);
 
 CPubKey HexToPubKey(const std::string &hex_in);
 CPubKey AddrToPubKey(const CChainParams &chainparams, CKeyStore *const keystore,
                      const std::string &addr_in);
 CScript CreateMultisigRedeemscript(const int required,
                                    const std::vector<CPubKey> &pubkeys);
 
 UniValue DescribeAddress(const CTxDestination &dest);
 
 RPCErrorCode RPCErrorFromTransactionError(TransactionError terr);
 UniValue JSONRPCTransactionError(TransactionError terr,
                                  const std::string &err_string = "");
 
 struct RPCArg {
     enum class Type {
         OBJ,
         ARR,
         STR,
         NUM,
         BOOL,
         //! Special type where the user must set the keys e.g. to define
         //! multiple addresses; as opposed to e.g. an options object where the
         //! keys are predefined
         OBJ_USER_KEYS,
         //! Special type representing a floating point amount (can be either NUM
         //! or STR)
         AMOUNT,
         //! Special type that is a STR with only hex chars
         STR_HEX,
     };
 
     enum class Optional {
         /** Required arg */
         NO,
         /**
          * Optional arg that is a named argument and has a default value of
          * `null`. When possible, the default value should be specified.
          */
         OMITTED_NAMED_ARG,
         /**
          * Optional argument with default value omitted because they are
          * implicitly clear. That is, elements in an array or object may not
          * exist by default.
          * When possible, the default value should be specified.
          */
         OMITTED,
     };
     using Fallback =
         boost::variant<Optional,
                        /* default value for optional args */ std::string>;
 
     //! The name of the arg (can be empty for inner args)
     const std::string m_name;
     const Type m_type;
     //! Only used for arrays or dicts
     const std::vector<RPCArg> m_inner;
     const Fallback m_fallback;
     const std::string m_description;
     //! Should be empty unless it is supposed to override the auto-generated
     //! summary line
     const std::string m_oneline_description;
 
     //! Should be empty unless it is supposed to override the
     //! auto-generated type strings. Vector length is either 0
     //! or 2, m_type_str.at(0) will override the type of the
     //! value in a key-value pair, m_type_str.at(1) will
     //! override the type in the argument description.
     const std::vector<std::string> m_type_str;
 
     RPCArg(const std::string &name, const Type &type, const Fallback &fallback,
            const std::string &description,
            const std::string &oneline_description = "",
            const std::vector<std::string> &type_str = {})
         : m_name{name}, m_type{type}, m_fallback{fallback},
           m_description{description},
           m_oneline_description{oneline_description}, m_type_str{type_str} {
         CHECK_NONFATAL(type != Type::ARR && type != Type::OBJ);
     }
 
     RPCArg(const std::string &name, const Type &type, const Fallback &fallback,
            const std::string &description, const std::vector<RPCArg> &inner,
            const std::string &oneline_description = "",
            const std::vector<std::string> &type_str = {})
         : m_name{name}, m_type{type}, m_inner{inner}, m_fallback{fallback},
           m_description{description},
           m_oneline_description{oneline_description}, m_type_str{type_str} {
         CHECK_NONFATAL(type == Type::ARR || type == Type::OBJ);
     }
 
     bool IsOptional() const;
 
     /**
      * Return the type string of the argument.
      * Set oneline to allow it to be overridden by a custom oneline type string
      * (m_oneline_description).
      */
     std::string ToString(bool oneline) const;
     /**
      * Return the type string of the argument when it is in an object (dict).
      * Set oneline to get the oneline representation (less whitespace)
      */
     std::string ToStringObj(bool oneline) const;
     /**
      * Return the description string, including the argument type and whether
      * the argument is required.
      */
     std::string ToDescriptionString() const;
 };
 
 struct RPCResult {
     const std::string m_cond;
     const std::string m_result;
 
     explicit RPCResult(std::string result)
         : m_cond{}, m_result{std::move(result)} {
         CHECK_NONFATAL(!m_result.empty());
     }
 
     RPCResult(std::string cond, std::string result)
         : m_cond{std::move(cond)}, m_result{std::move(result)} {
         CHECK_NONFATAL(!m_cond.empty());
         CHECK_NONFATAL(!m_result.empty());
     }
 };
 
 struct RPCResults {
     const std::vector<RPCResult> m_results;
 
     RPCResults() : m_results{} {}
 
     RPCResults(RPCResult result) : m_results{{result}} {}
 
     RPCResults(std::initializer_list<RPCResult> results) : m_results{results} {}
 
     /**
      * Return the description string.
      */
     std::string ToDescriptionString() const;
 };
 
 struct RPCExamples {
     const std::string m_examples;
     RPCExamples(std::string examples) : m_examples(std::move(examples)) {}
     RPCExamples() : m_examples(std::move("")) {}
     std::string ToDescriptionString() const;
 };
 
 class RPCHelpMan {
 public:
     RPCHelpMan(std::string name, std::string description,
                std::vector<RPCArg> args, RPCResults results,
                RPCExamples examples);
 
     std::string ToString() const;
     /** If the supplied number of args is neither too small nor too high */
     bool IsValidNumArgs(size_t num_args) const;
+    /**
+     * Check if the given request is valid according to this command or if
+     * the user is asking for help information, and throw help when appropriate.
+     */
+    inline void Check(const JSONRPCRequest &request) const {
+        if (request.fHelp || !IsValidNumArgs(request.params.size())) {
+            throw std::runtime_error(ToString());
+        }
+    }
 
 private:
     const std::string m_name;
     const std::string m_description;
     const std::vector<RPCArg> m_args;
     const RPCResults m_results;
     const RPCExamples m_examples;
 };
 
 #endif // BITCOIN_RPC_UTIL_H