diff --git a/src/test/rpc/RPCCall_test.cpp b/src/test/rpc/RPCCall_test.cpp
index 45914efd2d..6c75d59174 100644
--- a/src/test/rpc/RPCCall_test.cpp
+++ b/src/test/rpc/RPCCall_test.cpp
@@ -3002,13 +3002,31 @@ static RPCCallTestData const rpcCallTestArray[] = {
          "get_counts",
          "-1",
      },
-     RPCCallTestData::bad_cast,
-     R"()"},
+     RPCCallTestData::no_exception,
+     R"({
+    "method" : "get_counts",
+    "params" : [
+      {
+         "error" : "invalidParams",
+         "error_code" : 31,
+         "error_message" : "Invalid field 'min_count'."
+      }
+    ]
+    })"},
     {"get_counts: count too large.",
      __LINE__,
      {"get_counts", "4294967296"},
-     RPCCallTestData::bad_cast,
-     R"()"},
+     RPCCallTestData::no_exception,
+     R"({
+    "method" : "get_counts",
+    "params" : [
+      {
+         "error" : "invalidParams",
+         "error_code" : 31,
+         "error_message" : "Invalid field 'min_count'."
+      }
+    ]
+    })"},
 
     // json
     // ------------------------------------------------------------------------
diff --git a/src/xrpld/rpc/detail/RPCCall.cpp b/src/xrpld/rpc/detail/RPCCall.cpp
index 09af2b9db1..6089912564 100644
--- a/src/xrpld/rpc/detail/RPCCall.cpp
+++ b/src/xrpld/rpc/detail/RPCCall.cpp
@@ -546,7 +546,12 @@ private:
         Json::Value jvRequest(Json::objectValue);
 
         if (jvParams.size())
-            jvRequest[jss::min_count] = jvParams[0u].asUInt();
+        {
+            if (auto minCount = jvParseUInt(jvParams[0u]))
+                jvRequest[jss::min_count] = *minCount;
+            else
+                return RPC::invalid_field_error(jss::min_count);
+        }
 
         return jvRequest;
     }