diff --git a/lib/dynamic.js b/lib/dynamic.js
index 2438da28..10c5f17e 100644
--- a/lib/dynamic.js
+++ b/lib/dynamic.js
@@ -44,8 +44,9 @@ Dynamic.converters = [];
  * @param {Function} converter
  */
 
-Dynamic.define = function(name, converter) {
+Dynamic.define = function(name, converter, fromArgs) {
   converter.typeName = name;
+  converter.fromArgs = fromArgs !== false;
   this.converters.unshift(converter);
 };
 
@@ -56,8 +57,9 @@ Dynamic.define = function(name, converter) {
  * @returns {Boolean}
  */
 
-Dynamic.canConvert = function(type) {
-  return !!this.getConverter(type);
+Dynamic.canConvert = function(type, fromArgs) {
+  var converter = this.getConverter(type);
+  return converter && converter.fromArgs === !!fromArgs;
 };
 
 /**
diff --git a/lib/http-context.js b/lib/http-context.js
index 09c0ba32..dcc75702 100644
--- a/lib/http-context.js
+++ b/lib/http-context.js
@@ -210,7 +210,7 @@ HttpContext.prototype.buildArgs = function(method) {
 
     // For boolean and number types, convert certain strings to that type.
     // The user can also define new dynamic types.
-    if (Dynamic.canConvert(otype)) {
+    if (Dynamic.canConvert(otype, true)) {
       val = dynamic(val, otype, ctx);
     }