diff --git a/src/lib.rs b/src/lib.rs
index d48d15b..fcb87fb 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -6,11 +6,54 @@ use rosc::{OscMessage, OscType};
 
 pub trait MessageBehavior {
     fn to_osc_message(&self) -> OscMessage;
-    fn from_osc_message(msg: OscMessage) -> Result<Self, String>
+    fn from_osc_message(msg: OscMessage) -> Result<Self, FromMessageErr>
     where
         Self: Sized;
 }
 
+struct ArgCountErr {
+    expected_in: Vec<usize>,
+    actual: usize,
+    addr: String,
+}
+
+struct ArgTypeErr {
+    expected: OscType,
+    actual: OscType,
+    addr: String,
+    arg_count: usize,
+}
+
+struct IntRangeErr {
+    expected_lower: i32,
+    expected_upper: i32,
+    actual: i32,
+    addr: String,
+    arg_count: usize,
+}
+
+struct IntValErr {
+    expected_in: Vec<i32>,
+    actual: i32,
+    addr: String,
+    arg_count: usize,
+}
+
+struct StrValErr {
+    expected_in: Vec<String>,
+    actual: String,
+    addr: String,
+    arg_count: usize,
+}
+
+enum FromMessageErr {
+    ArgCount(ArgCountErr),
+    ArgType(ArgTypeErr),
+    IntRange(IntRangeErr),
+    IntVal(IntValErr),
+    StrVal(StrValErr),
+}
+
 struct VmcExtOk {
     loaded: i32,
     calibration_state: Option<i32>,
@@ -33,7 +76,7 @@ impl MessageBehavior for VmcExtOk {
         }
         return OscMessage { addr, args };
     }
-    fn from_osc_message(msg: OscMessage) -> Result<Self, String> {
+    fn from_osc_message(msg: OscMessage) -> Result<Self, FromMessageErr> {
         let mut result = VmcExtOk {
             loaded: -1,
             calibration_state: None,
@@ -46,11 +89,11 @@ impl MessageBehavior for VmcExtOk {
                     result.loaded = i;
                 }
                 _ => {
-                    return Err(String::from("arg type invalid"));
+                    return Err(FromMessageErr::ArgType(ArgTypeErr { expected: OscType::Int(0), actual: msg.args[0],addr: msg.addr.to_owned(), arg_count: 0}));
                 }
             }
         } else {
-            return Err(String::from("arg count invalid"));
+            return Err(FromMessageErr::ArgCount(ArgCountErr { expected_in: vec![1, 3, 4], actual: msg.args.len(), addr: msg.addr.to_owned()}));
         }
         if msg.args.len() == 3 || msg.args.len() == 4 {
             match msg.args[1] {
@@ -58,7 +101,7 @@ impl MessageBehavior for VmcExtOk {
                     result.calibration_state = Some(i);
                 }
                 _ => {
-                    return Err(String::from("arg type invalid"));
+                    return Err(FromMessageErr::ArgType(ArgTypeErr { expected: OscType::Int(0), actual: msg.args[1], addr: msg.addr.to_owned(), arg_count: 1}));
                 }
             }
             match msg.args[2] {
@@ -66,7 +109,7 @@ impl MessageBehavior for VmcExtOk {
                     result.calibration_mode = Some(i);
                 }
                 _ => {
-                    return Err(String::from("arg type invalid"));
+                    return Err(FromMessageErr::ArgType(ArgTypeErr { expected: OscType::Int(0), actual: msg.args[2], addr: msg.addr.to_owned(), arg_count: 2}));
                 }
             }
         }
@@ -76,7 +119,7 @@ impl MessageBehavior for VmcExtOk {
                     result.tracking_status = Some(i);
                 }
                 _ => {
-                    return Err(String::from("arg type invalid"));
+                    return Err(FromMessageErr::ArgType(ArgTypeErr { expected: OscType::Int(0), actual: msg.args[3], addr: msg.addr.to_owned(), arg_count: 3}));
                 }
             }
         }
@@ -95,13 +138,13 @@ impl MessageBehavior for VmcExtT {
             args: vec![OscType::from(self.time)],
         };
     }
-    fn from_osc_message(msg: OscMessage) -> Result<Self, String> {
+    fn from_osc_message(msg: OscMessage) -> Result<Self, FromMessageErr> {
         if msg.args.len() != 1 {
-            return Err(String::from("arg count invalid"));
+            return Err(FromMessageErr::ArgCount(ArgCountErr { expected_in: vec![1], actual: msg.args.len(), addr: msg.addr}));
         }
         match msg.args[0] {
             OscType::Float(f) => return Ok(VmcExtT { time: f }),
-            _ => return Err(String::from("arg type invalid")),
+            _ => return Err(FromMessageErr::ArgType(ArgTypeErr { expected: OscType::Float(0.0), actual: msg.args[0], addr: msg.addr, arg_count: 0})),
         }
     }
 }
@@ -139,26 +182,26 @@ impl MessageBehavior for VmcExtRootPos {
         }
         return OscMessage { addr, args };
     }
-    fn from_osc_message(msg: OscMessage) -> Result<Self, String> {
+    fn from_osc_message(msg: OscMessage) -> Result<Self, FromMessageErr> {
         let mut result: VmcExtRootPos;
         if msg.args.len() == 8 || msg.args.len() == 14 {
             let mut origin = Vector3::new(0.0, 0.0, 0.0);
             let name: String;
             match &msg.args[0] {
                 OscType::String(s) => name = s.to_owned(),
-                _ => return Err(String::from("arg type invalid")),
+                _ => return Err(FromMessageErr::ArgType(ArgTypeErr { expected: OscType::String(String::new()), actual: msg.args[0], addr: msg.addr, arg_count: 0})),
             }
             match msg.args[1] {
                 OscType::Float(f) => origin.x = f,
-                _ => return Err(String::from("arg type invalid")),
+                _ => return Err(FromMessageErr::ArgType(ArgTypeErr { expected: OscType::Float(0.0), actual: msg.args[1], addr: msg.addr, arg_count: 1})),
             }
             match msg.args[2] {
                 OscType::Float(f) => origin.y = f,
-                _ => return Err(String::from("arg type invalid")),
+                _ => return Err(FromMessageErr::ArgType(ArgTypeErr { expected: OscType::Float(0.0), actual: msg.args[2], addr: msg.addr, arg_count: 2})),
             }
             match msg.args[3] {
                 OscType::Float(f) => origin.z = f,
-                _ => return Err(String::from("arg type invalid")),
+                _ => return Err(FromMessageErr::ArgType(ArgTypeErr { expected: OscType::Float(0.0), actual: msg.args[3], addr: msg.addr, arg_count: 3})),
             }
             let mut quat = Quaternion {
                 x: 0.0,
@@ -168,19 +211,19 @@ impl MessageBehavior for VmcExtRootPos {
             };
             match msg.args[4] {
                 OscType::Float(f) => quat.x = f,
-                _ => return Err(String::from("arg type invalid")),
+                _ => return Err(FromMessageErr::ArgType(ArgTypeErr { expected: OscType::Float(0.0), actual: msg.args[4], addr: msg.addr, arg_count: 4})),
             }
             match msg.args[5] {
                 OscType::Float(f) => quat.y = f,
-                _ => return Err(String::from("arg type invalid")),
+                _ => return Err(FromMessageErr::ArgType(ArgTypeErr { expected: OscType::Float(0.0), actual: msg.args[5], addr: msg.addr, arg_count: 5})),
             }
             match msg.args[6] {
                 OscType::Float(f) => quat.z = f,
-                _ => return Err(String::from("arg type invalid")),
+                _ => return Err(FromMessageErr::ArgType(ArgTypeErr { expected: OscType::Float(0.0), actual: msg.args[6], addr: msg.addr, arg_count: 6})),
             }
             match msg.args[7] {
                 OscType::Float(f) => quat.w = f,
-                _ => return Err(String::from("arg type invalid")),
+                _ => return Err(FromMessageErr::ArgType(ArgTypeErr { expected: OscType::Float(0.0), actual: msg.args[7], addr: msg.addr, arg_count: 7})),
             }
             result = VmcExtRootPos {
                 name,
@@ -189,7 +232,7 @@ impl MessageBehavior for VmcExtRootPos {
                 mr_offset: None,
             };
         } else {
-            return Err(String::from("arg count invalid"));
+            return Err(FromMessageErr::ArgCount(ArgCountErr { expected_in: vec![8, 14], actual: msg.args.len(), addr: msg.addr}));
         }
         if msg.args.len() == 14 {
             result.mr_scale = Some(Vector3 {
@@ -204,27 +247,27 @@ impl MessageBehavior for VmcExtRootPos {
             });
             match msg.args[8] {
                 OscType::Float(f) => result.mr_scale.unwrap().x = f,
-                _ => return Err(String::from("arg type invalid")),
+                _ => return Err(FromMessageErr::ArgType(ArgTypeErr { expected: OscType::Float(0.0), actual: msg.args[8], addr: msg.addr, arg_count: 8})),
             }
             match msg.args[9] {
                 OscType::Float(f) => result.mr_scale.unwrap().y = f,
-                _ => return Err(String::from("arg type invalid")),
+                _ => return Err(FromMessageErr::ArgType(ArgTypeErr { expected: OscType::Float(0.0), actual: msg.args[9], addr: msg.addr, arg_count: 9})),
             }
             match msg.args[10] {
                 OscType::Float(f) => result.mr_scale.unwrap().z = f,
-                _ => return Err(String::from("arg type invalid")),
+                _ => return Err(FromMessageErr::ArgType(ArgTypeErr { expected: OscType::Float(0.0), actual: msg.args[10], addr: msg.addr, arg_count: 10})),
             }
             match msg.args[11] {
                 OscType::Float(f) => result.mr_offset.unwrap().x = f,
-                _ => return Err(String::from("arg type invalid")),
+                _ => return Err(FromMessageErr::ArgType(ArgTypeErr { expected: OscType::Float(0.0), actual: msg.args[11], addr: msg.addr, arg_count: 11})),
             }
             match msg.args[12] {
                 OscType::Float(f) => result.mr_offset.unwrap().y = f,
-                _ => return Err(String::from("arg type invalid")),
+                _ => return Err(FromMessageErr::ArgType(ArgTypeErr { expected: OscType::Float(0.0), actual: msg.args[12], addr: msg.addr, arg_count: 12})),
             }
             match msg.args[13] {
                 OscType::Float(f) => result.mr_offset.unwrap().z = f,
-                _ => return Err(String::from("arg type invalid")),
+                _ => return Err(FromMessageErr::ArgType(ArgTypeErr { expected: OscType::Float(0.0), actual: msg.args[13], addr: msg.addr, arg_count: 13})),
             }
         }
         return Ok(result);
@@ -1310,3 +1353,22 @@ impl MessageBehavior for VmcExtSetEye {
         return Ok(VmcExtSetEye { enable, position: Vector3::new(x, y, z)})
     }
 }
+
+struct VmcExtSetRes {
+    response: String
+}
+
+impl MessageBehavior for VmcExtSetRes {
+    fn to_osc_message(&self) -> OscMessage {
+        return OscMessage{addr: String::from("/VMC/Ext/Set/Res"), args: vec![OscType::from(self.response.to_owned())]};
+    }
+    fn from_osc_message(msg: OscMessage) -> Result<Self, String> {
+        if msg.args.len() != 1 {
+            return Err(String::from("arg count invalid"));
+        }
+        match &msg.args[0] {
+            OscType::String(s) => return Ok(VmcExtSetRes{response: s.to_owned()}),
+            _ => return Err(String::from("arg type invalid"))
+        }
+    }
+}