diff --git a/proc/src/proc_command.rs b/proc/src/proc_command.rs
index 8ad7776..2573d0f 100644
--- a/proc/src/proc_command.rs
+++ b/proc/src/proc_command.rs
@@ -62,6 +62,7 @@ impl ToTokens for CommandDef {
         let implementations = exposed.values().map(CommandArm::to_implementation);
         write_quote_to(out, quote! {
             /// Generated by [tengri_proc].
+            #[derive(Clone, Debug)]
             pub enum #enumeration {
                 #(#variants)*
             }
@@ -123,9 +124,11 @@ impl CommandArm {
                         if with_values {
                             let take_err = LitStr::new(&format!("{}: missing argument \"{}\" ({})",
                                 quote!{#ident}, quote!{#pat}, quote!{#ty}), Span::call_site());
+                            let give_err = LitStr::new(&format!("{}: missing value \"{}\" ({})",
+                                quote!{#ident}, quote!{#pat}, quote!{#ty}), Span::call_site());
                             write_quote_to(&mut out, quote! {
                                 : Context::get(state, &iter.next().expect(#take_err).value)
-                            });
+                                    .expect(#give_err) });
                         }
                     } else {
                         unreachable!("only typed args should be present at this position")
diff --git a/proc/src/proc_expose.rs b/proc/src/proc_expose.rs
index 9315f2e..0303509 100644
--- a/proc/src/proc_expose.rs
+++ b/proc/src/proc_expose.rs
@@ -70,23 +70,31 @@ impl ToTokens for ExposeImpl {
             out.append(token);
         }
         for (t, variants) in exposed.iter() {
-            let predefined = match format!("{}", quote! { #t }).as_str() {
-                "bool" => vec![
-                    quote! { ::tengri::dsl::Value::Sym(":true")  => true  },
-                    quote! { ::tengri::dsl::Value::Sym(":false") => false },
-                ],
+            let formatted_type = format!("{}", quote! { #t }); 
+            let predefined = match formatted_type.as_str() {
+                "bool" => quote! {
+                    ::tengri::dsl::Value::Sym(":true")  => true,
+                    ::tengri::dsl::Value::Sym(":false") => false,
+                },
                 "u8" | "u16" | "u32" | "u64" | "usize" |
-                "i8" | "i16" | "i32" | "i64" | "isize" => vec![
-                    quote! { ::tengri::dsl::Value::Num(n) => *n },
-                ],
-                _ => vec![],
+                "i8" | "i16" | "i32" | "i64" | "isize" => {
+                    let num_err = LitStr::new(
+                        &format!("{{n}}: failed to convert to {formatted_type}"),
+                        Span::call_site()
+                    );
+                    quote! {
+                        ::tengri::dsl::Value::Num(n) => TryInto::<#t>::try_into(*n)
+                            .unwrap_or_else(|_|panic!(#num_err)),
+                    }
+                },
+                _ => quote! {},
             };
             let values = variants.iter().map(|(k, v)|ExposeArm(k.clone(), v.clone()));
             let trait_impl = quote! {
                 impl ::tengri::dsl::Context<#t> for #target {
                     fn get (&self, dsl: &::tengri::dsl::Value) -> Option<#t> {
                         Some(match dsl {
-                            #(#predefined,)*
+                            #predefined
                             #(#values,)*
                             _ => return None
                         })
@@ -97,9 +105,9 @@ impl ToTokens for ExposeImpl {
                 out.append(token);
             }
         }
-        //if exposed.len() > 0 {
+        if exposed.len() > 0 {
             //panic!("{}", quote! {#out});
-        //}
+        }
     }
 }