diff --git a/crates/cgp-error/src/traits/can_raise_error.rs b/crates/cgp-error/src/traits/can_raise_error.rs
index 835592af..4fbbd1a8 100644
--- a/crates/cgp-error/src/traits/can_raise_error.rs
+++ b/crates/cgp-error/src/traits/can_raise_error.rs
@@ -1,4 +1,5 @@
 use cgp_component::*;
+use cgp_field::types::*;
 use cgp_macro::cgp_component;
 
 use crate::traits::has_error_type::HasErrorType;
@@ -11,6 +12,7 @@ use crate::traits::has_error_type::HasErrorType;
     provider: ErrorRaiser,
     derive_delegate: UseDelegate<SourceError>,
 }]
+#[use_namespace(cgp.core.error)]
 pub trait CanRaiseError<SourceError>: HasErrorType {
     fn raise_error(error: SourceError) -> Self::Error;
 }
diff --git a/crates/cgp-field/src/types/field.rs b/crates/cgp-field/src/types/field.rs
index 32073a44..ca4ddca2 100644
--- a/crates/cgp-field/src/types/field.rs
+++ b/crates/cgp-field/src/types/field.rs
@@ -84,11 +84,4 @@ where
     }
 }
 
-impl<Tag, Value> Eq for Field<Tag, Value>
-where
-    Value: Eq,
-{
-    fn assert_receiver_is_total_eq(&self) {
-        self.value.assert_receiver_is_total_eq()
-    }
-}
+impl<Tag, Value> Eq for Field<Tag, Value> where Value: Eq {}
diff --git a/crates/cgp-macro-lib/src/parse/delegate_components.rs b/crates/cgp-macro-lib/src/parse/delegate_components.rs
index d5a98895..9df0c55e 100644
--- a/crates/cgp-macro-lib/src/parse/delegate_components.rs
+++ b/crates/cgp-macro-lib/src/parse/delegate_components.rs
@@ -1,12 +1,12 @@
 use core::iter;
 
-use proc_macro2::TokenStream;
+use proc_macro2::{Span, TokenStream};
 use quote::{ToTokens, TokenStreamExt, quote};
 use syn::parse::discouraged::Speculative;
 use syn::parse::{Parse, ParseStream};
 use syn::punctuated::Punctuated;
-use syn::token::{At, Bracket, Colon, Comma, Gt, Lt, Pound, RArrow};
-use syn::{Attribute, Error, Generics, Ident, Token, Type, braced, bracketed, parse_quote};
+use syn::token::{At, Bracket, Colon, Comma, Gt, Lt, Pound, RArrow, Semi};
+use syn::{Attribute, Error, Generics, Ident, Token, Type, braced, bracketed, parse_quote, parse2};
 
 use crate::parse::{ComponentPaths, ImplGenerics, SimpleType, TypeGenerics};
 
@@ -99,22 +99,68 @@ impl Parse for DelegateComponents {
 
         let target_type: Type = input.parse()?;
 
-        let delegate_entries = {
-            let content;
-            braced!(content in input);
-            Punctuated::parse_terminated(&content)?
-        };
+        let content;
+        braced!(content in input);
+
+        let meta_entries = parse_meta_delegate_entries(&content, &target_type)?;
+
+        let delegate_entries: Punctuated<DelegateEntry<Type>, Comma> =
+            Punctuated::parse_terminated(&content)?;
+
+        let entries = meta_entries.into_iter().chain(delegate_entries).collect();
 
         Ok(Self {
             attributes,
             new_struct,
             target_type,
             target_generics,
-            entries: delegate_entries,
+            entries,
         })
     }
 }
 
+pub fn parse_meta_delegate_entries(
+    input: ParseStream,
+    target_type: &Type,
+) -> syn::Result<Vec<DelegateEntry<Type>>> {
+    let mut entries = Vec::new();
+
+    while input.peek(Ident) {
+        let fork = input.fork();
+        let keyword: Ident = fork.parse()?;
+
+        if keyword == "open" {
+            input.advance_to(&fork);
+
+            let components: Punctuated<Type, Comma> = Punctuated::parse_separated_nonempty(input)?;
+            let _: Semi = input.parse()?;
+
+            for component in components {
+                let value = DelegateValue::Type(parse2(
+                    quote!(RedirectLookup<#target_type, PathCons<#component, PathNil>>),
+                )?);
+
+                let key = DelegateKey {
+                    ty: component,
+                    generics: Default::default(),
+                };
+
+                let entry = DelegateEntry {
+                    keys: Punctuated::from_iter([key]),
+                    mode: DelegateMode::Provider(Colon(Span::call_site())),
+                    value,
+                };
+
+                entries.push(entry)
+            }
+        } else {
+            break;
+        }
+    }
+
+    Ok(entries)
+}
+
 impl Parse for DelegateEntry<Type> {
     fn parse(input: ParseStream) -> syn::Result<Self> {
         let components = if input.peek(Bracket) {
diff --git a/crates/cgp-tests/src/namespaces/extend.rs b/crates/cgp-tests/src/namespaces/extend.rs
index 13490859..3d19b6a2 100644
--- a/crates/cgp-tests/src/namespaces/extend.rs
+++ b/crates/cgp-tests/src/namespaces/extend.rs
@@ -16,7 +16,15 @@ where
     type Provider = Provider;
 }
 
-impl<Components> ExtendedNamespace<Components> for ErrorRaiserComponent {
+impl<Components, Error> ExtendedNamespace<Components>
+    for PathCons<
+        Symbol!("cgp"),
+        PathCons<
+            Symbol!("core"),
+            PathCons<Symbol!("error"), PathCons<ErrorRaiserComponent, PathCons<Error, PathNil>>>,
+        >,
+    >
+{
     type Provider = RedirectLookup<
         Components,
         PathCons<Symbol!("app"), PathCons<ErrorRaiserComponent, PathNil>>,
diff --git a/crates/cgp-tests/tests/namespace_tests/experiments.rs b/crates/cgp-tests/tests/namespace_tests/extend_namespace.rs
similarity index 100%
rename from crates/cgp-tests/tests/namespace_tests/experiments.rs
rename to crates/cgp-tests/tests/namespace_tests/extend_namespace.rs
diff --git a/crates/cgp-tests/tests/namespace_tests/mod.rs b/crates/cgp-tests/tests/namespace_tests/mod.rs
index 2a24debe..05efb2a4 100644
--- a/crates/cgp-tests/tests/namespace_tests/mod.rs
+++ b/crates/cgp-tests/tests/namespace_tests/mod.rs
@@ -1,3 +1,4 @@
-pub mod experiments;
+pub mod extend_namespace;
+pub mod open;
 pub mod redirect;
 pub mod use_namespace;
diff --git a/crates/cgp-tests/tests/namespace_tests/open.rs b/crates/cgp-tests/tests/namespace_tests/open.rs
new file mode 100644
index 00000000..fff4e71b
--- /dev/null
+++ b/crates/cgp-tests/tests/namespace_tests/open.rs
@@ -0,0 +1,23 @@
+use cgp::core::error::{ErrorRaiserComponent, ErrorTypeProviderComponent};
+use cgp::extra::error::ReturnError;
+use cgp::prelude::*;
+
+pub struct App;
+
+delegate_components! {
+    App {
+        open ErrorRaiserComponent;
+
+        ErrorTypeProviderComponent:
+            UseType<String>,
+        @ErrorRaiserComponent.String:
+            ReturnError,
+    }
+}
+
+check_components! {
+    App {
+        ErrorRaiserComponent:
+            String,
+    }
+}
diff --git a/crates/cgp-tests/tests/namespace_tests/use_namespace.rs b/crates/cgp-tests/tests/namespace_tests/use_namespace.rs
index ada8fe0e..6b8e16c3 100644
--- a/crates/cgp-tests/tests/namespace_tests/use_namespace.rs
+++ b/crates/cgp-tests/tests/namespace_tests/use_namespace.rs
@@ -1,4 +1,5 @@
-use cgp::core::error::ErrorTypeProviderComponent;
+use cgp::core::error::{ErrorRaiserComponent, ErrorTypeProviderComponent};
+use cgp::extra::error::ReturnError;
 use cgp::prelude::*;
 
 pub struct MyComponents;
@@ -16,5 +17,13 @@ delegate_components! {
     App {
         @cgp.core.error.ErrorTypeProviderComponent:
             UseType<String>,
+        @cgp.core.error.ErrorRaiserComponent.String:
+            ReturnError,
+    }
+}
+
+check_components! {
+    App {
+        ErrorRaiserComponent: String,
     }
 }