diff --git a/Cargo.lock b/Cargo.lock
index f940c4984..dae8a8276 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -730,11 +730,8 @@ dependencies = [
 name = "cairo-lang-macro"
 version = "0.0.1"
 dependencies = [
- "anyhow",
  "cairo-lang-macro-attributes",
  "cairo-lang-macro-stable",
- "serde",
- "serde_json",
 ]
 
 [[package]]
diff --git a/plugins/cairo-lang-macro-stable/src/lib.rs b/plugins/cairo-lang-macro-stable/src/lib.rs
index fcf853b96..58c5f4d2f 100644
--- a/plugins/cairo-lang-macro-stable/src/lib.rs
+++ b/plugins/cairo-lang-macro-stable/src/lib.rs
@@ -16,7 +16,7 @@ pub struct StableTokenStream(*mut c_char);
 #[derive(Debug)]
 pub enum StableAuxData {
     None,
-    Some(*mut c_char),
+    Some(StableSlice<u8>),
 }
 
 /// Diagnostic returned by the procedural macro.
diff --git a/plugins/cairo-lang-macro/Cargo.toml b/plugins/cairo-lang-macro/Cargo.toml
index 7ca51d792..73a14dac0 100644
--- a/plugins/cairo-lang-macro/Cargo.toml
+++ b/plugins/cairo-lang-macro/Cargo.toml
@@ -13,8 +13,5 @@ readme = "README.md"
 repository.workspace = true
 
 [dependencies]
-anyhow.workspace = true
 cairo-lang-macro-attributes = { path = "../cairo-lang-macro-attributes" }
 cairo-lang-macro-stable = { path = "../cairo-lang-macro-stable" }
-serde.workspace = true
-serde_json.workspace = true
diff --git a/plugins/cairo-lang-macro/src/lib.rs b/plugins/cairo-lang-macro/src/lib.rs
index acd3d27e0..fbee1b56a 100644
--- a/plugins/cairo-lang-macro/src/lib.rs
+++ b/plugins/cairo-lang-macro/src/lib.rs
@@ -56,21 +56,23 @@ impl Display for TokenStream {
 
 /// Auxiliary data returned by procedural macro.
 #[derive(Debug)]
-pub struct AuxData(String);
+pub struct AuxData(Vec<u8>);
 
 impl AuxData {
-    pub fn new(s: String) -> Self {
-        Self(s)
+    pub fn new(data: Vec<u8>) -> Self {
+        Self(data)
     }
+}
 
-    pub fn try_new<T: serde::Serialize>(value: T) -> Result<Self, serde_json::Error> {
-        Ok(Self(serde_json::to_string(&value)?))
+impl From<&[u8]> for AuxData {
+    fn from(bytes: &[u8]) -> Self {
+        Self(bytes.to_vec())
     }
 }
 
-impl Display for AuxData {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        write!(f, "{}", self.0)
+impl From<AuxData> for Vec<u8> {
+    fn from(aux_data: AuxData) -> Vec<u8> {
+        aux_data.0
     }
 }
 
@@ -346,8 +348,8 @@ impl AuxData {
     /// # Safety
     #[doc(hidden)]
     pub fn into_stable(self) -> StableAuxData {
-        let cstr = CString::new(self.0.to_string()).unwrap();
-        StableAuxData::Some(cstr.into_raw())
+        let value: Vec<u8> = self.into();
+        StableAuxData::Some(StableSlice::new(value))
     }
 
     /// Convert to native Rust representation, without taking the ownership of the string.
@@ -359,7 +361,11 @@ impl AuxData {
     pub unsafe fn from_stable(aux_data: &StableAuxData) -> Option<Self> {
         match aux_data {
             StableAuxData::None => None,
-            StableAuxData::Some(raw) => Some(Self::new(from_raw_cstr(*raw))),
+            StableAuxData::Some(raw) => {
+                let (ptr, n) = raw.raw_parts();
+                let value = slice::from_raw_parts(ptr, n);
+                Some(value.into())
+            }
         }
     }
 
@@ -373,7 +379,7 @@ impl AuxData {
     pub unsafe fn from_owned_stable(aux_data: StableAuxData) -> Option<Self> {
         match aux_data {
             StableAuxData::None => None,
-            StableAuxData::Some(raw) => Some(Self::new(from_raw_cstring(raw))),
+            StableAuxData::Some(raw) => Some(Self::new(raw.into_owned())),
         }
     }
 }
diff --git a/scarb/src/compiler/plugin/proc_macro/host.rs b/scarb/src/compiler/plugin/proc_macro/host.rs
index 6e29f8615..38ccfdc3e 100644
--- a/scarb/src/compiler/plugin/proc_macro/host.rs
+++ b/scarb/src/compiler/plugin/proc_macro/host.rs
@@ -49,13 +49,13 @@ pub struct ProcMacroInput {
 
 #[derive(Clone, Debug)]
 pub struct ProcMacroAuxData {
-    value: String,
+    value: Vec<u8>,
     macro_id: ProcMacroId,
     macro_package_id: PackageId,
 }
 
 impl ProcMacroAuxData {
-    pub fn new(value: String, macro_id: ProcMacroId, macro_package_id: PackageId) -> Self {
+    pub fn new(value: Vec<u8>, macro_id: ProcMacroId, macro_package_id: PackageId) -> Self {
         Self {
             value,
             macro_id,
@@ -210,7 +210,7 @@ impl MacroPlugin for ProcMacroHostPlugin {
                     token_stream = new_token_stream;
                     if let Some(new_aux_data) = new_aux_data {
                         aux_data = Some(ProcMacroAuxData::new(
-                            new_aux_data.to_string(),
+                            new_aux_data.into(),
                             input.id,
                             input.macro_package_id,
                         ));
diff --git a/scarb/tests/build_cairo_plugin.rs b/scarb/tests/build_cairo_plugin.rs
index ca6f2c214..b825cacf3 100644
--- a/scarb/tests/build_cairo_plugin.rs
+++ b/scarb/tests/build_cairo_plugin.rs
@@ -91,7 +91,7 @@ fn simple_project_with_code(t: &impl PathChild, code: impl ToString) {
 
 fn simple_project(t: &impl PathChild) {
     let code = indoc! {r#"
-        use cairo_lang_macro::{ProcMacroResult, TokenStream, attribute_macro};
+        use cairo_lang_macro::{ProcMacroResult, TokenStream, attribute_macro, AuxData};
 
         #[attribute_macro]
         pub fn some_macro(token_stream: TokenStream) -> ProcMacroResult {