diff --git a/pdl-live-react/src-tauri/src/compile/beeai.rs b/pdl-live-react/src-tauri/src/compile/beeai.rs
index a13fa0e0c..76d2d3c7c 100644
--- a/pdl-live-react/src-tauri/src/compile/beeai.rs
+++ b/pdl-live-react/src-tauri/src/compile/beeai.rs
@@ -191,7 +191,6 @@ fn with_tools(
 
 fn call_tools(model: &String, parameters: &HashMap<String, Value>) -> PdlBlock {
     let repeat = PdlBlock::Text(TextBlock {
-        def: None,
         metadata: None,
         role: None,
         parser: None,
@@ -207,6 +206,7 @@ fn call_tools(model: &String, parameters: &HashMap<String, Value>) -> PdlBlock {
                         tool_call_id: Some("${ tool.id }".to_string()),
                         content: Box::new(PdlBlock::Call(CallBlock {
                             metadata: Some(Metadata {
+                                def: None,
                                 defs: json_loads(
                                     &"args",
                                     &"pdl__args",
@@ -465,7 +465,6 @@ asyncio.run(invoke())
                     model_call.push(PdlBlock::Text(TextBlock {
                         role: Some(Role::System),
                         text: vec![PdlBlock::String(instructions)],
-                        def: None,
                         metadata: None,
                         parser: None,
                         description: Some("Model instructions".into()),
@@ -482,9 +481,9 @@ asyncio.run(invoke())
                 };
 
                 model_call.push(PdlBlock::Model(ModelBlock {
+                    metadata: None,
                     input: None,
                     description: Some(description),
-                    def: None,
                     model: model.clone(),
                     model_response: model_response,
                     pdl_result: None,
@@ -505,7 +504,6 @@ asyncio.run(invoke())
                     PdlBlock::Function(FunctionBlock {
                         function: HashMap::new(),
                         return_: Box::new(PdlBlock::Text(TextBlock {
-                            def: None,
                             metadata: None,
                             role: None,
                             parser: None,
@@ -515,8 +513,10 @@ asyncio.run(invoke())
                     }),
                 );
                 PdlBlock::Text(TextBlock {
-                    def: None,
-                    metadata: Some(Metadata { defs: Some(defs) }),
+                    metadata: Some(Metadata {
+                        def: None,
+                        defs: Some(defs),
+                    }),
                     role: None,
                     parser: None,
                     description: Some("Model call wrapper".to_string()),
@@ -534,7 +534,6 @@ asyncio.run(invoke())
         .collect::<Vec<_>>();
 
     let pdl: PdlBlock = PdlBlock::Text(TextBlock {
-        def: None,
         metadata: if tool_declarations.len() == 0 {
             None
         } else {
@@ -545,7 +544,10 @@ asyncio.run(invoke())
                     object: tool_declarations,
                 }),
             );
-            Some(Metadata { defs: Some(m) })
+            Some(Metadata {
+                def: None,
+                defs: Some(m),
+            })
         },
         description: Some(bee.workflow.workflow.name),
         role: None,
diff --git a/pdl-live-react/src-tauri/src/pdl/ast.rs b/pdl-live-react/src-tauri/src/pdl/ast.rs
index 8e5398f0b..599304208 100644
--- a/pdl-live-react/src-tauri/src/pdl/ast.rs
+++ b/pdl-live-react/src-tauri/src/pdl/ast.rs
@@ -56,6 +56,17 @@ pub enum PdlType {
 pub struct Metadata {
     #[serde(skip_serializing_if = "Option::is_none")]
     pub defs: Option<IndexMap<String, PdlBlock>>,
+
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub def: Option<String>,
+}
+impl Default for Metadata {
+    fn default() -> Self {
+        Self {
+            defs: None,
+            def: None,
+        }
+    }
 }
 
 /// Call a function
@@ -88,7 +99,6 @@ pub trait SequencingBlock {
     fn kind(&self) -> &str;
     fn description(&self) -> &Option<String>;
     fn role(&self) -> &Option<Role>;
-    fn def(&self) -> &Option<String>;
     fn metadata(&self) -> &Option<Metadata>;
     fn items(&self) -> &Vec<PdlBlock>;
     fn with_items(&self, items: Vec<PdlBlock>) -> Self;
@@ -118,9 +128,6 @@ pub struct LastOfBlock {
 
     #[serde(skip_serializing_if = "Option::is_none")]
     pub parser: Option<PdlParser>,
-
-    #[serde(skip_serializing_if = "Option::is_none")]
-    pub def: Option<String>,
 }
 impl SequencingBlock for LastOfBlock {
     fn kind(&self) -> &str {
@@ -132,9 +139,6 @@ impl SequencingBlock for LastOfBlock {
     fn role(&self) -> &Option<Role> {
         &self.role
     }
-    fn def(&self) -> &Option<String> {
-        return &self.def;
-    }
     fn metadata(&self) -> &Option<Metadata> {
         &self.metadata
     }
@@ -186,9 +190,6 @@ pub struct TextBlock {
 
     #[serde(skip_serializing_if = "Option::is_none")]
     pub parser: Option<PdlParser>,
-
-    #[serde(skip_serializing_if = "Option::is_none")]
-    pub def: Option<String>,
 }
 impl SequencingBlock for TextBlock {
     fn kind(&self) -> &str {
@@ -200,9 +201,6 @@ impl SequencingBlock for TextBlock {
     fn role(&self) -> &Option<Role> {
         &self.role
     }
-    fn def(&self) -> &Option<String> {
-        return &self.def;
-    }
     fn metadata(&self) -> &Option<Metadata> {
         &self.metadata
     }
@@ -237,7 +235,6 @@ impl SequencingBlock for TextBlock {
 impl TextBlock {
     pub fn new(text: Vec<PdlBlock>) -> Self {
         TextBlock {
-            def: None,
             metadata: None,
             description: None,
             role: None,
@@ -247,7 +244,16 @@ impl TextBlock {
     }
 
     pub fn def(&mut self, def: &str) -> &mut Self {
-        self.def = Some(def.into());
+        match &mut self.metadata {
+            Some(metadata) => {
+                metadata.def = Some(def.into());
+            }
+            None => {
+                let mut metadata: Metadata = Default::default();
+                metadata.def = Some(def.into());
+                self.metadata = Some(metadata);
+            }
+        }
         self
     }
 
@@ -295,12 +301,14 @@ pub struct PdlUsage {
 #[derive(Serialize, Deserialize, Debug, Clone)]
 #[serde(tag = "kind", rename = "model")]
 pub struct ModelBlock {
+    #[serde(flatten)]
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub metadata: Option<Metadata>,
+
     #[serde(skip_serializing_if = "Option::is_none")]
     pub description: Option<String>,
     pub model: String,
     #[serde(skip_serializing_if = "Option::is_none")]
-    pub def: Option<String>,
-    #[serde(skip_serializing_if = "Option::is_none")]
     pub parameters: Option<HashMap<String, Value>>,
     #[serde(skip_serializing_if = "Option::is_none")]
     pub input: Option<Box<PdlBlock>>,
@@ -318,7 +326,7 @@ pub struct ModelBlock {
 impl ModelBlock {
     pub fn new(model: &str) -> Self {
         ModelBlock {
-            def: None,
+            metadata: None,
             description: None,
             model_response: None,
             parameters: None,
@@ -433,15 +441,16 @@ pub struct ObjectBlock {
 #[derive(Serialize, Deserialize, Debug, Clone)]
 #[serde(tag = "kind")]
 pub struct DataBlock {
+    #[serde(flatten)]
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub metadata: Option<Metadata>,
+
     pub data: Value,
 
     /// Do not evaluate expressions inside strings.
     #[serde(skip_serializing_if = "Option::is_none")]
     pub raw: Option<bool>,
 
-    #[serde(skip_serializing_if = "Option::is_none")]
-    pub def: Option<String>,
-
     #[serde(skip_serializing_if = "Option::is_none")]
     pub parser: Option<PdlParser>,
 }
@@ -486,6 +495,10 @@ pub enum StringOrNull {
 #[derive(Serialize, Deserialize, Debug, Clone)]
 #[serde(tag = "kind", rename = "read")]
 pub struct ReadBlock {
+    #[serde(flatten)]
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub metadata: Option<Metadata>,
+
     /// Name of the file to read. If `None`, read the standard input.
     pub read: StringOrNull,
 
@@ -495,9 +508,6 @@ pub struct ReadBlock {
     /// Indicate if one or multiple lines should be read.
     pub multiline: Option<bool>,
 
-    #[serde(skip_serializing_if = "Option::is_none")]
-    pub def: Option<String>,
-
     #[serde(skip_serializing_if = "Option::is_none")]
     pub parser: Option<PdlParser>,
 }
diff --git a/pdl-live-react/src-tauri/src/pdl/interpreter.rs b/pdl-live-react/src-tauri/src/pdl/interpreter.rs
index 171a5d175..ba834127e 100644
--- a/pdl-live-react/src-tauri/src/pdl/interpreter.rs
+++ b/pdl-live-react/src-tauri/src/pdl/interpreter.rs
@@ -366,7 +366,7 @@ impl<'a> Interpreter<'a> {
         };
 
         let result = self.def(
-            &block.def,
+            &block.metadata.as_ref().and_then(|m| m.def.clone()),
             &buffer.clone().into(),
             &block.parser,
             state,
@@ -747,7 +747,7 @@ impl<'a> Interpreter<'a> {
         let mut trace = block.clone();
         if let Some(true) = block.raw {
             let result = self.def(
-                &block.def,
+                &block.metadata.as_ref().and_then(|m| m.def.clone()),
                 &resultify(&block.data),
                 &block.parser,
                 state,
@@ -756,7 +756,7 @@ impl<'a> Interpreter<'a> {
             Ok((result, vec![], PdlBlock::Data(trace)))
         } else {
             let result = self.def(
-                &block.def,
+                &block.metadata.as_ref().and_then(|m| m.def.clone()),
                 &self.eval_json(&block.data, state)?,
                 &block.parser,
                 state,
@@ -914,7 +914,7 @@ impl<'a> Interpreter<'a> {
 
         let trace = block.with_items(output_blocks);
         let result = self.def(
-            trace.def(),
+            &block.metadata().as_ref().and_then(|m| m.def.clone()),
             &trace.result_for(output_results),
             trace.parser(),
             state,