diff --git a/src/metadata/message.rs b/src/metadata/message.rs
index 55d424d5..ea176358 100644
--- a/src/metadata/message.rs
+++ b/src/metadata/message.rs
@@ -263,7 +263,7 @@ pub(crate) fn parse_message_contents_yaml(
     key: &'static str,
     parent_yaml_type: YamlObjectType,
 ) -> Result<Vec<MessageContent>, ParseMetadataError> {
-    let contents = match &value.data {
+    let mut contents = match &value.data {
         YamlData::String(s) => {
             vec![MessageContent::new(s.clone())]
         }
@@ -281,6 +281,8 @@ pub(crate) fn parse_message_contents_yaml(
         }
     };
 
+    contents.shrink_to_fit();
+
     if validate_message_contents(&contents).is_err() {
         Err(ParseMetadataError::new(
             value.span.start,
diff --git a/src/metadata/plugin_metadata.rs b/src/metadata/plugin_metadata.rs
index 880f4b04..38316265 100644
--- a/src/metadata/plugin_metadata.rs
+++ b/src/metadata/plugin_metadata.rs
@@ -377,10 +377,14 @@ fn get_vec<'a, T: TryFrom<&'a MarkedYaml, Error = impl Into<ParseMetadataError>>
     hash: &'a saphyr::AnnotatedHash<MarkedYaml>,
     key: &'static str,
 ) -> Result<Vec<T>, ParseMetadataError> {
-    get_as_slice(hash, key, YamlObjectType::PluginMetadata)?
+    let mut vec = get_as_slice(hash, key, YamlObjectType::PluginMetadata)?
         .iter()
         .map(|e| T::try_from(e).map_err(Into::into))
-        .collect::<Result<Vec<T>, _>>()
+        .collect::<Result<Vec<T>, _>>()?;
+
+    vec.shrink_to_fit();
+
+    Ok(vec)
 }
 
 impl EmitYaml for PluginMetadata {