diff --git a/cxx/src/api/convert.cpp b/cxx/src/api/convert.cpp
index f2eeae7d..ee48b0b2 100644
--- a/cxx/src/api/convert.cpp
+++ b/cxx/src/api/convert.cpp
@@ -147,36 +147,21 @@ loot::Vertex convert(const loot::rust::Vertex& vertex) {
 }
 
 ::rust::Box<loot::rust::Group> convert(const loot::Group& group) {
-  auto output = loot::rust::new_group(group.GetName());
-  output->set_after_groups(convert(group.GetAfterGroups()));
-  output->set_description(group.GetDescription());
-
-  return output;
+  return loot::rust::new_group(
+      group.GetName(), group.GetDescription(), convert(group.GetAfterGroups()));
 }
 
 ::rust::Box<loot::rust::File> convert(const loot::File& file) {
-  auto output = loot::rust::new_file(std::string(file.GetName()));
-
-  if (!file.GetDisplayName().empty()) {
-    output->set_display_name(file.GetDisplayName());
-  }
-
   try {
-    output->set_detail(
-        ::rust::Slice(convert<loot::rust::MessageContent>(file.GetDetail())));
+    return loot::rust::new_file(
+        std::string(file.GetName()),
+        file.GetDisplayName(),
+        file.GetCondition(),
+        ::rust::Slice(convert<loot::rust::MessageContent>(file.GetDetail())),
+        file.GetConstraint());
   } catch (const ::rust::Error& e) {
     std::rethrow_exception(mapError(e));
   }
-
-  if (file.IsConditional()) {
-    output->set_condition(file.GetCondition());
-  }
-
-    if (!file.GetConstraint().empty()) {
-    output->set_constraint(file.GetConstraint());
-  }
-
-  return output;
 }
 
 loot::rust::MessageType convert(loot::MessageType messageType) {
@@ -194,24 +179,17 @@ loot::rust::MessageType convert(loot::MessageType messageType) {
 
 ::rust::Box<loot::rust::MessageContent> convert(
     const loot::MessageContent& content) {
-  auto output = loot::rust::new_message_content(content.GetText());
-  output->set_language(content.GetLanguage());
-
-  return output;
+  return loot::rust::new_message_content(content.GetText(),
+                                         content.GetLanguage());
 }
 
 ::rust::Box<loot::rust::Message> convert(const loot::Message& message) {
   try {
-    auto output = loot::rust::multilingual_message(
+    return loot::rust::multilingual_message(
         convert(message.GetType()),
         ::rust::Slice(
-            convert<loot::rust::MessageContent>(message.GetContent())));
-
-    if (message.IsConditional()) {
-      output->set_condition(message.GetCondition());
-    }
-
-    return output;
+            convert<loot::rust::MessageContent>(message.GetContent())),
+        message.GetCondition());
   } catch (const ::rust::Error& e) {
     std::rethrow_exception(mapError(e));
   }
@@ -222,13 +200,7 @@ loot::rust::MessageType convert(loot::MessageType messageType) {
     const auto suggestion = tag.IsAddition()
                                 ? loot::rust::TagSuggestion::Addition
                                 : loot::rust::TagSuggestion::Removal;
-    auto output = loot::rust::new_tag(tag.GetName(), suggestion);
-
-    if (tag.IsConditional()) {
-      output->set_condition(tag.GetCondition());
-    }
-
-    return output;
+    return loot::rust::new_tag(tag.GetName(), suggestion, tag.GetCondition());
   } catch (const ::rust::Error& e) {
     std::rethrow_exception(mapError(e));
   }
@@ -236,30 +208,21 @@ loot::rust::MessageType convert(loot::MessageType messageType) {
 
 ::rust::Box<loot::rust::PluginCleaningData> convert(
     const loot::PluginCleaningData& data) {
-  auto output = loot::rust::new_plugin_cleaning_data(data.GetCRC(),
-                                                     data.GetCleaningUtility());
   try {
-    output->set_detail(
-        ::rust::Slice(convert<loot::rust::MessageContent>(data.GetDetail())));
+    return loot::rust::new_plugin_cleaning_data(
+        data.GetCRC(),
+        data.GetCleaningUtility(),
+        ::rust::Slice(convert<loot::rust::MessageContent>(data.GetDetail())),
+        data.GetITMCount(),
+        data.GetDeletedReferenceCount(),
+        data.GetDeletedNavmeshCount());
   } catch (const ::rust::Error& e) {
     std::rethrow_exception(mapError(e));
   }
-
-  output->set_itm_count(data.GetITMCount());
-  output->set_deleted_reference_count(data.GetDeletedReferenceCount());
-  output->set_deleted_navmesh_count(data.GetDeletedNavmeshCount());
-
-  return output;
 }
 
 ::rust::Box<loot::rust::Location> convert(const loot::Location& location) {
-  auto output = loot::rust::new_location(location.GetURL());
-
-  if (!location.GetName().empty()) {
-    output->set_name(location.GetName());
-  }
-
-  return output;
+  return loot::rust::new_location(location.GetURL(), location.GetName());
 }
 
 ::rust::Box<loot::rust::PluginMetadata> convert(
diff --git a/cxx/src/lib.rs b/cxx/src/lib.rs
index 955cf93c..35d52565 100644
--- a/cxx/src/lib.rs
+++ b/cxx/src/lib.rs
@@ -383,11 +383,16 @@ mod ffi {
     extern "Rust" {
         type Message;
 
-        pub fn new_message(message_type: MessageType, content: String) -> Result<Box<Message>>;
+        pub fn new_message(
+            message_type: MessageType,
+            content: String,
+            condition: &str,
+        ) -> Result<Box<Message>>;
 
         pub fn multilingual_message(
             message_type: MessageType,
             contents: &[Box<MessageContent>],
+            condition: &str,
         ) -> Result<Box<Message>>;
 
         pub fn message_type(&self) -> MessageType;
@@ -396,8 +401,6 @@ mod ffi {
 
         pub fn condition(&self) -> &str;
 
-        pub fn set_condition(&mut self, condition: String);
-
         pub fn boxed_clone(&self) -> Box<Message>;
     }
 
@@ -406,21 +409,19 @@ mod ffi {
 
         pub fn message_content_default_language() -> &'static str;
 
-        pub fn new_message_content(text: String) -> Box<MessageContent>;
+        pub fn new_message_content(text: String, language: &str) -> Box<MessageContent>;
 
         pub fn text(&self) -> &str;
 
         pub fn language(&self) -> &str;
 
-        pub fn set_language(&mut self, language: String);
-
         pub fn boxed_clone(&self) -> Box<MessageContent>;
     }
 
     extern "Rust" {
         type Group;
 
-        pub fn new_group(name: String) -> Box<Group>;
+        pub fn new_group(name: String, description: &str, after_groups: Vec<String>) -> Box<Group>;
 
         pub fn group_default_name() -> &'static str;
 
@@ -430,11 +431,7 @@ mod ffi {
 
         pub fn description(&self) -> &str;
 
-        pub fn set_description(&mut self, description: String);
-
         pub fn after_groups(&self) -> &[String];
-
-        pub fn set_after_groups(&mut self, groups: Vec<String>);
     }
 
     extern "Rust" {
@@ -582,25 +579,31 @@ mod ffi {
     extern "Rust" {
         type File;
 
-        pub fn new_file(name: String) -> Box<File>;
+        pub fn new_file(
+            name: String,
+            display_name: &str,
+            condition: &str,
+            detail: &[Box<MessageContent>],
+            constraint: &str,
+        ) -> Result<Box<File>>;
 
         pub fn filename(&self) -> &Filename;
 
         pub fn display_name(&self) -> &str;
 
-        pub fn set_display_name(&mut self, display_name: String);
+        // pub fn set_display_name(&mut self, display_name: String);
 
         pub fn detail(&self) -> &[MessageContent];
 
-        pub fn set_detail(&mut self, detail: &[Box<MessageContent>]) -> Result<()>;
+        // pub fn set_detail(&mut self, detail: &[Box<MessageContent>]) -> Result<()>;
 
         pub fn condition(&self) -> &str;
 
-        pub fn set_condition(&mut self, condition: String);
+        // pub fn set_condition(&mut self, condition: String);
 
         pub fn constraint(&self) -> &str;
 
-        pub fn set_constraint(&mut self, constraint: String);
+        // pub fn set_constraint(&mut self, constraint: String);
 
         pub fn boxed_clone(&self) -> Box<File>;
     }
@@ -618,7 +621,11 @@ mod ffi {
     extern "Rust" {
         type Tag;
 
-        pub fn new_tag(name: String, suggestion: TagSuggestion) -> Result<Box<Tag>>;
+        pub fn new_tag(
+            name: String,
+            suggestion: TagSuggestion,
+            condition: &str,
+        ) -> Result<Box<Tag>>;
 
         pub fn name(&self) -> &str;
 
@@ -626,8 +633,6 @@ mod ffi {
 
         pub fn condition(&self) -> &str;
 
-        pub fn set_condition(&mut self, condition: String);
-
         pub fn boxed_clone(&self) -> Box<Tag>;
     }
 
@@ -637,42 +642,36 @@ mod ffi {
         pub fn new_plugin_cleaning_data(
             crc: u32,
             cleaning_utility: String,
-        ) -> Box<PluginCleaningData>;
+            detail: &[Box<MessageContent>],
+            itm_count: u32,
+            deleted_reference_count: u32,
+            deleted_navmesh_count: u32,
+        ) -> Result<Box<PluginCleaningData>>;
 
         pub fn crc(&self) -> u32;
 
         pub fn itm_count(&self) -> u32;
 
-        pub fn set_itm_count(&mut self, count: u32);
-
         pub fn deleted_reference_count(&self) -> u32;
 
-        pub fn set_deleted_reference_count(&mut self, count: u32);
-
         pub fn deleted_navmesh_count(&self) -> u32;
 
-        pub fn set_deleted_navmesh_count(&mut self, count: u32);
-
         pub fn cleaning_utility(&self) -> &str;
 
         pub fn detail(&self) -> &[MessageContent];
 
-        pub fn set_detail(&mut self, detail: &[Box<MessageContent>]) -> Result<()>;
-
         pub fn boxed_clone(&self) -> Box<PluginCleaningData>;
     }
 
     extern "Rust" {
         type Location;
 
-        pub fn new_location(url: String) -> Box<Location>;
+        pub fn new_location(url: String, name: &str) -> Box<Location>;
 
         pub fn url(&self) -> &str;
 
         pub fn name(&self) -> &str;
 
-        pub fn set_name(&mut self, name: String);
-
         pub fn boxed_clone(&self) -> Box<Location>;
     }
 }
diff --git a/cxx/src/metadata.rs b/cxx/src/metadata.rs
index 6758bb94..e2974289 100644
--- a/cxx/src/metadata.rs
+++ b/cxx/src/metadata.rs
@@ -68,8 +68,14 @@ impl TryFrom<MessageType> for libloot::metadata::MessageType {
 #[repr(transparent)]
 pub struct MessageContent(libloot::metadata::MessageContent);
 
-pub fn new_message_content(text: String) -> Box<MessageContent> {
-    Box::new(MessageContent(libloot::metadata::MessageContent::new(text)))
+pub fn new_message_content(text: String, language: &str) -> Box<MessageContent> {
+    let mut content = libloot::metadata::MessageContent::new(text);
+
+    if !language.is_empty() {
+        content = content.with_language(language.to_owned());
+    }
+
+    Box::new(MessageContent(content))
 }
 
 pub fn message_content_default_language() -> &'static str {
@@ -86,8 +92,6 @@ impl MessageContent {
             pub fn text(&self) -> &str;
 
             pub fn language(&self) -> &str;
-
-            pub fn set_language(&mut self, language: String);
         }
     }
 }
@@ -128,22 +132,31 @@ pub struct Message(libloot::metadata::Message);
 pub fn new_message(
     message_type: MessageType,
     content: String,
+    condition: &str,
 ) -> Result<Box<Message>, VerboseError> {
-    Ok(Box::new(Message(libloot::metadata::Message::new(
-        message_type.try_into()?,
-        content,
-    ))))
+    let mut message = libloot::metadata::Message::new(message_type.try_into()?, content);
+
+    if !condition.is_empty() {
+        message = message.with_condition(condition.to_owned());
+    }
+
+    Ok(Box::new(Message(message)))
 }
 
 pub fn multilingual_message(
     message_type: MessageType,
     contents: &[Box<MessageContent>],
+    condition: &str,
 ) -> Result<Box<Message>, VerboseError> {
     let contents = to_vec_of_unwrapped(contents);
-    Ok(Box::new(Message(libloot::metadata::Message::multilingual(
-        message_type.try_into()?,
-        contents,
-    )?)))
+
+    let mut message = libloot::metadata::Message::multilingual(message_type.try_into()?, contents)?;
+
+    if !condition.is_empty() {
+        message = message.with_condition(condition.to_owned());
+    }
+
+    Ok(Box::new(Message(message)))
 }
 
 impl Message {
@@ -163,8 +176,6 @@ impl Message {
         to self.0 {
             #[into]
             pub fn message_type(&self) -> MessageType;
-
-            pub fn set_condition(&mut self, condition: String);
         }
     }
 }
@@ -190,8 +201,18 @@ impl From<Box<Message>> for libloot::metadata::Message {
 #[repr(transparent)]
 pub struct Group(libloot::metadata::Group);
 
-pub fn new_group(name: String) -> Box<Group> {
-    Box::new(Group(libloot::metadata::Group::new(name)))
+pub fn new_group(name: String, description: &str, after_groups: Vec<String>) -> Box<Group> {
+    let mut group = libloot::metadata::Group::new(name);
+
+    if !description.is_empty() {
+        group = group.with_description(description.to_owned());
+    }
+
+    if !after_groups.is_empty() {
+        group = group.with_after_groups(after_groups);
+    }
+
+    Box::new(Group(group))
 }
 
 pub fn group_default_name() -> &'static str {
@@ -211,11 +232,7 @@ impl Group {
         to self.0 {
             pub fn name(&self) -> &str;
 
-            pub fn set_description(&mut self, description: String);
-
             pub fn after_groups(&self) -> &[String];
-
-            pub fn set_after_groups(&mut self, groups: Vec<String>);
         }
     }
 }
@@ -374,8 +391,32 @@ impl From<Option<PluginMetadata>> for Optional<PluginMetadata> {
 #[repr(transparent)]
 pub struct File(libloot::metadata::File);
 
-pub fn new_file(name: String) -> Box<File> {
-    Box::new(File(libloot::metadata::File::new(name)))
+pub fn new_file(
+    name: String,
+    display_name: &str,
+    condition: &str,
+    detail: &[Box<MessageContent>],
+    constraint: &str,
+) -> Result<Box<File>, VerboseError> {
+    let mut file = libloot::metadata::File::new(name);
+
+    if !display_name.is_empty() {
+        file = file.with_display_name(display_name.to_owned());
+    }
+
+    if !condition.is_empty() {
+        file = file.with_condition(condition.to_owned());
+    }
+
+    if !detail.is_empty() {
+        file = file.with_detail(to_vec_of_unwrapped(detail))?;
+    }
+
+    if !constraint.is_empty() {
+        file = file.with_constraint(constraint.to_owned());
+    }
+
+    Ok(Box::new(File(file)))
 }
 
 impl File {
@@ -387,34 +428,34 @@ impl File {
         self.0.display_name().unwrap_or("")
     }
 
-    pub fn set_display_name(&mut self, display_name: String) {
-        self.0.set_display_name(display_name);
-    }
+    // pub fn set_display_name(&mut self, display_name: String) {
+    //     self.0.set_display_name(display_name);
+    // }
 
     pub fn detail(&self) -> &[MessageContent] {
         MessageContent::wrap_slice(self.0.detail())
     }
 
-    pub fn set_detail(&mut self, detail: &[Box<MessageContent>]) -> Result<(), VerboseError> {
-        self.0.set_detail(to_vec_of_unwrapped(detail))?;
-        Ok(())
-    }
+    // pub fn set_detail(&mut self, detail: &[Box<MessageContent>]) -> Result<(), VerboseError> {
+    //     self.0.set_detail(to_vec_of_unwrapped(detail))?;
+    //     Ok(())
+    // }
 
     pub fn condition(&self) -> &str {
         self.0.condition().unwrap_or("")
     }
 
-    pub fn set_condition(&mut self, condition: String) {
-        self.0.set_condition(condition);
-    }
+    // pub fn set_condition(&mut self, condition: String) {
+    //     self.0.set_condition(condition);
+    // }
 
     pub fn constraint(&self) -> &str {
         self.0.constraint().unwrap_or("")
     }
 
-    pub fn set_constraint(&mut self, constraint: String) {
-        self.0.set_constraint(constraint);
-    }
+    // pub fn set_constraint(&mut self, constraint: String) {
+    //     self.0.set_constraint(constraint);
+    // }
 
     pub fn boxed_clone(&self) -> Box<Self> {
         Box::new(Self(self.0.clone()))
@@ -461,11 +502,18 @@ unsafe impl TransparentWrapper for Filename {
 #[repr(transparent)]
 pub struct Tag(libloot::metadata::Tag);
 
-pub fn new_tag(name: String, suggestion: TagSuggestion) -> Result<Box<Tag>, VerboseError> {
-    Ok(Box::new(Tag(libloot::metadata::Tag::new(
-        name,
-        suggestion.try_into()?,
-    ))))
+pub fn new_tag(
+    name: String,
+    suggestion: TagSuggestion,
+    condition: &str,
+) -> Result<Box<Tag>, VerboseError> {
+    let mut tag = libloot::metadata::Tag::new(name, suggestion.try_into()?);
+
+    if !condition.is_empty() {
+        tag = tag.with_condition(condition.to_owned());
+    }
+
+    Ok(Box::new(Tag(tag)))
 }
 
 impl Tag {
@@ -482,8 +530,6 @@ impl Tag {
             pub fn name(&self) -> &str;
 
             pub fn is_addition(&self) -> bool;
-
-            pub fn set_condition(&mut self, condition: String);
         }
     }
 }
@@ -515,10 +561,24 @@ impl TryFrom<TagSuggestion> for libloot::metadata::TagSuggestion {
 #[repr(transparent)]
 pub struct PluginCleaningData(libloot::metadata::PluginCleaningData);
 
-pub fn new_plugin_cleaning_data(crc: u32, cleaning_utility: String) -> Box<PluginCleaningData> {
-    Box::new(PluginCleaningData(
-        libloot::metadata::PluginCleaningData::new(crc, cleaning_utility),
-    ))
+pub fn new_plugin_cleaning_data(
+    crc: u32,
+    cleaning_utility: String,
+    detail: &[Box<MessageContent>],
+    itm_count: u32,
+    deleted_reference_count: u32,
+    deleted_navmesh_count: u32,
+) -> Result<Box<PluginCleaningData>, VerboseError> {
+    let mut data = libloot::metadata::PluginCleaningData::new(crc, cleaning_utility)
+        .with_itm_count(itm_count)
+        .with_deleted_reference_count(deleted_reference_count)
+        .with_deleted_navmesh_count(deleted_navmesh_count);
+
+    if !detail.is_empty() {
+        data = data.with_detail(to_vec_of_unwrapped(detail))?;
+    }
+
+    Ok(Box::new(PluginCleaningData(data)))
 }
 
 impl PluginCleaningData {
@@ -526,11 +586,6 @@ impl PluginCleaningData {
         MessageContent::wrap_slice(self.0.detail())
     }
 
-    pub fn set_detail(&mut self, detail: &[Box<MessageContent>]) -> Result<(), VerboseError> {
-        self.0.set_detail(to_vec_of_unwrapped(detail))?;
-        Ok(())
-    }
-
     pub fn boxed_clone(&self) -> Box<Self> {
         Box::new(Self(self.0.clone()))
     }
@@ -541,16 +596,10 @@ impl PluginCleaningData {
 
             pub fn itm_count(&self) -> u32;
 
-            pub fn set_itm_count(&mut self, count: u32);
-
             pub fn deleted_reference_count(&self) -> u32;
 
-            pub fn set_deleted_reference_count(&mut self, count: u32);
-
             pub fn deleted_navmesh_count(&self) -> u32;
 
-            pub fn set_deleted_navmesh_count(&mut self, count: u32);
-
             pub fn cleaning_utility(&self) -> &str;
         }
     }
@@ -571,8 +620,14 @@ impl From<Box<PluginCleaningData>> for libloot::metadata::PluginCleaningData {
 #[repr(transparent)]
 pub struct Location(libloot::metadata::Location);
 
-pub fn new_location(url: String) -> Box<Location> {
-    Box::new(Location(libloot::metadata::Location::new(url)))
+pub fn new_location(url: String, name: &str) -> Box<Location> {
+    let mut location = libloot::metadata::Location::new(url);
+
+    if !name.is_empty() {
+        location = location.with_name(name.to_owned());
+    }
+
+    Box::new(Location(location))
 }
 
 impl Location {
@@ -587,8 +642,6 @@ impl Location {
     delegate! {
         to self.0 {
             pub fn url(&self) -> &str;
-
-            pub fn set_name(&mut self, name: String);
         }
     }
 }
diff --git a/cxx/src/tests/api/internals/main.cpp b/cxx/src/tests/api/internals/main.cpp
index dbcf9c75..4a09bb8a 100644
--- a/cxx/src/tests/api/internals/main.cpp
+++ b/cxx/src/tests/api/internals/main.cpp
@@ -4,7 +4,6 @@
 
 #include "libloot-cxx/src/lib.rs.h"
 #include "rust/cxx.h"
-
 #include "tests/api/internals/metadata/conditional_metadata_test.h"
 #include "tests/api/internals/metadata/file_test.h"
 #include "tests/api/internals/metadata/group_test.h"
@@ -43,20 +42,18 @@ TEST(new_game, shouldThrowIfGivenNonsense) {
 }
 
 TEST(Message, creation) {
-  auto content = new_message_content("a message");
-  content->set_language(
+  auto content = new_message_content(
+      "a message",
       ::rust::String(std::string(message_content_default_language())));
 
-  auto message = new_message(MessageType::Say, "message2");
-  message->set_condition("invalid condition");
+  auto message = new_message(MessageType::Say, "message2", "invalid condition");
 
   std::vector<::rust::Box<MessageContent>> contents;
   contents.push_back(std::move(content));
   auto multi_message = multilingual_message(
       MessageType::Say,
-      ::rust::Slice<const ::rust::Box<MessageContent>>(contents));
-
-  multi_message->set_condition("invalid condition");
+      ::rust::Slice<const ::rust::Box<MessageContent>>(contents),
+      "invalid condition");
 
   EXPECT_EQ(multi_message->content()[0].text(), "a message");
   EXPECT_EQ(multi_message->content()[0].language(), "en");
diff --git a/nodejs/src/metadata.rs b/nodejs/src/metadata.rs
index 8ec7f881..2b113be4 100644
--- a/nodejs/src/metadata.rs
+++ b/nodejs/src/metadata.rs
@@ -24,11 +24,11 @@ impl Group {
         let mut group = libloot::metadata::Group::new(name);
 
         if let Some(description) = description {
-            group.set_description(description);
+            group = group.with_description(description);
         }
 
         if let Some(after_groups) = after_groups {
-            group.set_after_groups(after_groups);
+            group = group.with_after_groups(after_groups);
         }
 
         Self(group)
@@ -44,20 +44,10 @@ impl Group {
         self.0.description()
     }
 
-    #[napi(setter)]
-    pub fn set_description(&mut self, description: String) {
-        self.0.set_description(description);
-    }
-
     #[napi(getter)]
     pub fn after_groups(&self) -> Vec<String> {
         self.0.after_groups().to_vec()
     }
-
-    #[napi(setter)]
-    pub fn set_after_groups(&mut self, after_groups: Vec<String>) {
-        self.0.set_after_groups(after_groups);
-    }
 }
 
 impl From<libloot::metadata::Group> for Group {
@@ -89,7 +79,7 @@ impl MessageContent {
         let mut content = libloot::metadata::MessageContent::new(text);
 
         if let Some(language) = language {
-            content.set_language(language);
+            content = content.with_language(language);
         }
 
         Self(content)
@@ -104,11 +94,6 @@ impl MessageContent {
     pub fn language(&self) -> &str {
         self.0.language()
     }
-
-    #[napi(setter)]
-    pub fn set_language(&mut self, language: String) {
-        self.0.set_language(language);
-    }
 }
 
 impl From<libloot::metadata::MessageContent> for MessageContent {
@@ -184,7 +169,7 @@ impl Message {
         };
 
         if let Some(condition) = condition {
-            message.set_condition(condition);
+            message = message.with_condition(condition);
         }
 
         Ok(Self(message))
@@ -204,11 +189,6 @@ impl Message {
     pub fn condition(&self) -> Option<&str> {
         self.0.condition()
     }
-
-    #[napi(setter)]
-    pub fn set_condition(&mut self, condition: String) {
-        self.0.set_condition(condition);
-    }
 }
 
 impl From<libloot::metadata::Message> for Message {
@@ -241,20 +221,20 @@ impl File {
         let mut file = libloot::metadata::File::new(name);
 
         if let Some(display_name) = display_name {
-            file.set_display_name(display_name);
+            file = file.with_display_name(display_name);
         }
 
         if let Some(detail) = detail {
             let detail = detail.into_iter().cloned().map(Into::into).collect();
-            file.set_detail(detail)?;
+            file = file.with_detail(detail)?;
         }
 
         if let Some(condition) = condition {
-            file.set_condition(condition);
+            file = file.with_condition(condition);
         }
 
         if let Some(constraint) = constraint {
-            file.set_constraint(constraint);
+            file = file.with_constraint(constraint);
         }
 
         Ok(Self(file))
@@ -270,42 +250,20 @@ impl File {
         self.0.display_name()
     }
 
-    #[napi(setter)]
-    pub fn set_display_name(&mut self, description: String) {
-        self.0.set_display_name(description);
-    }
-
     #[napi(getter)]
     pub fn detail(&self) -> Vec<MessageContent> {
         self.0.detail().iter().cloned().map(Into::into).collect()
     }
 
-    #[napi(setter)]
-    pub fn set_detail(&mut self, detail: Vec<&MessageContent>) -> Result<(), VerboseError> {
-        let detail = detail.into_iter().cloned().map(Into::into).collect();
-        self.0.set_detail(detail)?;
-        Ok(())
-    }
-
     #[napi(getter)]
     pub fn condition(&self) -> Option<&str> {
         self.0.condition()
     }
 
-    #[napi(setter)]
-    pub fn set_condition(&mut self, condition: String) {
-        self.0.set_condition(condition);
-    }
-
     #[napi(getter)]
     pub fn constraint(&self) -> Option<&str> {
         self.0.constraint()
     }
-
-    #[napi(setter)]
-    pub fn set_constraint(&mut self, constraint: String) {
-        self.0.set_constraint(constraint);
-    }
 }
 
 impl From<libloot::metadata::File> for File {
@@ -363,20 +321,20 @@ impl PluginCleaningData {
         let mut data = libloot::metadata::PluginCleaningData::new(crc, cleaning_utility);
 
         if let Some(count) = itm_count {
-            data.set_itm_count(count);
+            data = data.with_itm_count(count);
         }
 
         if let Some(count) = deleted_reference_count {
-            data.set_deleted_reference_count(count);
+            data = data.with_deleted_reference_count(count);
         }
 
         if let Some(count) = deleted_navmesh_count {
-            data.set_deleted_navmesh_count(count);
+            data = data.with_deleted_navmesh_count(count);
         }
 
         if let Some(detail) = detail {
             let detail = detail.into_iter().cloned().map(Into::into).collect();
-            data.set_detail(detail)?;
+            data = data.with_detail(detail)?;
         }
 
         Ok(Self(data))
@@ -392,31 +350,16 @@ impl PluginCleaningData {
         self.0.itm_count()
     }
 
-    #[napi(setter)]
-    pub fn set_itm_count(&mut self, count: u32) {
-        self.0.set_itm_count(count);
-    }
-
     #[napi(getter)]
     pub fn deleted_reference_count(&self) -> u32 {
         self.0.deleted_reference_count()
     }
 
-    #[napi(setter)]
-    pub fn set_deleted_reference_count(&mut self, count: u32) {
-        self.0.set_deleted_reference_count(count);
-    }
-
     #[napi(getter)]
     pub fn deleted_navmesh_count(&self) -> u32 {
         self.0.deleted_navmesh_count()
     }
 
-    #[napi(setter)]
-    pub fn set_deleted_navmesh_count(&mut self, count: u32) {
-        self.0.set_deleted_navmesh_count(count);
-    }
-
     #[napi(getter)]
     pub fn cleaning_utility(&self) -> &str {
         self.0.cleaning_utility()
@@ -426,13 +369,6 @@ impl PluginCleaningData {
     pub fn detail(&self) -> Vec<MessageContent> {
         self.0.detail().iter().cloned().map(Into::into).collect()
     }
-
-    #[napi(setter)]
-    pub fn set_detail(&mut self, detail: Vec<&MessageContent>) -> Result<(), VerboseError> {
-        let detail = detail.into_iter().cloned().map(Into::into).collect();
-        self.0.set_detail(detail)?;
-        Ok(())
-    }
 }
 
 impl From<libloot::metadata::PluginCleaningData> for PluginCleaningData {
@@ -475,7 +411,7 @@ impl Tag {
         let mut tag = libloot::metadata::Tag::new(name, suggestion.into());
 
         if let Some(condition) = condition {
-            tag.set_condition(condition);
+            tag = tag.with_condition(condition);
         }
 
         Self(tag)
@@ -495,11 +431,6 @@ impl Tag {
     pub fn condition(&self) -> Option<&str> {
         self.0.condition()
     }
-
-    #[napi(setter)]
-    pub fn set_condition(&mut self, condition: String) {
-        self.0.set_condition(condition);
-    }
 }
 
 impl From<libloot::metadata::Tag> for Tag {
@@ -526,7 +457,7 @@ impl Location {
         let mut location = libloot::metadata::Location::new(url);
 
         if let Some(name) = name {
-            location.set_name(name);
+            location = location.with_name(name);
         }
 
         Self(location)
@@ -541,11 +472,6 @@ impl Location {
     pub fn name(&self) -> Option<&str> {
         self.0.name()
     }
-
-    #[napi(setter)]
-    pub fn set_name(&mut self, name: String) {
-        self.0.set_name(name);
-    }
 }
 
 impl From<libloot::metadata::Location> for Location {
diff --git a/pyo3/src/metadata.rs b/pyo3/src/metadata.rs
index c5b2539e..42b310b0 100644
--- a/pyo3/src/metadata.rs
+++ b/pyo3/src/metadata.rs
@@ -10,7 +10,7 @@ use crate::error::VerboseError;
 
 pub(crate) const NONE_REPR: &str = "None";
 
-#[pyclass(eq, ord, str = "{0:?}")]
+#[pyclass(eq, ord, frozen, hash, str = "{0:?}")]
 #[repr(transparent)]
 #[derive(Clone, Debug, Default, Eq, PartialEq, Ord, PartialOrd, Hash)]
 pub struct Group(libloot::metadata::Group);
@@ -28,11 +28,11 @@ impl Group {
         let mut group = libloot::metadata::Group::new(name);
 
         if let Some(description) = description {
-            group.set_description(description);
+            group = group.with_description(description);
         }
 
         if let Some(after_groups) = after_groups {
-            group.set_after_groups(after_groups);
+            group = group.with_after_groups(after_groups);
         }
 
         Self(group)
@@ -48,21 +48,11 @@ impl Group {
         self.0.description()
     }
 
-    #[setter]
-    fn set_description(&mut self, description: String) {
-        self.0.set_description(description);
-    }
-
     #[getter]
     fn after_groups(&self) -> &[String] {
         self.0.after_groups()
     }
 
-    #[setter]
-    fn set_after_groups(&mut self, after_groups: Vec<String>) {
-        self.0.set_after_groups(after_groups);
-    }
-
     fn __repr__(slf: &Bound<'_, Self>) -> PyResult<String> {
         let class_name = slf.get_type().qualname()?;
         let inner = &slf.borrow().0;
@@ -74,12 +64,6 @@ impl Group {
             inner.after_groups().join(",")
         ))
     }
-
-    fn __hash__(&self) -> u64 {
-        let mut hasher = DefaultHasher::new();
-        self.0.hash(&mut hasher);
-        hasher.finish()
-    }
 }
 
 impl From<libloot::metadata::Group> for Group {
@@ -94,7 +78,7 @@ impl From<Group> for libloot::metadata::Group {
     }
 }
 
-#[pyclass(eq, ord, str = "{0:?}")]
+#[pyclass(eq, ord, frozen, hash, str = "{0:?}")]
 #[repr(transparent)]
 #[derive(Clone, Debug, Default, Eq, PartialEq, Ord, PartialOrd, Hash)]
 pub struct MessageContent(libloot::metadata::MessageContent);
@@ -112,7 +96,7 @@ impl MessageContent {
         let mut content = libloot::metadata::MessageContent::new(text);
 
         if let Some(language) = language {
-            content.set_language(language);
+            content = content.with_language(language);
         }
 
         Self(content)
@@ -128,11 +112,6 @@ impl MessageContent {
         self.0.language()
     }
 
-    #[setter]
-    fn set_language(&mut self, language: String) {
-        self.0.set_language(language);
-    }
-
     fn __repr__(slf: &Bound<'_, Self>) -> PyResult<String> {
         let class_name = slf.get_type().qualname()?;
         let inner = &slf.borrow().0;
@@ -143,12 +122,6 @@ impl MessageContent {
             inner.language()
         ))
     }
-
-    fn __hash__(&self) -> u64 {
-        let mut hasher = DefaultHasher::new();
-        self.0.hash(&mut hasher);
-        hasher.finish()
-    }
 }
 
 impl From<libloot::metadata::MessageContent> for MessageContent {
@@ -214,7 +187,7 @@ impl From<MessageType> for libloot::metadata::MessageType {
     }
 }
 
-#[pyclass(eq, ord, str = "{0:?}")]
+#[pyclass(eq, ord, frozen, hash, str = "{0:?}")]
 #[derive(Clone, Debug, Default, Eq, PartialEq, Ord, PartialOrd, Hash)]
 #[repr(transparent)]
 pub struct Message(libloot::metadata::Message);
@@ -245,7 +218,7 @@ impl Message {
         };
 
         if let Some(condition) = condition {
-            message.set_condition(condition);
+            message = message.with_condition(condition);
         }
 
         Ok(Self(message))
@@ -266,11 +239,6 @@ impl Message {
         self.0.condition()
     }
 
-    #[setter]
-    fn set_condition(&mut self, condition: String) {
-        self.0.set_condition(condition);
-    }
-
     fn __repr__(slf: &Bound<'_, Self>) -> PyResult<String> {
         let class_name = slf.get_type().qualname()?;
         let inner = &slf.borrow().0;
@@ -282,12 +250,6 @@ impl Message {
             inner.condition().unwrap_or(NONE_REPR),
         ))
     }
-
-    fn __hash__(&self) -> u64 {
-        let mut hasher = DefaultHasher::new();
-        self.0.hash(&mut hasher);
-        hasher.finish()
-    }
 }
 
 impl From<libloot::metadata::Message> for Message {
@@ -302,7 +264,7 @@ impl From<Message> for libloot::metadata::Message {
     }
 }
 
-#[pyclass(eq, ord, str = "{0:?}")]
+#[pyclass(eq, ord, frozen, hash, str = "{0:?}")]
 #[derive(Clone, Debug, Default, Eq, PartialEq, Ord, PartialOrd, Hash)]
 #[repr(transparent)]
 pub struct File(libloot::metadata::File);
@@ -321,20 +283,20 @@ impl File {
         let mut file = libloot::metadata::File::new(name);
 
         if let Some(display_name) = display_name {
-            file.set_display_name(display_name);
+            file = file.with_display_name(display_name);
         }
 
         if let Some(detail) = detail {
             let detail = detail.into_iter().map(Into::into).collect();
-            file.set_detail(detail)?;
+            file = file.with_detail(detail)?;
         }
 
         if let Some(condition) = condition {
-            file.set_condition(condition);
+            file = file.with_condition(condition);
         }
 
         if let Some(constraint) = constraint {
-            file.set_constraint(constraint);
+            file = file.with_constraint(constraint);
         }
 
         Ok(Self(file))
@@ -350,43 +312,21 @@ impl File {
         self.0.display_name()
     }
 
-    #[setter]
-    fn set_display_name(&mut self, description: String) {
-        self.0.set_display_name(description);
-    }
-
     #[getter]
     fn detail(&self) -> Vec<MessageContent> {
         self.0.detail().iter().cloned().map(Into::into).collect()
     }
 
-    #[setter]
-    fn set_detail(&mut self, detail: Vec<MessageContent>) -> Result<(), VerboseError> {
-        let detail = detail.into_iter().map(Into::into).collect();
-        self.0.set_detail(detail)?;
-        Ok(())
-    }
-
     #[getter]
     fn condition(&self) -> Option<&str> {
         self.0.condition()
     }
 
-    #[setter]
-    fn set_condition(&mut self, condition: String) {
-        self.0.set_condition(condition);
-    }
-
     #[getter]
     fn constraint(&self) -> Option<&str> {
         self.0.constraint()
     }
 
-    #[setter]
-    fn set_constraint(&mut self, constraint: String) {
-        self.0.set_constraint(constraint);
-    }
-
     fn __repr__(slf: &Bound<'_, Self>) -> PyResult<String> {
         let class_name = slf.get_type().qualname()?;
         let inner = &slf.borrow().0;
@@ -400,12 +340,6 @@ impl File {
             inner.constraint().unwrap_or(NONE_REPR)
         ))
     }
-
-    fn __hash__(&self) -> u64 {
-        let mut hasher = DefaultHasher::new();
-        self.0.hash(&mut hasher);
-        hasher.finish()
-    }
 }
 
 impl From<libloot::metadata::File> for File {
@@ -420,7 +354,7 @@ impl From<File> for libloot::metadata::File {
     }
 }
 
-#[pyclass(eq, ord, str = "{0:?}")]
+#[pyclass(eq, ord, frozen, hash, str = "{0:?}")]
 #[derive(Clone, Debug, Default, Eq, PartialEq, Ord, PartialOrd, Hash)]
 #[repr(transparent)]
 pub struct Filename(libloot::metadata::Filename);
@@ -441,12 +375,6 @@ impl Filename {
         let inner = &slf.borrow().0;
         Ok(format!("{}({})", class_name, inner.as_str(),))
     }
-
-    fn __hash__(&self) -> u64 {
-        let mut hasher = DefaultHasher::new();
-        self.0.hash(&mut hasher);
-        hasher.finish()
-    }
 }
 
 impl From<libloot::metadata::Filename> for Filename {
@@ -455,7 +383,7 @@ impl From<libloot::metadata::Filename> for Filename {
     }
 }
 
-#[pyclass(eq, ord, str = "{0:?}")]
+#[pyclass(eq, ord, frozen, hash, str = "{0:?}")]
 #[derive(Clone, Debug, Default, Eq, PartialEq, Ord, PartialOrd, Hash)]
 #[repr(transparent)]
 pub struct PluginCleaningData(libloot::metadata::PluginCleaningData);
@@ -475,20 +403,20 @@ impl PluginCleaningData {
         let mut data = libloot::metadata::PluginCleaningData::new(crc, cleaning_utility);
 
         if let Some(count) = itm_count {
-            data.set_itm_count(count);
+            data = data.with_itm_count(count);
         }
 
         if let Some(count) = deleted_reference_count {
-            data.set_deleted_reference_count(count);
+            data = data.with_deleted_reference_count(count);
         }
 
         if let Some(count) = deleted_navmesh_count {
-            data.set_deleted_navmesh_count(count);
+            data = data.with_deleted_navmesh_count(count);
         }
 
         if let Some(detail) = detail {
             let detail = detail.into_iter().map(Into::into).collect();
-            data.set_detail(detail)?;
+            data = data.with_detail(detail)?;
         }
 
         Ok(Self(data))
@@ -504,31 +432,16 @@ impl PluginCleaningData {
         self.0.itm_count()
     }
 
-    #[setter]
-    fn set_itm_count(&mut self, count: u32) {
-        self.0.set_itm_count(count);
-    }
-
     #[getter]
     fn deleted_reference_count(&self) -> u32 {
         self.0.deleted_reference_count()
     }
 
-    #[setter]
-    fn set_deleted_reference_count(&mut self, count: u32) {
-        self.0.set_deleted_reference_count(count);
-    }
-
     #[getter]
     fn deleted_navmesh_count(&self) -> u32 {
         self.0.deleted_navmesh_count()
     }
 
-    #[setter]
-    fn set_deleted_navmesh_count(&mut self, count: u32) {
-        self.0.set_deleted_navmesh_count(count);
-    }
-
     #[getter]
     fn cleaning_utility(&self) -> &str {
         self.0.cleaning_utility()
@@ -539,13 +452,6 @@ impl PluginCleaningData {
         self.0.detail().iter().cloned().map(Into::into).collect()
     }
 
-    #[setter]
-    fn set_detail(&mut self, detail: Vec<MessageContent>) -> Result<(), VerboseError> {
-        let detail = detail.into_iter().map(Into::into).collect();
-        self.0.set_detail(detail)?;
-        Ok(())
-    }
-
     fn __repr__(slf: &Bound<'_, Self>) -> PyResult<String> {
         let class_name = slf.get_type().qualname()?;
         let inner = &slf.borrow().0;
@@ -560,12 +466,6 @@ impl PluginCleaningData {
             repr_message_contents(inner.detail())
         ))
     }
-
-    fn __hash__(&self) -> u64 {
-        let mut hasher = DefaultHasher::new();
-        self.0.hash(&mut hasher);
-        hasher.finish()
-    }
 }
 
 impl From<libloot::metadata::PluginCleaningData> for PluginCleaningData {
@@ -598,7 +498,7 @@ impl TryFrom<TagSuggestion> for libloot::metadata::TagSuggestion {
     }
 }
 
-#[pyclass(eq, ord, str = "{0:?}")]
+#[pyclass(eq, ord, frozen, hash, str = "{0:?}")]
 #[derive(Clone, Debug, Default, Eq, PartialEq, Ord, PartialOrd, Hash)]
 #[repr(transparent)]
 pub struct Tag(libloot::metadata::Tag);
@@ -615,7 +515,7 @@ impl Tag {
         let mut tag = libloot::metadata::Tag::new(name, suggestion.try_into()?);
 
         if let Some(condition) = condition {
-            tag.set_condition(condition);
+            tag = tag.with_condition(condition);
         }
 
         Ok(Self(tag))
@@ -636,11 +536,6 @@ impl Tag {
         self.0.condition()
     }
 
-    #[setter]
-    fn set_condition(&mut self, condition: String) {
-        self.0.set_condition(condition);
-    }
-
     fn __repr__(slf: &Bound<'_, Self>) -> PyResult<String> {
         let class_name = slf.get_type().qualname()?;
         let inner = &slf.borrow().0;
@@ -657,12 +552,6 @@ impl Tag {
             inner.condition().unwrap_or(NONE_REPR)
         ))
     }
-
-    fn __hash__(&self) -> u64 {
-        let mut hasher = DefaultHasher::new();
-        self.0.hash(&mut hasher);
-        hasher.finish()
-    }
 }
 
 impl From<libloot::metadata::Tag> for Tag {
@@ -677,7 +566,7 @@ impl From<Tag> for libloot::metadata::Tag {
     }
 }
 
-#[pyclass(eq, ord, str = "{0:?}")]
+#[pyclass(eq, ord, frozen, hash, str = "{0:?}")]
 #[derive(Clone, Debug, Default, Eq, PartialEq, Ord, PartialOrd, Hash)]
 #[repr(transparent)]
 pub struct Location(libloot::metadata::Location);
@@ -690,7 +579,7 @@ impl Location {
         let mut location = libloot::metadata::Location::new(url);
 
         if let Some(name) = name {
-            location.set_name(name);
+            location = location.with_name(name);
         }
 
         Self(location)
@@ -706,11 +595,6 @@ impl Location {
         self.0.name()
     }
 
-    #[setter]
-    fn set_name(&mut self, name: String) {
-        self.0.set_name(name);
-    }
-
     fn __repr__(slf: &Bound<'_, Self>) -> PyResult<String> {
         let class_name = slf.get_type().qualname()?;
         let inner = &slf.borrow().0;
@@ -721,12 +605,6 @@ impl Location {
             inner.name().unwrap_or(NONE_REPR)
         ))
     }
-
-    fn __hash__(&self) -> u64 {
-        let mut hasher = DefaultHasher::new();
-        self.0.hash(&mut hasher);
-        hasher.finish()
-    }
 }
 
 impl From<libloot::metadata::Location> for Location {
diff --git a/src/metadata/file.rs b/src/metadata/file.rs
index 7ac5b102..ca1deec8 100644
--- a/src/metadata/file.rs
+++ b/src/metadata/file.rs
@@ -38,14 +38,14 @@ impl File {
     /// CommonMark.
     #[must_use]
     pub fn with_display_name(mut self, display_name: String) -> Self {
-        self.set_display_name(display_name);
+        self.display_name = Some(display_name.into_boxed_str());
         self
     }
 
     /// Set the condition string.
     #[must_use]
     pub fn with_condition(mut self, condition: String) -> Self {
-        self.set_condition(condition);
+        self.condition = Some(condition.into_boxed_str());
         self
     }
 
@@ -56,14 +56,15 @@ impl File {
         mut self,
         detail: Vec<MessageContent>,
     ) -> Result<Self, MultilingualMessageContentsError> {
-        self.set_detail(detail)?;
+        validate_message_contents(&detail)?;
+        self.detail = detail.into_boxed_slice();
         Ok(self)
     }
 
     /// Set the constraint string.
     #[must_use]
     pub fn with_constraint(mut self, constraint: String) -> Self {
-        self.set_constraint(constraint);
+        self.constraint = Some(constraint.into_boxed_str());
         self
     }
 
@@ -77,13 +78,6 @@ impl File {
         self.display_name.as_deref()
     }
 
-    /// Set the name to be displayed for the file in messages, formatted using
-    /// CommonMark.
-    pub fn set_display_name(&mut self, display_name: String) -> &mut Self {
-        self.display_name = Some(display_name.into_boxed_str());
-        self
-    }
-
     /// Get the detail message content of the file.
     ///
     /// If this file causes an error message to be displayed, the detail message
@@ -93,39 +87,15 @@ impl File {
         &self.detail
     }
 
-    /// Set the detail message content, which may be appended to any messages
-    /// generated for this file. If multilingual, one language must be
-    /// [MessageContent::DEFAULT_LANGUAGE].
-    pub fn set_detail(
-        &mut self,
-        detail: Vec<MessageContent>,
-    ) -> Result<&mut Self, MultilingualMessageContentsError> {
-        validate_message_contents(&detail)?;
-        self.detail = detail.into_boxed_slice();
-        Ok(self)
-    }
-
     /// Get the condition string.
     pub fn condition(&self) -> Option<&str> {
         self.condition.as_deref()
     }
 
-    /// Set the condition string.
-    pub fn set_condition(&mut self, condition: String) -> &mut Self {
-        self.condition = Some(condition.into_boxed_str());
-        self
-    }
-
     /// Get the constraint string.
     pub fn constraint(&self) -> Option<&str> {
         self.constraint.as_deref()
     }
-
-    /// Set the constraint string.
-    pub fn set_constraint(&mut self, constraint: String) -> &mut Self {
-        self.constraint = Some(constraint.into_boxed_str());
-        self
-    }
 }
 
 /// Represents a case-insensitive filename.
diff --git a/src/metadata/group.rs b/src/metadata/group.rs
index 14615acd..f37dfc7c 100644
--- a/src/metadata/group.rs
+++ b/src/metadata/group.rs
@@ -29,14 +29,14 @@ impl Group {
     /// Set a description for the group.
     #[must_use]
     pub fn with_description(mut self, description: String) -> Self {
-        self.set_description(description);
+        self.description = Some(description.into_boxed_str());
         self
     }
 
     /// Set the names of the groups that this group loads after.
     #[must_use]
     pub fn with_after_groups(mut self, after_groups: Vec<String>) -> Self {
-        self.set_after_groups(after_groups);
+        self.after_groups = after_groups.into_boxed_slice();
         self
     }
 
@@ -53,22 +53,10 @@ impl Group {
         self.description.as_deref()
     }
 
-    /// Set a description for the group.
-    pub fn set_description(&mut self, description: String) -> &mut Self {
-        self.description = Some(description.into_boxed_str());
-        self
-    }
-
     /// Get the names of the groups that this group loads after.
     pub fn after_groups(&self) -> &[String] {
         &self.after_groups
     }
-
-    /// Set the names of the groups that this group loads after.
-    pub fn set_after_groups(&mut self, after_groups: Vec<String>) -> &mut Self {
-        self.after_groups = after_groups.into_boxed_slice();
-        self
-    }
 }
 
 impl std::default::Default for Group {
diff --git a/src/metadata/location.rs b/src/metadata/location.rs
index 606f2eda..86348ddf 100644
--- a/src/metadata/location.rs
+++ b/src/metadata/location.rs
@@ -25,7 +25,7 @@ impl Location {
     /// Set a name for the URL, eg. the page or site name.
     #[must_use]
     pub fn with_name(mut self, name: String) -> Self {
-        self.set_name(name);
+        self.name = Some(name.into_boxed_str());
         self
     }
 
@@ -38,12 +38,6 @@ impl Location {
     pub fn name(&self) -> Option<&str> {
         self.name.as_deref()
     }
-
-    /// Set a name for the URL, eg. the page or site name.
-    pub fn set_name(&mut self, name: String) -> &mut Self {
-        self.name = Some(name.into_boxed_str());
-        self
-    }
 }
 
 impl TryFromYaml for Location {
diff --git a/src/metadata/message.rs b/src/metadata/message.rs
index 19f1bb15..0a780661 100644
--- a/src/metadata/message.rs
+++ b/src/metadata/message.rs
@@ -64,7 +64,7 @@ impl MessageContent {
     /// Set the language code to the given value.
     #[must_use]
     pub fn with_language(mut self, language: String) -> Self {
-        self.set_language(language);
+        self.language = language.into_boxed_str();
         self
     }
 
@@ -77,12 +77,6 @@ impl MessageContent {
     pub fn language(&self) -> &str {
         &self.language
     }
-
-    /// Set the language code to the given value.
-    pub fn set_language(&mut self, language: String) -> &mut Self {
-        self.language = language.into_boxed_str();
-        self
-    }
 }
 
 impl std::default::Default for MessageContent {
@@ -196,7 +190,7 @@ impl Message {
     /// Set the condition string.
     #[must_use]
     pub fn with_condition(mut self, condition: String) -> Self {
-        self.set_condition(condition);
+        self.condition = Some(condition.into_boxed_str());
         self
     }
 
@@ -214,12 +208,6 @@ impl Message {
     pub fn condition(&self) -> Option<&str> {
         self.condition.as_deref()
     }
-
-    /// Set the condition string.
-    pub fn set_condition(&mut self, condition: String) -> &mut Self {
-        self.condition = Some(condition.into_boxed_str());
-        self
-    }
 }
 
 pub(crate) fn validate_message_contents(
diff --git a/src/metadata/plugin_cleaning_data.rs b/src/metadata/plugin_cleaning_data.rs
index ee3f28ee..7dac15ed 100644
--- a/src/metadata/plugin_cleaning_data.rs
+++ b/src/metadata/plugin_cleaning_data.rs
@@ -40,21 +40,21 @@ impl PluginCleaningData {
     /// Set the number of Identical To Master records found in the plugin.
     #[must_use]
     pub fn with_itm_count(mut self, itm_count: u32) -> Self {
-        self.set_itm_count(itm_count);
+        self.itm_count = itm_count;
         self
     }
 
     /// Set the number of deleted references found in the plugin.
     #[must_use]
     pub fn with_deleted_reference_count(mut self, deleted_reference_count: u32) -> Self {
-        self.set_deleted_reference_count(deleted_reference_count);
+        self.deleted_reference_count = deleted_reference_count;
         self
     }
 
     /// Set the number of deleted navmeshes found in the plugin.
     #[must_use]
     pub fn with_deleted_navmesh_count(mut self, deleted_navmesh_count: u32) -> Self {
-        self.set_deleted_navmesh_count(deleted_navmesh_count);
+        self.deleted_navmesh_count = deleted_navmesh_count;
         self
     }
 
@@ -65,7 +65,8 @@ impl PluginCleaningData {
         mut self,
         detail: Vec<MessageContent>,
     ) -> Result<Self, MultilingualMessageContentsError> {
-        self.set_detail(detail)?;
+        validate_message_contents(&detail)?;
+        self.detail = detail.into_boxed_slice();
         Ok(self)
     }
 
@@ -79,34 +80,16 @@ impl PluginCleaningData {
         self.itm_count
     }
 
-    /// Set the number of Identical To Master records found in the plugin.
-    pub fn set_itm_count(&mut self, itm_count: u32) -> &mut Self {
-        self.itm_count = itm_count;
-        self
-    }
-
     /// Get the number of deleted references found in the plugin.
     pub fn deleted_reference_count(&self) -> u32 {
         self.deleted_reference_count
     }
 
-    /// Set the number of deleted references found in the plugin.
-    pub fn set_deleted_reference_count(&mut self, deleted_reference_count: u32) -> &mut Self {
-        self.deleted_reference_count = deleted_reference_count;
-        self
-    }
-
     /// Get the number of deleted navmeshes found in the plugin.
     pub fn deleted_navmesh_count(&self) -> u32 {
         self.deleted_navmesh_count
     }
 
-    /// Set the number of deleted navmeshes found in the plugin.
-    pub fn set_deleted_navmesh_count(&mut self, deleted_navmesh_count: u32) -> &mut Self {
-        self.deleted_navmesh_count = deleted_navmesh_count;
-        self
-    }
-
     /// Get the cleaning utility that was used to check the plugin.
     ///
     /// The string may include a cleaning utility name, possibly related
@@ -122,18 +105,6 @@ impl PluginCleaningData {
     pub fn detail(&self) -> &[MessageContent] {
         &self.detail
     }
-
-    /// Set the detail message content, which may be appended to any messages
-    /// generated for this cleaning data. If multilingual, one language must be
-    /// [MessageContent::DEFAULT_LANGUAGE].
-    pub fn set_detail(
-        &mut self,
-        detail: Vec<MessageContent>,
-    ) -> Result<&mut Self, MultilingualMessageContentsError> {
-        validate_message_contents(&detail)?;
-        self.detail = detail.into_boxed_slice();
-        Ok(self)
-    }
 }
 
 impl TryFromYaml for PluginCleaningData {
diff --git a/src/metadata/tag.rs b/src/metadata/tag.rs
index be2b7e72..08edd9e5 100644
--- a/src/metadata/tag.rs
+++ b/src/metadata/tag.rs
@@ -38,7 +38,7 @@ impl Tag {
     /// Set the condition string.
     #[must_use]
     pub fn with_condition(mut self, condition: String) -> Self {
-        self.set_condition(condition);
+        self.condition = Some(condition.into_boxed_str());
         self
     }
 
@@ -56,12 +56,6 @@ impl Tag {
     pub fn condition(&self) -> Option<&str> {
         self.condition.as_deref()
     }
-
-    /// Set the condition string.
-    pub fn set_condition(&mut self, condition: String) -> &mut Self {
-        self.condition = Some(condition.into_boxed_str());
-        self
-    }
 }
 
 impl TryFromYaml for Tag {