diff --git a/main/lib/helgoboss-learn b/main/lib/helgoboss-learn
index 41f3f1320..0c3a1cd04 160000
--- a/main/lib/helgoboss-learn
+++ b/main/lib/helgoboss-learn
@@ -1 +1 @@
-Subproject commit 41f3f1320953645a9795b723f04d207c72a40d6f
+Subproject commit 0c3a1cd04da93387e0dc52612b0e562ab42bd961
diff --git a/main/src/application/unit_model.rs b/main/src/application/unit_model.rs
index d18309fbc..7321faef8 100644
--- a/main/src/application/unit_model.rs
+++ b/main/src/application/unit_model.rs
@@ -2992,5 +2992,5 @@ fn compile_common_lua(
         Ok(val)
     })?;
     env.set("require", require)?;
-    lua.compile_and_execute(compartment.as_ref(), code, env)
+    lua.compile_and_execute(compartment.to_string(), code, env)
 }
diff --git a/main/src/domain/lua_module_container.rs b/main/src/domain/lua_module_container.rs
index 771ad40a9..57de1d9f2 100644
--- a/main/src/domain/lua_module_container.rs
+++ b/main/src/domain/lua_module_container.rs
@@ -5,8 +5,10 @@ use camino::Utf8Path;
 use include_dir::Dir;
 use mlua::{Function, Lua, Value};
 use std::borrow::Cow;
+use std::cell::RefCell;
 use std::fs;
 use std::path::PathBuf;
+use std::rc::Rc;
 
 /// Allows executing Lua code as a module that may require other modules.
 pub struct LuaModuleContainer<F> {
@@ -45,21 +47,56 @@ where
     pub fn execute_as_module<'lua>(
         &self,
         lua: &'lua Lua,
-        name: &str,
+        normalized_path: Option<String>,
+        display_name: String,
         code: &str,
     ) -> anyhow::Result<Value<'lua>> {
-        execute_as_module(name, code, self.finder.clone(), lua)
+        execute_as_module(
+            lua,
+            normalized_path,
+            display_name,
+            code,
+            self.finder.clone(),
+            SharedAccumulator::default(),
+        )
     }
 }
 
+#[derive(Default)]
+struct Accumulator {
+    required_modules_stack: Vec<String>,
+}
+
+impl Accumulator {
+    /// The given module must be normalized, i.e. it should contain the extension.
+    pub fn push_module(&mut self, normalized_path: String) -> anyhow::Result<()> {
+        let stack = &mut self.required_modules_stack;
+        tracing::debug!(msg = "Pushing module onto stack", %normalized_path, ?stack);
+        if stack.iter().any(|path| path == &normalized_path) {
+            bail!("Detected cyclic Lua module dependency: {normalized_path}");
+        }
+        stack.push(normalized_path);
+        Ok(())
+    }
+
+    pub fn pop_module(&mut self) {
+        let stack = &mut self.required_modules_stack;
+        tracing::debug!(msg = "Popping top module from stack", ?stack);
+        stack.pop();
+    }
+}
+
+type SharedAccumulator = Rc<RefCell<Accumulator>>;
+
 fn find_and_execute_module<'lua>(
-    finder: impl LuaModuleFinder + Clone + 'static,
     lua: &'lua Lua,
-    path: &str,
+    finder: impl LuaModuleFinder + Clone + 'static,
+    accumulator: SharedAccumulator,
+    required_path: &str,
 ) -> anyhow::Result<Value<'lua>> {
     // Validate
     let root_info = || format!("\n\nModule root path: {}", finder.module_root_path());
-    let path = Utf8Path::new(path);
+    let path = Utf8Path::new(required_path);
     if path.is_absolute() {
         bail!("Required paths must not start with a slash. They are always relative to the preset sub directory.{}", root_info());
     }
@@ -83,16 +120,25 @@ fn find_and_execute_module<'lua>(
         return Ok(Value::Table(table));
     }
     // Find module and get its source
-    let source = if path.extension().is_some() {
+    let (normalized_path, source) = if path
+        .extension()
+        .is_some_and(|ext| matches!(ext, "luau" | "lua"))
+    {
         // Extension given. Just get file directly.
-        finder
+        let source = finder
             .find_source_by_path(path.as_str())
-            .with_context(|| format!("Couldn't find Lua module [{path}].{}", root_info()))?
+            .with_context(|| format!("Couldn't find Lua module [{path}].{}", root_info()))?;
+        (path.to_string(), source)
     } else {
         // No extension given. Try ".luau" and ".lua".
         ["luau", "lua"]
             .into_iter()
-            .find_map(|ext| finder.find_source_by_path(path.with_extension(ext).as_str()))
+            .find_map(|ext| {
+                let path_with_extension = format!("{path}.{ext}");
+                tracing::debug!(msg = "Finding module by path...", %path_with_extension);
+                let source = finder.find_source_by_path(&path_with_extension)?;
+                Some((path_with_extension, source))
+            })
             .with_context(|| {
                 format!(
                     "Couldn't find Lua module [{path}]. Tried with extension \".lua\" and \".luau\".{}", root_info()
@@ -100,7 +146,14 @@ fn find_and_execute_module<'lua>(
             })?
     };
     // Execute module
-    execute_as_module(path.as_str(), source.as_ref(), Ok(finder), lua)
+    execute_as_module(
+        lua,
+        Some(normalized_path.clone()),
+        normalized_path,
+        source.as_ref(),
+        Ok(finder),
+        accumulator,
+    )
 }
 
 pub fn lua_module_path_without_ext(path: &str) -> &str {
@@ -110,21 +163,30 @@ pub fn lua_module_path_without_ext(path: &str) -> &str {
 }
 
 fn execute_as_module<'lua>(
-    name: &str,
+    lua: &'lua Lua,
+    normalized_path: Option<String>,
+    display_name: String,
     code: &str,
     finder: Result<impl LuaModuleFinder + Clone + 'static, &'static str>,
-    lua: &'lua Lua,
+    accumulator: SharedAccumulator,
 ) -> anyhow::Result<Value<'lua>> {
     let env = create_fresh_environment(lua, true)?;
-    let require = create_require_function(finder, lua)?;
+    let require = create_require_function(lua, finder, accumulator.clone())?;
     env.set("require", require)?;
-    let value = compile_and_execute(lua, name, code, env)
-        .with_context(|| format!("Couldn't compile and execute Lua module {name}"))?;
+    let pop_later = if let Some(p) = normalized_path {
+        accumulator.borrow_mut().push_module(p)?;
+        true
+    } else {
+        false
+    };
+    let value = compile_and_execute(lua, display_name.clone(), code, env)
+        .with_context(|| format!("Couldn't compile and execute Lua module {display_name}"))?;
+    if pop_later {
+        accumulator.borrow_mut().pop_module();
+    }
     Ok(value)
-    // TODO-high CONTINUE It doesn't seem to be straightforward to save the Values of the
-    //  already loaded modules because of lifetime challenges. Not a big deal, no need
-    //  to cache. But we should at least track what has already been loaded / maintain
-    //  some kind of stack in order to fail on cycles.
+    // TODO-medium-performance Instead of just detecting cycles, we could cache the module execution result and return
+    //  it whenever it's queried again.
     // match self.modules.entry(path) {
     //     Entry::Occupied(e) => Ok(e.into_mut()),
     //     Entry::Vacant(e) => {
@@ -143,13 +205,15 @@ fn execute_as_module<'lua>(
 }
 
 fn create_require_function<'lua>(
-    finder: Result<impl LuaModuleFinder + Clone + 'static, &'static str>,
     lua: &'lua Lua,
+    finder: Result<impl LuaModuleFinder + Clone + 'static, &'static str>,
+    accumulator: SharedAccumulator,
 ) -> anyhow::Result<Function<'lua>> {
-    let require = lua.create_function_mut(move |lua, path: String| {
+    let require = lua.create_function_mut(move |lua, required_path: String| {
         let finder = finder.clone().map_err(mlua::Error::runtime)?;
-        let value = find_and_execute_module(finder.clone(), lua, &path)
-            .map_err(|e| mlua::Error::runtime(format!("{e:#}")))?;
+        let value =
+            find_and_execute_module(lua, finder.clone(), accumulator.clone(), &required_path)
+                .map_err(|e| mlua::Error::runtime(format!("{e:#}")))?;
         Ok(value)
     })?;
     Ok(require)
@@ -204,7 +268,9 @@ impl LuaModuleFinder for FsDirLuaModuleFinder {
             return None;
         }
         let absolute_path = self.dir.join(path);
+        tracing::debug!(msg = "find_source_by_path", ?absolute_path);
         let content = fs::read_to_string(absolute_path).ok()?;
+        tracing::debug!(msg = "find_source_by_path successful");
         Some(content.into())
     }
 }
diff --git a/main/src/domain/lua_support.rs b/main/src/domain/lua_support.rs
index bf0fb849e..7174df6fa 100644
--- a/main/src/domain/lua_support.rs
+++ b/main/src/domain/lua_support.rs
@@ -53,11 +53,11 @@ impl SafeLua {
     /// Compiles and executes the given code in one go (shouldn't be used for repeated execution!).
     pub fn compile_and_execute<'a>(
         &'a self,
-        name: &str,
+        display_name: String,
         code: &str,
         env: Table<'a>,
     ) -> anyhow::Result<Value<'a>> {
-        compile_and_execute(&self.0, name, code, env)
+        compile_and_execute(&self.0, display_name, code, env)
     }
 
     /// Creates a fresh environment for this Lua state.
@@ -96,13 +96,13 @@ pub fn create_fresh_environment(lua: &Lua, allow_side_effects: bool) -> anyhow::
 /// Compiles and executes the given code in one go (shouldn't be used for repeated execution!).
 pub fn compile_and_execute<'a>(
     lua: &'a Lua,
-    name: &str,
+    display_name: String,
     code: &str,
     env: Table<'a>,
 ) -> anyhow::Result<Value<'a>> {
     let lua_chunk = lua
         .load(code)
-        .set_name(name)
+        .set_name(display_name)
         .set_mode(ChunkMode::Text)
         .set_environment(env);
     let value = lua_chunk.eval().map_err(|e| match e {
diff --git a/main/src/infrastructure/data/preset.rs b/main/src/infrastructure/data/preset.rs
index 482cc041b..369d5ad1a 100644
--- a/main/src/infrastructure/data/preset.rs
+++ b/main/src/infrastructure/data/preset.rs
@@ -155,6 +155,8 @@ pub struct PresetInfo<S> {
 #[derive(Clone, Eq, PartialEq, Debug)]
 pub struct CommonPresetInfo {
     pub id: String,
+    /// Path relative to the namespace root including extension.
+    pub normalized_relative_path: String,
     pub file_type: PresetFileType,
     pub origin: PresetOrigin,
     pub meta_data: CommonPresetMetaData,
@@ -198,7 +200,10 @@ impl fmt::Display for PresetOrigin {
 }
 
 struct PresetBasics {
+    /// Path relative to the **preset** root, without extension.
     id: String,
+    /// Path relative to the **preset namespace** root, including extension.
+    relative_path_within_namespace: String,
     file_type: PresetFileType,
 }
 
@@ -226,7 +231,15 @@ impl PresetBasics {
                 relative_dir_path.to_string_lossy().replace('\\', "/");
             format!("{prefix}{relative_dir_path_with_slashes}/{id_leaf}")
         };
-        let basics = Self { id, file_type };
+        let relative_path_within_namespace: PathBuf =
+            relative_file_path.components().skip(1).collect();
+        let basics = Self {
+            id,
+            relative_path_within_namespace: relative_path_within_namespace
+                .to_string_lossy()
+                .to_string(),
+            file_type,
+        };
         Some(basics)
     }
 }
@@ -410,9 +423,7 @@ impl<S: SpecificPresetMetaData> FileBasedCompartmentPresetManager<S> {
         preset_info: &PresetInfo<S>,
     ) -> anyhow::Result<CompartmentPresetModel> {
         let file_content: Cow<str> = match &preset_info.common.origin {
-            PresetOrigin::User {
-                absolute_file_path: absolute_path,
-            } => fs::read_to_string(absolute_path)
+            PresetOrigin::User { absolute_file_path } => fs::read_to_string(absolute_file_path)
                 .map_err(|_| {
                     anyhow!(
                         "Couldn't read preset file \"{}\" anymore.",
@@ -440,10 +451,8 @@ impl<S: SpecificPresetMetaData> FileBasedCompartmentPresetManager<S> {
             PresetFileType::Lua => {
                 let lua = SafeLua::new()?;
                 let script_name = preset_info.common.origin.to_string();
-                let module_finder: Result<Rc<dyn LuaModuleFinder>, _> = match &preset_info
-                    .common
-                    .origin
-                {
+                let origin = &preset_info.common.origin;
+                let module_finder: Result<Rc<dyn LuaModuleFinder>, _> = match origin {
                     PresetOrigin::User {
                         absolute_file_path: _,
                     } => {
@@ -471,11 +480,12 @@ impl<S: SpecificPresetMetaData> FileBasedCompartmentPresetManager<S> {
                         Ok(Rc::new(IncludedDirLuaModuleFinder::new(module_root)))
                     }
                 };
-                let module_container = LuaModuleContainer::new(module_finder);
                 let lua = lua.start_execution_time_limit_countdown()?;
+                let module_container = LuaModuleContainer::new(module_finder);
                 let value = module_container.execute_as_module(
                     lua.as_ref(),
-                    &script_name,
+                    Some(preset_info.common.normalized_relative_path.clone()),
+                    script_name,
                     &file_content,
                 )?;
                 let compartment_content: realearn_api::persistence::Compartment =
@@ -647,6 +657,7 @@ fn load_preset_info<M: SpecificPresetMetaData>(
     let preset_info = PresetInfo {
         common: CommonPresetInfo {
             id: basics.id,
+            normalized_relative_path: basics.relative_path_within_namespace,
             file_type: basics.file_type,
             origin,
             meta_data: preset_meta_data.common,
diff --git a/main/src/infrastructure/ui/import.rs b/main/src/infrastructure/ui/import.rs
index 108bb1958..258bbf713 100644
--- a/main/src/infrastructure/ui/import.rs
+++ b/main/src/infrastructure/ui/import.rs
@@ -410,5 +410,5 @@ fn execute_lua_import_script<'a>(
     let preset_dir = BackboneShell::realearn_compartment_preset_dir_path(active_compartment);
     let module_finder = FsDirLuaModuleFinder::new(preset_dir.join(whoami::username()));
     let module_container = LuaModuleContainer::new(Ok(module_finder));
-    module_container.execute_as_module(lua.as_ref(), "Import", code)
+    module_container.execute_as_module(lua.as_ref(), None, "Import".to_string(), code)
 }
diff --git a/resources/main-presets/factory/playtime_util.luau b/resources/main-presets/factory/playtime_util.luau
index 20824e88c..d0c5ae040 100644
--- a/resources/main-presets/factory/playtime_util.luau
+++ b/resources/main-presets/factory/playtime_util.luau
@@ -43,7 +43,6 @@ function playtime_util.scroll_vertically(amount: number)
     return scroll("Y", amount)
 end
 
-
 function playtime_util.slot_state_text_feedback()
     return util.partial_mapping {
         glue = {