diff --git a/CHANGELOG.md b/CHANGELOG.md
index 26615d1a..16a3e02c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -20,6 +20,7 @@
 - **aiken-lang**: fix compiler wrongly requiring MillerLoopResult to be 'serialisable' when manipulated as a top-level value. See #921. @KtorZ
 - **aiken-lang**: fix type-checker oversight regarding serialisation of generics. See #939. @KtorZ
 - **aiken-lang**: fix type-checker not raising error when comparing non-serialisable types. See #940. @KtorZ
+- **aiken-project**: show a warning when ignoring modules in lib/validator because they have an invalid name. See #916. @KtorZ
 
 ### Changed
 
@@ -39,6 +40,7 @@
 - **aiken-lang**: altered internal representation of 2-tuples to distinguish them from pairs. @KtorZ @Microproofs
 - **aiken-lang**: some more code gen cleanup. @Microproofs
 - **aiken-lang**: new optimization for wrapped builtins found in the stdlib. @Microproofs
+- **aiken-project**: slightly restyle warnings to be less noisy. @KtorZ
 
 
 ## v1.0.26-alpha - 2024-03-25
diff --git a/crates/aiken-project/src/error.rs b/crates/aiken-project/src/error.rs
index 4235309b..715d888f 100644
--- a/crates/aiken-project/src/error.rs
+++ b/crates/aiken-project/src/error.rs
@@ -8,7 +8,10 @@ use aiken_lang::{
 use miette::{
     Diagnostic, EyreContext, LabeledSpan, MietteHandlerOpts, NamedSource, RgbColors, SourceCode,
 };
-use owo_colors::{OwoColorize, Stream::Stdout};
+use owo_colors::{
+    OwoColorize,
+    Stream::{Stderr, Stdout},
+};
 use std::{
     fmt::{Debug, Display},
     io,
@@ -501,9 +504,9 @@ impl Diagnostic for Error {
 
 #[derive(thiserror::Error)]
 pub enum Warning {
-    #[error("You do not have any validators to build!")]
+    #[error("{}", "You do not have any validators to build!".if_supports_color(Stderr, |s| s.yellow()))]
     NoValidators,
-    #[error("While trying to make sense of your code...")]
+    #[error("{}", "While trying to make sense of your code...".if_supports_color(Stderr, |s| s.yellow()))]
     Type {
         path: PathBuf,
         src: String,
@@ -511,15 +514,18 @@ pub enum Warning {
         #[source]
         warning: tipo::error::Warning,
     },
-    #[error("{name} is already a dependency.")]
+    #[error("{}", format!("{name} is already a dependency.").if_supports_color(Stderr, |s| s.yellow()))]
     DependencyAlreadyExists { name: PackageName },
+    #[error("{}", format!("Ignoring file with invalid module name at: {path:?}").if_supports_color(Stderr, |s| s.yellow()))]
+    InvalidModuleName { path: PathBuf },
 }
 
 impl ExtraData for Warning {
     fn extra_data(&self) -> Option<String> {
         match self {
-            Warning::NoValidators { .. } => None,
-            Warning::DependencyAlreadyExists { .. } => None,
+            Warning::NoValidators { .. }
+            | Warning::DependencyAlreadyExists { .. }
+            | Warning::InvalidModuleName { .. } => None,
             Warning::Type { warning, .. } => warning.extra_data(),
         }
     }
@@ -528,17 +534,17 @@ impl ExtraData for Warning {
 impl GetSource for Warning {
     fn path(&self) -> Option<PathBuf> {
         match self {
-            Warning::NoValidators => None,
-            Warning::Type { path, .. } => Some(path.clone()),
-            Warning::DependencyAlreadyExists { .. } => None,
+            Warning::InvalidModuleName { path } | Warning::Type { path, .. } => Some(path.clone()),
+            Warning::NoValidators | Warning::DependencyAlreadyExists { .. } => None,
         }
     }
 
     fn src(&self) -> Option<String> {
         match self {
-            Warning::NoValidators => None,
             Warning::Type { src, .. } => Some(src.clone()),
-            Warning::DependencyAlreadyExists { .. } => None,
+            Warning::NoValidators
+            | Warning::InvalidModuleName { .. }
+            | Warning::DependencyAlreadyExists { .. } => None,
         }
     }
 }
@@ -551,46 +557,32 @@ impl Diagnostic for Warning {
     fn source_code(&self) -> Option<&dyn SourceCode> {
         match self {
             Warning::Type { named, .. } => Some(named),
-            Warning::NoValidators => None,
-            Warning::DependencyAlreadyExists { .. } => None,
+            Warning::NoValidators
+            | Warning::InvalidModuleName { .. }
+            | Warning::DependencyAlreadyExists { .. } => None,
         }
     }
 
     fn labels(&self) -> Option<Box<dyn Iterator<Item = LabeledSpan> + '_>> {
         match self {
             Warning::Type { warning, .. } => warning.labels(),
-            Warning::NoValidators => None,
-            Warning::DependencyAlreadyExists { .. } => None,
+            Warning::InvalidModuleName { .. }
+            | Warning::NoValidators
+            | Warning::DependencyAlreadyExists { .. } => None,
         }
     }
 
     fn code<'a>(&'a self) -> Option<Box<dyn Display + 'a>> {
-        fn boxed<'a>(s: Box<dyn Display + 'a>) -> Box<dyn Display + 'a> {
-            Box::new(format!(
-                "      {} {}",
-                "Warning"
-                    .if_supports_color(Stdout, |s| s.yellow())
-                    .if_supports_color(Stdout, |s| s.bold()),
-                format!("{s}").if_supports_color(Stdout, |s| s.yellow())
-            ))
-        }
-
-        match self {
-            Warning::Type { warning, .. } => Some(boxed(Box::new(format!(
-                "aiken::check{}",
-                warning.code().map(|s| format!("::{s}")).unwrap_or_default()
-            )))),
-            Warning::NoValidators => Some(boxed(Box::new("aiken::check"))),
-            Warning::DependencyAlreadyExists { .. } => {
-                Some(boxed(Box::new("aiken::packages::already_exists")))
-            }
-        }
+        None
     }
 
     fn help<'a>(&'a self) -> Option<Box<dyn Display + 'a>> {
         match self {
             Warning::Type { warning, .. } => warning.help(),
             Warning::NoValidators => None,
+            Warning::InvalidModuleName { .. } => Some(Box::new(
+                "Module names are lowercase, (ascii) alpha-numeric and may contain dashes or underscores.",
+            )),
             Warning::DependencyAlreadyExists { .. } => Some(Box::new(
                 "If you need to change the version, try 'aiken packages upgrade' instead.",
             )),
diff --git a/crates/aiken-project/src/lib.rs b/crates/aiken-project/src/lib.rs
index b165545f..064c5d11 100644
--- a/crates/aiken-project/src/lib.rs
+++ b/crates/aiken-project/src/lib.rs
@@ -855,19 +855,27 @@ where
     }
 
     fn aiken_files(&mut self, dir: &Path, kind: ModuleKind) -> Result<(), Error> {
-        let paths = walkdir::WalkDir::new(dir)
+        walkdir::WalkDir::new(dir)
             .follow_links(true)
             .into_iter()
             .filter_map(Result::ok)
             .filter(|e| e.file_type().is_file())
-            .map(|d| d.into_path())
-            .filter(move |d| is_aiken_path(d, dir));
+            .try_for_each(|d| {
+                let path = d.into_path();
+                let keep = is_aiken_path(&path, dir);
+                let ext = path.extension();
 
-        for path in paths {
-            self.add_module(path, dir, kind)?;
-        }
+                if !keep && ext.unwrap_or_default() == "ak" {
+                    self.warnings
+                        .push(Warning::InvalidModuleName { path: path.clone() });
+                }
 
-        Ok(())
+                if keep {
+                    self.add_module(path, dir, kind)
+                } else {
+                    Ok(())
+                }
+            })
     }
 
     fn add_module(&mut self, path: PathBuf, dir: &Path, kind: ModuleKind) -> Result<(), Error> {