diff --git a/src/lib.rs b/src/lib.rs
index c9664a8..cd0787a 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -127,17 +127,23 @@ pub fn parse_stdin_with_reader<R: Read>(reader: &mut R) -> HashMap<String, Strin
     parse_env_content(&buffer)
 }
 
-pub fn parse_args(vars: &[String]) -> HashMap<String, String> {
-    vars.iter()
-        .filter_map(|arg| {
-            let parts: Vec<&str> = arg.splitn(2, '=').collect();
-            if parts.len() == 2 {
-                Some((parts[0].to_string(), parts[1].to_string()))
-            } else {
-                None
-            }
-        })
-        .collect()
+pub fn parse_args(vars: &[String]) -> Result<HashMap<String, String>, String> {
+    vars.iter().try_fold(HashMap::new(), |mut acc, arg| {
+        let parts: Vec<&str> = arg.splitn(2, '=').collect();
+        if parts.len() == 2 {
+            let key = parser::key_parser()
+                .parse(parts[0])
+                .map_err(|_| format!("Invalid key format in argument: {}", arg.bold().red()))?;
+            acc.insert(key, parts[1].to_string());
+            Ok(acc)
+        } else {
+            Err(format!(
+                "Invalid argument format {}. Expected format is {}",
+                arg.bold().red(),
+                "KEY=value".bold()
+            ))
+        }
+    })
 }
 
 pub fn parse_env_content(content: &str) -> HashMap<String, String> {
diff --git a/src/main.rs b/src/main.rs
index 4be14ee..2ef674c 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -200,7 +200,13 @@ fn main() {
         if !atty::is(Stream::Stdin) {
             parse_stdin()
         } else {
-            parse_args(&cli.vars)
+            match parse_args(&cli.vars) {
+                Ok(vars) => vars,
+                Err(e) => {
+                    eprintln!("Error parsing arguments: {}", e);
+                    process::exit(1);
+                }
+            }
         }
     } else {
         HashMap::new()
diff --git a/src/parser.rs b/src/parser.rs
index 9b1ac42..9d61924 100644
--- a/src/parser.rs
+++ b/src/parser.rs
@@ -12,6 +12,11 @@ pub enum Line {
     },
 }
 
+// Parser for keys
+pub fn key_parser() -> impl Parser<char, String, Error = Simple<char>> + Clone {
+    text::ident().padded()
+}
+
 pub fn parser() -> impl Parser<char, Vec<Line>, Error = Simple<char>> + Clone {
     // Parser for comments
     let comment = just('#')
@@ -19,8 +24,8 @@ pub fn parser() -> impl Parser<char, Vec<Line>, Error = Simple<char>> + Clone {
         .map(|(chars, _)| chars.into_iter().collect::<String>())
         .map(Line::Comment);
 
-    // Parser for keys
-    let key = text::ident().padded();
+
+    let key = key_parser();
 
     // Parser for single-quoted values
     let single_quoted_value = just('\'')