diff --git a/crates/aura-cli/src/main.rs b/crates/aura-cli/src/main.rs
index 8e8c66c..9b85f6e 100644
--- a/crates/aura-cli/src/main.rs
+++ b/crates/aura-cli/src/main.rs
@@ -114,7 +114,9 @@ fn run_sample() -> RunReport {
 fn main() {
     let mut args = std::env::args().skip(1);
     match args.next().as_deref() {
-        Some("run") => println!("{}", run_sample().to_json()),
+        // strict: a bare `run` proceeds; a trailing token falls through to the
+        // usage-error path rather than masquerading as a successful run (#16).
+        Some("run") if args.next().is_none() => println!("{}", run_sample().to_json()),
         Some("--help") | Some("-h") => println!("usage: aura run"),
         _ => {
             eprintln!("aura: usage: aura run");