diff --git a/socktop/src/main.rs b/socktop/src/main.rs
index 746c0c9..2c7991a 100644
--- a/socktop/src/main.rs
+++ b/socktop/src/main.rs
@@ -124,6 +124,15 @@ pub(crate) fn parse_args<I: IntoIterator<Item = String>>(args: I) -> Result<Pars
                 }
             }
             _ => {
+                // An unrecognized option must never fall through to the
+                // positional URL slot: an older binary handed a newer flag
+                // would otherwise "connect" to the flag text — and offer to
+                // save it over a named profile's URL.
+                if arg.starts_with('-') {
+                    return Err(format!(
+                        "Unknown option '{arg}'. Usage: {prog} [--tls-ca CERT_PEM|-t CERT_PEM] [--verify-hostname] [--profile NAME|-P NAME] [--save] [--demo] [--compact] [--no-kill] [ws://HOST:PORT/ws]"
+                    ));
+                }
                 if url.is_none() {
                     url = Some(arg);
                 } else {
@@ -155,6 +164,11 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
         Ok(v) => v,
         Err(msg) => {
             eprintln!("{msg}");
+            // --help produces the bare usage text and exits cleanly; real
+            // parse errors must be visible to scripts and CI as a failure.
+            if !msg.starts_with("Usage:") {
+                std::process::exit(2);
+            }
             return Ok(());
         }
     };
diff --git a/socktop/tests/cli_args.rs b/socktop/tests/cli_args.rs
index 6118a69..defcdce 100644
--- a/socktop/tests/cli_args.rs
+++ b/socktop/tests/cli_args.rs
@@ -156,3 +156,29 @@ fn test_no_kill_env_var_accepted() {
         String::from_utf8_lossy(&out.stderr)
     );
 }
+
+#[test]
+fn test_unknown_option_rejected_not_treated_as_url() {
+    // Regression guard for the socktop.io incident (Aug 2026): socktop 1.60.1
+    // parsed the then-unknown --no-kill flag as the positional websocket URL,
+    // which made it prompt to overwrite the 'local' profile's URL with the
+    // literal string "--no-kill". Unknown options must fail loudly instead of
+    // falling through to the URL slot.
+    let exe = env!("CARGO_BIN_EXE_socktop");
+    let out = Command::new(exe)
+        .args(["--not-a-real-flag", "--dry-run", "ws://127.0.0.1:3000/ws"])
+        .output()
+        .expect("run socktop with unknown flag");
+    assert_eq!(
+        out.status.code(),
+        Some(2),
+        "unknown option should exit 2, got: {:?}\nstderr: {}",
+        out.status.code(),
+        String::from_utf8_lossy(&out.stderr)
+    );
+    let err = String::from_utf8_lossy(&out.stderr);
+    assert!(
+        err.contains("Unknown option '--not-a-real-flag'"),
+        "stderr should name the rejected option\n{err}"
+    );
+}