fix: clarify whoami api key source

src/cortex-cli/src/cli/handlers.rs

@@ -551,7 +551,7 @@ pub async fn run_whoami() -> Result<()> {
         && !token.is_empty()
     {
         println!(
-            "Authenticated via CORTEX_API_KEY: {}",
+            "Authenticated via CORTEX_API_KEY environment variable: {}",
             safe_format_key(&token)
         );
         return Ok(());

src/cortex-cli/tests/whoami_env_label.rs

@@ -0,0 +1,27 @@
+use std::process::Command;
+
+#[test]
+fn whoami_cortex_api_key_names_environment_variable_source() {
+    let output = Command::new(env!("CARGO_BIN_EXE_Cortex"))
+        .arg("whoami")
+        .env("CORTEX_API_KEY", "test-key-for-whoami")
+        .env_remove("CORTEX_AUTH_TOKEN")
+        .output()
+        .expect("run Cortex whoami");
+
+    let stdout = String::from_utf8_lossy(&output.stdout);
+    let stderr = String::from_utf8_lossy(&output.stderr);
+
+    assert!(
+        output.status.success(),
+        "whoami failed\nstdout:\n{stdout}\nstderr:\n{stderr}"
+    );
+    assert!(
+        stdout.contains("Authenticated via CORTEX_API_KEY environment variable:"),
+        "expected environment variable source label\nstdout:\n{stdout}\nstderr:\n{stderr}"
+    );
+    assert!(
+        !stdout.contains("Authenticated via CORTEX_API_KEY:"),
+        "stale auth-source wording should not be present\nstdout:\n{stdout}\nstderr:\n{stderr}"
+    );
+}