improvement: add useful error message when attempting to use unauthenticated cursor-agent (#5300)

Signed-off-by: Alex Holder <alexeeyre@gmail.com>

crates/goose/src/providers/cursor_agent.rs

@@ -47,6 +47,17 @@ impl CursorAgentProvider {
         })
     }
 
+    /// Get authentication status from cursor-agent
+    async fn get_authentication_status(&self) -> bool {
+        Command::new(&self.command)
+            .arg("status")
+            .output()
+            .await
+            .ok()
+            .map(|output| String::from_utf8_lossy(&output.stdout).contains("✓ Logged in as"))
+            .unwrap_or(false)
+    }
+
     /// Search for cursor-agent executable in common installation locations
     fn find_cursor_agent_executable(command_name: &str) -> Option<String> {
         let home = std::env::var("HOME").ok()?;
@@ -319,6 +330,11 @@ impl CursorAgentProvider {
         })?;
 
         if !exit_status.success() {
+            if !self.get_authentication_status().await {
+                return Err(ProviderError::Authentication(
+                    "You are not logged in to cursor-agent. Please run 'cursor-agent login' to authenticate first."
+                        .to_string()));
+            }
             return Err(ProviderError::RequestFailed(format!(
                 "Command failed with exit code: {:?}",
                 exit_status.code()