diff --git a/src/headless.rs b/src/headless.rs
index c76b4b1..4185cf8 100644
--- a/src/headless.rs
+++ b/src/headless.rs
@@ -37,40 +37,8 @@ pub fn run(config_or_task: &str, cwd_override: Option<&str>, name_override: Opti
         return run_once(&configs);
     }
 
-    // --once: run multi-agent once with AI integration, no loop
     if once {
-        let running = Arc::new(AtomicBool::new(true));
-        setup_ctrlc(running.clone());
-        let agents = spawn_and_wait(&configs, &running);
-        if agents.is_empty() { return Ok(()); }
-        write_state(&agents);
-
-        if agents.len() > 1 {
-            eprintln!("\n  ◐ AI integrating...");
-            match integrate_results(&agents, "", 1) {
-                Ok(d) => {
-                    let data = serde_json::json!({
-                        "cycle": 1,
-                        "agents": agents.iter().map(|a| a.to_ai_json()).collect::<Vec<_>>(),
-                        "decision": &d,
-                    });
-                    atomic_write(
-                        &format!("{STATE_DIR}/decision.json"),
-                        serde_json::to_string_pretty(&data).unwrap_or_default().as_bytes(),
-                    );
-                    eprintln!("  ✓ Done\n");
-                    println!("{d}");
-                }
-                Err(e) => eprintln!("  ✗ {e}"),
-            }
-        } else {
-            println!("{}", strip_dir_listing(&agents[0].output));
-        }
-
-        let all: Vec<usize> = (0..agents.len()).collect();
-        let path = save_session(1, &agents, "", &all);
-        eprintln!("  saved: {path}");
-        return Ok(());
+        return execute_once(configs);
     }
 
     let running = Arc::new(AtomicBool::new(true));
@@ -183,13 +151,14 @@ pub fn run_preset(preset_name: &str) -> Result<(), String> {
         .ok_or_else(|| format!("unknown preset: {preset_name}"))?;
     let once = std::env::args().any(|a| a == "--once");
     if once {
-        run_once_multi(configs)
+        execute_once(configs)
     } else {
         run_with_configs(configs)
     }
 }
 
-fn run_once_multi(configs: Vec<config::AgentConfig>) -> Result<(), String> {
+/// Single-cycle execution: agents → AI integration → save → exit.
+fn execute_once(configs: Vec<config::AgentConfig>) -> Result<(), String> {
     let _ = std::fs::remove_dir_all(STATE_DIR);
     create_state_dir();
     let running = Arc::new(AtomicBool::new(true));
@@ -198,7 +167,7 @@ fn run_once_multi(configs: Vec<config::AgentConfig>) -> Result<(), String> {
     if agents.is_empty() { return Ok(()); }
     write_state(&agents);
 
-    if agents.len() > 1 {
+    let decision = if agents.len() > 1 {
         eprintln!("\n  ◐ AI integrating...");
         match integrate_results(&agents, "", 1) {
             Ok(d) => {
@@ -213,15 +182,18 @@ fn run_once_multi(configs: Vec<config::AgentConfig>) -> Result<(), String> {
                 );
                 eprintln!("  ✓ Done\n");
                 println!("{d}");
+                d
             }
-            Err(e) => eprintln!("  ✗ {e}"),
+            Err(e) => { eprintln!("  ✗ {e}"); String::new() }
         }
     } else {
-        println!("{}", strip_dir_listing(&agents[0].output));
-    }
+        let out = strip_dir_listing(&agents[0].output).to_string();
+        println!("{out}");
+        out
+    };
 
     let all: Vec<usize> = (0..agents.len()).collect();
-    let path = save_session(1, &agents, "", &all);
+    let path = save_session(1, &agents, &decision, &all);
     eprintln!("  saved: {path}");
     Ok(())
 }