feat(headless): add --once flag for single-cycle multi-agent execution

src/headless.rs

@@ -12,6 +12,9 @@ pub fn run(config_or_task: &str, cwd_override: Option<&str>, name_override: Opti
     let _ = std::fs::remove_dir_all(STATE_DIR);
     create_state_dir();
 
+    let args: Vec<String> = std::env::args().collect();
+    let once = args.iter().any(|a| a == "--once");
+
     let is_multi = config_or_task.ends_with(".json") || std::path::Path::new(config_or_task).is_dir();
     let (configs, interval) = if is_multi {
         let loaded = config::load_full(config_or_task);
@@ -34,6 +37,42 @@ 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(());
+    }
+
     let running = Arc::new(AtomicBool::new(true));
     setup_ctrlc(running.clone());
 
@@ -142,8 +181,50 @@ pub fn run(config_or_task: &str, cwd_override: Option<&str>, name_override: Opti
 pub fn run_preset(preset_name: &str) -> Result<(), String> {
     let configs = config::preset(preset_name)
         .ok_or_else(|| format!("unknown preset: {preset_name}"))?;
+    let once = std::env::args().any(|a| a == "--once");
+    if once {
+        run_once_multi(configs)
+    } else {
         run_with_configs(configs)
     }
+}
+
+fn run_once_multi(configs: Vec<config::AgentConfig>) -> Result<(), String> {
+    let _ = std::fs::remove_dir_all(STATE_DIR);
+    create_state_dir();
+    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}");
+    Ok(())
+}
 
 fn run_with_configs(configs: Vec<config::AgentConfig>) -> Result<(), String> {
     let _ = std::fs::remove_dir_all(STATE_DIR);