diff --git a/crates/cli/src/main.rs b/crates/cli/src/main.rs
index d0cdc63..9dacc38 100644
--- a/crates/cli/src/main.rs
+++ b/crates/cli/src/main.rs
@@ -275,8 +275,8 @@ enum Commands {
         device: String,
     },
 
-    /// Show a MessageBox asking the user to do something
-    Prompt {
+    /// Show a notification to the user (fire-and-forget, no response needed)
+    Inform {
         /// Device label
         device: String,
         /// Message to display
@@ -342,7 +342,7 @@ enum Commands {
         /// Device label
         device: String,
         /// Number of lines
-        #[arg(long, default_value = "100")]
+        #[arg(long, default_value = "20")]
         lines: u32,
     },
 }
@@ -537,7 +537,7 @@ fn main() {
             println!("All windows minimized on {}.", device);
         }
 
-        Commands::Prompt {
+        Commands::Inform {
             device,
             message,
             title,
@@ -547,19 +547,14 @@ fn main() {
             if let Some(t) = title {
                 body["title"] = json!(t);
             }
-            let data = req(
+            req(
                 &cfg,
                 "POST",
-                &format!("/devices/{}/prompt", device),
+                &format!("/devices/{}/inform", device),
                 Some(body),
-                30,
+                10,
             );
-            let answer = data["answer"].as_str().unwrap_or("");
-            if !answer.is_empty() {
-                println!("{}", answer);
-            } else {
-                println!("Prompt confirmed.");
-            }
+            println!("User informed on {}.", device);
         }
 
         Commands::Run {
diff --git a/crates/client/src/main.rs b/crates/client/src/main.rs
index 383431d..ffda017 100644
--- a/crates/client/src/main.rs
+++ b/crates/client/src/main.rs
@@ -430,6 +430,26 @@ async fn handle_message(
             }
         }
 
+        ServerMessage::InformRequest { request_id, message, title } => {
+            let msg = message.clone();
+            let ttl = title.clone().unwrap_or_else(|| "Helios".to_string());
+            // Fire-and-forget: show MessageBox in background thread, don't block
+            std::thread::spawn(move || {
+                #[cfg(windows)]
+                unsafe {
+                    use windows::core::PCWSTR;
+                    use windows::Win32::UI::WindowsAndMessaging::{MessageBoxW, MB_OK, MB_ICONINFORMATION, HWND_DESKTOP};
+                    let msg_w: Vec<u16> = msg.encode_utf16().chain(std::iter::once(0)).collect();
+                    let ttl_w: Vec<u16> = ttl.encode_utf16().chain(std::iter::once(0)).collect();
+                    MessageBoxW(HWND_DESKTOP, PCWSTR(msg_w.as_ptr()), PCWSTR(ttl_w.as_ptr()), MB_OK | MB_ICONINFORMATION);
+                }
+                #[cfg(not(windows))]
+                let _ = (msg, ttl);
+            });
+            display::log_ok("inform", &message);
+            ClientMessage::Ack { request_id }
+        }
+
         ServerMessage::PromptRequest { request_id, message, title: _ } => {
             display::prompt_waiting(&message);
             let answer = tokio::task::spawn_blocking(|| {
diff --git a/crates/common/src/protocol.rs b/crates/common/src/protocol.rs
index a087b74..94740ad 100644
--- a/crates/common/src/protocol.rs
+++ b/crates/common/src/protocol.rs
@@ -58,6 +58,12 @@ pub enum ServerMessage {
         message: String,
         title: Option<String>,
     },
+    /// Show a non-blocking notification to the user (fire-and-forget)
+    InformRequest {
+        request_id: Uuid,
+        message: String,
+        title: Option<String>,
+    },
     /// Execute a shell command on the client
     ExecRequest {
         request_id: Uuid,
diff --git a/crates/server/src/api.rs b/crates/server/src/api.rs
index 251e2b9..b89715c 100644
--- a/crates/server/src/api.rs
+++ b/crates/server/src/api.rs
@@ -401,6 +401,22 @@ pub async fn clipboard_set(
     }
 }
 
+/// POST /devices/:label/inform
+pub async fn inform_user(
+    Path(label): Path<String>,
+    State(state): State<AppState>,
+    Json(body): Json<PromptBody>,
+) -> impl IntoResponse {
+    match dispatch(&state, &label, "inform", |rid| ServerMessage::InformRequest {
+        request_id: rid,
+        message: body.message.clone(),
+        title: body.title.clone(),
+    }).await {
+        Ok(_) => (StatusCode::OK, Json(serde_json::json!({ "ok": true }))).into_response(),
+        Err(e) => e.into_response(),
+    }
+}
+
 /// POST /devices/:label/prompt
 #[derive(Deserialize)]
 pub struct PromptBody {
diff --git a/crates/server/src/main.rs b/crates/server/src/main.rs
index f20e46e..118e64c 100644
--- a/crates/server/src/main.rs
+++ b/crates/server/src/main.rs
@@ -49,6 +49,7 @@ async fn main() -> anyhow::Result<()> {
         .route("/devices/:label/screenshot", post(api::request_screenshot))
         .route("/devices/:label/exec", post(api::request_exec))
         .route("/devices/:label/prompt", post(api::prompt_user))
+        .route("/devices/:label/inform", post(api::inform_user))
         .route("/devices/:label/windows", get(api::list_windows))
         .route("/devices/:label/windows/minimize-all", post(api::minimize_all))
         .route("/devices/:label/logs", get(api::logs))