turn errors reach every surface: Error event end-to-end, no more silent empty replies

src/api/handlers.rs

@@ -253,11 +253,11 @@ async fn handle_conversation_stream(
     let server_clone = server.clone();
     let conv = conversation_id.clone();
 
-    tokio::spawn(async move {
+    let turn = tokio::spawn(async move {
-        let _ = crate::server::turn::run_turn(
+        crate::server::turn::run_turn(
             server_clone, conv, &be_tx, event_bus,
             cancel, interject,
-        ).await;
+        ).await
     });
 
     // Drain the turn's BackendEvent stream. run_turn already handles message
@@ -268,12 +268,23 @@ async fn handle_conversation_stream(
     while let Some(result) = be_rx.recv().await {
         let be = match result {
             Ok(be) => be,
-            Err(_) => break,
+            Err(e) => {
+                eprintln!("Turn stream error ({conversation_id}): {e:#}");
+                let _ = tx.send(StreamEvent::Error { message: format!("{e:#}") }).await;
+                break;
+            }
         };
         if tx.send(StreamEvent::from(be)).await.is_err() {
             break;
         }
     }
+    // The channel closing means run_turn returned; a turn that died before
+    // emitting anything must still reach the surface as an error, not as a
+    // silently-ended stream (an empty reply reads as the agent going mute).
+    if let Ok(Err(e)) = turn.await {
+        eprintln!("Turn failed ({conversation_id}): {e:#}");
+        let _ = tx.send(StreamEvent::Error { message: format!("{e:#}") }).await;
+    }
     Ok(())
 }
 

src/api/models.rs

@@ -284,6 +284,10 @@ pub enum StreamEvent {
     Interstitial { text: String, register: crate::backend::Register },
     #[serde(rename = "primary_complete")]
     PrimaryComplete,
+    /// The turn failed in the substrate. Mirrors BackendEvent::Error so a
+    /// dead turn is never a silently-ended stream.
+    #[serde(rename = "error")]
+    Error { message: String },
     #[serde(rename = "done")]
     Done,
     #[serde(rename = "ping")]
@@ -315,6 +319,7 @@ impl StreamEvent {
             StreamEvent::Outfit { .. } => "outfit",
             StreamEvent::Interstitial { .. } => "interstitial",
             StreamEvent::PrimaryComplete => "primary_complete",
+            StreamEvent::Error { .. } => "error",
             StreamEvent::Done => "done",
             StreamEvent::Ping => "ping",
         }
@@ -360,6 +365,7 @@ impl From<crate::backend::BackendEvent> for StreamEvent {
             BE::Interstitial { text, register } => Self::Interstitial { text, register },
             BE::Keepalive => Self::Ping,
             BE::PrimaryComplete => Self::PrimaryComplete,
+            BE::Error { message } => Self::Error { message },
             BE::Done => Self::Done,
         }
     }
@@ -404,6 +410,7 @@ impl From<StreamEvent> for crate::backend::BackendEvent {
             StreamEvent::Interstitial { text, register } => BE::Interstitial { text, register },
             StreamEvent::Ping => BE::Keepalive,
             StreamEvent::PrimaryComplete => BE::PrimaryComplete,
+            StreamEvent::Error { message } => BE::Error { message },
             StreamEvent::Done => BE::Done,
         }
     }

src/backend/mod.rs

@@ -151,6 +151,11 @@ pub enum BackendEvent {
     /// events. The substrate does not hold the user hostage to N+1: the
     /// primary yields, the subconscious presses on.
     PrimaryComplete,
+    /// The turn failed in the substrate (agent load, provider call, tool
+    /// plumbing). Every surface must show this loud — a swallowed turn
+    /// error reads as the agent going silent, which is worse than any
+    /// error text.
+    Error { message: String },
     /// Stream ended cleanly.
     Done,
 }

src/main.rs

@@ -1238,6 +1238,14 @@ async fn run_chat(
                 BackendEvent::Surfacing { source, content, .. } => {
                     if !json { eprintln!("\n  [{}] {}", source, content); }
                 }
+                BackendEvent::Error { message } => {
+                    if json {
+                        let out = serde_json::json!({"agent": agent.name, "error": message});
+                        println!("{}", serde_json::to_string_pretty(&out)?);
+                        return Ok(());
+                    }
+                    eprintln!("\n  [turn error] {}", message);
+                }
                 BackendEvent::Done => break,
                 _ => {}
             }
@@ -1278,6 +1286,7 @@ async fn run_chat(
                 BackendEvent::Token(t) => { print!("{}", t); std::io::stdout().flush().ok(); }
                 BackendEvent::Reasoning(r) => eprintln!("\n  [thinking] {}", r),
                 BackendEvent::Surfacing { source, content, .. } => eprintln!("\n  [{}] {}", source, content),
+                BackendEvent::Error { message } => eprintln!("\n  [turn error] {}", message),
                 BackendEvent::Done => break,
                 _ => {}
             }

src/ui/chat/events.rs

@@ -395,6 +395,19 @@ impl ChatState {
                 }
                 BackendEvent::Keepalive => {
                 }
+                BackendEvent::Error { message } => {
+                    // A dead turn must land visibly and release the input —
+                    // leaving `busy` set would freeze the pane on a failure.
+                    self.finalize_streaming();
+                    self.messages.push(ChatMessage::System {
+                        text: format!("turn error: {message}"),
+                        ts: Instant::now(),
+                    });
+                    self.busy = false;
+                    self.cancel_token = None;
+                    self.phase = TurnPhase::Idle;
+                    self.tool_calls_this_turn = 0;
+                }
                 BackendEvent::PrimaryComplete => {
                     self.finalize_streaming();
                     self.busy = false;