error handling

Author: evanliu048

crates/chat-cli/src/api_client/clients/streaming_client.rs

@@ -139,6 +139,7 @@ impl StreamingClient {
 
         match &self.inner {
             inner::Inner::Codewhisperer(client) => {
+                let model_id_opt: Option<String> = user_input_message.model_id.clone();
                 let conversation_state = amzn_codewhisperer_streaming_client::types::ConversationState::builder()
                     .set_conversation_id(conversation_id)
                     .current_message(
@@ -170,10 +171,18 @@ impl StreamingClient {
                                 && err.meta().message() == Some("Input is too long."))
                         });
 
+                        let is_model_unavailable = model_id_opt.is_some()
+                            && e.raw_response().is_some_and(|resp| resp.status().as_u16() == 500)
+                            && e.as_service_error().is_some_and(|err| {
+                                err.meta().message()
+                == Some("Encountered unexpectedly high load when processing the request, please try again.".into())
+                            });
                         if is_quota_breach {
                             Err(ApiClientError::QuotaBreach("quota has reached its limit"))
                         } else if is_context_window_overflow {
                             Err(ApiClientError::ContextWindowOverflow)
+                        } else if is_model_unavailable {
+                            Err(ApiClientError::ModelOverloadedError())
                         } else {
                             Err(e.into())
                         }

crates/chat-cli/src/api_client/error.rs

@@ -65,6 +65,11 @@ pub enum ApiClientError {
 
     #[error(transparent)]
     AuthError(#[from] AuthError),
+
+    #[error(
+        "The model you've selected is temporarily unavailable. Please use '/model' to select a different model and try again."
+    )]
+    ModelOverloadedError(),
 }
 
 #[cfg(test)]

crates/chat-cli/src/cli/chat/conversation_state.rs

@@ -606,7 +606,7 @@ impl ConversationState {
             user_input_message_context: None,
             user_intent: None,
             images: None,
-            model_id: self.current_model_id.to_owned(),
+            model_id: self.current_model_id.clone(),
         };
 
         // If the last message contains tool uses, then add cancelled tool results to the summary

crates/chat-cli/src/cli/chat/mod.rs

@@ -282,7 +282,7 @@ impl ChatArgs {
         let model_id: Option<String> = if let Some(model_name) = self.model {
             let model_name_lower = model_name.to_lowercase();
             match MODEL_OPTIONS.iter().find(|(_, name, _)| name == &model_name_lower) {
-                Some((_, _, id)) => Some(id.to_string()),
+                Some((_, _, id)) => Some((*id).to_string()),
                 None => {
                     let available_names: Vec<&str> = MODEL_OPTIONS.iter().map(|(_, name, _)| *name).collect();
                     bail!(