feat: add typed engine run exits

crates/agen/examples/engine_cli.rs

@@ -39,7 +39,7 @@ use tracing::info;
 use tracing_subscriber::EnvFilter;
 
 use agen::{
-    Engine,
+    Engine, EngineRunExit, StopReason,
     interceptor::{Interceptor, PostToolAction, ToolResultInfo},
     llm_client::{
         LlmClient,
@@ -476,12 +476,9 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
 
     // One-shot mode
     if let Some(prompt) = args.prompt {
-        match engine.run(&prompt).await {
-            Ok(_) => {}
-            Err(e) => {
-                eprintln!("\n❌ Error: {}", e);
-                std::process::exit(1);
-            }
+        let output = engine.run(&prompt).await;
+        if let EngineRunExit::Interrupted(StopReason::Unexpected(error)) = output.result {
+            eprintln!("\n❌ Error: {error}");
         }
 
         return Ok(());
@@ -500,13 +497,8 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
         return Ok(());
     }
 
-    let mut locked = match engine.run(first_input).await {
-        Ok(out) => out.engine,
-        Err(e) => {
-            eprintln!("\n❌ Error: {}", e);
-            return Ok(());
-        }
-    };
+    let output = engine.run(first_input).await;
+    let mut locked = output.engine;
 
     loop {
         print!("\n👤 You: ");
@@ -525,11 +517,8 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
             break;
         }
 
-        match locked.run(input).await {
-            Ok(_) => {}
-            Err(e) => {
-                eprintln!("\n❌ Error: {}", e);
-            }
+        if let EngineRunExit::Interrupted(StopReason::Unexpected(error)) = locked.run(input).await {
+            eprintln!("\n❌ Error: {error}");
         }
     }