diff --git a/src/config/agent.rs b/src/config/agent.rs
index 813df3a..2f44477 100644
--- a/src/config/agent.rs
+++ b/src/config/agent.rs
@@ -32,6 +32,9 @@ impl Agent {
     ) -> Result<Self> {
         let functions_dir = Config::agent_functions_dir(name)?;
         let definition_file_path = functions_dir.join("index.yaml");
+        if !definition_file_path.exists() {
+            bail!("Unknown agent `{name}`");
+        }
         let functions_file_path = functions_dir.join("functions.json");
         let variables_path = Config::agent_variables_file(name)?;
         let rag_path = Config::agent_rag_file(name, "rag")?;
diff --git a/src/config/mod.rs b/src/config/mod.rs
index 8e3e2c3..33bde56 100644
--- a/src/config/mod.rs
+++ b/src/config/mod.rs
@@ -205,7 +205,7 @@ impl Default for Config {
             agent: None,
             model: Default::default(),
             functions: Default::default(),
-            working_mode: WorkingMode::Command,
+            working_mode: WorkingMode::Cmd,
             last_message: None,
         }
     }
@@ -1199,6 +1199,9 @@ impl Config {
             Some(name) => {
                 let rag_path = config.read().rag_file(name)?;
                 if !rag_path.exists() {
+                    if config.read().working_mode.is_cmd() {
+                        bail!("Unknown RAG '{name}'")
+                    }
                     Rag::init(config, name, &rag_path, &[], abort_signal).await?
                 } else {
                     Rag::load(config, name, &rag_path)?
@@ -1376,7 +1379,7 @@ impl Config {
 
     pub fn apply_prelude(&mut self) -> Result<()> {
         let prelude = match self.working_mode {
-            WorkingMode::Command => self.prelude.as_ref(),
+            WorkingMode::Cmd => self.prelude.as_ref(),
             WorkingMode::Repl => self.repl_prelude.as_ref().or(self.prelude.as_ref()),
             WorkingMode::Serve => return Ok(()),
         };
@@ -2043,12 +2046,15 @@ pub fn load_env_file() -> Result<()> {
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 pub enum WorkingMode {
-    Command,
+    Cmd,
     Repl,
     Serve,
 }
 
 impl WorkingMode {
+    pub fn is_cmd(&self) -> bool {
+        *self == WorkingMode::Cmd
+    }
     pub fn is_repl(&self) -> bool {
         *self == WorkingMode::Repl
     }
diff --git a/src/main.rs b/src/main.rs
index 3c52f0d..299dc6b 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -50,7 +50,7 @@ async fn main() -> Result<()> {
     } else if text.is_none() && cli.file.is_empty() {
         WorkingMode::Repl
     } else {
-        WorkingMode::Command
+        WorkingMode::Cmd
     };
     setup_logger(working_mode.is_serve())?;
     let config = Arc::new(RwLock::new(Config::init(working_mode)?));
diff --git a/src/render/mod.rs b/src/render/mod.rs
index 97161f8..b2ed55d 100644
--- a/src/render/mod.rs
+++ b/src/render/mod.rs
@@ -26,5 +26,5 @@ pub async fn render_stream(
 }
 
 pub fn render_error(err: anyhow::Error) {
-    eprintln!("{}", error_text(&pretty_error(&err)));
+    eprint!("{}", error_text(&pretty_error(&err)));
 }