feat: Support extending the system prompt (#1167)

crates/goose-cli/src/cli_prompt.rs

@@ -0,0 +1,16 @@
+/// Returns a system prompt extension that explains CLI-specific functionality
+pub fn get_cli_prompt() -> String {
+    String::from(
+        "You are being accessed through a command-line interface. The following slash commands are available
+- you can let the user know about them if they need help:
+
+- /exit or /quit - Exit the session
+- /t - Toggle between Light/Dark/Ansi themes
+- /? or /help - Display help message
+
+Additional keyboard shortcuts:
+- Ctrl+C - Interrupt the current interaction (resets to before the interrupted request)
+- Ctrl+J - Add a newline
+- Up/Down arrows - Navigate command history"
+    )
+}

crates/goose-cli/src/commands/session.rs

@@ -161,6 +161,11 @@ pub async fn build_session(
 
     let prompt = Box::new(RustylinePrompt::new());
 
+    // Add CLI-specific system prompt extension
+    agent
+        .extend_system_prompt(crate::cli_prompt::get_cli_prompt())
+        .await;
+
     display_session_info(resume, &provider_name, &model, &session_file);
     Session::new(agent, prompt, session_file)
 }

crates/goose-cli/src/main.rs

@@ -9,6 +9,7 @@ pub static APP_STRATEGY: Lazy<AppStrategyArgs> = Lazy::new(|| AppStrategyArgs {
     app_name: "goose".to_string(),
 });
 
+mod cli_prompt;
 mod commands;
 mod log_usage;
 mod logging;