feat(cli): add /new to start a fresh session without restarting (#10767)

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

@@ -244,6 +244,7 @@ impl GooseCompleter {
             "/mode".to_string(),
             "/model".to_string(),
             "/recipe".to_string(),
+            "/new".to_string(),
         ];
         commands.extend(
             list_commands()
@@ -694,6 +695,18 @@ mod tests {
         assert_eq!(candidates.len(), 0);
     }
 
+    #[test]
+    fn test_complete_slash_commands_new() {
+        let cache = create_test_cache();
+        let completer = GooseCompleter::new(cache);
+
+        let (pos, candidates) = completer.complete_slash_commands("/new").unwrap();
+        assert_eq!(pos, 0);
+        assert_eq!(candidates.len(), 1);
+        assert_eq!(candidates[0].display, "/new");
+        assert_eq!(candidates[0].replacement, "/new ");
+    }
+
     #[test]
     fn test_complete_model_names() {
         let cache = create_test_cache();

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

@@ -27,6 +27,7 @@ pub enum InputResult {
     Plan(PlanCommandOptions),
     EndPlan,
     Clear,
+    New,
     Recipe(Option<String>),
     Compact,
     ToggleFullToolOutput,
@@ -239,6 +240,7 @@ fn handle_slash_command(input: &str) -> Option<InputResult> {
     const CMD_PLAN: &str = "/plan";
     const CMD_ENDPLAN: &str = "/endplan";
     const CMD_CLEAR: &str = "/clear";
+    const CMD_NEW: &str = "/new";
     const CMD_RECIPE: &str = "/recipe";
     const CMD_COMPACT: &str = "/compact";
     const CMD_SUMMARIZE_DEPRECATED: &str = "/summarize";
@@ -335,6 +337,7 @@ fn handle_slash_command(input: &str) -> Option<InputResult> {
         }
         s if s == CMD_ENDPLAN => Some(InputResult::EndPlan),
         s if s == CMD_CLEAR => Some(InputResult::Clear),
+        s if s == CMD_NEW => Some(InputResult::New),
         s if s.starts_with(CMD_RECIPE) => parse_recipe_command(s),
         s if s == CMD_COMPACT => Some(InputResult::Compact),
         // Match "/skills" exactly or "/skills " with args - avoids matching e.g. "/skillsextra"
@@ -492,6 +495,7 @@ fn help_text() -> String {
 /skills - List available skills or enable skills by name (usage: /skills [<name>...])
 /? or /help - Display this help message
 /clear - Clears the current chat history
+/new - Start a fresh session in this process, keeping the current provider, model and extensions
 
 Navigation:
 Enter - Send message
@@ -667,6 +671,14 @@ mod tests {
         assert!(handle_slash_command("/unknown").is_none());
     }
 
+    #[test]
+    fn test_handle_slash_command_new() {
+        assert!(matches!(
+            handle_slash_command("/new"),
+            Some(InputResult::New)
+        ));
+    }
+
     #[test]
     fn help_lists_builtin_agent_commands() {
         let help = help_text();

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

@@ -685,6 +685,10 @@ impl CliSession {
                 history.save(editor);
                 self.handle_clear().await?;
             }
+            InputResult::New => {
+                history.save(editor);
+                self.handle_new().await?;
+            }
             InputResult::PromptCommand(opts) => {
                 history.save(editor);
                 self.handle_prompt_command(opts).await?;
@@ -1080,6 +1084,92 @@ impl CliSession {
         Ok(())
     }
 
+    async fn handle_new(&mut self) -> Result<()> {
+        let provider = self.agent.provider().await?;
+        if provider.manages_own_context() {
+            output::render_error(&format!(
+                "Starting a new session is not supported for provider '{}' because it manages its own conversation context.",
+                provider.get_name()
+            ));
+            return Ok(());
+        }
+
+        let new_session_id = match self.prepare_successor_session().await {
+            Ok(id) => id,
+            Err(e) => {
+                output::render_error(&format!("Failed to start a new session: {}", e));
+                return Ok(());
+            }
+        };
+
+        let extension_configs = self.agent.get_extension_configs().await;
+
+        self.agent
+            .emit_hook(goose::hooks::HookEvent::SessionEnd, &self.session_id)
+            .await;
+
+        self.agent.discard_pending_steers(&self.session_id).await;
+
+        self.session_id = new_session_id;
+        self.messages.clear();
+        self.run_mode = RunMode::Normal;
+        self.agent.set_goal(None).await;
+        self.agent.set_grind(None).await;
+
+        if let Err(e) = self
+            .agent
+            .update_goose_mode(self.agent.goose_mode().await, &self.session_id)
+            .await
+        {
+            output::render_error(&format!("Failed to apply the current mode: {}", e));
+        }
+
+        if !extension_configs.is_empty() {
+            output::goose_mode_message("Restarting extensions for the new session...");
+        }
+
+        // MCP clients pin themselves to the first session id they see a request for, so
+        // extensions must be torn down and re-added under the new session id.
+        for name in self.agent.list_extensions().await {
+            if let Err(e) = self.agent.remove_extension(&name, &self.session_id).await {
+                output::render_extension_error(&name, &e.to_string());
+            }
+        }
+
+        let mut unavailable = Vec::new();
+        for config in extension_configs {
+            let name = config.name();
+            if let Err(e) = self.agent.add_extension(config, &self.session_id).await {
+                output::render_extension_error(&name, &e.to_string());
+                unavailable.push(name);
+            }
+        }
+
+        if let Err(e) = self.update_completion_cache().await {
+            output::render_error(&format!("Failed to refresh completions: {}", e));
+        }
+
+        let mut started = format!("Started a new session · {}\n", self.session_id);
+        if !unavailable.is_empty() {
+            started.push_str(&format!(
+                "Continuing without these extensions: {}\n",
+                unavailable.join(", ")
+            ));
+        }
+        output::render_message(&Message::assistant().with_text(started), self.debug);
+        Ok(())
+    }
+
+    async fn prepare_successor_session(&self) -> Result<String> {
+        let session_manager = &self.agent.config.session_manager;
+        let old_session = session_manager.get_session(&self.session_id, false).await?;
+        let new_session_id =
+            create_successor_session(session_manager, &old_session, self.agent.goose_mode().await)
+                .await?;
+        self.agent.persist_extension_state(&new_session_id).await?;
+        Ok(new_session_id)
+    }
+
     async fn handle_recipe(&mut self, filepath_opt: Option<String>) {
         println!("{}", console::style("Generating Recipe").green());
 
@@ -1987,6 +2077,40 @@ impl CliSession {
     }
 }
 
+async fn create_successor_session(
+    session_manager: &SessionManager,
+    old_session: &goose::session::Session,
+    goose_mode: GooseMode,
+) -> Result<String> {
+    let new_session = session_manager
+        .create_session(
+            old_session.working_dir.clone(),
+            "CLI Session".to_string(),
+            old_session.session_type,
+            goose_mode,
+        )
+        .await?;
+
+    let mut builder = session_manager
+        .update(&new_session.id)
+        .recipe(old_session.recipe.clone())
+        .user_recipe_values(old_session.user_recipe_values.clone());
+
+    if let Some(provider_name) = old_session.provider_name.clone() {
+        builder = builder.provider_name(provider_name);
+    }
+    if let Some(model_config) = old_session.model_config.clone() {
+        builder = builder.model_config(model_config);
+    }
+    if let Some(project_id) = old_session.project_id.clone() {
+        builder = builder.project_id(Some(project_id));
+    }
+
+    builder.apply().await?;
+
+    Ok(new_session.id)
+}
+
 fn message_has_text(message: &Message) -> bool {
     message.content.iter().any(
         |content| matches!(content, MessageContent::Text(text) if !text.text.trim().is_empty()),
@@ -2955,4 +3079,77 @@ mod tests {
             expected
         );
     }
+
+    #[tokio::test]
+    async fn new_session_inherits_provider_model_and_working_dir() {
+        let temp_dir = tempfile::TempDir::new().unwrap();
+        let sm = SessionManager::new(temp_dir.path().to_path_buf());
+
+        let old = sm
+            .create_session(
+                temp_dir.path().to_path_buf(),
+                "CLI Session".to_string(),
+                goose::session::SessionType::User,
+                GooseMode::Auto,
+            )
+            .await
+            .unwrap();
+
+        sm.update(&old.id)
+            .provider_name("anthropic")
+            .model_config(goose_providers::model::ModelConfig::new("test-model"))
+            .accumulated_usage(goose_providers::conversation::token_usage::Usage::new(
+                Some(100),
+                Some(50),
+                Some(150),
+            ))
+            .apply()
+            .await
+            .unwrap();
+
+        sm.add_message(&old.id, &Message::user().with_text("hello"))
+            .await
+            .unwrap();
+
+        let mut extension_data = goose::session::ExtensionData::new();
+        extension_data.set_extension_state("test", "v0", serde_json::json!("marker"));
+        sm.update(&old.id)
+            .extension_data(extension_data)
+            .apply()
+            .await
+            .unwrap();
+
+        let old = sm.get_session(&old.id, false).await.unwrap();
+
+        let new_id = create_successor_session(&sm, &old, GooseMode::Chat)
+            .await
+            .unwrap();
+
+        assert_ne!(new_id, old.id);
+
+        let new_session = sm.get_session(&new_id, true).await.unwrap();
+        assert_eq!(new_session.provider_name, old.provider_name);
+        assert_eq!(
+            new_session.model_config.as_ref().map(|m| &m.model_name),
+            old.model_config.as_ref().map(|m| &m.model_name)
+        );
+        assert_eq!(new_session.goose_mode, GooseMode::Chat);
+        assert_eq!(new_session.working_dir, old.working_dir);
+        assert_eq!(new_session.session_type, old.session_type);
+        assert!(new_session.conversation.unwrap().messages().is_empty());
+        assert_eq!(new_session.usage.total_tokens, None);
+        assert_eq!(old.accumulated_usage.total_tokens, Some(150));
+        assert_eq!(new_session.accumulated_usage.total_tokens, None);
+
+        let reloaded_old = sm.get_session(&old.id, true).await.unwrap();
+        let old_messages = reloaded_old.conversation.unwrap().messages().to_vec();
+        assert_eq!(old_messages.len(), 1);
+        assert_eq!(old_messages[0].as_concat_text(), "hello");
+        assert_eq!(
+            reloaded_old
+                .extension_data
+                .get_extension_state("test", "v0"),
+            Some(&serde_json::json!("marker"))
+        );
+    }
 }