allow running goose run with no session persistence (#2517)

crates/goose-cli/src/cli.rs

@@ -315,6 +315,16 @@ enum Command {
         )]
         interactive: bool,
 
+        /// Run without storing a session file
+        #[arg(
+            long = "no-session",
+            help = "Run without storing a session file",
+            long_help = "Execute commands without creating or using a session file. Useful for automated runs.",
+            conflicts_with = "resume",
+            conflicts_with = "identifier"
+        )]
+        no_session: bool,
+
         /// Identifier for this run session
         #[command(flatten)]
         identifier: Option<Identifier>,
@@ -459,6 +469,7 @@ pub async fn cli() -> Result<()> {
                     let mut session: crate::Session = build_session(SessionBuilderConfig {
                         identifier: identifier.map(extract_identifier),
                         resume,
+                        no_session: false,
                         extensions,
                         remote_extensions,
                         builtins,
@@ -499,6 +510,7 @@ pub async fn cli() -> Result<()> {
             interactive,
             identifier,
             resume,
+            no_session,
             debug,
             extensions,
             remote_extensions,
@@ -558,6 +570,7 @@ pub async fn cli() -> Result<()> {
             let mut session = build_session(SessionBuilderConfig {
                 identifier: identifier.map(extract_identifier),
                 resume,
+                no_session,
                 extensions,
                 remote_extensions,
                 builtins,
@@ -625,7 +638,18 @@ pub async fn cli() -> Result<()> {
                 Ok(())
             } else {
                 // Run session command by default
-                let mut session = build_session(SessionBuilderConfig::default()).await;
+                let mut session = build_session(SessionBuilderConfig {
+                    identifier: None,
+                    resume: false,
+                    no_session: false,
+                    extensions: Vec::new(),
+                    remote_extensions: Vec::new(),
+                    builtins: Vec::new(),
+                    extensions_override: None,
+                    additional_system_prompt: None,
+                    debug: false,
+                })
+                .await;
                 setup_logging(
                     session.session_file().file_stem().and_then(|s| s.to_str()),
                     None,

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

@@ -34,6 +34,7 @@ pub async fn agent_generator(
     let base_session = build_session(SessionBuilderConfig {
         identifier,
         resume: false,
+        no_session: false,
         extensions: requirements.external,
         remote_extensions: requirements.remote,
         builtins: requirements.builtin,

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

@@ -21,6 +21,8 @@ pub struct SessionBuilderConfig {
     pub identifier: Option<Identifier>,
     /// Whether to resume an existing session
     pub resume: bool,
+    /// Whether to run without a session file
+    pub no_session: bool,
     /// List of stdio extension commands to add
     pub extensions: Vec<String>,
     /// List of remote extension commands to add
@@ -54,7 +56,17 @@ pub async fn build_session(session_config: SessionBuilderConfig) -> Session {
     let _ = agent.update_provider(new_provider).await;
 
     // Handle session file resolution and resuming
-    let session_file = if session_config.resume {
+    let session_file = if session_config.no_session {
+        // Use a temporary path that won't be written to
+        #[cfg(unix)]
+        {
+            std::path::PathBuf::from("/dev/null")
+        }
+        #[cfg(windows)]
+        {
+            std::path::PathBuf::from("NUL")
+        }
+    } else if session_config.resume {
         if let Some(identifier) = session_config.identifier {
             let session_file = session::get_path(identifier);
             if !session_file.exists() {
@@ -87,7 +99,7 @@ pub async fn build_session(session_config: SessionBuilderConfig) -> Session {
         session::get_path(id)
     };
 
-    if session_config.resume {
+    if session_config.resume && !session_config.no_session {
         // Read the session metadata
         let metadata = session::read_metadata(&session_file).unwrap_or_else(|e| {
             output::render_error(&format!("Failed to read session metadata: {}", e));

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

@@ -527,6 +527,8 @@ fn shorten_path(path: &str, debug: bool) -> String {
 pub fn display_session_info(resume: bool, provider: &str, model: &str, session_file: &Path) {
     let start_session_msg = if resume {
         "resuming session |"
+    } else if session_file.to_str() == Some("/dev/null") || session_file.to_str() == Some("NUL") {
+        "running without session |"
     } else {
         "starting session |"
     };
@@ -538,11 +540,15 @@ pub fn display_session_info(resume: bool, provider: &str, model: &str, session_f
         style("model:").dim(),
         style(model).cyan().dim(),
     );
+
+    if session_file.to_str() != Some("/dev/null") && session_file.to_str() != Some("NUL") {
         println!(
             "    {} {}",
             style("logging to").dim(),
             style(session_file.display()).dim().cyan(),
         );
+    }
+
     println!(
         "    {} {}",
         style("working directory:").dim(),