fix: use login shells for macos panes

refs #350

23 files changed, 362 insertions, 62 deletions

diff --git a/docs/next/CHANGELOG.md b/docs/next/CHANGELOG.md
index 20f39658..ec56a4b5 100644
--- a/docs/next/CHANGELOG.md
+++ b/docs/next/CHANGELOG.md
@@ -4,6 +4,7 @@
 
 ### Fixed
 - The OpenCode integration no longer treats `session.created` or `session.updated` plugin events as idle signals, so active sessions stay marked working until OpenCode reports `session.status` or `session.idle`. (#351)
+- New interactive panes now use login-shell startup on macOS by default so Homebrew and other login PATH setup is available, with `terminal.shell_mode = "non_login"` as an opt-out. (#350)
 
 ## [0.6.5] - 2026-05-29
 
diff --git a/docs/next/website/src/content/docs/configuration.mdx b/docs/next/website/src/content/docs/configuration.mdx
index 936cc3ac..48a5a321 100644
--- a/docs/next/website/src/content/docs/configuration.mdx
+++ b/docs/next/website/src/content/docs/configuration.mdx
@@ -56,6 +56,15 @@ default_shell = "nu"
 
 When unset or empty, Herdr uses `$SHELL`, then `/bin/sh`. This is an executable name or path, not a shell command line. Existing panes keep their current shell until they are recreated. Command panes still run through `/bin/sh -c`; detached custom command keybindings use Herdr's existing `/bin/sh -lc` path.
 
+Set how Herdr starts newly created interactive pane shells:
+
+```toml
+[terminal]
+shell_mode = "auto"
+```
+
+`shell_mode = "auto"` starts login shells on macOS so login-only PATH setup such as `/usr/libexec/path_helper` and Homebrew shell initialization runs in new panes. On other platforms, it keeps the existing non-login shell behavior. Use `"login"` to force login-shell startup, or `"non_login"` to opt out. Command panes, detached custom command keybindings, and explicit argv launches keep their existing command execution paths.
+
 Set the working directory policy for new panes, tabs, and workspaces:
 
 ```toml
diff --git a/src/app/api.rs b/src/app/api.rs
index df20cd34..a26b2856 100644
--- a/src/app/api.rs
+++ b/src/app/api.rs
@@ -311,7 +311,7 @@ impl App {
             cwd,
             self.state.pane_scrollback_limit_bytes,
             self.state.host_terminal_theme,
-            &self.state.default_shell,
+            crate::pane::PaneShellConfig::new(&self.state.default_shell, self.state.shell_mode),
             self.event_tx.clone(),
             self.render_notify.clone(),
             self.render_dirty.clone(),
@@ -644,7 +644,7 @@ mod tests {
             live_cwd.clone(),
             0,
             crate::terminal_theme::TerminalTheme::default(),
-            "/bin/sh",
+            crate::pane::PaneShellConfig::new("/bin/sh", crate::config::ShellModeConfig::NonLogin),
             events,
             std::sync::Arc::new(tokio::sync::Notify::new()),
             std::sync::Arc::new(std::sync::atomic::AtomicBool::new(false)),
diff --git a/src/app/api/panes.rs b/src/app/api/panes.rs
index 4620329f..67bac8d3 100644
--- a/src/app/api/panes.rs
+++ b/src/app/api/panes.rs
@@ -50,7 +50,7 @@ impl App {
             split_cwd,
             scrollback_limit_bytes,
             host_terminal_theme,
-            &default_shell,
+            crate::pane::PaneShellConfig::new(&default_shell, self.state.shell_mode),
             params.focus,
         ) {
             Some(Ok(result)) => result,
diff --git a/src/app/api/tabs.rs b/src/app/api/tabs.rs
index f605d143..4057eced 100644
--- a/src/app/api/tabs.rs
+++ b/src/app/api/tabs.rs
@@ -86,7 +86,7 @@ impl App {
                     cwd,
                     scrollback_limit_bytes,
                     host_terminal_theme,
-                    &default_shell,
+                    crate::pane::PaneShellConfig::new(&default_shell, self.state.shell_mode),
                 )
             });
         match result {
diff --git a/src/app/creation.rs b/src/app/creation.rs
index 0f63d60d..f8edd676 100644
--- a/src/app/creation.rs
+++ b/src/app/creation.rs
@@ -110,7 +110,7 @@ impl App {
             initial_cwd,
             self.state.pane_scrollback_limit_bytes,
             self.state.host_terminal_theme,
-            &self.state.default_shell,
+            crate::pane::PaneShellConfig::new(&self.state.default_shell, self.state.shell_mode),
         )?;
         let root_pane = ws.tabs[idx].root_pane;
         self.terminal_runtimes.insert(terminal.id.clone(), runtime);
@@ -142,7 +142,7 @@ impl App {
             cols,
             self.state.pane_scrollback_limit_bytes,
             self.state.host_terminal_theme,
-            &self.state.default_shell,
+            crate::pane::PaneShellConfig::new(&self.state.default_shell, self.state.shell_mode),
             self.event_tx.clone(),
             self.render_notify.clone(),
             self.render_dirty.clone(),
diff --git a/src/app/input/mod.rs b/src/app/input/mod.rs
index 76a32fc1..cfcc3039 100644
--- a/src/app/input/mod.rs
+++ b/src/app/input/mod.rs
@@ -417,7 +417,7 @@ impl AppState {
                 cwd,
                 self.pane_scrollback_limit_bytes,
                 self.host_terminal_theme,
-                &self.default_shell,
+                crate::pane::PaneShellConfig::new(&self.default_shell, self.shell_mode),
             ) {
                 let new_id = new_pane.pane_id;
                 terminal_runtimes.insert(new_pane.terminal.id.clone(), new_pane.runtime);
diff --git a/src/app/input/mouse.rs b/src/app/input/mouse.rs
index a9badfa9..e3ad0bc5 100644
--- a/src/app/input/mouse.rs
+++ b/src/app/input/mouse.rs
@@ -1975,7 +1975,7 @@ mod tests {
             80,
             app.state.pane_scrollback_limit_bytes,
             app.state.host_terminal_theme,
-            &app.state.default_shell,
+            crate::pane::PaneShellConfig::new(&app.state.default_shell, app.state.shell_mode),
             app.event_tx.clone(),
             app.render_notify.clone(),
             app.render_dirty.clone(),
diff --git a/src/app/input/navigate.rs b/src/app/input/navigate.rs
index e7581c5b..6a7e8d7c 100644
--- a/src/app/input/navigate.rs
+++ b/src/app/input/navigate.rs
@@ -1820,7 +1820,7 @@ last_pane = "prefix+tab"
             80,
             app.state.pane_scrollback_limit_bytes,
             app.state.host_terminal_theme,
-            &app.state.default_shell,
+            crate::pane::PaneShellConfig::new(&app.state.default_shell, app.state.shell_mode),
             app.event_tx.clone(),
             app.render_notify.clone(),
             app.render_dirty.clone(),
diff --git a/src/app/input/terminal.rs b/src/app/input/terminal.rs
index 0a35c3be..5447e2b0 100644
--- a/src/app/input/terminal.rs
+++ b/src/app/input/terminal.rs
@@ -845,7 +845,7 @@ mod tests {
             80,
             app.state.pane_scrollback_limit_bytes,
             app.state.host_terminal_theme,
-            &app.state.default_shell,
+            crate::pane::PaneShellConfig::new(&app.state.default_shell, app.state.shell_mode),
             app.event_tx.clone(),
             app.render_notify.clone(),
             app.render_dirty.clone(),
diff --git a/src/app/mod.rs b/src/app/mod.rs
index 1291d2a0..d8071c4d 100644
--- a/src/app/mod.rs
+++ b/src/app/mod.rs
@@ -289,6 +289,7 @@ impl App {
                 80,
                 config.advanced.scrollback_limit_bytes,
                 &config.terminal.default_shell,
+                config.terminal.shell_mode,
                 config.session.resume_agents_on_restore,
                 event_tx.clone(),
                 render_notify.clone(),
@@ -499,6 +500,7 @@ impl App {
             cjk_ime_cursor_shape: config.experimental.cjk_ime_cursor_shape.to_decscusr(),
             kitty_graphics_enabled: config.experimental.kitty_graphics,
             default_shell: config.terminal.default_shell.clone(),
+            shell_mode: config.terminal.shell_mode,
             new_terminal_cwd: config.terminal.new_cwd.clone(),
             pane_scrollback_limit_bytes: config.advanced.scrollback_limit_bytes,
             accent: crate::config::parse_color(&config.ui.accent),
@@ -606,6 +608,7 @@ impl App {
             snapshot,
             config.advanced.scrollback_limit_bytes,
             &config.terminal.default_shell,
+            config.terminal.shell_mode,
             imports,
             app.event_tx.clone(),
             app.render_notify.clone(),
@@ -1143,6 +1146,7 @@ impl App {
 
         if !invalid_section("terminal") {
             self.state.default_shell = config.terminal.default_shell.clone();
+            self.state.shell_mode = config.terminal.shell_mode;
             self.state.new_terminal_cwd = config.terminal.new_cwd.clone();
         }
 
@@ -1707,7 +1711,7 @@ mod tests {
         std::fs::create_dir_all(path.parent().unwrap()).unwrap();
         std::fs::write(
             &path,
-            "[terminal]\ndefault_shell = \"nu\"\nnew_cwd = \"home\"\n[keys]\nnew_workspace = \"prefix+m\"\nprefix = \"ctrl+a\"\n[ui]\nagent_panel_scope = \"current\"\nredraw_on_focus_gained = false\n[ui.toast]\ndelivery = \"herdr\"\n",
+            "[terminal]\ndefault_shell = \"nu\"\nshell_mode = \"non_login\"\nnew_cwd = \"home\"\n[keys]\nnew_workspace = \"prefix+m\"\nprefix = \"ctrl+a\"\n[ui]\nagent_panel_scope = \"current\"\nredraw_on_focus_gained = false\n[ui.toast]\ndelivery = \"herdr\"\n",
         )
         .unwrap();
         std::env::set_var(crate::config::CONFIG_PATH_ENV_VAR, &path);
@@ -1735,6 +1739,10 @@ mod tests {
         assert!(app.state.request_client_config_reload);
         assert_eq!(app.state.default_shell, "nu");
         assert_eq!(
+            app.state.shell_mode,
+            crate::config::ShellModeConfig::NonLogin
+        );
+        assert_eq!(
             app.state.new_terminal_cwd,
             crate::config::NewTerminalCwdConfig::Home
         );
@@ -1996,6 +2004,42 @@ mod tests {
     }
 
     #[test]
+    fn reload_config_preserves_invalid_terminal_section_but_applies_valid_ui() {
+        let _guard = config_env_lock().lock().unwrap();
+        let path = temp_config_path("reload-config-invalid-terminal-section");
+        std::fs::create_dir_all(path.parent().unwrap()).unwrap();
+        std::fs::write(
+            &path,
+            "[terminal]\ndefault_shell = \"nu\"\nshell_mode = \"sideways\"\nnew_cwd = \"home\"\n[ui.toast]\ndelivery = \"terminal\"\n",
+        )
+        .unwrap();
+        std::env::set_var(crate::config::CONFIG_PATH_ENV_VAR, &path);
+
+        let mut app = test_app();
+        let original_default_shell = app.state.default_shell.clone();
+        let original_shell_mode = app.state.shell_mode;
+        let original_new_cwd = app.state.new_terminal_cwd.clone();
+        let report = app.reload_config();
+
+        assert_eq!(report.status, crate::config::ConfigReloadStatus::Partial);
+        assert_eq!(app.state.default_shell, original_default_shell);
+        assert_eq!(app.state.shell_mode, original_shell_mode);
+        assert_eq!(app.state.new_terminal_cwd, original_new_cwd);
+        assert_eq!(
+            app.state.toast_config.delivery,
+            crate::config::ToastDelivery::Terminal
+        );
+        assert!(app
+            .state
+            .config_diagnostic
+            .as_deref()
+            .is_some_and(|message| message.contains("invalid terminal config")));
+
+        std::env::remove_var(crate::config::CONFIG_PATH_ENV_VAR);
+        let _ = std::fs::remove_dir_all(path.parent().unwrap());
+    }
+
+    #[test]
     fn settings_save_toast_delivery_persists_then_applies_live_config() {
         let _guard = config_env_lock().lock().unwrap();
         let path = temp_config_path("settings-save-toast-delivery");
diff --git a/src/app/state.rs b/src/app/state.rs
index 012d79e4..a9c1b8a3 100644
--- a/src/app/state.rs
+++ b/src/app/state.rs
@@ -1157,6 +1157,7 @@ pub struct AppState {
     pub cjk_ime_cursor_shape: u8,
     pub kitty_graphics_enabled: bool,
     pub default_shell: String,
+    pub shell_mode: crate::config::ShellModeConfig,
     pub new_terminal_cwd: NewTerminalCwdConfig,
     pub pane_scrollback_limit_bytes: usize,
     #[allow(dead_code)] // kept for backward compat; palette.accent is the source of truth
@@ -1461,6 +1462,7 @@ impl AppState {
             cjk_ime_cursor_shape: 2, // steady_block
             kitty_graphics_enabled: false,
             default_shell: String::new(),
+            shell_mode: crate::config::ShellModeConfig::Auto,
             new_terminal_cwd: NewTerminalCwdConfig::Follow,
             pane_scrollback_limit_bytes: crate::config::DEFAULT_SCROLLBACK_LIMIT_BYTES,
             accent: Color::Cyan,
diff --git a/src/config.rs b/src/config.rs
index b4fcf1ef..ab194cf5 100644
--- a/src/config.rs
+++ b/src/config.rs
@@ -19,7 +19,8 @@ pub use self::{
     },
     model::{
         validated_sidebar_bounds, AgentPanelScopeConfig, Config, ConfigReloadReport,
-        ConfigReloadStatus, KeysConfig, NewTerminalCwdConfig, ToastConfig, ToastDelivery,
+        ConfigReloadStatus, KeysConfig, NewTerminalCwdConfig, ShellModeConfig, ToastConfig,
+        ToastDelivery,
     },
     sound::SoundConfig,
     theme::{parse_color, CustomThemeColors, ThemeConfig},
diff --git a/src/config/model.rs b/src/config/model.rs
index 84d03bc2..77af2f75 100644
--- a/src/config/model.rs
+++ b/src/config/model.rs
@@ -63,11 +63,22 @@ impl<'de> Deserialize<'de> for NewTerminalCwdConfig {
     }
 }
 
+#[derive(Debug, Clone, Copy, Default, PartialEq, Eq, Deserialize, Serialize)]
+#[serde(rename_all = "snake_case")]
+pub enum ShellModeConfig {
+    #[default]
+    Auto,
+    Login,
+    NonLogin,
+}
+
 #[derive(Debug, Default, Deserialize)]
 #[serde(default)]
 pub struct TerminalConfig {
     /// Executable used for new interactive panes. Empty means SHELL, then /bin/sh.
     pub default_shell: String,
+    /// Startup mode for new interactive pane shells.
+    pub shell_mode: ShellModeConfig,
     /// CWD policy for new interactive panes, tabs, and workspaces.
     pub new_cwd: NewTerminalCwdConfig,
 }
@@ -494,13 +505,16 @@ mod tests {
     fn terminal_default_shell_defaults_empty_and_parses() {
         let default_config = Config::default();
         assert!(default_config.terminal.default_shell.is_empty());
+        assert_eq!(default_config.terminal.shell_mode, ShellModeConfig::Auto);
 
         let toml = r#"
 [terminal]
 default_shell = "nu"
+shell_mode = "non_login"
 "#;
         let config: Config = toml::from_str(toml).unwrap();
         assert_eq!(config.terminal.default_shell, "nu");
+        assert_eq!(config.terminal.shell_mode, ShellModeConfig::NonLogin);
     }
 
     #[test]
diff --git a/src/main.rs b/src/main.rs
index 163ce66e..a3d19876 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -84,6 +84,10 @@ const DEFAULT_CONFIG: &str = r##"# herdr configuration
 # Empty means $SHELL, then /bin/sh.
 # default_shell = ""
 
+# Startup mode for new interactive pane shells: "auto", "login", or "non_login".
+# "auto" uses login shells on macOS and keeps the current behavior elsewhere.
+# shell_mode = "auto"
+
 # CWD policy for new panes, tabs, and workspaces when no explicit --cwd is provided.
 # Use "follow" to inherit the source pane/workspace, "home" for $HOME,
 # "current" for Herdr's process directory, or a fixed path such as "~/Projects".
diff --git a/src/pane.rs b/src/pane.rs
index 885fb11d..97aeb9cb 100644
--- a/src/pane.rs
+++ b/src/pane.rs
@@ -1,5 +1,6 @@
 use std::cell::Cell;
-use std::io::{Read, Write};
+use std::io::{self, Read, Write};
+use std::path::Path;
 use std::sync::{
     atomic::{AtomicBool, AtomicU16, AtomicU32, Ordering},
     Arc, Mutex,
@@ -637,6 +638,96 @@ fn pane_shell_from(configured_shell: &str, env_shell: Option<String>) -> String
         .unwrap_or_else(|| "/bin/sh".into())
 }
 
+#[derive(Clone, Copy)]
+pub(crate) struct PaneShellConfig<'a> {
+    pub(crate) default_shell: &'a str,
+    pub(crate) mode: crate::config::ShellModeConfig,
+}
+
+impl<'a> PaneShellConfig<'a> {
+    pub(crate) fn new(default_shell: &'a str, mode: crate::config::ShellModeConfig) -> Self {
+        Self {
+            default_shell,
+            mode,
+        }
+    }
+}
+
+fn shell_mode_uses_login_shell(
+    mode: crate::config::ShellModeConfig,
+    target_is_macos: bool,
+) -> bool {
+    match mode {
+        crate::config::ShellModeConfig::Auto => target_is_macos,
+        crate::config::ShellModeConfig::Login => true,
+        crate::config::ShellModeConfig::NonLogin => false,
+    }
+}
+
+fn is_executable_file(path: &Path) -> bool {
+    let Ok(metadata) = path.metadata() else {
+        return false;
+    };
+    if !metadata.is_file() {
+        return false;
+    }
+    #[cfg(unix)]
+    {
+        use std::os::unix::fs::PermissionsExt;
+        metadata.permissions().mode() & 0o111 != 0
+    }
+    #[cfg(not(unix))]
+    {
+        true
+    }
+}
+
+fn resolve_shell_for_login_mode(shell: &str) -> io::Result<String> {
+    if shell.contains(std::path::MAIN_SEPARATOR) {
+        let path = Path::new(shell);
+        return is_executable_file(path)
+            .then(|| shell.to_string())
+            .ok_or_else(|| {
+                io::Error::new(
+                    io::ErrorKind::NotFound,
+                    format!("login shell {shell:?} is not executable"),
+                )
+            });
+    }
+
+    std::env::var_os("PATH")
+        .and_then(|path| {
+            std::env::split_paths(&path)
+                .map(|dir| dir.join(shell))
+                .find(|candidate| is_executable_file(candidate))
+        })
+        .and_then(|path| path.into_os_string().into_string().ok())
+        .ok_or_else(|| {
+            io::Error::new(
+                io::ErrorKind::NotFound,
+                format!("login shell {shell:?} was not found on PATH"),
+            )
+        })
+}
+
+fn pane_shell_command_builder_for_target(
+    shell_config: PaneShellConfig<'_>,
+    target_is_macos: bool,
+) -> io::Result<CommandBuilder> {
+    let shell = pane_shell(shell_config.default_shell);
+    if shell_mode_uses_login_shell(shell_config.mode, target_is_macos) {
+        let mut cmd = CommandBuilder::new_default_prog();
+        cmd.env("SHELL", resolve_shell_for_login_mode(&shell)?);
+        Ok(cmd)
+    } else {
+        Ok(CommandBuilder::new(&shell))
+    }
+}
+
+fn pane_shell_command_builder(shell_config: PaneShellConfig<'_>) -> io::Result<CommandBuilder> {
+    pane_shell_command_builder_for_target(shell_config, cfg!(target_os = "macos"))
+}
+
 #[cfg(unix)]
 fn duplicate_fd(fd: std::os::fd::RawFd) -> std::io::Result<std::os::fd::RawFd> {
     let duplicated = unsafe { libc::dup(fd) };
@@ -909,7 +1000,7 @@ impl PaneRuntime {
         cwd: std::path::PathBuf,
         scrollback_limit_bytes: usize,
         host_terminal_theme: crate::terminal_theme::TerminalTheme,
-        default_shell: &str,
+        shell_config: PaneShellConfig<'_>,
         events: mpsc::Sender<AppEvent>,
         render_notify: Arc<Notify>,
         render_dirty: Arc<AtomicBool>,
@@ -921,7 +1012,7 @@ impl PaneRuntime {
             cwd,
             scrollback_limit_bytes,
             host_terminal_theme,
-            default_shell,
+            shell_config,
             None,
             events,
             render_notify,
@@ -936,14 +1027,13 @@ impl PaneRuntime {
         cwd: std::path::PathBuf,
         scrollback_limit_bytes: usize,
         host_terminal_theme: crate::terminal_theme::TerminalTheme,
-        default_shell: &str,
+        shell_config: PaneShellConfig<'_>,
         initial_history_ansi: Option<&str>,
         events: mpsc::Sender<AppEvent>,
         render_notify: Arc<Notify>,
         render_dirty: Arc<AtomicBool>,
     ) -> std::io::Result<Self> {
-        let shell = pane_shell(default_shell);
-        let mut cmd = CommandBuilder::new(&shell);
+        let mut cmd = pane_shell_command_builder(shell_config)?;
         cmd.cwd(cwd);
         cmd.env(crate::HERDR_ENV_VAR, crate::HERDR_ENV_VALUE);
         apply_pane_terminal_env(&mut cmd);
@@ -2294,6 +2384,135 @@ mod tests {
     }
 
     #[test]
+    fn shell_mode_auto_uses_login_shell_only_on_macos() {
+        assert!(shell_mode_uses_login_shell(
+            crate::config::ShellModeConfig::Auto,
+            true
+        ));
+        assert!(!shell_mode_uses_login_shell(
+            crate::config::ShellModeConfig::Auto,
+            false
+        ));
+        assert!(shell_mode_uses_login_shell(
+            crate::config::ShellModeConfig::Login,
+            false
+        ));
+        assert!(!shell_mode_uses_login_shell(
+            crate::config::ShellModeConfig::NonLogin,
+            true
+        ));
+    }
+
+    #[test]
+    fn login_shell_builder_uses_default_prog_with_resolved_shell_env() {
+        let cmd = pane_shell_command_builder_for_target(
+            PaneShellConfig::new("/bin/sh", crate::config::ShellModeConfig::Login),
+            false,
+        )
+        .unwrap();
+        assert!(cmd.is_default_prog());
+        assert_eq!(
+            cmd.get_env("SHELL").and_then(std::ffi::OsStr::to_str),
+            Some("/bin/sh")
+        );
+    }
+
+    #[test]
+    fn auto_shell_builder_uses_login_shell_on_macos_target() {
+        let cmd = pane_shell_command_builder_for_target(
+            PaneShellConfig::new("/bin/sh", crate::config::ShellModeConfig::Auto),
+            true,
+        )
+        .unwrap();
+        assert!(cmd.is_default_prog());
+        assert_eq!(
+            cmd.get_env("SHELL").and_then(std::ffi::OsStr::to_str),
+            Some("/bin/sh")
+        );
+    }
+
+    #[test]
+    fn auto_shell_builder_keeps_direct_shell_on_non_macos_target() {
+        let cmd = pane_shell_command_builder_for_target(
+            PaneShellConfig::new("/bin/sh", crate::config::ShellModeConfig::Auto),
+            false,
+        )
+        .unwrap();
+        assert!(!cmd.is_default_prog());
+        assert_eq!(cmd.get_argv(), &[std::ffi::OsString::from("/bin/sh")]);
+    }
+
+    #[test]
+    fn login_shell_builder_rejects_missing_shell_instead_of_falling_back() {
+        let err = pane_shell_command_builder_for_target(
+            PaneShellConfig::new(
+                "/__herdr_missing_shell__",
+                crate::config::ShellModeConfig::Login,
+            ),
+            false,
+        )
+        .unwrap_err();
+        assert_eq!(err.kind(), io::ErrorKind::NotFound);
+    }
+
+    #[test]
+    fn login_shell_builder_resolves_bare_shell_names_from_path() {
+        let _lock = crate::integration::integration_env_lock();
+        let base = std::env::temp_dir().join(format!(
+            "herdr-login-shell-path-{}-{}",
+            std::process::id(),
+            std::time::SystemTime::now()
+                .duration_since(std::time::UNIX_EPOCH)
+                .unwrap()
+                .as_nanos()
+        ));
+        let bin = base.join("bin");
+        std::fs::create_dir_all(&bin).unwrap();
+        let shell = bin.join("fake-shell");
+        std::fs::write(&shell, "#!/bin/sh\nexit 0\n").unwrap();
+        #[cfg(unix)]
+        {
+            use std::os::unix::fs::PermissionsExt;
+            std::fs::set_permissions(&shell, std::fs::Permissions::from_mode(0o755)).unwrap();
+        }
+        let original_path = std::env::var_os("PATH");
+        std::env::set_var("PATH", &bin);
+
+        let cmd = pane_shell_command_builder_for_target(
+            PaneShellConfig::new("fake-shell", crate::config::ShellModeConfig::Login),
+            false,
+        )
+        .unwrap();
+
+        assert!(cmd.is_default_prog());
+        assert_eq!(
+            cmd.get_env("SHELL").and_then(std::ffi::OsStr::to_str),
+            shell.to_str()
+        );
+        match original_path {
+            Some(path) => std::env::set_var("PATH", path),
+            None => std::env::remove_var("PATH"),
+        }
+        let _ = std::fs::remove_dir_all(base);
+    }
+
+    #[test]
+    fn login_shell_resolution_preserves_shell_paths() {
+        assert_eq!(resolve_shell_for_login_mode("/bin/sh").unwrap(), "/bin/sh");
+    }
+
+    #[test]
+    fn non_login_shell_builder_execs_resolved_shell_directly() {
+        let cmd = pane_shell_command_builder(PaneShellConfig::new(
+            "/bin/sh",
+            crate::config::ShellModeConfig::NonLogin,
+        ))
+        .unwrap();
+        assert!(!cmd.is_default_prog());
+        assert_eq!(cmd.get_argv(), &[std::ffi::OsString::from("/bin/sh")]);
+    }
+
+    #[test]
     fn pane_terminal_identity_overrides_outer_terminal_env() {
         let output = capture_shell_output("printf '%s\\n%s\\n' \"$TERM\" \"$COLORTERM\"", &[]);
         assert_eq!(output, "xterm-256color\ntruecolor\n");
diff --git a/src/persist/restore.rs b/src/persist/restore.rs
index 916478b6..881fca6c 100644
--- a/src/persist/restore.rs
+++ b/src/persist/restore.rs
@@ -36,7 +36,7 @@ struct PaneRestoreStartup<'a> {
 
 struct RestoreRuntimeContext<'a> {
     scrollback_limit_bytes: usize,
-    default_shell: &'a str,
+    shell_config: crate::pane::PaneShellConfig<'a>,
     resume_agents_on_restore: bool,
     events: mpsc::Sender<AppEvent>,
     render_notify: Arc<Notify>,
@@ -68,6 +68,7 @@ pub fn restore(
     cols: u16,
     scrollback_limit_bytes: usize,
     default_shell: &str,
+    shell_mode: crate::config::ShellModeConfig,
     resume_agents_on_restore: bool,
     events: mpsc::Sender<AppEvent>,
     render_notify: Arc<Notify>,
@@ -80,7 +81,7 @@ pub fn restore(
         rows,
         cols,
         scrollback_limit_bytes,
-        default_shell,
+        crate::pane::PaneShellConfig::new(default_shell, shell_mode),
         resume_agents_on_restore,
         &mut imported_panes,
         events,
@@ -94,6 +95,7 @@ pub fn restore_handoff(
     snapshot: &SessionSnapshot,
     scrollback_limit_bytes: usize,
     default_shell: &str,
+    shell_mode: crate::config::ShellModeConfig,
     imports: &mut HashMap<u32, crate::handoff_runtime::ImportedHandoffRuntime>,
     events: mpsc::Sender<AppEvent>,
     render_notify: Arc<Notify>,
@@ -105,7 +107,7 @@ pub fn restore_handoff(
         24,
         80,
         scrollback_limit_bytes,
-        default_shell,
+        crate::pane::PaneShellConfig::new(default_shell, shell_mode),
         false,
         imports,
         events,
@@ -159,7 +161,7 @@ fn restore_with_imports_strict(
     rows: u16,
     cols: u16,
     scrollback_limit_bytes: usize,
-    default_shell: &str,
+    shell_config: crate::pane::PaneShellConfig<'_>,
     resume_agents_on_restore: bool,
     imported_panes: &mut HashMap<u32, crate::handoff_runtime::ImportedHandoffRuntime>,
     events: mpsc::Sender<AppEvent>,
@@ -172,7 +174,7 @@ fn restore_with_imports_strict(
         rows,
         cols,
         scrollback_limit_bytes,
-        default_shell,
+        shell_config,
         resume_agents_on_restore,
         imported_panes,
         events,
@@ -199,7 +201,7 @@ fn restore_with_imports(
     rows: u16,
     cols: u16,
     scrollback_limit_bytes: usize,
-    default_shell: &str,
+    shell_config: crate::pane::PaneShellConfig<'_>,
     resume_agents_on_restore: bool,
     imported_panes: &mut HashMap<u32, crate::handoff_runtime::ImportedHandoffRuntime>,
     events: mpsc::Sender<AppEvent>,
@@ -212,7 +214,7 @@ fn restore_with_imports(
         rows,
         cols,
         scrollback_limit_bytes,
-        default_shell,
+        shell_config,
         resume_agents_on_restore,
         imported_panes,
         events,
@@ -228,7 +230,7 @@ fn restore_with_imports_and_failures(
     rows: u16,
     cols: u16,
     scrollback_limit_bytes: usize,
-    default_shell: &str,
+    shell_config: crate::pane::PaneShellConfig<'_>,
     resume_agents_on_restore: bool,
     imported_panes: &mut HashMap<u32, crate::handoff_runtime::ImportedHandoffRuntime>,
     events: mpsc::Sender<AppEvent>,
@@ -243,7 +245,7 @@ fn restore_with_imports_and_failures(
     for (idx, ws_snap) in snapshot.workspaces.iter().enumerate() {
         let runtime_context = RestoreRuntimeContext {
             scrollback_limit_bytes,
-            default_shell,
+            shell_config,
             resume_agents_on_restore,
             events: events.clone(),
             render_notify: render_notify.clone(),
@@ -454,7 +456,7 @@ fn restore_tab(
                 cwd.clone(),
                 runtime_context.scrollback_limit_bytes,
                 crate::terminal_theme::TerminalTheme::default(),
-                runtime_context.default_shell,
+                runtime_context.shell_config,
                 startup.initial_history_ansi,
                 runtime_context.events.clone(),
                 runtime_context.render_notify.clone(),
@@ -1053,6 +1055,7 @@ mod tests {
             80,
             0,
             "/bin/true",
+            crate::config::ShellModeConfig::NonLogin,
             false,
             events,
             Arc::new(Notify::new()),
@@ -1152,6 +1155,7 @@ mod tests {
             80,
             0,
             "/bin/sh",
+            crate::config::ShellModeConfig::NonLogin,
             true,
             events,
             Arc::new(Notify::new()),
@@ -1187,6 +1191,7 @@ mod tests {
             40,
             4096,
             "/bin/sh",
+            crate::config::ShellModeConfig::NonLogin,
             false,
             events,
             render_notify,
@@ -1225,6 +1230,7 @@ mod tests {
             40,
             4096,
             "/bin/sh",
+            crate::config::ShellModeConfig::NonLogin,
             false,
             events,
             render_notify,
diff --git a/src/server/notifications.rs b/src/server/notifications.rs
index 0ed681ac..f0b2d746 100644
--- a/src/server/notifications.rs
+++ b/src/server/notifications.rs
@@ -113,7 +113,7 @@ mod tests {
             live_cwd.clone(),
             0,
             crate::terminal_theme::TerminalTheme::default(),
-            "/bin/sh",
+            crate::pane::PaneShellConfig::new("/bin/sh", crate::config::ShellModeConfig::NonLogin),
             events,
             std::sync::Arc::new(tokio::sync::Notify::new()),
             std::sync::Arc::new(std::sync::atomic::AtomicBool::new(false)),
diff --git a/src/terminal/runtime.rs b/src/terminal/runtime.rs
index b1a25ee9..c7bb8810 100644
--- a/src/terminal/runtime.rs
+++ b/src/terminal/runtime.rs
@@ -84,7 +84,7 @@ impl TerminalRuntime {
         cwd: std::path::PathBuf,
         scrollback_limit_bytes: usize,
         host_terminal_theme: crate::terminal_theme::TerminalTheme,
-        default_shell: &str,
+        shell_config: crate::pane::PaneShellConfig<'_>,
         events: mpsc::Sender<AppEvent>,
         render_notify: Arc<Notify>,
         render_dirty: Arc<AtomicBool>,
@@ -96,7 +96,7 @@ impl TerminalRuntime {
             cwd,
             scrollback_limit_bytes,
             host_terminal_theme,
-            default_shell,
+            shell_config,
             events,
             render_notify,
             render_dirty,
@@ -111,7 +111,7 @@ impl TerminalRuntime {
         cwd: std::path::PathBuf,
         scrollback_limit_bytes: usize,
         host_terminal_theme: crate::terminal_theme::TerminalTheme,
-        default_shell: &str,
+        shell_config: crate::pane::PaneShellConfig<'_>,
         initial_history_ansi: Option<&str>,
         events: mpsc::Sender<AppEvent>,
         render_notify: Arc<Notify>,
@@ -124,7 +124,7 @@ impl TerminalRuntime {
             cwd,
             scrollback_limit_bytes,
             host_terminal_theme,
-            default_shell,
+            shell_config,
             initial_history_ansi,
             events,
             render_notify,
diff --git a/src/ui/mobile.rs b/src/ui/mobile.rs
index c1dd57b6..9b400f51 100644
--- a/src/ui/mobile.rs
+++ b/src/ui/mobile.rs
@@ -1005,7 +1005,7 @@ mod tests {
             live_cwd.clone(),
             0,
             crate::terminal_theme::TerminalTheme::default(),
-            "/bin/sh",
+            crate::pane::PaneShellConfig::new("/bin/sh", crate::config::ShellModeConfig::NonLogin),
             events,
             std::sync::Arc::new(tokio::sync::Notify::new()),
             std::sync::Arc::new(std::sync::atomic::AtomicBool::new(false)),
diff --git a/src/ui/sidebar.rs b/src/ui/sidebar.rs
index 4c68aeb4..692e0236 100644
--- a/src/ui/sidebar.rs
+++ b/src/ui/sidebar.rs
@@ -1286,7 +1286,7 @@ mod tests {
             live_cwd.clone(),
             0,
             crate::terminal_theme::TerminalTheme::default(),
-            "/bin/sh",
+            crate::pane::PaneShellConfig::new("/bin/sh", crate::config::ShellModeConfig::NonLogin),
             events,
             std::sync::Arc::new(tokio::sync::Notify::new()),
             std::sync::Arc::new(std::sync::atomic::AtomicBool::new(false)),
diff --git a/src/workspace.rs b/src/workspace.rs
index a302f3f8..4bab61a7 100644
--- a/src/workspace.rs
+++ b/src/workspace.rs
@@ -103,7 +103,7 @@ impl Workspace {
         cols: u16,
         scrollback_limit_bytes: usize,
         host_terminal_theme: crate::terminal_theme::TerminalTheme,
-        default_shell: &str,
+        shell_config: crate::pane::PaneShellConfig<'_>,
         events: mpsc::Sender<AppEvent>,
         render_notify: Arc<Notify>,
         render_dirty: Arc<AtomicBool>,
@@ -114,7 +114,7 @@ impl Workspace {
             cols,
             scrollback_limit_bytes,
             host_terminal_theme,
-            default_shell,
+            shell_config,
             events,
             render_notify,
             render_dirty,
@@ -139,7 +139,7 @@ impl Workspace {
             cols,
             scrollback_limit_bytes,
             host_terminal_theme,
-            "",
+            crate::pane::PaneShellConfig::new("", crate::config::ShellModeConfig::NonLogin),
             events,
             render_notify,
             render_dirty,
@@ -154,7 +154,7 @@ impl Workspace {
         cols: u16,
         scrollback_limit_bytes: usize,
         host_terminal_theme: crate::terminal_theme::TerminalTheme,
-        default_shell: &str,
+        shell_config: crate::pane::PaneShellConfig<'_>,
         events: mpsc::Sender<AppEvent>,
         render_notify: Arc<Notify>,
         render_dirty: Arc<AtomicBool>,
@@ -181,7 +181,7 @@ impl Workspace {
                 cols,
                 scrollback_limit_bytes,
                 host_terminal_theme,
-                default_shell,
+                shell_config,
                 events,
                 render_notify,
                 render_dirty,
@@ -244,7 +244,7 @@ impl Workspace {
         cwd: PathBuf,
         scrollback_limit_bytes: usize,
         host_terminal_theme: crate::terminal_theme::TerminalTheme,
-        default_shell: &str,
+        shell_config: crate::pane::PaneShellConfig<'_>,
     ) -> std::io::Result<(usize, TerminalState, TerminalRuntime)> {
         self.create_tab_with_runtime(
             rows,
@@ -252,7 +252,7 @@ impl Workspace {
             cwd,
             scrollback_limit_bytes,
             host_terminal_theme,
-            default_shell,
+            shell_config,
             None,
         )
     }
@@ -264,7 +264,7 @@ impl Workspace {
         cwd: PathBuf,
         scrollback_limit_bytes: usize,
         host_terminal_theme: crate::terminal_theme::TerminalTheme,
-        default_shell: &str,
+        shell_config: crate::pane::PaneShellConfig<'_>,
         argv: Option<&[String]>,
     ) -> std::io::Result<(usize, TerminalState, TerminalRuntime)> {
         let number = self.tabs.len() + 1;
@@ -302,7 +302,7 @@ impl Workspace {
                 cols,
                 scrollback_limit_bytes,
                 host_terminal_theme,
-                default_shell,
+                shell_config,
                 events,
                 render_notify,
                 render_dirty,
@@ -368,7 +368,7 @@ impl Workspace {
         cwd: Option<PathBuf>,
         scrollback_limit_bytes: usize,
         host_terminal_theme: crate::terminal_theme::TerminalTheme,
-        default_shell: &str,
+        shell_config: crate::pane::PaneShellConfig<'_>,
     ) -> std::io::Result<crate::workspace::tab::NewPane> {
         let new_pane = self
             .active_tab_mut()
@@ -380,7 +380,7 @@ impl Workspace {
                 cwd,
                 scrollback_limit_bytes,
                 host_terminal_theme,
-                default_shell,
+                shell_config,
             )?;
         self.register_new_pane(new_pane.pane_id);
         Ok(new_pane)
@@ -395,7 +395,7 @@ impl Workspace {
         cwd: Option<PathBuf>,
         scrollback_limit_bytes: usize,
         host_terminal_theme: crate::terminal_theme::TerminalTheme,
-        default_shell: &str,
+        shell_config: crate::pane::PaneShellConfig<'_>,
         focus_new_pane: bool,
     ) -> Option<std::io::Result<(usize, crate::workspace::tab::NewPane)>> {
         self.split_pane_with_runtime(
@@ -406,7 +406,7 @@ impl Workspace {
             cwd,
             scrollback_limit_bytes,
             host_terminal_theme,
-            default_shell,
+            shell_config,
             focus_new_pane,
             None,
         )
@@ -433,7 +433,7 @@ impl Workspace {
             cwd,
             scrollback_limit_bytes,
             host_terminal_theme,
-            "",
+            crate::pane::PaneShellConfig::new("", crate::config::ShellModeConfig::NonLogin),
             focus_new_pane,
             Some(argv),
         )
@@ -449,7 +449,7 @@ impl Workspace {
         cwd: Option<PathBuf>,
         scrollback_limit_bytes: usize,
         host_terminal_theme: crate::terminal_theme::TerminalTheme,
-        default_shell: &str,
+        shell_config: crate::pane::PaneShellConfig<'_>,
         focus_new_pane: bool,
         argv: Option<&[String]>,
     ) -> Option<std::io::Result<(usize, crate::workspace::tab::NewPane)>> {
@@ -475,7 +475,7 @@ impl Workspace {
                 cwd,
                 scrollback_limit_bytes,
                 host_terminal_theme,
-                default_shell,
+                shell_config,
             )
         } {
             Ok(new_pane) => new_pane,
diff --git a/src/workspace/tab.rs b/src/workspace/tab.rs
index 100e67d0..f3ad594e 100644
--- a/src/workspace/tab.rs
+++ b/src/workspace/tab.rs
@@ -53,7 +53,7 @@ impl Tab {
         cols: u16,
         scrollback_limit_bytes: usize,
         host_terminal_theme: crate::terminal_theme::TerminalTheme,
-        default_shell: &str,
+        shell_config: crate::pane::PaneShellConfig<'_>,
         events: mpsc::Sender<AppEvent>,
         render_notify: Arc<Notify>,
         render_dirty: Arc<AtomicBool>,
@@ -65,7 +65,7 @@ impl Tab {
             cols,
             scrollback_limit_bytes,
             host_terminal_theme,
-            default_shell,
+            shell_config,
             events,
             render_notify,
             render_dirty,
@@ -92,7 +92,7 @@ impl Tab {
             cols,
             scrollback_limit_bytes,
             host_terminal_theme,
-            "",
+            crate::pane::PaneShellConfig::new("", crate::config::ShellModeConfig::NonLogin),
             events,
             render_notify,
             render_dirty,
@@ -108,7 +108,7 @@ impl Tab {
         cols: u16,
         scrollback_limit_bytes: usize,
         host_terminal_theme: crate::terminal_theme::TerminalTheme,
-        default_shell: &str,
+        shell_config: crate::pane::PaneShellConfig<'_>,
         events: mpsc::Sender<AppEvent>,
         render_notify: Arc<Notify>,
         render_dirty: Arc<AtomicBool>,
@@ -136,7 +136,7 @@ impl Tab {
                 initial_cwd.clone(),
                 scrollback_limit_bytes,
                 host_terminal_theme,
-                default_shell,
+                shell_config,
                 events.clone(),
                 render_notify.clone(),
                 render_dirty.clone(),
@@ -194,7 +194,7 @@ impl Tab {
         cwd: Option<PathBuf>,
         scrollback_limit_bytes: usize,
         host_terminal_theme: crate::terminal_theme::TerminalTheme,
-        default_shell: &str,
+        shell_config: crate::pane::PaneShellConfig<'_>,
     ) -> std::io::Result<NewPane> {
         self.split_focused_with_runtime(
             direction,
@@ -203,7 +203,7 @@ impl Tab {
             cwd,
             scrollback_limit_bytes,
             host_terminal_theme,
-            default_shell,
+            shell_config,
             None,
         )
     }
@@ -226,7 +226,7 @@ impl Tab {
             cwd,
             scrollback_limit_bytes,
             host_terminal_theme,
-            "",
+            crate::pane::PaneShellConfig::new("", crate::config::ShellModeConfig::NonLogin),
             Some(SplitCommand::Shell { command, extra_env }),
         )
     }
@@ -248,7 +248,7 @@ impl Tab {
             cwd,
             scrollback_limit_bytes,
             host_terminal_theme,
-            "",
+            crate::pane::PaneShellConfig::new("", crate::config::ShellModeConfig::NonLogin),
             Some(SplitCommand::Argv { argv }),
         )
     }
@@ -261,7 +261,7 @@ impl Tab {
         cwd: Option<PathBuf>,
         scrollback_limit_bytes: usize,
         host_terminal_theme: crate::terminal_theme::TerminalTheme,
-        default_shell: &str,
+        shell_config: crate::pane::PaneShellConfig<'_>,
         command: Option<SplitCommand<'_>>,
     ) -> std::io::Result<NewPane> {
         let previous_focus = self.layout.focused();
@@ -308,7 +308,7 @@ impl Tab {
                 actual_cwd.clone(),
                 scrollback_limit_bytes,
                 host_terminal_theme,
-                default_shell,
+                shell_config,
                 self.events.clone(),
                 self.render_notify.clone(),
                 self.render_dirty.clone(),