feat(quick-pane): add constrained agent window

ui/src-tauri/src/ui_state.rs

@@ -37,6 +37,34 @@ pub struct LastSeenState {
     pub last_activity: Option<String>,
 }
 
+#[derive(Clone, Debug, Deserialize, PartialEq, Serialize)]
+#[serde(rename_all = "camelCase", deny_unknown_fields)]
+pub struct QuickPaneSettings {
+    pub workspace: String,
+    pub provider: String,
+    pub model: String,
+    pub follow_up_provider: String,
+    pub follow_up_model: String,
+    pub instructions: String,
+    pub maximum_seconds: u32,
+    pub maximum_tool_calls: u32,
+}
+
+impl Default for QuickPaneSettings {
+    fn default() -> Self {
+        Self {
+            workspace: String::new(),
+            provider: String::new(),
+            model: String::new(),
+            follow_up_provider: String::new(),
+            follow_up_model: String::new(),
+            instructions: "Answer quickly. Do not use subagents. Prefer read-only inspection. Escalate mutations, multi-step work, or work likely to exceed budget.".to_owned(),
+            maximum_seconds: 60,
+            maximum_tool_calls: 6,
+        }
+    }
+}
+
 #[derive(Clone, Debug, Deserialize, PartialEq, Serialize)]
 #[serde(rename_all = "camelCase", deny_unknown_fields)]
 pub struct UiStateV1 {
@@ -61,6 +89,8 @@ pub struct UiStateV1 {
     pub default_new_session_worktree: Option<String>,
     #[serde(default, skip_serializing_if = "Option::is_none")]
     pub dismissed_collision_warning: Option<bool>,
+    #[serde(default)]
+    pub quick_pane: QuickPaneSettings,
 }
 
 impl Default for UiStateV1 {
@@ -77,6 +107,7 @@ impl Default for UiStateV1 {
             interface_scale: None,
             default_new_session_worktree: None,
             dismissed_collision_warning: None,
+            quick_pane: QuickPaneSettings::default(),
         }
     }
 }
@@ -182,6 +213,39 @@ pub fn validate(state: &UiStateV1) -> Result<(), String> {
     if total_string_bytes > MAX_TOTAL_STRING_BYTES {
         return Err("UI state strings exceed the total size limit".to_owned());
     }
+    let quick = &state.quick_pane;
+    let quick_is_default = quick.workspace.is_empty()
+        && quick.provider.is_empty()
+        && quick.model.is_empty()
+        && quick.follow_up_provider.is_empty()
+        && quick.follow_up_model.is_empty();
+    if !quick_is_default {
+        bounded(&quick.workspace, "quick-pane workspace")?;
+        if !Path::new(&quick.workspace).is_absolute() || !Path::new(&quick.workspace).is_dir() {
+            return Err("Quick-pane workspace must be an existing absolute directory".to_owned());
+        }
+        bounded(&quick.provider, "quick-pane provider")?;
+        bounded(&quick.model, "quick-pane model")?;
+        bounded(&quick.follow_up_provider, "quick-pane follow-up provider")?;
+        bounded(&quick.follow_up_model, "quick-pane follow-up model")?;
+    }
+    if quick.instructions.is_empty() || quick.instructions.len() > 4096 {
+        return Err("Quick-pane instructions must contain 1 to 4096 bytes".to_owned());
+    }
+    if !(1..=600).contains(&quick.maximum_seconds) || !(1..=64).contains(&quick.maximum_tool_calls)
+    {
+        return Err("Quick-pane limits are outside the supported range".to_owned());
+    }
+    total_string_bytes = total_string_bytes
+        .saturating_add(quick.workspace.len())
+        .saturating_add(quick.provider.len())
+        .saturating_add(quick.model.len())
+        .saturating_add(quick.follow_up_provider.len())
+        .saturating_add(quick.follow_up_model.len())
+        .saturating_add(quick.instructions.len());
+    if total_string_bytes > MAX_TOTAL_STRING_BYTES {
+        return Err("UI state strings exceed the total size limit".to_owned());
+    }
     if let Some(scale) = state.interface_scale {
         if !scale.is_finite() || !(0.5..=2.0).contains(&scale) {
             return Err("Interface scale is outside the supported range".to_owned());
@@ -368,6 +432,22 @@ mod tests {
             .collect()
     }
 
+    #[test]
+    fn quick_pane_settings_validate_complete_existing_workspace() {
+        let root = temp_dir("quick-pane");
+        fs::create_dir_all(&root).unwrap();
+        let mut state = UiStateV1::default();
+        state.quick_pane.workspace = root.to_string_lossy().into_owned();
+        state.quick_pane.provider = "provider".into();
+        state.quick_pane.model = "quick-model".into();
+        state.quick_pane.follow_up_provider = "provider".into();
+        state.quick_pane.follow_up_model = "follow-up-model".into();
+        assert!(validate(&state).is_ok());
+        state.quick_pane.maximum_seconds = 0;
+        assert!(validate(&state).is_err());
+        fs::remove_dir_all(root).unwrap();
+    }
+
     #[test]
     fn second_save_replaces_valid_state_without_leaving_temporary_files() {
         let root = temp_dir("replace");