feat(tui): lazy-create the session on first use with the v2 engine

apps/kimi-code/src/tui/commands/add-dir.ts

@@ -1,15 +1,19 @@
 import { NO_ACTIVE_SESSION_MESSAGE } from '../constant/kimi-tui';
 import { ChoicePickerComponent } from '../components/dialogs/choice-picker';
 import type { SlashCommandHost } from './dispatch';
+import { slashBusyMessage, slashCommandBusyReason } from './resolve';
 
 type AddDirChoice = 'session' | 'remember' | 'cancel';
 
 export async function handleAddDirCommand(host: SlashCommandHost, args: string): Promise<void> {
   const input = args.trim();
-  const session = host.session;
+  let session = host.session;
 
   if (input.length === 0 || input.toLowerCase() === 'list') {
-    const additionalDirs = session?.summary?.additionalDirs ?? [];
+    // With no session yet (v2 session-less startup) the pending startup
+    // directories live in appState and will be passed to the lazy-created
+    // session; reflect them instead of reporting an empty list.
+    const additionalDirs = session?.summary?.additionalDirs ?? host.state.appState.additionalDirs;
     if (additionalDirs.length === 0) {
       host.showStatus('No additional directories configured.');
       return;
@@ -19,8 +23,24 @@ export async function handleAddDirCommand(host: SlashCommandHost, args: string):
   }
 
   if (session === undefined) {
-    host.showError(NO_ACTIVE_SESSION_MESSAGE);
-    return;
+    if (!host.engineV2) {
+      host.showError(NO_ACTIVE_SESSION_MESSAGE);
+      return;
+    }
+    // The path-adding form needs a live session; lazy-create it on first use
+    // (the read-only `list`/bare forms above tolerate a missing session).
+    session = await host.ensureSession();
+    if (session === undefined) return;
+    // A first prompt may have started a turn during the await; /add-dir is
+    // idle-only, so re-check the busy gate resolved before it.
+    const busyReason = slashCommandBusyReason({
+      isStreaming: host.state.appState.streamingPhase !== 'idle',
+      isCompacting: host.state.appState.isCompacting,
+    });
+    if (busyReason !== undefined) {
+      host.showError(slashBusyMessage('add-dir', busyReason));
+      return;
+    }
   }
 
   host.mountEditorReplacement(

apps/kimi-code/src/tui/commands/config.ts

@@ -93,6 +93,13 @@ export async function handlePlanCommand(host: SlashCommandHost, args: string): P
     return;
   }
 
+  // The session may already be in the requested mode (e.g. it was created
+  // with config.defaultPlanMode applied), and re-entering plan mode throws.
+  if (host.state.appState.planMode === enabled) {
+    host.showNotice(`Plan mode is already ${enabled ? 'on' : 'off'}`);
+    return;
+  }
+
   await applyPlanMode(host, session, enabled);
 }
 
@@ -117,10 +124,12 @@ async function applyPlanMode(host: SlashCommandHost, session: Session, enabled:
 
 export async function handleYoloCommand(host: SlashCommandHost, args: string): Promise<void> {
   const session = host.session;
-  if (session === undefined) {
+  if (session === undefined && !host.engineV2) {
     host.showError(NO_ACTIVE_SESSION_MESSAGE);
     return;
   }
+  // v2 session-less: the chosen mode is recorded in appState and passed to the
+  // lazy-created session; apply the runtime permission only when one exists.
 
   const subcmd = args.trim().toLowerCase();
   const currentMode = host.state.appState.permissionMode;
@@ -130,7 +139,7 @@ export async function handleYoloCommand(host: SlashCommandHost, args: string): P
       host.showNotice('YOLO mode is already on');
       return;
     }
-    await session.setPermission('yolo');
+    await session?.setPermission('yolo');
     host.setAppState({ permissionMode: 'yolo' });
     host.showNotice('YOLO mode: ON', 'Tool actions auto-approved; the agent may still ask you questions.');
     return;
@@ -141,30 +150,32 @@ export async function handleYoloCommand(host: SlashCommandHost, args: string): P
       host.showNotice('YOLO mode is already off');
       return;
     }
-    await session.setPermission('manual');
+    await session?.setPermission('manual');
     host.setAppState({ permissionMode: 'manual' });
     host.showNotice('YOLO mode: OFF');
     return;
   }
 
   // toggle
   if (currentMode === 'yolo') {
-    await session.setPermission('manual');
+    await session?.setPermission('manual');
     host.setAppState({ permissionMode: 'manual' });
     host.showNotice('YOLO mode: OFF');
   } else {
-    await session.setPermission('yolo');
+    await session?.setPermission('yolo');
     host.setAppState({ permissionMode: 'yolo' });
     host.showNotice('YOLO mode: ON', 'Tool actions auto-approved; the agent may still ask you questions.');
   }
 }
 
 export async function handleAutoCommand(host: SlashCommandHost, args: string): Promise<void> {
   const session = host.session;
-  if (session === undefined) {
+  if (session === undefined && !host.engineV2) {
     host.showError(NO_ACTIVE_SESSION_MESSAGE);
     return;
   }
+  // v2 session-less: the chosen mode is recorded in appState and passed to the
+  // lazy-created session; apply the runtime permission only when one exists.
 
   const subcmd = args.trim().toLowerCase();
   const currentMode = host.state.appState.permissionMode;
@@ -174,7 +185,7 @@ export async function handleAutoCommand(host: SlashCommandHost, args: string): P
       host.showNotice('Auto mode is already on');
       return;
     }
-    await session.setPermission('auto');
+    await session?.setPermission('auto');
     host.setAppState({ permissionMode: 'auto' });
     host.showNotice('Auto mode: ON', 'All actions auto-approved; the agent will not ask you questions.');
     return;
@@ -185,19 +196,19 @@ export async function handleAutoCommand(host: SlashCommandHost, args: string): P
       host.showNotice('Auto mode is already off');
       return;
     }
-    await session.setPermission('manual');
+    await session?.setPermission('manual');
     host.setAppState({ permissionMode: 'manual' });
     host.showNotice('Auto mode: OFF');
     return;
   }
 
   // toggle
   if (currentMode === 'auto') {
-    await session.setPermission('manual');
+    await session?.setPermission('manual');
     host.setAppState({ permissionMode: 'manual' });
     host.showNotice('Auto mode: OFF');
   } else {
-    await session.setPermission('auto');
+    await session?.setPermission('auto');
     host.setAppState({ permissionMode: 'auto' });
     host.showNotice('Auto mode: ON', 'All actions auto-approved; the agent will not ask you questions.');
   }
@@ -463,6 +474,14 @@ async function performModelSwitch(
   effort: ThinkingEffort,
   persist: boolean,
 ): Promise<void> {
+  let session = host.session;
+  if (session === undefined && host.engineV2) {
+    // A first prompt may still be inside lazy creation: wait it out so the
+    // switch lands on the new session instead of being overwritten by its
+    // assembly.
+    await host.waitForLazyCreation();
+    session = host.session;
+  }
   if (host.state.appState.streamingPhase !== 'idle') {
     host.showError('Cannot switch models while streaming — press Esc or Ctrl-C first.');
     return;
@@ -476,7 +495,6 @@ async function performModelSwitch(
   let effectiveAlias = alias;
   let effectiveEffort = effort;
 
-  const session = host.session;
   try {
     if (session === undefined && runtimeChanged) {
       await host.authFlow.activateModelAfterLogin(alias, effort);
@@ -875,7 +893,14 @@ async function applyPermissionChoice(host: SlashCommandHost, mode: PermissionMod
   }
 
   try {
-    await host.requireSession().setPermission(mode);
+    if (host.session !== undefined) {
+      await host.session.setPermission(mode);
+    } else if (!host.engineV2) {
+      host.showError(NO_ACTIVE_SESSION_MESSAGE);
+      return;
+    }
+    // v2 session-less: the chosen mode is recorded in appState and passed to
+    // the lazy-created session.
   } catch (error) {
     const msg = formatErrorMessage(error);
     host.showError(`Failed to set permission mode: ${msg}`);