docs(plan): clarify interactive plan editing with Ctrl+X (#22076)

docs/cli/plan-mode.md

@@ -61,20 +61,44 @@ Gemini CLI takes action.
     [`ask_user`](../tools/ask-user.md). Provide your preferences to help guide
     the design.
 3.  **Review the plan:** Once Gemini CLI has a proposed strategy, it creates a
-    detailed implementation plan as a Markdown file in your plans directory. You
-    can open and read this file to understand the proposed changes.
+    detailed implementation plan as a Markdown file in your plans directory.
+    - **View:** You can open and read this file to understand the proposed
+      changes.
+    - **Edit:** Press `Ctrl+X` to open the plan directly in your configured
+      external editor.
+
 4.  **Approve or iterate:** Gemini CLI will present the finalized plan for your
     approval.
     - **Approve:** If you're satisfied with the plan, approve it to start the
       implementation immediately: **Yes, automatically accept edits** or **Yes,
       manually accept edits**.
-    - **Iterate:** If the plan needs adjustments, provide feedback. Gemini CLI
-      will refine the strategy and update the plan.
+    - **Iterate:** If the plan needs adjustments, provide feedback in the input
+      box or [edit the plan file directly](#collaborative-plan-editing). Gemini
+      CLI will refine the strategy and update the plan.
     - **Cancel:** You can cancel your plan with `Esc`.
 
 For more complex or specialized planning tasks, you can
 [customize the planning workflow with skills](#custom-planning-with-skills).
 
+### Collaborative plan editing
+
+You can collaborate with Gemini CLI by making direct changes or leaving comments
+in the implementation plan. This is often faster and more precise than
+describing complex changes in natural language.
+
+1.  **Open the plan:** Press `Ctrl+X` when Gemini CLI presents a plan for
+    review.
+2.  **Edit or comment:** The plan opens in your configured external editor (for
+    example, VS Code or Vim). You can:
+    - **Modify steps:** Directly reorder, delete, or rewrite implementation
+      steps.
+    - **Leave comments:** Add inline questions or feedback (for example, "Wait,
+      shouldn't we use the existing `Logger` class here?").
+3.  **Save and close:** Save your changes and close the editor.
+4.  **Review and refine:** Gemini CLI automatically detects the changes, reviews
+    your comments, and adjusts the implementation strategy. It then presents the
+    refined plan for your final approval.
+
 ## How to exit Plan Mode
 
 You can exit Plan Mode at any time, whether you have finalized a plan or want to

docs/reference/keyboard-shortcuts.md

@@ -229,6 +229,9 @@ a `key` combination.
   the numbered radio option and confirm when the full number is entered.
 - `Ctrl + O`: Expand or collapse paste placeholders (`[Pasted Text: X lines]`)
   inline when the cursor is over the placeholder.
+- `Ctrl + X` (while a plan is presented): Open the plan in an external editor to
+  [collaboratively edit or comment](../cli/plan-mode.md#collaborative-plan-editing)
+  on the implementation strategy.
 - `Double-click` on a paste placeholder (alternate buffer mode only): Expand to
   view full content inline. Double-click again to collapse.