Added Plan mode

Author: digitarald

release-notes/v1_106.md

@@ -73,6 +73,14 @@ Navigation End -->
 
 ## Chat
 
+### Plan Mode
+
+A new Plan Mode helps developers break down complex tasks step-by-step before any code is written. Select **Plan** from the agents dropdown in the Chat view to get started. When tackling a multi-step implementation, VS Code prompts you with clarifying questions and generates a detailed implementation plan that you approve first, ensuring all requirements and context are captured upfront.
+
+We recommend spending time iterating on the plan before implementation. You can refine requirements, adjust scope, and address open questions multiple times to build a solid foundation. Once you approve the plan, Copilot implements it either locally in VS Code or via [cloud agents](https://code.visualstudio.com/docs/copilot/copilot-coding-agent), giving you greater control and visibility into the development process. This helps you catch gaps or missing decisions early, reducing rework and improving code quality.
+
+You can also create your own custom plan agent tailored to your team's specific workflow and tools. Use the **Configure Custom Agent** menu to copy the built-in Plan Mode as a starting point, then customize the planning style, tools, and prompts to match your development process. Learn more about [planning in VS Code chat](https://code.visualstudio.com/docs/copilot/chat/chat-planning) and [creating custom agents](https://code.visualstudio.com/docs/copilot/customization/custom-agents).
+
 ### Agent Sessions
 
 The Agent Sessions view provides a centralized location for managing your active chat sessions, both local in VS Code and sessions created by background agents in other environments, such as [Copilot coding agent](/docs/copilot/copilot-coding-agent.md), [GitHub Copilot CLI](https://github.com/features/copilot/cli/), or [OpenAI's Codex](https://marketplace.visualstudio.com/items?itemName=OpenAI.chatgpt). The Agent Sessions view will be enabled by default, and it can be managed via the `setting(chat.agentSessionsViewLocation)` setting.
@@ -463,7 +471,7 @@ When you run the **Manage Accounts** command, you'll see a quick pick menu listi
 
 ### Python
 
-#### Python Environments Extension: Support for python.poetryPath setting 
+#### Python Environments Extension: Support for python.poetryPath setting
 The Python Environments Extension now respects the existing `python.poetryPath` user setting. This allows you to specify which Poetry executable to use. The provided path will be searched for and selected when managing Poetry environments.
 
 #### Python Environments Extension: Improved venv creation: dev-requirements.txt detection