plan agent: Improve open editor handoff

[aeschli]

Open a plan in an editor should work seamlessly
To look at:

• save as plan command on code block
• add a savePlan tool

[vs-code-engineering]

Hi @aeschli. As a member of the team, you can help us triage this issue by referring to https://github.com/microsoft/vscode-copilot/wiki/Copilot-Inbox-Tracker and assigning an owner directly.

[aeschli]

We started out the discussion with
a) a command option for handoffs
b) a new save-plan command that parses out the current conversation into a plan-ish markdown file

I brought up the concern that Github Copilot also wants to adopt handoffs, so surfacing a VS Code command ids is not practical. @digitarald did you mean VS Code command or slash command?
Do we need to worry about compatibility with Github Copilot?
What would the UX be. Code completion showing all VS Command ids? Only a few of them would make sense, and they will not be easy to find by normal users
In VS Code, there are only very few command IDs documented and kept stable: https://code.visualstudio.com/api/references/commands
Can you illustrate your suggestion here?

[pwang347]

Just thinking out loud, I wonder if handoffs are what we want for the planning -> file scenario. Seems maybe there could be some sort of tool like writeNotes or similar which the agent can write to some temporary/hidden file and access, then through the UI we could have a button to actually view the contents.

[OrenMe]

There's already the memories api for that, might be useful

[digitarald]

@aeschli Outside of suggesting a specific solution, I see two constraints:

1. When a user opt to Move Plan into Editor it open the plan in editor immediately.
2. If a user creates their own planning mode, they should be able to use the same mechanism to create an artifact from the chat response (root cause analysis, tdd, etc).

@jo-oikawa fyi, we need UX to shape a better plan-to-file handoff.