TL;DR When Claude proposes a task in a card, Start runs it in a new session, nested under the current one in the sidebar and, by default, in the same environment and the same folder; Do it here sends it to this session as a message; Options lets you pick environment, model, worktree and permissions before you click Start. If both sessions are going to touch files, turn Worktree on in Options before Start.
The card shows up when Claude, while doing what you asked, finds something worth fixing that doesn't belong to that task: dead code, stale docs, a missing test, a confirmed TODO, a bug spotted in passing. Until now that idea had two fates: derail the current session or get lost. Now it's a card in the chat with a title, a one or two sentence summary and three buttons, and the session you start from it hangs under the current one in the sidebar.
The part that matters is in the fine print of Start: the nested session inherits the current session's environment, and in Desktop an environment works in the project folder itself unless Worktree is turned on. Two sessions editing one checkout is exactly what a worktree prevents.
This is what it looks like in my app (card and sidebar rebuilt from my screenshots of October 22, 2026, with neutral project names):
How it works
The Desktop session carries a tool Claude uses to propose a task outside the current one's scope: a title, a one or two sentence summary and a full prompt. The card shows the title and the summary, and you can open the whole prompt. That prompt is all the new session will know: it starts without the current conversation and on a checkout that may not have this session's changes, so the tool makes Claude write it self contained, with repository relative paths and whatever context it depends on. Claude can also withdraw a suggestion that has gone stale, as long as you haven't acted on it.
What each button does, per the Desktop docs:
- Start runs the task in another session. By default, in the current session's environment. The card then shows that session's state, and the sidebar lists it under the current one, the job Agent View does for the sessions you dispatch from the terminal. The release note adds that each nested session sends its own requests to your inference provider: it counts against your plan or your API like any other session.
- Do it here sends the task to the current session as a message. No new session: Claude does it next, with all the context it already has and your uncommitted changes in view.
- Options opens the settings of the session Start is about to create: environment, model, worktree and permissions. It's where you change where the task runs, before it exists.
- Start all appears when the card lists several tasks: it starts each one in its own session without waiting for the previous one to finish. Four tasks are four sessions sending requests at once.
- The X dismisses the card. The idea isn't saved anywhere, so if you want it later, write it down first.
Where the nested session runs
The Desktop docs say two things that together explain the risk. One: the task starts in the current session's environment. Two: Worktree is off by default, and with it off Claude works in the project folder itself. If your current session runs in the project folder, as most do, Start without a stop at Options opens a second session on the same checkout. While this session edits files, the nested one edits the same ones.
With Worktree on in Options, the nested session works in an isolated copy of the repository, under .claude/worktrees/ inside the project unless you changed the location in Settings. The price is the usual one with worktrees: the copy starts from what's committed, so it doesn't see this session's uncommitted changes, and at the end there's a branch to merge. Desktop's worktrees, and the disk they take, have a tip of their own.
The rule I use: Do it here when the task touches what I'm touching or needs what's already in the conversation; Start when it's independent, and then Options with Worktree if both sessions are going to write. I haven't measured in the app what happens when both write at once without a worktree: the docs only say they share the environment, and that's enough for me not to try it on a repo I care about.
In cloud sessions and on the earlier layout
In a cloud session, and in local or SSH sessions on the earlier Code tab layout, the card is called Suggested task and has one main button that says where the task will start, for example Send to cloud or Start with worktree. The other destinations, Do it here included, sit in the caret beside the button. That's the version Desktop added first, in v1.40609.0, for cloud sessions: tasks you start on your machine, in the cloud, or in the same session with one click. Third party deployments lost Send to cloud in v2.31226.0.
If your new session has no environment selector under the prompt box, you have the earlier layout: update the app from Claude → Check for Updates… on macOS or Help → Check for Updates… on Windows.
Reference
| Button | What it does | When |
|---|---|---|
| Start | New session, nested under the current one, in the same environment by default | An independent task; with Worktree in Options if both sessions write |
| Do it here | Sends the task to this session as a message | The task touches the same files or needs the current context |
| Options | Environment, model, worktree and permissions of the session Start will create | Before Start, whenever you don't want the current environment as is |
| Start all | One session per task, all at once | Several independent tasks; each one consumes on its own |
| X | Dismisses the card | The idea isn't worth it, or you note it somewhere else first |
Official docs: Start a task that Claude suggests · Run a session in its own worktree
Requirements
- Nested sessions and the card with Start, Do it here and Options arrived with the current Code tab layout, in Claude Desktop v3.1623.0 (bundling Claude Code 2.1.304), for local and SSH sessions. In the cloud and on the earlier layout, the Suggested task card with its caret.
- The screenshots are from my Mac on October 22, 2026.