[FEATURE] Let a session start another session programmatically, visible in the sidebar

Problem Statement

We want to start Claude Code sessions without a person clicking, and still have each one show up in the desktop sidebar as a real conversation.

The visibility is the part we cannot give up. When an agent reaches a decision only a human can make, someone has to open that exact conversation and carry on from there. Today anything we can start programmatically is invisible in the app, and the only thing that is visible requires a click.

Proposed Solution

Expose mcp__ccd_session__start_session (and hand_off_to_session). They appear to exist already on the ccd_session MCP server, next to spawn_task, but behind a server-side feature flag (2371478310).

With them, a session could start another session, get its id back, and the new session would show up in the sidebar like any other, with the parent able to stop or detach it.

Alternative Solutions

• claude -p runs fine headlessly, but its transcript records "entrypoint":"sdk-cli", and the desktop app filters those out of its session list.
• claude --bg runs, but does not appear in the sidebar, and its sessions do not reliably survive.
• spawn_task does give a real sidebar session, but needs a human click for each one, which is the thing we are trying to remove.

Priority

High - Significant impact on productivity

Feature Category

Developer tools/SDK

Use Case Example

1. A scheduled job picks the next ready ticket from our GitHub board.
2. It starts a session scoped to that ticket, in its own git worktree.
3. The session shows up in the sidebar, so we can see what is running at a glance.
4. If the agent needs a design decision or a physical device, we open that session and take over.
5. Otherwise it finishes on its own and opens a pull request.