The launcher form that starts a session in the selected project: the shared composer plus the actual submit, the Context selector, and the system-prompt preview.

## TLDR

- A typed prompt starts an attended conversation; a preset starts unattended routine work that ends at settle with its armed handoff firing.
- The options sent and the prompt previewed come from the same mapping the run uses, so the form cannot disagree with the session it starts; a picked device relays the run there, its secret token riding in memory only.
- Preflight warnings spend words before the session is spent, never blocking: an untrusted project dooming a web run, an agent CLI that cannot start (the GitHub CLI checked only when a PR or merge is armed, nothing probed for Actions or device runs), a repo whose disabled auto-merge makes an armed merge land immediately, and Haiku's known failure to finish properly.
- A start answers immediately: an optimistic rail row appears and the view jumps to the run before its record exists.

## Before writing SPEC.md files

Read https://raw.githubusercontent.com/brillout/sdd/refs/heads/main/sdd.md
