Run a phase
An epic is a plan. This is where it becomes commits.
You do not have to run all of it. A phase at a time is the normal way, and the first one is the one worth watching.
Plan first, run second
On the epic screen there are three buttons and the difference between them matters.
Plan Structure First works out the phases and what belongs in each. It writes nothing to your code.
Generate All Phases fills those phases with work units. Still nothing written to your code.
Run Phase 1 Only is the first one that touches a repository.
Everything before that last button is a plan you can argue with. That is the point of the split, and it is why an epic prepared for you arrives generated but not run.
What a run does
It takes one phase, works through its work units in order, and commits as it goes. Each work unit has acceptance criteria written when the epic was decomposed, and those are what it is working against.
It runs on a branch. Your default branch is not touched.
Watching it
The phase card shows which work unit is in flight and what it has finished. The log is the full record of what the model was asked and what it answered, and it is kept whether the run succeeded or not.
You can stop it. A stopped run leaves the commits it already made, on the branch it made them on.
When a work unit fails
It stops on that work unit rather than carrying on past it. The failure is on the card with the error that caused it.
Fix the cause and resume. It picks up at the work unit that failed, not at the beginning of the phase.
How you know it failed
Nothing happens after you press it. Check the AI key. A run needs a working Claude key on the active galaxy, and a key that was valid when you added it can have been rotated since.
It stops on the first work unit every time. Usually the branch. If the repository has uncommitted changes from something else, the run refuses rather than committing on top of work it did not make.
Commits appear but the tests do not pass. That is a real result, not a malfunction. The acceptance criteria are in the work unit and the gap between them and the code is the thing to read.