| name | fan-out-fan-in |
| description | Use this workflow skill only when the user wants explicit parallelization or the task should be split into isolated worktrees and merged back without separate PRs. |
Fan Out Fan In
Use this when the user explicitly wants parallel agent work or the task is naturally decomposable into independent file scopes.
Workflow
- Read the plan from a file such as
scratch/plan.md or from inline instructions.
- Record the parent branch and commit with
git branch --show-current and git rev-parse HEAD.
- Stop if
git status --short is not clean. Do not fan out from a dirty tree.
- Scan recent history and existing worktrees with
git log --oneline -20 and git worktree list so you do not duplicate work.
- Split the work into units that do not edit the same files. If two units need the same file, merge them or sequence them.
- For each unit, create an isolated worktree from the parent commit with
git worktree add ../worktree-unit-N -b fan-out-unit-N "$PARENT_COMMIT".
- In each worktree, implement only the assigned scope, run the relevant validation, and commit with
fan-out: [unit-name].
- Merge unit branches back into the parent branch one at a time, validating after each merge and again at the end.
- Remove successful worktrees and branches. Preserve failed ones for inspection.
Repo Rules
- Prefer repo validations over generic ones:
- TypeScript:
bun run lint, bun run build, bun test
- Fast repo checks:
bash scripts/all_fast_validate_checks.sh
- Android:
(cd android && ./gradlew <task>)
- Write logs that matter to
scratch/ if they are too long to inspect inline.
- Do not create PRs or push branches as part of fan-out work.
- Do not proceed if the work cannot be partitioned cleanly.
