diff --git a/docs/REFACTORING.md b/docs/REFACTORING.md
index a5fc2a2..3594c8b 100644
--- a/docs/REFACTORING.md
+++ b/docs/REFACTORING.md
@@ -235,6 +235,56 @@ talks only to `app.Service` and reacts to events via `fyne.Do`.
 
 ---
 
+## 3.1 Task completion checklist
+
+Track progress here. Mark tasks complete as they land and pass review.
+
+### Phase 0 — Safety net
+- [ ] T0.1 — Add test script + `go vet` + `go test -race`
+- [ ] T0.2 — Add characterization tests
+
+### Phase 1 — Split flat `core` package
+- [ ] T1.1 — Create `src/domain`; move Job/RunRecord/Config/etc
+- [ ] T1.2 — Create `src/platform/winproc`; move `configureHiddenWindow`
+- [ ] T1.3 — Create `src/runner`; move runner logic
+- [ ] T1.4 — Create `src/scheduler`; move scheduler
+- [ ] T1.5 — Create `src/storage`; move store/paths
+- [ ] T1.6 — Create `src/platform/autostart`; move autostart logic
+- [ ] T1.7 — Create `src/platform/desktop`; move desktop integration
+- [ ] T1.8 — Delete empty `src/core`; build + test both platforms
+
+### Phase 2 — Domain cleanup
+- [ ] T2.1 — Add `src/domain/schedule.go`; Schedule value object
+- [ ] T2.2 — Migrate `scheduler` to use Schedule
+- [ ] T2.3 — Split `domain.Job` (durable) from `domain.JobRuntime` (transient)
+- [ ] T2.4 — Update `storage`: load/save Job only; move runtime init
+
+### Phase 3 — Application service layer
+- [ ] T3.1 — Create `src/app/service.go`; owns state behind mutex
+- [ ] T3.2 — Add `src/app/events.go`; Event types + Observer
+- [ ] T3.3 — Add state-mutating operations to service
+- [ ] T3.4 — Convert `scheduler` to use service; inject Clock
+- [ ] T3.5 — Move display helpers to `src/app/format.go`
+- [ ] T3.6 — Add `src/app` unit tests (no Fyne)
+
+### Phase 4 — Carve up the GUI
+- [ ] T4.1 — Rename `gui` → `ui`; split app.go into run.go + mainwindow.go
+- [ ] T4.2 — Extract `jobs_view.go`
+- [ ] T4.3 — Extract `job_dialog.go`
+- [ ] T4.4 — Extract `history_view.go`
+- [ ] T4.5 — Extract `settings_view.go`
+- [ ] T4.6 — Extract `tray.go`, `singleinstance.go`, `layout.go`
+- [ ] T4.7 — Confirm app.go is gone; smoke test both platforms
+
+### Phase 5 — Hardening & docs
+- [ ] T5.1 — Surface errors from service + storage
+- [ ] T5.2 — Introduce `autostart.Manager` interface
+- [ ] T5.3 — Fill test gaps (folder filtering, cleanup, migration, concurrency)
+- [ ] T5.4 — Run `go test -race ./...` clean on both platforms
+- [ ] T5.5 — Update docs (ARCHITECTURE.md, TESTS.md, README)
+
+---
+
 ## 4. Definition of done
 
 - `go vet ./...` clean; `go test -race ./...` green on Windows and Linux.