# Manual smoke — F6 diff-view toggle (live)

Pre-req: a real machine (not CI). Step 4 uses a live Claude turn — Claude Code
installed + signed in (the `claude-code` provider rides that login, INV-8). The
rest of F6 needs no credentials and no network.

1. `npm run build`, launch the extension (F5 in VS Code opens the committed
   `sandbox/` playground), open `playground.md`.
2. Edit a sentence by hand, then **Cmd/Ctrl-Alt-D** (or run **Cowriting: Toggle
   Diff View**). ✅ A diff opens: the readonly baseline on the left, your live
   document on the right; the tab title reads `playground.md — my changes since
   opened <time>`. Your hand edit shows as a change.
3. Keep typing **in the diff's right pane**. ✅ Editing continues in place;
   decorations/threads still work. Toggle again. ✅ The diff tab closes and the
   normal editor is back.
4. Select a sentence → right-click → **Ask Claude to Edit Selection** → give an
   instruction → **✓ Accept Proposal**. Now toggle the diff. ✅ The accepted
   text is **not** shown as a change (the baseline advanced past the landing —
   INV-18); only your own subsequent edits show.
5. Run **Cowriting: Pin Diff Baseline to Now**. ✅ The diff empties (baseline =
   now); the title reads `pinned <time>`. Type → your changes show against the
   pin.
6. Reload the window (Developer: Reload Window). ✅ Toggle: the baseline is the
   same as before the reload (persisted in workspace storage, not the repo —
   INV-19; `git status` shows nothing new).
7. Toggle on a file outside the workspace folder. ✅ A warning, no diff.