INT. THE EDITOR YOU ALREADY USE — DAY
Keep the editor you already write in.
Lastslate Companion Mode is a small window that sits beside whatever you draft in. Point it at your script file and it reads the whole thing again every time you save, then answers questions about it — and tells you which scenes to go look at. It only ever reads. It never writes a word into your file.
macOS 12+ · Windows 10/11 · 64-bit · Free to download
Companion Mode opens from the File menu.
Three steps, then you forget it’s there
-
1
Choose your script file. Final Draft
.fdx, Fountain, plain text, or a PDF — saved anywhere on this computer. - 2 Keep writing in your editor. Every time you save, Lastslate picks up the change and says what moved — “Script updated · Scenes 33 and 34 changed.”
- 3 Ask anything. Pacing, character arcs, a scene that isn’t landing. Answers come back with the scene numbers to check. It analyzes; you write.
It never writes to your file
The companion opens your script read-only. It never holds a write handle, never saves over your work, and never leaves files next to it. There is no editor in that window, no pagination, no drafts — just the chat. The file stays exactly as your own editor left it, and nothing you write is ever used to train an AI model.
Ask about a passage without retyping it
Select a line or a scene in your editor and press the shortcut — ⌥⌘L on Mac, Ctrl+Shift+L on Windows. The passage arrives in the chat as an attachment and the window comes forward, ready for the question.
Tuck it away when you need the room
One click shrinks the window to a small pill that floats above your editor — still watching, still reading every save. Click the pill to bring the conversation back.
Works with the editor you have
Final Draft, Fade In, Highland, Slugline, or any plain-text editor that writes Fountain — the file on disk is the integration point, so nothing has to be installed into your editor. Switching scripts is one shortcut away, and each script keeps its own conversation.
Companion Mode lives in the File menu. On Windows? Lastslate for Windows.