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A design canvas is the unit of work in Cortex Design: a persistent board of frames, notes and images with a reference of its own, the one you paste between surfaces. Every canvas is created from, and stays linked to, one thread. That thread is the canvas’s host, and a host is a Cortex Chat conversation or a Cortex Code session, never both at once. This page covers what lives on a canvas, how a canvas is created and which thread it belongs to, the two places canvases are listed, and what happens when you rename or delete one. It ends with the limits that apply.

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What a canvas holds

A new canvas is titled Untitled canvas until you rename it, and its host defaults to Chat.

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Not the same as the other canvases

Three things in Cortex are called a canvas or look like one, and they are separate objects that share no storage.

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Create a canvas

There are three ways in, and they produce the same object.
1

Ask for it inside a Chat or Code turn

Ask Cortex for the design in the thread. If it draws without naming an existing canvas, a new canvas is created and bound to the thread you are in. Cortex confirms in the transcript with a line naming the canvas, its revision and its counts, and says it can be opened in Cortex Design.From a Code session, a mode that only answers or only plans can read a canvas but not write one. Use a mode that can act. See Ask, Plan, Agent.
2

Use New canvas in the rail

The CANVASES rail beside a thread has a New canvas control, which creates an empty canvas hosted by that thread.
3

Use New design in the desktop app

In the Design window, New design (⌘N) opens a sheet asking for a NAME, what to START FROM, a BRIEF, and a MODEL. The Design quickstart walks through it field by field.

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The host thread

A canvas remembers which thread produced it, and the binding can be changed after the fact:
  • Attach a conversation and the canvas becomes Chat-hosted; any Code session binding is cleared.
  • Attach a Code session and the canvas becomes Code-hosted; any conversation binding is cleared.
  • Clear the binding and the canvas keeps its contents but shows no thread.
  • Attaching both kinds at once is refused: A Design canvas binds a Chat conversation or a Code session, not both.
  • You have to own the thread you are binding to. Another account’s thread answers as not found.
Deleting the host thread does not delete the canvas. It only unbinds it, and the canvas then shows no thread.

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The canvases rail, in the web app

Beside an open Chat thread or Code session, the rail is headed CANVASES and lists only the canvases whose host matches that surface and that thread. A Chat thread never shows Code canvases. If the list is long the rail says that it is showing the first canvases and that older ones are not listed yet. If it cannot load, it says Canvases could not be loaded. and offers Retry. A signed-out visitor gets no rail at all: it draws nothing rather than showing a locked state. The Design window opens on Designs, every canvas in your account rather than one thread’s worth. Each tile carries a version badge such as V7 and a source chip saying where the design came from: Chat, Code, Bot, Library or Blank. The header line under the title reports the state of the list: Nothing here yet before you have made anything, Syncing your designs… while it loads, and a count with the last sync time once it is loaded. When the service cannot be reached, the gallery does not pretend. It shows Couldn't reach Cortex — showing last sync {time}, or a banner headed Couldn't load your designs explaining that the list is your last sync, with Work offline and Retry. Canvases you already have open stay readable from the local cache, and edits queue and sync when you reconnect.
The Bot-managed filter belongs to a capability that is not available yet: a Cortex Bot cannot open or change a design canvas today, so nothing is bot-managed. See Bot jobs.

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Rename a design

Rename a design from the Design window. The host binding is unaffected, so the thread that started it still points at the same canvas. A title is at most 200 characters; a longer one is refused with A canvas title is at most 200 characters. The names you give your canvases, and the thread titles shown beside them, are encrypted at rest. See Security and privacy.

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Delete a design

Deleting a canvas hides it. Its versions and its images stay, so the canvas can come back.
  1. Choose delete on the design. The app confirms with a dialog naming the design, lists what goes with it, and offers Keep it or Delete design.
  2. A toast then offers Undo for ten seconds.
  3. After that window the canvas stays hidden until you restore it, permanently delete it, or erase the account. The general retention sweep does not remove design canvases you still hold.
  4. The thread the design came from is not affected.
A hidden canvas still counts as yours until it is permanently deleted, so it still occupies one of your 200 canvases. If you are at the cap, permanently delete a hidden canvas rather than only hiding another one.

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Limits

Creating a canvas past the cap is refused with This account already has the maximum number of Design canvases. See Quota exceeded. A canvas past the document limit is refused on save with This canvas is too large to save., and one with too many pieces on it with This canvas has too many nodes. Split the work across canvases when you hit either. A signed-out visitor is refused on every Design surface with Design canvases need an account. Sign in to keep your work. See Entitlement required. A canvas that belongs to another account answers exactly as one that does not exist, because Cortex does not reveal whether a canvas exists outside your account. See Not found.