Canvas

Canvas is the in-chat writing and editing workspace, and it is wired directly into Just4o.chat Files. Open Canvas from chat to start a blank draft or open an existing compatible file from your Files library. The file picker inside Canvas is populated from the same file manager that powers account and project files.

Canvas works best with text-first files. Plain text and Markdown files can be edited and saved back to Files. PDFs and supported document formats such as Word or RTF can also be opened, but they appear as extracted text for reference and are currently read only in Canvas.

Canvas also changes how the model works. Once Canvas is open, the model can directly use read and write-style tools in a loop: it can read line ranges from the active file, inspect what it finds, then propose diff-based edits back into the document and continue iterating. That extra tool use is powerful, but it can be more expensive than standard chat because the model may take multiple tool rounds and Canvas mode uses higher billing multipliers than a normal response.

Those tools are only attached when you actually bring up Canvas. In a normal chat, the model does not get Canvas read/write access, so there is no accidental Canvas token usage in the background.

The Files integration is scope-aware. If you create a new file from Canvas while chatting inside a project, saving that draft creates a project-scoped file in Just4o.chat Files. If you do the same in a global chat, the saved file lands in your global file library. That means Canvas is not a separate storage system—it is an editing layer on top of Files.