Canvas pane

The Canvas is a second pane that opens to the right of the chat thread. It appears when the reply contains content the linear thread cannot hold well — a long code block, a Mermaid diagram, a structured document, a runnable Python script. Inline replies stay short and readable; everything else moves out of the way.

The Canvas is not a richer chat, and it is not a place you edit by hand. It is a live view of the chat's workspace — the files the agent writes, the files you upload, and the files code runs produce — surfaced without your having to ask.

What the Canvas is

The Canvas opens automatically the first time a reply produces Canvas-worthy content. It has two parts: a file tree on the left and a viewer on the right. The tree groups the chat's workspace files by where they came from — AI files the agent wrote (/user/code), Uploaded files you attached or @-pinned (/user/uploads), and Code output a run produced (/user/output); empty groups are hidden. Pick a file and it opens in the viewer, where you toggle between Source and Preview to read raw code or see the rendered result, and Download saves that file.

When it auto-opens

The Canvas opens for several render kinds the inline thread would crowd: Code (any language), HTML, Mermaid diagrams, SVG, long Markdown documents the agent produced, and runnable scripts — Python (sandbox), Node (sandbox), Script (sandbox). run_code executes over the chat's shared workspace — it reads scripts the agent wrote under /user/code and harvests whatever the run leaves in /user/output, so results surface as Code output rows in the file tree, not just beside the script; a run can also install packages on their own as a separate step, showing Installing dependencies while it works. Only agent-written and code-output files auto-open the Canvas — files you upload appear in the tree but do not grab the screen. Short snippets the inline thread can hold do not trigger the Canvas — a twenty-line script renders inline with its own Copy control, as below.

Editing in the Canvas

The Canvas is a render surface for whatever the agent produced. Editing the rendered content means asking the agent to revise it — a follow-up message in the thread ("change the timeout to 30 seconds", "make the diagram horizontal") triggers a new generation that replaces the Canvas content. There is no direct-edit mode; the agent owns the files it writes, and the files you upload stay exactly as you sent them.

Persistence across the chat

The Canvas content is part of the chat, not a separate file. Reopening the chat later reopens the Canvas with the latest content; switching to another chat closes the Canvas pane until that chat produces or carries Canvas content of its own. Sharing the chat with Share chat carries the Canvas across — the viewer sees the same Source / Preview toggle, in read-only mode.

Where this fits

The Canvas is the answer to "what happens when the reply is too big for the thread". It composes with everything else in Chat — agents, attachments, voice, shared chats — without those features needing to know about it. The next read that sometimes matters: Build a custom tool walks an agent that produces runnable Python in the Canvas, end to end, on a fresh instance.