Direct answer
Canvas is a human visual editor for app artifacts built as HTML or React projects that AgentGrid.io can load in the visual editor. Markdown documents and stored files are not Canvas artifacts. Preview shows the saved app; Canvas initializes an editable view. Historical versions are read-only. Apps with unsupported project structures stay Preview-only.
Human-controlled workflow
Instruct the human to enter Canvas, wait for first-entry initialization, edit supported elements, review the draft, use saved/Draft preview where shown, then select Save or press ⌘S. The durable verification is a new Version history entry.
State boundary
| State | Meaning |
|---|---|
| Saved state | Current artifact content that has reached AgentGrid.io and is available through normal artifact and agent workflows. |
| Draft | Unsaved Canvas work awaiting human review and Save. |
| Historical preview | Read-only prior revision. |
Do not claim access to a Canvas draft. Do not claim that an unsaved draft survives reload, session restart, or agent activity. Operate on the saved artifact unless the product explicitly supplies a different state.
Conflict and recovery rules
- Treat partial-write warnings as requiring human review before Save.
- If the artifact changed while Canvas was open, the page is stale: it no longer shows the latest saved version. Stop and ask the human to reload the current saved state.
- Do not overwrite a newer saved version to preserve an uncommitted draft.
- Recover an unwanted saved result through History compare or Restore.
- Publishing and restoration are not actions taken from a read-only historical view.
Alternatives
When Canvas is unavailable, initialization fails, or the project is preview-only, use a connected agent or Edit with AI. Canvas does not replace source-level editing.
Escalate persistent initialization or save failures through Troubleshooting.