Getting started
Which AI assistants can I use?
Any AI that supports MCP and can register a remote MCP server (HTTP) with OAuth authentication. The dia web app has setup steps for Claude (web and desktop), Claude Code, and Cursor. See Connect your AI.
How do I sign in?
With a Google account.
How do I stop an AI from using dia?
Open AI integration (AI 連携) in the sidebar and choose Disconnect (接続を解除) under Connected apps (接続中のアプリ). The disconnected AI can no longer use dia.
Diagrams
Can I move elements by hand?
No. dia lays out diagrams automatically. To move things, ask your AI to change the arrows, the groups (frames around elements), or the flow direction (top to bottom or left to right).
Can I edit text or colors in the web app?
No. Your AI edits diagram content. In the web app you can change the names of diagrams, documents, and projects, and the descriptions of documents and projects. To tell your AI exactly where to make a change, select the element and use Copy as AI instruction (AI への指示にコピー).
Can I reorder diagrams or move a diagram to another document?
Not in the web app. Ask your AI; it can reorder diagrams and copy them to another document.
Can I turn a standard document into a steps document later?
No. The kind is fixed when the document is created. Ask your AI to create a new steps document and copy the diagrams into it.
How long can names be?
Project, document, and diagram names can be up to 20 characters.
Sharing and downloading
Can people with the shared link edit my diagrams?
No. People with the link can view diagrams and descriptions and download them. They can’t see version history or the JSON. See Sharing and downloading.
How do I stop sharing?
In Share (共有), set General access (一般的なアクセス) to Restricted (制限付き). The current link stops working.
Why can’t I download a PNG?
The diagram is too large for PNG (the limit is 8 million pixels, width × height). Download it as SVG, or ask your AI to split the diagram.
Changes and deleting
My AI changed a diagram in a way I didn’t want. Can I undo it?
Yes. In Version history (バージョン履歴) in the right panel, open an earlier version and choose Restore this version (このバージョンに戻す). You can also ask your AI to restore the previous version.
Can I recover something I deleted?
No. Deleting a project, document, diagram, or icon can’t be undone. Deleting a diagram also deletes its version history.
I deleted a custom icon and now a diagram won’t display.
A diagram that uses a deleted icon can’t be displayed until your AI replaces the icon. Ask your AI to switch to a different icon.
Screen
Can I view diagrams on my phone?
Yes. On narrow screens, the diagram list and the description open as panels from the bottom of the screen, and Present, Download, and Share are in More actions (その他の操作).
Is there a dark mode?
Yes. Choose Light (ライト), Dark (ダーク), or System (システム) under Theme (テーマ) in the account menu, or in Settings (設定) → Account (アカウント). System follows your device’s setting.