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How to make and share diagrams with OpenCode

OpenCode (the open-source coding agent for the terminal) can draw architecture diagrams, flowcharts, and sequence diagrams, but on its own they end up as text in the chat or a file only you can open. Connect Diagram once and every diagram OpenCode makes becomes a link you can share, which stays current as the diagram changes.

Set up OpenCode, freeHow Diagram works

1. Connect Diagram to OpenCode

Add this to ~/.config/opencode/opencode.json (merge it if the file already has an "mcp" section):

{
  "$schema": "https://opencode.ai/config.json",
  "mcp": {
    "diagram": {
      "type": "remote",
      "url": "https://diagram.la/mcp",
      "enabled": true
    }
  }
}

Sign in once: Then run opencode mcp auth diagram: a browser tab opens to sign in with Google.

2. Ask for a diagram

Run opencode in your repo, then describe what you want in plain words. For example:

OpenCode draws it, keeps it in your repo’s diagrams/ folder, and gives you a link. You never have to mention Diagram again: it knows to use it.

3. Share the link

Paste it in Slack, a pull request, or a doc. Diagrams start private; add people to the project, share it with your team, or make one public. When it changes, ask OpenCode to update it: the link stays the same and every version is kept.

Questions

Is Diagram free to use with OpenCode?
Yes. Diagram is free for 5 projects, and there's nothing to install.
Who can see my diagrams?
Only you, until you share. Add people to a project, share it with your team through an org, or make a single diagram public so anyone with the link can open it.
What happens when the diagram changes?
Ask OpenCode to update it. The new version lands at the same link, and every earlier version is kept.
Does OpenCode need an API key?
No. OpenCode signs in to Diagram with your Google account in the browser.

Diagrams in other tools