DiagramHow to make diagrams in Codex
How to make diagrams in CodexAsk Codex CLI (OpenAI’s coding agent in the terminal) for a diagram in plain words and it draws one. On its own, the result stays in the chat or in a file only you can open. Connect Diagram once, and every diagram Codex CLI makes is saved at a link you can share, which stays current as the diagram changes. It takes three steps.
1. Connect Diagram to Codex CLI
Run this in a terminal, in your repo. It connects Diagram and starts Codex CLI:
codex mcp remove diagram ; codex mcp add diagram --url https://diagram.la/mcp ; codex "Set up Diagram for this repo, then ask me what to draw. If you don't have the Diagram tools, tell me the connection didn't work."
Sign in once: Codex opens a browser tab as soon as it adds Diagram: sign in to Diagram and click Allow.
2. Ask Codex CLI for a diagram
In Codex, then describe what you want in plain words. For example:
- “Make an architecture diagram of this repo and give me a link I can share.”
- “Draw the flow of a background job from the queue to the database.”
- “Diagram the modules in this package and what depends on what.”
- “Update the architecture diagram after the change you just made.”
Codex CLI draws it, saves it to Diagram as a draft only you can see, and gives you a link. Keep the link open: when you ask for a change, the page updates by itself. Nothing is left in a local file you’d have to remember to upload, and you never have to mention Diagram again: it knows to use it.
3. Publish it and share the link
When it looks right, tell Codex CLI to publish it. It asks first and says who will be able to see it: the people on its project. Then paste the link in Slack, a pull request, or a doc. To change it later, ask Codex CLI: the link stays the same and every version is kept.
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