Install Better Design from the ChatGPT plugin directory
ChatGPT and Codex share one plugin directory, so this listing is the same one the Codex app uses. Open the Plugins tab, open Better Design, select the plus button, and sign in when ChatGPT asks.
Use Better Design in a chat
Start a new chat after you install the plugin, because a chat that was already open does not load it. Type @ and choose Better Design to call it on purpose. The Installed row in the Plugins tab lists the plugins you have.
What the agent can use after setup
Better Design gives the agent design context and review tools. The agent still writes the code, and your repository stays the source of truth.
- Find a catalog design system or create one for your brand before frontend work starts.
- Load UI principles for visual choices and UX principles for flows and behavior.
- Get component and icon guidance that matches the chosen system.
- Run review rules, comprehension checks and spacing checks on rendered pages.
Fix the Better Design plugin in ChatGPT
- Better Design does not answer: start a new chat, then call it with @Better Design.
- ChatGPT asks you to sign in again: finish the sign-in, because the plugin needs it before its tools run.
- You cannot install plugins in a work account: your workspace administrator controls which plugins and MCP servers members can use.
- You removed the plugin but it still has access: disconnect the MCP server connection in ChatGPT too, because removing the plugin does not do that.
Questions
Do I need an API key for ChatGPT?
No. You sign in with OAuth when you install the plugin.
Is this the same plugin as in the Codex app?
Yes. ChatGPT and Codex use one plugin directory, and Codex in the ChatGPT desktop app installs the same listing.
Can I add Better Design as a custom MCP server instead?
Developer mode lets you add a custom MCP server for testing, but your account and workspace policy decide whether you can turn it on. The plugin is the simpler route.