There’s a reproducible bug in Figma’s OAuth (not MCP) flow for private apps.
If you are already logged into Figma with only an account that does not have access to your private OAuth app, then when you go to start the OAuth flow it crashes with a misleading error message:
“OAuth app with client id {your client id} doesn't exist”
Your app likely does exist, but Figma’s account selector is happening too late in the flow.
Unfortunately there is no prompt=select_account parameter implemented by Figma.
The solution is to completely sign out of Figma in the browser you are using to test the OAuth flow, then try again.
I hope this saves time for people searching for this.
Question
Bug Report: OAuth
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