Samuel, it works! 
I deleted the server, re-added https://newsblur.com/mcp, and this time the browser window opened and the OAuth went straight through. My AI assistant (Littlebird) can now see all 28 tools on my Premium Archive account, and I’ve just pulled my first live articles through it — correct stories, correct timestamps, the lot.
Thank you for digging into this properly. The diagnosis was genuinely interesting — I’d never have guessed that a missing browser user agent on the OAuth discovery requests was the culprit. It’s rare to get this level of attention from the person who built the thing, and as a very happy NewsBlur user of several years, I appreciate it hugely.
Thank you for NewsBlur. It’s a wonderful product.
This integration is a game-changer for me! And Premium Archive is well worth it!
Graham (GraBird)