I didn't. That would be both grossly unethical and, in the USA, illegal if I didn't disclose it.

See comment here: https://news.ycombinator.com/item?id=45624613

I'm getting accused of paid shilling a lot right now.

(If Anthropic had paid me to write this they would probably have asked me NOT to spend a section of the article pointing out flaws in their MCP specification!)