Source of Truth with MDN MCP

AI cod­ing tools are becom­ing a nor­mal part of web devel­op­ment, but they still have a very prac­ti­cal prob­lem: they do not auto­mat­i­cal­ly know what changed after their train­ing cutoff.

A mod­el might know an old­er ver­sion of a CSS fea­ture. It might miss that a brows­er shipped sup­port last month. It might con­fuse two sim­i­lar APIs. Or it might give you a con­fi­dent answer about brows­er com­pat­i­bil­i­ty that sounds right but is out of date.

MDN’s new MCP serv­er is an attempt to give agents author­i­ta­tive, accu­rate infor­ma­tion about HTML, CSS, and JavaScript.