WebMCP Challenge – OpenAI

I don’t understand the point of WebMCP. Any website that you could do interesting things with programmatically either already has an API or doesn’t want to provide programmatic access for business reasons. So who is this for?

If you care about web standards, please for the love of god do not participate in this challenge. “WebMCP” is an extension to the `document` global under `document.modelContext`. The `document` object exists to represent the visual and structural node tree of an application. The `modelContext` extension is essentially an API gateway, and this proposal staples a global RPC registry with structured JSON payloads onto the DOM. It ignores the standard Request/Response API, and it does all of its work on the main thread. It forces developers into manual state-synchronization hell just to maintain a facade for a screen-scraping LLM, meeting them halfway so increasingly capable bots can “book flights on your website.” The API makes no considerations for API versioning, so any WebMCP tools you write are carved in stone.

I have no idea who at Google is advocating for this, but it’s a half-baked idea that goes against 20 years of web standard work. At least put this under the `window` or `navigator` global, goddamn.