Already 14 months old when the scout caught it.
WebMCP
What it is
A proposed web standard, incubating in the W3C Web Machine Learning Community Group, that lets a web page declare its own functions — JavaScript calls or plain HTML forms — as named, schema-typed tools an in-browser AI agent can discover and invoke directly. Instead of an agent scraping the DOM and guessing what a button does, the site publishes its capabilities (via an API surface such as navigator.modelContext) the same way a server exposes an MCP tool list. Despite the name, sources are split on how literally it implements the MCP wire protocol versus simply borrowing its tool-description shape; it's best understood as a sibling spec aimed at the browser rather than an extension of MCP itself.
Why it's emerging now
It's a synthesis of two separate 2025 efforts — a Microsoft "Web Model Context" explainer and an open-source Chrome extension project (MCP-B) — that the Chrome and Edge teams merged into one W3C proposal. Chrome shipped an early preview in Chrome 146 Canary and has since moved it toward an origin trial (Chrome 149) with DevTools support, which is what's driven a wave of "what is WebMCP" explainers from practitioner blogs and dev-tooling vendors this year. It's a backfill relative to when it actually cleared two independent sources (around February 2026) — search surfaced it only now because the recent Chrome DevTools work reignited coverage — but it isn't on your ledger and is a genuinely distinct concept from MCP itself, so it's worth briefing despite being months old.
How it relates to what you know
It's the browser-native counterpart to MCP already on your ledger: MCP standardizes how a model-serving application discovers and calls tools on a server; WebMCP standardizes the same discovery-and-call pattern for tools a web page exposes directly to a browser-resident agent, without a separate MCP server in between. It's a concrete instance of the same "sites declare machine-actionable capabilities" shift behind the agentic-commerce and personal-agent protocols you've seen elsewhere (Legal Context Protocol, Personal Agent Protocol) — here applied to ordinary websites rather than business APIs.