WebMCP

WebMCP: A draft browser API for pages to register JavaScript tools that an in-browser agent can call. Example: The draft documents document.modelContext.registerTool(). Next in the glossary is Act layer: The part of agent readiness about completing tasks: MCP servers, CLIs, APIs with OpenAPI, WebMCP and agent payments.

Definition

A draft browser API for pages to register JavaScript tools that an in-browser agent can call.

Example, with source

The draft documents document.modelContext.registerTool(). (github.com, read 4 November 2026)

Where it appears on this site

• WebMCP
• Tool descriptions and agent success

Neighbouring terms

• Tool annotations: Hints on a tool such as readOnlyHint and destructiveHint that tell clients how risky a call is.