Agent ↔ tools and data
WebMCP
A proposed browser API that lets web pages expose JavaScript functions as tools that AI agents in the browser can call.
- Status
- Draft Community Group Report (2 October 2026)
- Governance
- W3C Web Machine Learning Community Group (editors from Microsoft and Google)
- Sources
- Project siteSpecification
What to know
- Pages register tools through a ModelContext interface on the document, and there is also a declarative form-based variant.
- It is a Community Group report, not a W3C Standard and not on the Standards Track.
- The draft includes a permissions policy integration and a security section covering prompt injection.
- A web-platform-tests suite tracks browser implementations.
When to use it
Use it when you want browser-based agents to do things on your site through defined functions instead of clicking through the UI.
Related standards
MCP · Model Context ProtocolA2A · Agent2Agent ProtocolSKILL.md · Agent SkillsAGENTS.md · AGENTS.mdACP · Agent Client ProtocolPAP · Personal Agent ProtocolAG-UI · Agent User Interaction Protocol (AG-UI)A2UI · A2UIMCP Apps · MCP AppsTAP · Trusted Agent ProtocolPACT · Personal Agent Consent & Trust Protocol (PACT)ANP · Agent Network ProtocolOASF · Open Agentic Schema Frameworkllms.txt · llms.txtAgent Spec · Open Agent Specification
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Reviewed Oct 7, 2026. Spotted something out of date? Email hello@agentatlas.dev.