WebMCP vs. MCP: what runs in the browser, what runs elsewhere
A practical map of where browser-exposed WebMCP tools fit within the much broader Model Context Protocol ecosystem.
Read 7-minute guide 10 in-depth resources
WebMCP field manual
From first principles to production evidence.
Original, source-linked guidance for deciding where WebMCP fits, designing narrow contracts, sharing state safely, and proving that the result works.
Status-sensitive claims reviewed Aug 31, 2026. WebMCP remains an experimental Community Group draft.
Start here
Three foundations
Is your web app ready for WebMCP? Run a baseline audit first
Start with the workflows, semantics, and verification signals your application already exposes before deciding which actions deserve tools.
Read 8-minute guideDesign WebMCP tool contracts agents can choose correctly
Make intent, inputs, side effects, and outcomes legible without persuasive, ambiguous, or overloaded prose.
Read 8-minute guideEvergreen library
Learn the system, then build it.
10 of 10 resources
Explainer 7 min
WebMCP vs. MCP: what runs in the browser, what runs elsewhere
A practical map of where browser-exposed WebMCP tools fit within the much broader Model Context Protocol ecosystem.
Read resourceHow-to 8 min
Is your web app ready for WebMCP? Run a baseline audit first
Start with the workflows, semantics, and verification signals your application already exposes before deciding which actions deserve tools.
Read resourceHow-to 9 min
Build your first imperative WebMCP tool from an existing UI action
Expose one narrow action while keeping the visible interface, application services, and business rules intact.
Read resourceArchitecture 8 min
Design WebMCP tool contracts agents can choose correctly
Make intent, inputs, side effects, and outcomes legible without persuasive, ambiguous, or overloaded prose.
Read resourceArchitecture 7 min
One action, two interfaces: keep WebMCP and your UI in sync
Give human controls and agent tools the same services, rules, state, and verification path.
Read resourceHow-to 7 min
WebMCP lifecycle in SPAs: register, scope, abort, and re-register
Treat tool registration as route- and component-owned state so stale tools never outlive the interface that gives them meaning.
Read resourceTesting 9 min
How to test WebMCP beyond “the tool registered”
Meaningful evidence covers contracts, authorization, selection, state changes, and verified outcomes.
Read resourceSecurity 10 min
A practical security and privacy review for WebMCP tools
Review WebMCP as another path into existing application behavior, with explicit attention to session privilege, misleading intent, excess data, and untrusted content.
Read resourceField guide 7 min
Measure WebMCP lift without inventing a universal ROI number
Compare equivalent completed journeys and publish the counting rules, evidence, and limitations behind the result.
Read resourceField guide 6 min
The WebMCP Challenge submission checklist, without deadline surprises
A practical field guide to the live app, public source, demo, evidence, and freeze discipline the challenge expects.
Read resourceQuestions, answered
30 direct answers without the hand-waving.
Browser support, schemas, security, evidence, challenge tracking, and the difference between MCP and WebMCP.
Browse all FAQsLatest signal
WebMCP explicitly brings headless handoffs into scope
Commit 50c4b7f moves headless browsing scenarios into the proposal's stated goals when page-exposed tools support task completion or transitions between human-in-the-loop and headless experiences. It still excludes purely server-side autonomous workflows and continues to position WebMCP as complementary to backend MCP; WebMCP remains an experimental Community Group draft, not a W3C Standard.
WebMCP specification repository
Open the live pulse