webmcp-context-provider

name	webmcp-context-provider
description	Implement the WebMCP provideContext API — bulk tool registration, contextual metadata, page state sharing, and dynamic context updates. Use when providing rich context and multiple tools to agents simultaneously.

WebMCP Context Provider

Before writing code

Fetch live docs:

1. Fetch https://webmachinelearning.github.io/webmcp/ for the provideContext method specification
2. Web-search webmcp provideContext specification for the API shape and options
3. Web-search webmcp context metadata agent for contextual data patterns
4. Web-search site:developer.chrome.com webmcp context for Chrome-specific context features

Conceptual Architecture

What provideContext Does

navigator.modelContext.provideContext(options) is a method for bulk registration of multiple tools and providing additional contextual metadata to agents. While registerTool adds one tool at a time, provideContext can set up an entire tool surface in a single call.

Note: This API is still being specified and may change. Always fetch the latest spec before implementing.

Why Context Matters

Agents make better decisions when they understand the current page state:

• What page the user is on (product detail, cart, checkout)
• User's authentication state and preferences
• Current cart contents and totals
• Available promotions or special offers
• Site capabilities and limitations

provideContext vs registerTool

Aspect	registerTool	provideContext
Granularity	One tool at a time	Multiple tools + metadata
Metadata	Tool-level only	Page-level context included
Use case	Dynamic, individual tools	Page initialization, bulk setup
Lifecycle	Register/unregister individually	Set/clear entire context

Contextual Metadata Patterns

Provide agents with situational awareness:

Product page context:

navigator.modelContext.provideContext({
  tools: [viewDetails, addToCart, compareProducts],
  metadata: {
    pageType: "product-detail",
    productId: "sku-12345",
    productName: "Wireless Headphones",
    price: 79.99,
    inStock: true,
    userAuthenticated: true
  }
});

Cart page context:

navigator.modelContext.provideContext({
  tools: [updateQuantity, removeItem, applyCoupon, checkout],
  metadata: {
    pageType: "shopping-cart",
    itemCount: 3,
    subtotal: 247.50,
    currency: "USD",
    hasShippingAddress: true,
    hasSavedPayment: true
  }
});

Dynamic Context Updates

Update context as the page state changes:

// Initial page load — browse tools
navigator.modelContext.provideContext({
  tools: [searchProducts, viewDetails],
  metadata: { pageType: "catalog", authenticated: false }
});

// User logs in — expand tools
navigator.modelContext.clearContext();
navigator.modelContext.provideContext({
  tools: [searchProducts, viewDetails, addToCart, getCartContents, checkout],
  metadata: { pageType: "catalog", authenticated: true, userName: "Alice" }
});

// Navigate to cart — switch tools
navigator.modelContext.clearContext();
navigator.modelContext.provideContext({
  tools: [updateQuantity, removeItem, applyCoupon, checkout],
  metadata: { pageType: "cart", itemCount: 3 }
});

SPA Route-Based Context

In single-page applications, update context on route changes:

router.on("routeChange", (route) => {
  navigator.modelContext.clearContext();

  switch (route.name) {
    case "catalog":
      provideCatalogContext();
      break;
    case "product":
      provideProductContext(route.params.id);
      break;
    case "cart":
      provideCartContext();
      break;
    case "checkout":
      provideCheckoutContext();
      break;
  }
});

Best Practices

• Use provideContext for initial page setup; use registerTool / unregisterTool for incremental changes
• Include page type and user state in metadata so agents understand the current context
• Clear context on navigation and re-provide for the new page
• Keep metadata lightweight — summaries, not full data dumps
• Avoid including sensitive user data (email, address) in metadata — agents don't need it
• Update context when significant state changes occur (login, cart update, page navigation)

Fetch the specification for the exact provideContext options shape, metadata fields, and any new features before implementing.