document.modelContext. Keeping that core small makes it portable across
native browser implementations, strict polyfills, and libraries that only need
to expose tools.
@mcp-b/webmcp-types, @mcp-b/webmcp-polyfill, and usewebmcp stay close to
this portable surface.
MCP-B adds capabilities from the broader MCP model, including compatibility
helpers such as listTools() and deprecated callTool(), plus prompts,
resources, sampling, elicitation, and browser transports. These capabilities
are exposed by BrowserMcpServer, @mcp-b/global, and related packages. They
are MCP-B extensions, not standard WebMCP methods.
Libraries and sites that only publish tools should target the strict core.
Applications that require iframe, extension, relay, desktop-client, prompt, or
resource integration require the MCP-B extension layer.
This boundary preserves runtime portability.
Use Choose a runtime for package selection.