WebMCP DevTools

A developer tool for inspecting, testing, and monitoring WebMCP tools registered via navigator.modelContext.

WebMCP DevTools — A developer tool for inspecting, testing, and monitoring WebMCP tools. WebMCP (Web Model Context Protocol) is a browser-native API that allows web pages to register tools for AI models via navigator.modelContext. WebMCP DevTools gives you a powerful side panel to work with these tools in real-time. FEATURES • Tool Detection — Automatically detects all WebMCP tools registered on the current page • Declarative WebMCP — Auto-detects declarative tool definitions • Cross-Tab Aggregation — Unified view of tools from all open tabs • Schema Visualization — View input schemas as collapsible tree structures with advanced schema support • Interactive Form Generation — Auto-generates forms from JSON Schema for easy tool execution • Tool Execution — Execute tools directly from the side panel with instant results • AI Assistant — Built-in chat panel with streaming output, Markdown rendering, and code highlighting • Performance Statistics — Track success rate, average/min/max execution duration • Execution History — Review recent executions with full input/output details • Event Timeline — Track tool registration and change events in real-time • Snapshots & Diff — Save tool definition snapshots and compare changes • Export — Export as JSON, Markdown, Postman Collection, or TypeScript code • i18n — English and Chinese with one-click toggle • Themes — System-aware dark/light theme with manual override GETTING STARTED Enable the WebMCP flag: chrome://flags/#enable-webmcp-testing Click the extension icon to open the side panel Navigate to a page with WebMCP tools Inspect, execute, and monitor tools from the panel v2.1.0 — Tool Generator, Page Content Reading & Site Profiles New features: - Tool Generator: scan pages to discover forms, buttons and links, then auto-generate and inject WebMCP tool definitions - Page Content: read page metadata, text, tables, forms, and links for AI context - Contextual Prompts: page-level prompt templates for smarter AI interaction - Site Profiles: save tool definitions per domain and auto-inject on page load - UI redesign: tab bar with icons and overflow dropdown for better usability