WebMCP DevTools

Tracking since Apr 7, 2026.

Changelog

• May 1, 2026
  description

  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

  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

• Apr 24, 2026
  description

  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
  • Schema Visualization — View input schemas as collapsible tree structures
  • 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
  • Event Timeline — Track tool registration, unregistration, and change events in real-time
  • Execution History — Review the last 20 executions with input/output details
  • Snapshots & Diff — Save tool definition snapshots and compare changes over time
  • Export — Export tool definitions as JSON, Markdown, Postman Collection, or JavaScript code
  • Internationalization — Full English and Chinese (中文) language support
  • Dark & Light Theme — System-aware theme with manual toggle
  
  🎯 WHO IS THIS FOR?
  
  • Web developers building WebMCP-compatible tools
  • AI/ML engineers integrating browser-based tool APIs
  • QA engineers testing WebMCP tool implementations
  • Anyone exploring Google's Web Model Context Protocol
  
  📋 HOW TO USE
  
  1. Enable WebMCP: Go to chrome://flags/#enable-webmcp-testing and enable the flag
  2. Open the side panel: Click the WebMCP DevTools icon in the toolbar
  3. Navigate to a page with registered WebMCP tools
  4. Inspect, test, and monitor your tools!
  
  🔒 PRIVACY
  
  This extension does NOT collect, store, or transmit any personal data. All data is stored locally in your browser. See our privacy policy for details.
  
  ⚡ PERMISSIONS EXPLAINED
  
  • activeTab & scripting: To detect WebMCP tools on the current page
  • sidePanel: To display the developer tool interface
  • storage: To save your preferences and snapshots locally
  • host_permissions: To work on any webpage with WebMCP tools

  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

• Apr 24, 2026
  permissions

  sidePanel, activeTab, scripting, storage

  sidePanel, activeTab, scripting, storage, alarms

Permissions & access

Permissions

sidePanelactiveTabscriptingstoragealarms

Host access

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Screenshots