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January 2025
Breaking ChangesMajor Release
v1.0.0
Breaking Changes: Version 1.0.0 introduces breaking changes. Please review the migration guide below before upgrading.

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Major Changes

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Package Renaming

Several packages have been renamed for clarity and consistency:
Old NameNew NameMigration
@mcp-b/mcp-react-hooks@mcp-b/react-webmcpUpdate import statements
useMcpServer() hookuseWebMCP()Replace hook calls

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API Changes

@mcp-b/react-webmcp
  • Removed useMcpServer() hook - use useWebMCP() instead
  • New useWebMCPContext() hook for read-only context
  • Automatic registration/cleanup (no manual useEffect needed)
  • Built-in Zod support for type-safe schemas
Before (v0.x):
const { registerTool } = useMcpServer();

useEffect(() => {
  const tool = registerTool('my_tool', { description: '...' }, handler);
  return () => tool.remove();
}, []);
After (v1.0):
useWebMCP({
  name: 'my_tool',
  description: '...',
  handler
});
// Auto-registers and cleans up
Version 1.0.0 aligns with the W3C Web Model Context API proposal:
  • registerTool() is now the recommended approach (returns unregister())
  • provideContext() only for base tools (replaces all base tools)
  • Two-bucket tool management system introduced

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New Features

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@mcp-b/global

  • ✨ Two-bucket tool management (base vs dynamic tools)
  • ✨ IIFE build for CDN usage (no build step required)
  • ✨ Event-based tool call handling
  • ✨ Improved TypeScript types

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@mcp-b/react-webmcp

  • ✨ useWebMCP() hook with automatic lifecycle management
  • ✨ useWebMCPContext() for read-only tools
  • ✨ Execution state tracking (isExecuting, lastResult, error)
  • ✨ McpClientProvider and useMcpClient() for consuming tools

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@mcp-b/transports

  • ✨ Enhanced origin validation
  • ✨ Keep-alive support for extension transports
  • ✨ Server discovery for tab clients
  • ✨ Cross-extension communication support

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@mcp-b/extension-tools

  • ✨ 62+ Chrome Extension API wrappers
  • ✨ Comprehensive TypeScript definitions
  • ✨ Zod-based validation
  • ✨ Manifest V3 compatible

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Migration Guide

1

Update package names

# Remove old packages
pnpm remove @mcp-b/mcp-react-hooks

# Install new packages
pnpm add @mcp-b/react-webmcp @mcp-b/global zod
2

Update imports

// Before
import { useMcpServer } from '@mcp-b/mcp-react-hooks';

// After
import { useWebMCP } from '@mcp-b/react-webmcp';
3

Replace useMcpServer with useWebMCP

// Before
const { registerTool } = useMcpServer();
useEffect(() => {
  const tool = registerTool('my_tool', config, handler);
  return () => tool.remove();
}, []);

// After
useWebMCP({
  name: 'my_tool',
  description: 'Tool description',
  inputSchema: { /* Zod schemas */ },
  handler: async (args) => { /* ... */ }
});
4

Update vanilla JS tool registration

// Before - still works but not recommended
window.navigator.modelContext.provideContext({
  tools: [/* all your tools */]
});

// After - recommended for most tools
const reg = window.navigator.modelContext.registerTool({
  name: 'my_tool',
  description: '...',
  inputSchema: {},
  async execute(args) { /* ... */ }
});

// Clean up when needed
reg.unregister();
5

Test your integration

  • Verify all tools register correctly
  • Test tool execution with MCP-B extension
  • Check that tools unregister on component unmount
  • Validate input schemas work as expected

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Bug Fixes

  • Fixed tool name collision errors
  • Improved error messages for schema validation
  • Fixed memory leaks in React StrictMode
  • Corrected TypeScript definitions for transport options
  • Fixed race condition in extension port connections

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Performance Improvements

  • Reduced bundle size by 30%
  • Optimized tool registration performance
  • Improved transport message handling
  • Better memory management in long-running sessions
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December 2024
Minor Releases
v0.9.x

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Version 0.9.5

  • Added experimental React hooks package
  • Improved documentation
  • Bug fixes for transport disconnections

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Version 0.9.0

  • Initial public release
  • Basic MCP support for web browsers
  • Tab transport implementation
  • Extension transport for Chrome extensions

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Upcoming Features

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Version 1.1.0 (Planned - Q1 2025)

  • 🔄 Firefox extension support
  • 🔄 Enhanced developer tools
  • 🔄 Performance monitoring
  • 🔄 Tool analytics and insights

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Version 1.2.0 (Planned - Q2 2025)

  • 🔄 Safari extension support
  • 🔄 Advanced caching strategies
  • 🔄 Tool versioning support
  • 🔄 Multi-language tool descriptions

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Deprecation Notices

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Deprecated in 1.0.0

The following will be removed in version 2.0.0 (estimated Q3 2025):
  • @mcp-b/mcp-react-hooks package (use @mcp-b/react-webmcp)
  • useMcpServer() hook (use useWebMCP())
  • Implicit tool registration patterns (use explicit registerTool())

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Migration Timeline

VersionReleaseDeprecated FeaturesRemoved Features
1.0.0Jan 2025Old package names-
1.5.0Jun 2025--
2.0.0Sep 2025-Old packages, useMcpServer()

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Breaking Change Policy

WebMCP follows Semantic Versioning:
  • Major versions (X.0.0): Breaking changes, major new features
  • Minor versions (1.X.0): New features, backward compatible
  • Patch versions (1.0.X): Bug fixes, backward compatible

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Deprecation Process

  1. Announce: Deprecated features announced in release notes
  2. Warn: Console warnings added in code
  3. Grace period: Minimum 6 months before removal
  4. Remove: Removed in next major version

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Stay Updated

GitHub Releases

View detailed release notes

NPM Changelog

Browse version history

Discord Community

Discuss updates and ask questions

Migration Guides

Step-by-step upgrade instructions

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Reporting Issues

Found a bug or regression? Please report it:
  1. Check existing issues
  2. Create a new issue with:
    • Version numbers
    • Steps to reproduce
    • Expected vs actual behavior
    • Browser and extension versions
For security vulnerabilities, please email [email protected] instead of creating a public issue.