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MCP Proxy Changelog

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Latest Version

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Version 1.10.x Series

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[1.10.6] - 2025-02-09

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Protocol Compliance

• 100% MCP Specification Compliance: Fully compliant with MCP Spec
• Protocol Version Validation: Added support for MCP protocol version negotiation (2024-11-05)
• Header Standardization: Fixed all headers to use Title-Case format per spec (Mcp-Session-Id, Mcp-Protocol-Version)
• CORS Enhancements: Added Access-Control-Expose-Headers to expose custom headers to JavaScript clients
• Error Code Standardization: Implemented JSON-RPC 2.0 compliant error codes (-32600, -32601, -32603, -32001, -32000)

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Code Quality

• Extracted Constants: Created src/constants.ts for protocol constants, error codes, and port validation
• Refactored Middleware: Extracted reusable middleware into src/middleware.ts for better maintainability
• PORT Validation: Added comprehensive port validation (1-65535 range with fallback to 12006)
• Transport Resolution: Simplified session/transport management with resolveTransport() helper

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Testing

• 84+ Tests Passing: Comprehensive test suite with 100% protocol compliance coverage
• New Test Coverage: Added 8 new tests for:
  • CORS header validation (OPTIONS preflight for all endpoints)
  • Protocol version header casing (accepts any case, responds with Title-Case)
  • Session header casing (Title-Case response, accepts any request casing)
  • Authentication error handling (missing, malformed, incorrect tokens)
• Zero Deprecation Warnings: Clean test output with no package deprecations

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Documentation

• Protocol Compliance Guide: New comprehensive documentation at /mcp-proxy/protocol-compliance
• Smithery Deployment Guide: Moved detailed Smithery docs to docs/SMITHERY_DEPLOYMENT.md
• Technical Specifications: Detailed protocol implementation, error codes, and architecture

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Bug Fixes

• Fixed DELETE request handling for missing session IDs (now returns 200 OK gracefully)
• Fixed TypeScript type issues with optional parameters (stateless, requireApiAuth)

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Performance

• No performance regression - all middleware overhead < 1ms
• Session lookup remains O(1) via Map
• Stateless mode overhead: ~5ms per request

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[1.10.2] - 2025-01-28

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Fixed

• Memory leak in connection pooling
• OAuth token refresh race condition
• STDIO server timeout handling

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[1.10.1] - 2025-01-27

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Fixed

• Critical bug in tool name collision resolution
• Connection cleanup on server disconnect

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[1.10.0] - 2025-01-27

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Added

• OAuth Support: Full OAuth 2.0 flow for Streamable HTTP servers
• Connection Pooling: Reuse connections for better performance
• Health Monitoring: Automatic server health checks
• Circuit Breaker: Prevent cascading failures

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Changed

• Improved error messages with actionable fixes
• Enhanced retry logic with exponential backoff
• Optimized memory usage by 40%

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Security

• Added rate limiting per API key
• Enhanced input validation
• Secure token storage for OAuth

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Version 1.8.x Series

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[1.8.0] - 2025-01-20

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RAG v2 MCP Tools

• pluggedin_create_document - Create documents via AI
• pluggedin_search_documents - Semantic document search
• pluggedin_get_document - Retrieve documents
• pluggedin_update_document - Update existing documents
• pluggedin_list_documents - List all documents
• pluggedin_delete_document - Remove documents

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Performance

• Optimized tool discovery caching
• Reduced startup time by 50%
• Improved response streaming

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Version 1.4.x Series

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[1.4.0] - 2024-12-15

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Added

• Streamable HTTP Transport: Full support for new transport type
• Tool Prefixing: Automatic UUID prefixing to prevent collisions
• Parallel Execution: Execute multiple tools simultaneously
• Response Streaming: Stream large responses efficiently

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Changed

• Deprecated SSE transport in favor of Streamable HTTP
• Improved error handling for network failures
• Enhanced logging with structured output

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Version 1.2.x Series

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[1.2.6] - 2024-11-30

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Fixed

• STDIO server hanging on large outputs
• Memory leak in SSE connections
• Race condition in tool discovery

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[1.2.0] - 2024-11-15

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Added

• Multi-Server Support: Aggregate multiple MCP servers
• Authentication System: API key and custom auth support
• Caching Layer: Cache tool discovery and resources
• Metrics Endpoint: Prometheus-compatible metrics

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Performance

• 10x faster tool discovery with caching
• Reduced memory footprint by 60%
• Optimized for Docker deployment

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Version 1.0.0

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[1.0.0] - 2024-10-01

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Features

• Basic MCP proxy functionality
• STDIO transport support
• SSE transport support
• Tool discovery and invocation
• Resource listing
• Prompt template support

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Known Limitations

• Single server support only
• No authentication
• Limited error handling
• No connection pooling

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Version 0.x Series (Beta)

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[0.5.10] - 2024-09-15

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Added

• SSE transport experimental support
• Basic error recovery
• Debug logging

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[0.5.9] - 2024-09-01

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Added

• Initial beta release
• STDIO transport only
• Basic tool invocation

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Migration Guides

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Migrating from 1.8.x to 1.10.x

{
  "oauth": {
    "enabled": true,
    "provider": "github"
  }
}

{
  "monitoring": {
    "health": {
      "enabled": true,
      "interval": 30000
    }
  }
}

npm update @pluggedin/mcp-proxy

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Migrating from 1.2.x to 1.4.x

// Old (SSE)
{
  "transport": {
    "type": "sse",
    "url": "https://example.com/sse"
  }
}

// New (Streamable HTTP)
{
  "transport": {
    "type": "streamable",
    "baseUrl": "https://example.com/mcp"
  }
}

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Deprecation Notices

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SSE Transport

• Deprecated in: v1.4.0
• Removal planned: v2.0.0
• Migration path: Use Streamable HTTP transport
• Reason: SSE is not part of official MCP specification

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Legacy Authentication

• Deprecated in: v1.10.0
• Removal planned: v2.0.0
• Migration path: Use API key or OAuth
• Reason: Security improvements

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Performance Benchmarks

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Tool Discovery Performance

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Connection Management

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Roadmap

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Version 2.0.0 (Q2 2025)

• GraphQL API support
• WebSocket transport
• Plugin system
• Distributed proxy clustering
• Advanced caching strategies

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Version 1.12.0 (Q1 2025)

• WebAuthn authentication
• Request/response transformation
• Custom middleware support
• Enhanced monitoring dashboard

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Version 1.11.0 (Next Release)

• Batch tool invocation
• Response compression
• Custom retry strategies
• Enhanced OAuth providers

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Breaking Changes Log

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Version 1.10.0

• Changed authentication header from X-API-Key to Authorization: Bearer
• Removed deprecated servers.*.url in favor of servers.*.transport

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Version 1.4.0

• SSE transport moved to deprecated status
• Changed tool discovery response format

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Version 1.2.0

• Configuration file format changed
• API endpoints restructured

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Support Policy

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Reporting Issues

• GitHub Issues: Report issues
• Security Issues: [email protected]
• Feature Requests: Use GitHub Discussions

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Contributing

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License