mcp-proxy-tracing

MCP Rust Proxy Server

A fast and efficient Model Context Protocol (MCP) proxy server written in Rust. This proxy aggregates multiple MCP servers and provides a unified interface, with built-in monitoring, health checks, and a web UI for management.

New Features:

• 🎯 AI Context Tracing Framework: Track which context units influenced AI responses
• 🔍 Self-Aware AI: LLMs can inspect their own context provenance and quality
• 📊 Quality Feedback Loop: Continuous improvement through feedback propagation
• 🌐 Modern Yew UI: Built-in web dashboard for monitoring (see YEW_UI_INTEGRATION.md)

Features

Core Proxy Features

• Multi-Server Proxy: Aggregate multiple MCP servers into a single endpoint
• Multiple Transports: Support for stdio, HTTP/SSE, and WebSocket transports
• Multi-Version Protocol Support: Automatic translation between MCP protocol versions (2024-11-05, 2025-03-26, 2025-06-18)
• Tool Name Prefixing: Prevent naming conflicts with mcp__proxy__{server}__{tool} format
• File-based Logging: All server output captured to rotating log files with real-time streaming
• Configuration Management: YAML/JSON configuration with environment variable substitution
• Server Lifecycle Management: Start, stop, and restart individual servers
• Health Monitoring: Automatic health checks with configurable intervals
• Web UI Dashboard: Real-time server status monitoring and control
• Metrics Collection: Prometheus-compatible metrics for monitoring
• Connection Pooling: Efficient connection management with automatic reconnection
• Graceful Shutdown: Clean shutdown of all servers and connections

AI Context Tracing Features (NEW)

• Provenance Tracking: Complete lineage manifests showing context → response relationships
• Multi-Factor Weighting: Composite scoring (retrieval 40%, recency 30%, type 20%, length 10%)
• Hybrid Storage: DashMap in-memory cache + SQLite persistence with WAL mode
• Bidirectional Queries: Find responses using a context, or contexts in a response
• Feedback Propagation: Quality ratings automatically update all contributing contexts
• Version Tracking: Full evolution history for context units
• Quality Signals: High/low-rated contexts exposed as MCP resources
• Self-Improvement: LLMs can rate their own responses to improve future performance

Context Tracing MCP Integration

5 Tools for explicit operations:

• mcp__proxy__tracing__get_trace - View response lineage
• mcp__proxy__tracing__query_context_impact - Assess context impact
• mcp__proxy__tracing__get_response_contexts - List contributing contexts
• mcp__proxy__tracing__get_evolution_history - Track version history
• mcp__proxy__tracing__submit_feedback - Submit quality ratings

4 Resources for automatic context enrichment:

• trace://quality/top-contexts - High-quality information sources
• trace://quality/deprecated-contexts - Low-quality contexts to avoid
• trace://quality/recent-feedback - Quality feedback trends
• trace://stats/cache - Performance metrics

See TRACING_TOOLS_QUICKSTART.md for LLM agent usage guide.

Quick Start

1. Create a configuration file mcp-proxy.yaml:

servers:
  example-server:
    command: "mcp-server-example"
    args: ["--port", "8080"]
    transport:
      type: stdio
    restartOnFailure: true

proxy:
  port: 3000
  host: "0.0.0.0"

webUI:
  enabled: true
  port: 3001

2. Run the proxy server:

cargo run -- --config mcp-proxy.yaml

3. Access the web UI at http://localhost:3001

Using with Claude CLI (Stdio Mode)

The proxy can run as an MCP server for Claude CLI, aggregating all your backend servers:

# Build the proxy
cargo build --release  # or use debug: cargo build

# Run with Claude CLI
claude --mcp-config '{"mcpServers":{"proxy":{"command":"./target/debug/mcp-rust-proxy","args":["--config","mcp-proxy-config.yaml","--stdio"]}}}'

What Claude gets:

• All tools from all configured backend servers (filesystem, git, memory, etc.)
• Tool names prefixed: mcp__proxy__{server}__{tool} to prevent conflicts
• 5 context tracing tools for self-awareness
• 4 context quality resources for automatic context enrichment

Example tools available:

• mcp__proxy__memory__create_entities - From memory server
• mcp__proxy__git__commit - From git server
• mcp__proxy__tracing__submit_feedback - Built-in tracing
• And many more...

See TRACING_TOOLS_QUICKSTART.md for full agent documentation.

Using with Claude Code (HTTP Mode)

MCP Rust Proxy works seamlessly with Claude Code to manage multiple MCP servers. Here are some example configurations:

Example 1: Multiple Tool Servers