MCP Nexus - HackMD

# MCP Nexus To perform tasks and provide insights, AI agents require structured interfaces for interacting with external systems. Two open standards enable this: **[Model Context Protocol (MCP)](https://github.com/modelcontextprotocol)**, which provides predictable access to tools (resources and actions), and **[Agent-to-Agent Protocol (A2A)](https://github.com/google/A2A?tab=readme-ov-file#conceptual-overview)**, which facilitates communication between agents. This document explores MCP's architecture, scaling challenges, and MCP Nexus, our innovative decentralized MCP server network. ## Context Matters MCP allows AI agents to **access external tools and resources**, like weather systems or on-chain data, in a predictable way. This is comparable to how oracles provide trusted data to blockchain smart contracts. First proposed by [Anthropic](https://www.anthropic.com/news/model-context-protocol) and recently adopted by OpenAI and Google, MCP has become the industry standard for interactions between agents and tools. Though AI decision-making is probabilistic, MCP provides **deterministic function calls** that users can review and approve. For example, a user planning an evening activity might interact with a client, such as Claude for Desktop. This client queries the MCP server, which retrieves data from an external weather system and returns it in a standardized format for the model to analyze. <picture> <source srcset="https://hackmd.io/_uploads/BJ21Ab9kxe.png" media="(prefers-color-scheme: dark)"> <img src="https://hackmd.io/_uploads/rk8eQThRyl.png" alt="Diagram of MCP servers and the internet"> </picture> Most [MCP servers are **open-source**](https://github.com/modelcontextprotocol/servers?tab=readme-ov-file#model-context-protocol-servers) and can be deployed in two ways: 1. **Local** hosting: Run directly on a user's device for private access 2. **Remote** hosting: Operate on external infrastructure for better scalability and availability > 26 March, 2025: The latest [MCP specifications](https://modelcontextprotocol.io/specification/2025-03-26/changelog#major-changes) enable streamable HTTP support on MCP servers with stateless connections, session IDs, and improves scalability. > 19 April, 2025: [Typescript Server SDK](https://github.com/modelcontextprotocol/typescript-sdk/tree/main/src/examples#streamable-http-transport) now supports streamable HTTP transport. ## The Problem While MCP servers make AI agents useful, their implementation presents several challenges. ### Challenge: Operational Overhead for End-Users and Developers A single AI agent, such as a travel booking assistant, requires multiple MCP servers to function effectively, as shown in the figure. Requiring end-users to manage these servers creates significant barriers to entry and is impractical. Remote hosting by developers isn't a much better solution. It adds substantial responsibilities: **security vulnerability** management, **version compatibility** maintenance, and **infrastructure reliability**. <picture> <source srcset="https://hackmd.io/_uploads/Skx4fU91eg.png" media="(prefers-color-scheme: dark)"> <img src="https://hackmd.io/_uploads/SklNGU5kgg.png" alt="Challenge: operational overhead for end-users and devs"> </picture> ### Challenge: Inefficient Resource Utilization When multiple AI agent builders host their own MCP servers, they create redundant infrastructure. As shown in the figure, different agent implementations frequently require the same types of MCP servers but maintain separate instances, leading to unnecessary duplication. This inefficient architecture results in: **wasted resources**, duplicated **security efforts**, and redundant **maintenance overhead**. <picture> <source srcset="https://hackmd.io/_uploads/rysKHzckge.png" media="(prefers-color-scheme: dark)"> <img src="https://hackmd.io/_uploads/BkoYHfckxe.png" alt="Challenge: Inefficient Resource Utilization"> </picture> ## The Solution: MCP Nexus We are building *MCP Nexus*, a **distributed infrastructure platform** with a **unified API gateway** that eliminates server management overhead for AI agent developers. Similar to how RPC endpoints standardize blockchain interactions, MCP Nexus provides a single integration point for accessing diverse MCP servers. With MCP Nexus, agent developers and clients like Cursor can seamlessly connect to secure, high-performance MCP servers. This frees agent builders to focus on better serving their users. <picture> <source srcset="https://hackmd.io/_uploads/BkntfU5yxx.png" media="(prefers-color-scheme: dark)"> <img src="https://hackmd.io/_uploads/BkntfU5yxx.png" alt="MCP Nexus"> </picture> ### Key Components At the heart of MCP Nexus are *nodes*. Each node hosts **multiple** MCP servers, lightweight microservices that provide specialized tools to agents. These nodes form an interconnected network for communicating with external systems. Built-in metadata within each node enables efficient service discovery and fault tolerance. ### Workflow As illustrated in the figure, the workflow follows these steps: 1. Client Interaction: An agent connects to MCP Nexus through a unified gateway using streamable HTTP or SSE requests, compliant with MCP specifications. 2. Authentication and Routing: MCP Nexus routes the request to the appropriate node and verifies authentication and authorization. 3. Node Execution: Nodes execute the required functions. 4. Response Delivery: MCP Nexus returns responses and artifacts to the client, supporting multi-round interactions. ### Architectural Foundation MCP Nexus is built on three critical design principles: 1. **Unified API Gateway**: A single integration point for all MCP servers, streamlining access and simplifying developer workflows. 2. **High Availability Infrastructure**: Ensures 99.9% uptime through: - **Load Balancing**: Distributes request traffic across nodes through horizontal scaling. - **Fault Tolerance**: Handles system failures via automatic failover. 3. **Functionality and Security Guarantees**: Maintains robust functionality and security by whitelisting trusted MCP servers and implementing proactive vulnerability patching. Two core mechanisms support these principles, ensuring MCP Nexus operates efficiently and securely. - **Dynamic Resource Allocation**: Our algorithm assigns whitelisted MCP servers to compute nodes based on real-time demand and resource availability. The system optimizes server-to-node distribution for maximum efficiency, adapting instantly to load changes to maintain continuous uptime. - **Coordination Engine**: The coordination engine implements server-node assignments determined by our resource allocation mechanism across the Nexus network. Using Kubernetes, it orchestrates containerized workloads to ensure scalability and resilience. ### Server Onboarding Pipeline Most MCP servers are open-source and available as npm or PyPI packages. We follow a rigorous process to select and support servers. <picture> <source srcset="https://hackmd.io/_uploads/ryHVRrcJle.png" media="(prefers-color-scheme: dark)"> <img src="https://hackmd.io/_uploads/HyEVCS9Jee.png" alt="Server Management Pipeline"> </picture> - **Request-Based Onboarding:** Select MCP servers based on developer demand and specific feature requests. - **Functionality and Security Validation:** Each server undergoes comprehensive static/dynamic analysis for vulnerabilities (OWASP compliance) and extensive testing. - **Standardized Containerization:** Package servers in Docker containers with version-pinned dependencies for consistency across environments and easier scaling. - **Automated Deployment:** Automate deployment through our resource allocation and coordination engine for seamless updates and scaling. - **Version Management:** Put each new version of MCP server through our rigorous validation process, from functionality testing to security verification. ## Conclusion This document explored the challenges of MCP servers and demonstrates how MCP Nexus addresses them through its unified gateway infrastructure, which simplifies implementation. Future documents will examine the verifiability and decentralization of MCP Nexus. For questions, feedback, or insights, please reach out. ## Additional Readings 1. [MCP protocol docs](https://modelcontextprotocol.io/docs/concepts/architecture) provide an excellent high-level overview of the core architecture 2. [MCP Specifications](https://modelcontextprotocol.io/specification/2025-03-26/architecture) offer detailed technical documentation 3. [Workshop on MCP](https://www.youtube.com/watch?v=kQmXtrmQ5Zg) dives into practical techniques 4. [Orchestration Layer for Agentic Web](https://hackmd.io/@ekai/orchestration) 5. [Reverse Auctions and Real-Time Markets](https://hackmd.io/@ekai/agentic-auctions)