Choosing the Right MCP Server Architecture: 5 Patterns and Nacos Integration Guide

MCP Architecture Evolution and Challenges

With the explosion of large AI models, the Model Context Protocol (MCP) has become a key standard for connecting AI models with applications. Enterprises face challenges such as authentication limits, diverse deployment modes, and technical debt when adopting MCP.

Five MCP Architecture Patterns

Architecture 1: MCP Client Directly Connects to Remote Server (SSE)

Analogy: calling an expert directly. The client uses Server‑Sent Events (SSE) to keep an HTTP long‑connection with a remote MCP server.

Pros: simple, low deployment cost, excellent real‑time streaming, centralized monitoring.

Cons: network hiccups break the experience, all data goes to the cloud (privacy concerns), server endpoint is exposed.

Suitable for SaaS, lightweight clients, or public cloud services with modest security requirements.

Architecture 2: MCP Client → Proxy → Remote Server (SSE)

Analogy: a translator in the middle. The client connects to a proxy, which forwards traffic to the remote server.

Pros: higher security via the proxy, intelligent routing and load‑balancing, ability to aggregate multiple back‑ends.

Cons: added complexity and latency, proxy becomes a potential failure point.

Suitable for multi‑tenant environments, enterprise gateways, and scenarios needing multiple model calls.

Architecture 3: MCP Client Directly Connects to Local Server (STDIO)

Analogy: a personal assistant at home. The client communicates with a local MCP server via STDIO (process‑to‑process I/O).

Pros: maximum data security, near‑zero network latency, works offline.

Cons: requires strong local compute resources, each environment needs separate deployment, updates are cumbersome.

Suitable for finance, medical, or industrial systems with strict data‑privacy and latency requirements.

Architecture 4: MCP Client → Local Proxy → Local Server (STDIO)

Analogy: a private secretary coordinating multiple local experts. The client talks to a local proxy, which then talks to the local server.

Pros: abstracts service details, supports multiple local instances with automatic failover, enables resource isolation across business lines.

Cons: more complex local environment, higher maintenance effort, additional compute overhead.

Suitable for large enterprises needing high availability and isolated resources.

Architecture 5: MCP Client → Local Proxy → Remote Server (STDIO+SSE)

Analogy: a super assistant handling both local tasks and external experts. The client uses STDIO to talk to a local proxy, which then uses SSE to reach a remote server.

Pros: best for hybrid cloud strategies, seamless switch between local and cloud resources, consistent client experience.

Cons: most complex, highest maintenance and debugging difficulty, performance can vary with network conditions.

Suitable for large enterprises pursuing hybrid cloud, global multi‑region deployments, or elastic scaling.

Nacos Empowering MCP Architecture

Nacos (versions before 3.0) provides three core capabilities that align well with MCP needs: service discovery & registration, dynamic configuration, and service governance (routing, load‑balancing, traffic control).

Since Nacos 3.0, it offers dedicated MCP support, including automatic server discovery and dynamic installation.

Nacos MCP Router

The Nacos MCP Router (https://github.com/nacos-group/nacos-mcp-router) bridges MCP and Nacos, offering three key functions:

MCP server search based on task description and keywords.

Adding MCP servers supporting stdio and SSE protocols, enhancing software‑supply‑chain security.

Tool proxy invocation, allowing flexible switching between local and remote servers.

Deployment Example

1. Install the router (NodeJS environment): $ pnpm i nacos-mcp-router@latest 2. Configure the MCP client to use the router:

{
  "mcpServers": {
    "nacos-mcp-router": {
      "command": "npx",
      "args": ["nacos-mcp-router@latest"],
      "env": {
        "NACOS_ADDR": "127.0.0.1:8848",
        "NACOS_USERNAME": "nacos",
        "NACOS_PASSWORD": "your_password"
      }
    }
  }
}

3. Use the MCP service via the router:

search_mcp_server(task_description="Generate a cat image", key_words="image generation")
add_mcp_server(mcp_server_name="image-generator")
use_tool(mcp_server_name="image-generator", mcp_tool_name="generate_image", params={"prompt": "an orange cat"})

Guidelines for Enterprise MCP Deployment

When selecting an architecture, consider three key factors:

Data security & privacy : highly sensitive data → local architectures (3 or 4); general data → cloud or hybrid (1, 2, 5).

Performance & latency : low‑latency critical apps → local; typical workloads → cloud is sufficient.

Scalability : rapid elastic scaling → cloud; predictable stable load → local may be more cost‑effective.

Industry‑specific recommendations:

Finance : Architecture 4 (local proxy + local server) for strict security.

Internet : Architecture 2 (proxy + remote) for high concurrency.

Manufacturing : Architecture 5 (hybrid) balances real‑time control and cloud analytics.

Government : Architecture 3 (direct local) for maximum data protection.

Conclusion & Outlook

MCP is becoming the bridge between large AI models and existing business data, but its current design lacks enterprise‑grade features such as centralized registration, controlled software supply chain, and secure access control. By integrating Nacos for service discovery, configuration, and governance, and using Higress for secure access, we provide a complete enterprise‑ready MCP solution.

Future work includes tighter MCP specifications, richer Nacos‑MCP plugins, and broader support for multi‑cloud environments.