MCP Router

A cloud-agnostic Node.js orchestration server that routes requests to pluggable tool adapters (Claude, Cursor, custom tools) via the MCP protocol pattern. Deployable on EKS (AWS) or AKS (Azure) without code changes.

Architecture decisions

Decision	Choice	Reason
Protocol	HTTP + SSE	Universal, no WS infra needed, works through all proxies
Adapter loading	Dynamic import() scan	Drop-in plugins, zero router changes
Auth	Delegated to Ingress	Keeps router stateless and horizontally scalable
K8s packaging	Helm + plain YAML	Works with ArgoCD, Flux, or raw kubectl
Image	Distroless nonroot	Minimal attack surface, no shell

Quick start

cp .env.example .env          # add your ANTHROPIC_API_KEY
npm install
npm run dev

Call the router

# List available tools
curl http://localhost:3000/mcp/tools

# Stream a Claude completion (SSE)
curl -N -X POST http://localhost:3000/mcp \
  -H 'Content-Type: application/json' \
  -d '{
    "tool": "claude",
    "stream": true,
    "input": {
      "messages": [{"role":"user","content":"Explain MCP in one paragraph"}]
    }
  }'

# Buffered JSON response
curl -X POST http://localhost:3000/mcp \
  -H 'Content-Type: application/json' \
  -d '{"tool":"custom","stream":false,"input":{"input":"hello world"}}'

Adding a new adapter

1. cp src/adapters/custom.js src/adapters/my-tool.js
2. Change name in meta()
3. Update InputSchema and implement execute() as an async generator
4. Restart — the registry auto-discovers the new file

No changes to the router, registry, or Kubernetes manifests.

Deploy to Kubernetes

Prerequisites

• kubectl configured for your cluster (EKS or AKS)
• helm v3
• Your image pushed to ECR or ACR

Create secrets

kubectl create secret generic mcp-router-secrets \
  --from-literal=ANTHROPIC_API_KEY=sk-... \
  --from-literal=CURSOR_API_KEY=optional

Helm install

helm install mcp-router ./helm/mcp-router \
  --set image.repository=<your-registry>/mcp-router \
  --set image.tag=<git-sha>

Or plain kubectl

kubectl apply -f k8s/manifests.yaml

Cloud-specific ingress notes

EKS: install aws-load-balancer-controller and add annotation:

kubernetes.io/ingress.class: alb
alb.ingress.kubernetes.io/scheme: internet-facing

AKS: install ingress-nginx via Helm (same chart works on both clouds):

helm install ingress-nginx ingress-nginx/ingress-nginx

The default values.yaml targets nginx, which is cloud-agnostic.

Environment variables

Variable	Required	Description
ANTHROPIC_API_KEY	For claude adapter	Anthropic API key
CURSOR_API_URL	For cursor adapter	Cursor REST endpoint URL
CURSOR_API_KEY	For cursor adapter	Bearer token for Cursor API
CURSOR_CLI_PATH	For cursor adapter	Path to Cursor binary (alternative to REST)
PORT	No (default 3000)	HTTP port
LOG_LEVEL	No (default info)	Pino log level
NODE_ENV	No	Set to production to disable pretty-printing

API reference

POST /mcp

{
  "tool": "claude",
  "stream": true,
  "input": { /* adapter-specific, validated by Zod schema */ }
}

SSE events (when stream: true):

data: {"type":"text","data":"Hello"}
data: {"type":"done","data":{"stop_reason":"end_turn","usage":{...}}}
data: {"type":"error","data":"Something went wrong"}

GET /mcp/tools

Returns registered adapters and their descriptions.

GET /health/live

Kubernetes liveness probe.

GET /health/ready

Kubernetes readiness probe — 503 until adapters are loaded.