HTTP server

If your MCP server speaks MCP’s streamable-HTTP transport natively (JSON-RPC 2.0 over HTTP POST), Krypton treats it like any other Agent.

Ports refresher: client traffic to :8080 (gateway), introspection / UI on :8090 (control plane). See Ports & endpoints for the full breakdown.

Container contract

Your container needs to:

• Listen on spec.port (default 8080)
• Accept POST at spec.invocationPath (default /) with JSON-RPC 2.0 bodies
• Implement initialize, notifications/initialized, tools/list, tools/call
• Honor Accept: text/event-stream if you want strict MCP clients (Postman MCP, MCP Inspector) — return SSE frames when requested, plain JSON otherwise

Deploy

apiVersion: krypton.ai/v1alpha1
kind: Agent
metadata:
  name: my-mcp
  namespace: agents
spec:
  image: my-registry/my-mcp-server:v1
  imagePullPolicy: IfNotPresent
  protocol: mcp
  port: 8080
  invocationPath: /
  mode: always-on
  minReplicas: 1
  maxReplicas: 3

kubectl apply -f my-mcp.yaml

The pod starts, the Service exposes it inside the cluster, the operator UI surfaces its tools.

Sample servers

Two pick-your-language flavours, both self-contained:

• examples/mcp/go — ~200-line Go server, stdlib only
• examples/mcp/python — minimal FastMCP server

Both expose three toy tools (echo, add, time/now). Deploy either in the kind cluster:

kubectl apply -f examples/mcp/go/agent.yaml
# or
kubectl apply -f examples/mcp/python/agent.yaml

Then either:

• Open http://localhost:8090/ui/mcp/agents/mcp-hello for tool introspection in the UI, or
• Hit the typed control-plane endpoints directly:

curl http://localhost:8090/v1/agents/agents/mcp-hello/mcp/tools
curl -X POST http://localhost:8090/v1/agents/agents/mcp-hello/mcp/tools/add \
     -H 'Content-Type: application/json' \
     -d '{"a": 2, "b": 3}'

Raw MCP protocol path

For tools that want the unmodified MCP wire protocol (MCP Inspector, Postman’s MCP request type, etc.), point them at the gateway:

POST http://<gateway>/v1/agents/{namespace}/{name}/
Content-Type: application/json
Accept: text/event-stream

{"jsonrpc":"2.0","id":1,"method":"tools/list"}

The gateway forwards bodies verbatim and preserves streaming — your server’s Accept-aware code path serves SSE if the client asks for it.