MCP Server Discovery

Auto-discover MCP servers from Docker, Kubernetes, filesystem, or Python entrypoints.

Configuration

discovery:
  enabled: true
  refresh_interval_s: 30
  auto_register: true

  sources:
    - type: docker
      mode: additive

Sources

Docker/Podman

sources:
  - type: docker
    mode: additive
    socket_path: /var/run/docker.sock  # optional

Container labels:

# docker-compose.yml
services:
  my-mcp-server:
    image: my-mcp-server:latest
    labels:
      mcp.hangar.enabled: "true"
      mcp.hangar.name: "my-mcp-server"
      mcp.hangar.mode: "http"
      mcp.hangar.port: "8080"

Kubernetes

sources:
  - type: kubernetes
    mode: authoritative
    namespaces: [mcp-servers]
    label_selector: "app.kubernetes.io/component=mcp-server"
    in_cluster: true

Pod annotations:

apiVersion: v1
kind: Pod
metadata:
  annotations:
    mcp-hangar.io/enabled: "true"
    mcp-hangar.io/name: "data-processor"
    mcp-hangar.io/mode: "http"
    mcp-hangar.io/port: "8080"

Filesystem

sources:
  - type: filesystem
    mode: additive
    path: /etc/mcp-hangar/mcp_servers.d/
    pattern: "*.yaml"
    watch: true

MCP Server file:

# /etc/mcp-hangar/mcp_servers.d/custom.yaml
name: custom-tool
enabled: true
mode: subprocess
connection:
  command: python
  args: [-m, my_mcp_server]

Python Entrypoints

sources:
  - type: entrypoint
    mode: additive
    group: mcp.mcp_servers

# pyproject.toml
[project.entry-points."mcp.mcp_servers"]
my_mcp_server = "my_package.server:create_server"

def create_server():
    return {
        "name": "my-tools",
        "mode": "subprocess",
        "command": ["python", "-m", "my_package.server"]
    }

Discovery Modes

Security

discovery:
  security:
    max_mcp_servers_per_source: 100
    max_registration_rate: 10  # per minute
    require_health_check: true
    quarantine_on_failure: true
    allowed_namespaces: [mcp-servers]
    denied_namespaces: [kube-system, default]

Tools

Conflict Resolution

1. Static config wins — Manual config always takes precedence
2. Higher priority source wins — K8s (1) > Docker (2) > Filesystem (3) > Entrypoints (4)
3. TTL expiration — Authoritative sources deregister after TTL

Prometheus Metrics