Provider Discovery¶

Auto-discover MCP providers 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-provider:
    image: my-mcp-server:latest
    labels:
      mcp.hangar.enabled: "true"
      mcp.hangar.name: "my-provider"
      mcp.hangar.mode: "http"
      mcp.hangar.port: "8080"

Label	Required	Default
`mcp.hangar.enabled`	yes	-
`mcp.hangar.name`	no	container name
`mcp.hangar.mode`	no	`http`
`mcp.hangar.port`	no	`8080`
`mcp.hangar.group`	no	-

Kubernetes¶

sources:
  - type: kubernetes
    mode: authoritative
    namespaces: [mcp-providers]
    label_selector: "app.kubernetes.io/component=mcp-provider"
    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/providers.d/
    pattern: "*.yaml"
    watch: true

Provider file:

# /etc/mcp-hangar/providers.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.providers

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

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

Discovery Modes¶

Mode	Behavior
`additive`	Only adds providers, never removes
`authoritative`	Adds and removes (for dynamic environments)

Security¶

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

Tools¶

Tool	Description
`registry_discover`	Trigger discovery cycle
`registry_sources`	List sources with status
`registry_quarantine`	List quarantined providers
`registry_approve`	Approve quarantined provider

Conflict Resolution¶

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

Prometheus Metrics¶

Metric	Description
`mcp_hangar_discovery_providers_total`	Providers per source
`mcp_hangar_discovery_registrations_total`	New registrations
`mcp_hangar_discovery_errors_total`	Errors by source
`mcp_hangar_discovery_latency_seconds`	Cycle duration