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Caddy MCP

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Documentation — Installation, deployment, usage across the API, agent, and MCP interfaces, and guidance for provisioning the Caddy backing server are maintained in the official documentation.

Caddy Reverse Proxy administrative and configuration orchestrator. Built with the highest architectural standards, incorporating dynamic facades, custom API routing, and FastMCP tool decoration.

Table of Contents


Overview

Caddy MCP provides a high-performance, model-optimized interface to Caddy capabilities. It isolates the model from underlying API transport complexity, ensuring safe, idempotent, and highly traceable system interactions.


Features

  • Dynamic Facade Orchestration: Integrates multi-inheritance clients cleanly under a single facade.
  • Battle-Tested Resilience: Out-of-the-box credential authentication, connection polling, and request retry strategies.
  • FastMCP Declarative Tools: Fast, native schema registration with full inline validation.
  • Complete Test Intent Diversity: Deep, automated unit, integration, and mock tests ensuring high code coverage.

⚙️ Dynamic Tool Selection & Visibility

This MCP server supports dynamic toolset selection and visibility filtering at runtime. This allows you to restrict the set of exposed tools in order to prevent blowing up the LLM's context window.

You can configure tool filtering via multiple input channels:

  • CLI Arguments: Pass --tools or --toolsets (or their disabled counterparts --disabled-tools and --disabled-toolsets) during startup.
  • Environment Variables: Define standard environment variables:
    • MCP_ENABLED_TOOLS / MCP_DISABLED_TOOLS
    • MCP_ENABLED_TAGS / MCP_DISABLED_TAGS
  • HTTP SSE Request Headers: Pass custom headers during transport initialization:
    • x-mcp-enabled-tools / x-mcp-disabled-tools
    • x-mcp-enabled-tags / x-mcp-disabled-tags
  • HTTP SSE Request Query Parameters: Append query parameters directly to your transport connection URL:
    • ?tools=tool1,tool2
    • ?tags=tag1

When query strings or parameters are supplied, an LLM-free Knowledge Graph resolution layer (using DynamicToolOrchestrator) matches query intents against known tool tags, names, or descriptions, with safe fallback and automated 24-hour background cache refreshing.


Installation

Pick the extra that matches what you want to run:

Extra Installs Use when
caddy-mcp[mcp] Slim MCP server only (agent-utilities[mcp] — FastMCP/FastAPI) You only run the MCP server (smallest install / image)
caddy-mcp[agent] Full agent runtime (agent-utilities[agent,logfire] — Pydantic AI + the epistemic-graph engine) You run the integrated agent
caddy-mcp[all] Everything (mcp + agent) Development / both surfaces
# MCP server only (recommended for tool hosting — slim deps)
uv pip install "caddy-mcp[mcp]"

# Full agent runtime (Pydantic AI + epistemic-graph engine)
uv pip install "caddy-mcp[agent]"

# Everything (development)
uv pip install "caddy-mcp[all]"      # or: python -m pip install "caddy-mcp[all]"

Container images (:mcp vs :agent)

One multi-stage docker/Dockerfile builds two right-sized images, selected by --target:

Image tag Build target Contents Entrypoint
knucklessg1/caddy-mcp:mcp --target mcp caddy-mcp[mcp] — slim, no engine/pydantic-ai/dspy/llama-index/tree-sitter caddy-mcp
knucklessg1/caddy-mcp:latest --target agent (default) caddy-mcp[agent] — full agent runtime + epistemic-graph engine caddy-agent
docker build --target mcp   -t knucklessg1/caddy-mcp:mcp    docker/   # slim MCP server
docker build --target agent -t knucklessg1/caddy-mcp:latest docker/   # full agent

docker/mcp.compose.yml runs the slim :mcp server; docker/agent.compose.yml runs the agent (:latest) with a co-located :mcp sidecar.

Knowledge-graph database (epistemic-graph)

The full agent ([agent] / :latest) embeds the epistemic-graph engine (pulled in transitively via agent-utilities[agent]). For production — or to share one knowledge graph across multiple agents — run epistemic-graph as its own database container and point the agent at it instead of embedding it. Deployment recipes (single-node + Raft HA), connection config, and the full database architecture (with diagrams) are documented in the epistemic-graph deployment guide. The slim [mcp] server does not require the database.


Usage

You can launch the FastMCP server in stdio mode via Python module execution:

import asyncio
from caddy_mcp.mcp_server import get_mcp_instance

async def main():
    mcp = get_mcp_instance()
    # Execute stdio loop or launch server
    print("MCP Server ready.")

if __name__ == "__main__":
    asyncio.run(main())

For direct shell launch, execute:

python -m caddy_mcp.mcp_server

Environment Variables

Package environment variables

Variable Example Description
CADDY_URL http://localhost:2019 Caddy Administration API URL endpoint
CADDY_TOKEN your_secure_bearer_token Optional bearer token if API is secured
CADDY_MCP_BASE_URL http://localhost:2019 Alternate Caddy Admin API URL (fallback when CADDY_URL is unset)
CADDY_MCP_USERNAME — Basic-auth username for the Caddy Admin API
CADDY_MCP_PASSWORD — Basic-auth password for the Caddy Admin API
CADDY_MCP_SSL_VERIFY true Verify TLS certificates when calling the Caddy Admin API
CONFIGTOOL true Toggle the Caddy config / debug / PKI / reverse-proxy tools

Inherited agent-utilities variables (apply to every connector)

Variable Example Description
TRANSPORT stdio MCP transport: stdio
HOST 0.0.0.0 Bind host (HTTP transports)
PORT 8000 Bind port (HTTP transports)
MCP_TOOL_MODE condensed Tool surface: condensed
MCP_ENABLED_TOOLS — Comma-separated tool allow-list
MCP_DISABLED_TOOLS — Comma-separated tool deny-list
MCP_ENABLED_TAGS — Comma-separated tag allow-list
MCP_DISABLED_TAGS — Comma-separated tag deny-list
EUNOMIA_TYPE none Authorization mode: none
EUNOMIA_POLICY_FILE mcp_policies.json Embedded Eunomia policy file
EUNOMIA_REMOTE_URL — Remote Eunomia authorization server URL
ENABLE_OTEL False Enable OpenTelemetry export
OTEL_EXPORTER_OTLP_ENDPOINT — OTLP collector endpoint
MCP_CLIENT_AUTH — Outbound MCP auth (oidc-client-credentials for fleet calls)
OIDC_CLIENT_ID — OIDC client id (service-account auth)
OIDC_CLIENT_SECRET — OIDC client secret (service-account auth)
DEBUG False Verbose logging
PYTHONUNBUFFERED 1 Unbuffered stdout (recommended in containers)
MCP_URL http://localhost:8000/mcp URL of the MCP server the agent connects to
PROVIDER openai LLM provider for the agent
MODEL_ID gpt-4o Model id for the agent
ENABLE_WEB_UI True Serve the AG-UI web interface

7 package + 22 inherited variable(s). Auto-generated from .env.example + the shared agent-utilities set — do not edit.

Every variable the server reads, grouped by purpose. A local template is supplied inside .env.example — copy it as .env and fill out your specific service endpoint parameters before starting execution.

Connection & Credentials

Variable Description Default
CADDY_URL Caddy Administration API URL endpoint http://localhost:2019
CADDY_TOKEN Optional bearer token if the Admin API is secured —

MCP server / transport

Variable Description Default
TRANSPORT stdio, streamable-http, or sse stdio
HOST Bind host (HTTP transports) 0.0.0.0
PORT Bind port (HTTP transports) 8000
MCP_TOOL_MODE Tool surface: condensed, verbose, or both condensed
MCP_ENABLED_TOOLS / MCP_DISABLED_TOOLS Comma-separated tool allow/deny list —
MCP_ENABLED_TAGS / MCP_DISABLED_TAGS Comma-separated tag allow/deny list —
DEBUG Verbose logging False
PYTHONUNBUFFERED Unbuffered stdout (recommended in containers) 1

Tool toggles

Each action-routed tool can be disabled individually via its toggle env var (set to false). See the MCP Tools table above for the authoritative names.

Variable Description Default
CONFIGTOOL Toggle the Caddy config / debug / PKI / reverse-proxy tools True

Telemetry & governance

Variable Description Default
ENABLE_OTEL Enable OpenTelemetry export True
OTEL_EXPORTER_OTLP_ENDPOINT OTLP collector endpoint —
OTEL_EXPORTER_OTLP_PUBLIC_KEY / OTEL_EXPORTER_OTLP_SECRET_KEY OTLP auth keys —
OTEL_EXPORTER_OTLP_PROTOCOL OTLP protocol (e.g. http/protobuf) —
EUNOMIA_TYPE Authorization mode: none, embedded, remote none
EUNOMIA_POLICY_FILE Embedded policy file mcp_policies.json
EUNOMIA_REMOTE_URL Remote Eunomia server URL —

Agent CLI (full [agent] runtime only)

Variable Description Default
MCP_URL URL of the MCP server the agent connects to http://localhost:8000/mcp
PROVIDER LLM provider (e.g. openai) openai
MODEL_ID Model id (e.g. gpt-4o) gpt-4o
ENABLE_WEB_UI Serve the AG-UI web interface True

MCP Tools

The table below is auto-generated from the live server — do not edit by hand.

Condensed action-routed tools (default — MCP_TOOL_MODE=condensed)

MCP Tool Toggle Env Var Description
caddy_mcp_config CONFIGTOOL Manage Caddy configuration and server control.
caddy_mcp_debug CONFIGTOOL Inspect Caddy observability and profiling endpoints (metrics, expvar, pprof).
caddy_mcp_pki CONFIGTOOL Manage Caddy PKI app CAs and certificates.
caddy_mcp_reverse_proxy CONFIGTOOL Query Caddy reverse proxy upstream health and status.

Verbose 1:1 API-mapped tools (MCP_TOOL_MODE=verbose or both)

21 per-operation tools — one per public API method (click to expand)
MCP Tool Toggle Env Var Description
caddy_adapt_config APITOOL Adapts a configuration to Caddy JSON without loading or running it.
caddy_delete_config APITOOL Deletes the value at the named path.
caddy_delete_id APITOOL DELETE config via @id tag.
caddy_get_config APITOOL Exports Caddy's current configuration at the named path.
caddy_get_debug_pprof APITOOL Fetches a Go pprof profile from the admin endpoint (GET /debug/pprof/).
caddy_get_debug_vars APITOOL Returns the Go expvar variables published on the admin endpoint (GET /debug/vars).
caddy_get_id APITOOL GET config via @id tag. E.g. id_path='my_proxy/upstreams'
caddy_get_metrics APITOOL Scrapes Caddy's Prometheus metrics from the admin endpoint (GET /metrics).
caddy_get_pki_ca APITOOL Returns information about a particular PKI app CA.
caddy_get_pki_ca_certificates APITOOL Returns the certificate chain of a particular PKI app CA.
caddy_get_reverse_proxy_upstreams APITOOL Returns the current status of the configured reverse proxy upstreams.
caddy_get_routes APITOOL Retrieve Caddy route mappings.
caddy_load_config APITOOL Sets Caddy's configuration, overriding any previous configuration.
caddy_patch_config APITOOL Replaces an existing object or array element at the named path.
caddy_patch_id APITOOL PATCH config via @id tag.
caddy_post_config APITOOL Sets or replaces object, or appends to array at the named path.
caddy_post_id APITOOL POST config via @id tag.
caddy_put_config APITOOL Creates new object or inserts into array at the named path.
caddy_put_id APITOOL PUT config via @id tag.
caddy_set_config APITOOL Alias for post_config.
caddy_stop_server APITOOL Gracefully shuts down the server and exits the process.

4 action-routed tool(s) (default) · 21 verbose 1:1 tool(s). Each is enabled unless its <DOMAIN>TOOL toggle is set false; MCP_TOOL_MODE selects the surface (condensed default · verbose 1:1 · both). Auto-generated — do not edit.

See docs/overview.md or docs/concepts.md for deeper operational examples.


Architecture

This package uses the standardized Agent-Utilities dynamic facade architecture:

graph TD
    User([User Agent]) --> Server[FastMCP Server]
    Server --> Facade[Api Dynamic Facade]
    Facade --> ClientBase[ApiClientBase]
    Facade --> Auth[Credentials Auth Handler]
    ClientBase --> Service([External Service API])

Deployment

Bare-Metal (Standard pip)

  1. Set up your Python virtual environment (>= 3.10).
  2. Install the package: pip install .[all]
  3. Export credentials:
    export CADDY_URL="http://localhost:2019"
    
  4. Run: python -m caddy_mcp.mcp_server

Container (Docker Compose)

A standard compose structure is provided inside the docker/ folder. Build and deploy:

docker compose -f docker/compose.yml up --build -d

Additional Deployment Options

caddy-mcp can also run as a local container (Docker / Podman / uv) or be consumed from a remote deployment. The Deployment guide has full, copy-paste mcp_config.json for all four transports — stdio, streamable-http, local container / uv, and remote URL:

  • Local container / uv — launch the server from mcp_config.json via uvx, docker run, or podman run, or point at a local streamable-http container by url.
  • Remote URL — connect to a server deployed behind Caddy at http://caddy-mcp.arpa/mcp using the "url" key.

Contributing

Please audit all code changes against ecosystem guidelines in CONTRIBUTING.md if available, and run:

pre-commit run --all-files

Documentation

The complete documentation is published as the official documentation site and is the recommended reference for installation, deployment, and day-to-day operation.

Page Contents
Installation pip, source, extras, prebuilt Docker image
Deployment run the MCP and agent servers, Compose, Caddy + Technitium, env config
Usage the MCP tools, the Api client, the agent
Backing Platform deploy Caddy with Docker and connect the Admin API
Overview integration architecture and tool surface
Concepts concept registry (CONCEPT:CADDY-*)

AGENTS.md is the canonical contributor/agent guidance.

License

This project is licensed under the MIT License. See the LICENSE file for complete details.

Deploy with agent-os-genesis

This package can be provisioned for you — skill-guided — by the agent-os-genesis universal skill (its single-package deploy mode): it picks your install method, seeds secrets to OpenBao/Vault (or .env), trusts your enterprise CA, registers the MCP server, and verifies it — the same machinery that stands up the whole Agent OS, narrowed to just this package. Ask your agent to "deploy caddy-mcp with agent-os-genesis".

Install mode Command
Bare-metal, prod (PyPI) uvx caddy-mcp · or uv tool install caddy-mcp
Bare-metal, dev (editable) uv pip install -e ".[all]" · or pip install -e ".[all]"
Container, prod deploy knucklessg1/caddy-mcp:latest via docker-compose / swarm / podman / podman-compose / kubernetes
Container, dev (editable) deploy docker/compose.dev.yml (source-mounted at /src; edits live on restart)

Secrets are read-existing + seeded via vault_sync — you are only prompted for what's missing.

Metadata

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