Question about different kinds of MCP servers

[binduwavell]

It is not clear to me if this supports HTTP+SSE and/or Stremable HTTP MCP servers?

How does this handle pre-packaged docker containers like mcp/fetch?

[binduwavell]

I tried to run the mcp/fetch container with this mcp-compose.yml:

version: '1'
proxy_auth:
  enabled: true
  api_key: "your-secure-api-key"
servers:
  fetch:
    image: mcp/fetch
    runtime: docker
    protocol: stdio
    capabilities: [tools]
    networks: [mcp-net]

And got this error

Errors encountered:
- Server 'fetch' failed to start: failed to start container for server 'fetch': no container runtime available, cannot start container with image 'mcp/fetch'

I'm in a distrobox environment so it's podman under the hood but I don't have a podman cli, but I do have a docker cli. I tried setting the runtime to podman in case that helped. Same error either way.

[binduwavell]

Errors encountered:
- Server 'fetch' failed to start: failed to start container for server 'fetch': no container runtime available, cannot start container with image 'mcp/fetch'

This was on me. Since I'm inside a distrobox container I don't have docker or podman. I did have an alias named docker that ran distrobox-host-exec podman so your runtime.go was not able to locate the docker (or podman) binary on the path.

Ii removed the alias and created a ~/bin/podman bash script and got ~/bin on the path and then update the runtime in mcp-compose.yml to say podman. Now it makes it further but I'm still running into isssues:

Detected Podman runtime
Starting 1 MCP server(s) in parallel...
Processing server 'fetch'...
[i] Server fetch                          will start in STDIO mode (no HTTP config detected).
Starting container 'mcp-compose-fetch' for server 'fetch' (Direct STDIO mode).
Container 'mcp-compose-fetch' will join network: mcp-net
[✔] Server fetch                          Started (415.91ms). Proxy will attempt HTTP connection.

=== PARALLEL STARTUP SUMMARY ===
Servers processed: 1
Successfully started: 1
Failed: 0

✅ Startup completed. 1/1 servers are running.
Servers are accessible via Docker network 'mcp-net'

=== NETWORK TOPOLOGY ===
Network 'mcp-net': fetch
Use 'mcp-compose down' to stop them.

It seems the mcp/fetch container starts and then exits. So while this says the server is running and accessible it is not running.

[binduwavell]

I ran mcp-compose proxy and now the fetch container seems to stay running. Now I'm unsure if I can access from clients with HTTP+SSE, Streamable HTTP and/or STDIO.

Inspector seems to connect and allow me to initiate, but then does not seem to list tools, resources, prompts or to allow testing the same.

I tried running the "standard" inspector from anthropic but I didn't figure out how to get it to connect. I tried various combinations of Authorization headers with Bearer and the key from the mcp-compose.yaml and Bearer with the key from the proxy CLI call. I tried making these the same and using that with Bearer. I was not yet able to connect.

What happens if I pass an API key to proxy. Does it have to be the same as we configured in mcp-compose.yaml. What happens if it in different or not supplied at all?

[phildougherty]

I added proper http and sse support the other day

Example http

filesystem:
build:
context: ./custom_mcp/filesystem
dockerfile: Dockerfile
runtime: docker
protocol: http
http_port: 3000
command: "node"
args: ["/app/dist/index.js", "--transport", "http", "--host", "0.0.0.0", "--port", "3000", "/projects"]
env:
NODE_ENV: "production"
capabilities: [resources, tools]
volumes:
- "/home/phil:/projects:rw"
networks: [mcp-net]

Example SSE

mcp-cron-oi:
build:
context: ./custom_mcp/mcp-cron-oi
dockerfile: Dockerfile
runtime: docker
protocol: sse
http_port: 8080
sse_path: "/sse"
command: "/app/mcp-cron"
args: ["--transport", "sse", "--address", "0.0.0.0", "--port", "8080", "--db-path", "/data/mcp-cron.db"]
env:
TZ: "America/New_York"
capabilities: [tools, resources]
volumes:
- "/home/phil:/workspace:rw"
- "mcp-cron-data:/data"
networks: [mcp-net]