Dockette / Dummy

🐳 Dummy Docker images for testing. Start with dockette/dummy:mcp, an MCP server with 2 tools.

🕹 f3l1x.io | 💻 f3l1x | 🐦 @xf3l1x

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Motivation

dockette/dummy holds small images that do almost nothing. Use them to test a client, a gateway, or a proxy, without a real backend.

Every image is published to Docker Hub as dockette/dummy, one tag per variant. Each variant lives in its own folder in this repository.

Tag	Folder	Description
mcp	mcp/	MCP server with 2 tools, built with Bun.

dockette/dummy:mcp

A minimal MCP server. It answers 2 questions only: who it is and what time it is. The server speaks the Streamable HTTP transport on /mcp in stateless mode.

Tools

Tool	Arguments	Returns
whoami	none	The value of the MCP_WHO environment variable.
time	none	The current time as an ISO-8601 timestamp (UTC).

Usage

docker run --rm -p 3000:3000 -e MCP_WHO=alice dockette/dummy:mcp

Or with Docker Compose:

services:
    dummy:
        image: dockette/dummy:mcp
        ports:
            - 3000:3000
        environment:
            - MCP_WHO=alice

Add the server to your MCP client (Claude Code, Cursor, …):

{
  "mcpServers": {
    "dummy": {
      "url": "http://localhost:3000/mcp"
    }
  }
}

Or call it with curl:

curl -sS http://localhost:3000/mcp \
    -H 'Content-Type: application/json' \
    -H 'Accept: application/json, text/event-stream' \
    -d '{"jsonrpc":"2.0","id":1,"method":"tools/call","params":{"name":"whoami","arguments":{}}}'

Configuration

Variable	Default	Description
MCP_WHO	dummy	The text that the whoami tool returns.
MCP_PORT	3000	The HTTP port that the server listens on.

Endpoints

Endpoint	Method	Description
/mcp	POST	MCP Streamable HTTP transport.
/health	GET	Health check. Returns 200 JSON.

Development

Every target works on one variant. DOCKER_VARIANT selects it and defaults to mcp.

make install      # install dependencies (bun)
make dev          # run the server with a file watcher
make test         # run the tests (bun test)
make typecheck    # run the TypeScript compiler

make build        # build the Docker image (dockette/dummy:mcp)
make test-docker  # smoke test the Docker image
make push         # build and push a multi-arch image to Docker Hub

Add a variant with a new folder and a Dockerfile in it, then add the folder name to the image matrix in .github/workflows/docker.yml.

See how to contribute to this package.

This package is currently maintaining by these authors.

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