create-atk-plugin

name	create-atk-plugin
description	Creates an ATK plugin for a project. Use when asked to make a tool installable via ATK, create plugin files, add ATK support, or configure lifecycle management for a dev tool.

Creating an ATK Plugin

ATK (AI Toolkit) is a CLI that manages AI development tools through a declarative YAML manifest. Users install plugins with atk add, configure with atk setup, and manage lifecycle with atk start/stop/install/uninstall/status/logs.

• ATK Home: ~/.atk/ — contains manifest.yaml and plugins/ directory
• Plugin directory: ~/.atk/plugins/<name>/ — contains plugin.yaml, .env, lifecycle scripts
• Install ATK: uv tool install atk-cli

CLI Reference

Command	Purpose
atk add <source>	Add plugin (local path, git URL, or registry name)
atk setup [plugin]	Configure environment variables interactively
atk install [plugin]	Run install lifecycle
atk uninstall <plugin>	Run uninstall lifecycle (keeps manifest entry)
atk start [plugin]	Start service
atk stop [plugin]	Stop service
atk restart [plugin]	Stop then start (no separate restart lifecycle)
atk status [plugin]	Show plugin status
atk logs <plugin>	View service logs
atk mcp show <plugin>	Show MCP configuration (use --json for raw JSON)
atk run <plugin> <script>	Run a custom script from the plugin directory
atk remove <plugin>	Stop + uninstall + delete plugin entirely
atk upgrade [plugin]	Update to latest version

atk uninstall vs atk remove: uninstall runs cleanup but keeps the plugin directory and manifest entry (use to test idempotency). remove is a full wipe — stops, uninstalls, deletes directory and manifest entry.

---

Part 1: Generic — Applies to All Plugin Types

The Zero-Friction Principle

ATK exists so users can run atk add <name> and have a working tool with no debugging, no manual setup, no guesswork. Every plugin must uphold this contract.

If ATK says "installed", it works

When install.sh exits 0, the service must be fully operational. If any dependency is missing or any step fails, the script must exit non-zero with a clear error. ATK interprets exit 0 as success — lying about success leaves the user with a broken tool and no idea why.

Fail fast with actionable errors

# DON'T: warn and continue
if ! command -v ollama &>/dev/null; then
  echo "Warning: Ollama not found, embeddings may not work"
fi

# DO: fail with exact instructions
if ! command -v ollama &>/dev/null; then
  echo "ERROR: Ollama is required but not installed."
  echo "  macOS:  brew install ollama"
  echo "  Linux:  curl -fsSL https://ollama.com/install.sh | sh"
  echo "  Other:  https://ollama.com/download"
  echo "Then run: atk install <name>"
  exit 1
fi

Check every dependency before doing work

Verify prerequisites before any expensive operation (clone, build, start):

• External tools: installed AND running if needed
• Models/data: available or downloadable; fail if download fails
• Network: connectivity if the install needs to download anything

Health checks must verify the service

No sleep 5 and hope. Use retry loops that actually hit the endpoint:

for i in $(seq 1 15); do
  if curl -sf http://localhost:8787/health >/dev/null 2>&1; then
    echo "  ✅ API: http://localhost:8787"
    break
  fi
  [ "$i" -eq 15 ] && { echo "  ❌ API failed to start"; exit 1; }
  sleep 2
done

This applies to both install.sh and start.sh — if they exit 0, the service must be up and healthy.

---

plugin.yaml Schema

schema_version: "2026-01-23"
name: my-plugin
description: What this plugin does

vendor:
  name: Author / Upstream Name
  url: https://github.com/org/repo
  docs: https://docs.example.com

service:
  type: docker-compose          # docker-compose | docker | systemd | script
  compose_file: docker-compose.yml   # required for docker-compose
  unit_name: my-service              # required for systemd

ports:
  - port: 8080
    name: api
    protocol: http               # http | https | tcp
    description: Main API endpoint

env_vars:
  - name: MY_API_KEY
    required: true
    secret: true
    description: API key for the service
  - name: MY_OPTION
    required: false
    default: "some-value"
    description: Optional configuration

lifecycle:
  install: ./install.sh        # or inline: docker compose pull && docker compose up -d
  uninstall: ./uninstall.sh
  start: docker compose up -d
  stop: docker compose down
  status: docker compose ps --filter "status=running" --services | grep -q my-service
  logs: docker compose logs -f
  health_endpoint: http://localhost:8080/health

mcp:
  transport: stdio               # stdio | sse
  command: uv
  args: [ "run", "--directory", "$ATK_PLUGIN_DIR", "server.py" ]
  env:
    - MY_API_KEY

Required fields

• schema_version: Always "2026-01-23"
• name: Plugin identifier
• description: Human-readable description

Service types

Type	Default lifecycle	When to use
docker-compose	docker compose up/down	Docker-based tools
docker	docker run/stop	Single container tools
systemd	systemctl start/stop	System services
script	Must define all lifecycle commands	Everything else

env_vars rules

Each declared var is prompted at atk add/setup and stored in .env. ATK injects all .env values into every lifecycle command via os.environ.

Fields: name (required), description, required (default: false), default, secret (default: false)

IMPORTANT: Only declare vars that are actually consumed:

• By lifecycle scripts (read as $VAR_NAME in shell)
• By the application at runtime (read from os.environ)

mcp section

If the plugin exposes an MCP server:

• transport: stdio (command-based) or sse (URL-based)
• command/args: For stdio. Use $ATK_PLUGIN_DIR for paths — ATK substitutes it with the plugin's absolute path
• endpoint: For SSE
• env: List of env var names to inject into the MCP process at runtime. Only include vars the MCP server reads from os.environ — do NOT list vars only used by lifecycle scripts

Full env var pipeline: plugin.yaml env_vars → prompted at atk add → stored in ~/.atk/plugins/<name>/.env → mcp.env names are the filter: only vars listed there are pulled from .env and injected into the MCP process at runtime. A var in env_vars but absent from mcp.env is stored in .env but never reaches the MCP server. To verify the full pipeline worked: run atk mcp show <name> --json and confirm every expected var appears in the "env" object.

stdio example:

mcp:
  transport: stdio
  command: uv
  args: [ "run", "--directory", "$ATK_PLUGIN_DIR", "server.py" ]
  env:
    - MY_API_KEY

sse example:

mcp:
  transport: sse
  endpoint: http://localhost:8080/mcp

atk mcp show <plugin> --json outputs raw JSON for MCP client configuration:

{
  "my-plugin": {
    "command": "uv",
    "args": [
      "run",
      "--directory",
      "/Users/.../.atk/plugins/my-plugin",
      "server.py"
    ],
    "env": {
      "MY_API_KEY": "secret-value"
    }
  }
}

---

Lifecycle Events: Rules and Patterns

General rules:

1. All scripts run with cwd=plugin_dir — paths are relative to the plugin directory
2. .env vars are merged into the environment before any command runs
3. Exit 0 = success; for status, exit 0 = running, non-zero = stopped
4. ATK checks required env vars before start and install. Checks port conflicts before start.
5. If install is defined, uninstall MUST also be defined (enforced by schema validation)
6. No restart command — ATK runs stop then start for restart
7. For simple one-liners, put the command directly in plugin.yaml instead of creating a separate script

install — The most critical script

Install IS update. There is no separate update command. atk install must converge to desired state every time.

Idempotency rule: Always build from scratch. Always rm -rf and fresh clone/install — no conditional "if exists, pull; else clone" logic.

Use set -e in install.sh: fail fast on errors.

start

Always clean stale runtime files (sockets, PID files) before starting — daemons often refuse to start if these exist, even if the old process is dead.

stop

Do NOT use set -e in stop.sh — processes may already be stopped, and that's fine. Partial cleanup is better than no cleanup.

status

Exit 0 = running, non-zero = stopped. Keep it simple.

uninstall

Must remove ALL resources the plugin created: containers, images, volumes, vendor clones, data directories.

Do NOT use set -e in uninstall.sh — same reasoning as stop.

---

Environment Variable Audit Checklist

Before finalizing your plugin, verify every env var:

Question	If no
Is this var read by any lifecycle script?	Remove from env_vars
Is this var read by the application at runtime?	Remove from env_vars
Is this var read by the MCP server from os.environ?	Remove from mcp.env
Does the var have a concrete consumer?	Remove it — phantom vars waste user time

To verify "Is this var read by the MCP server from os.environ?": Check the upstream README or source code. For npx-based packages: find the source with npm view @scope/package repository.url, then search for process.env.VAR_NAME (Node.js) or os.environ (Python). Do not assume — a var absent from the server's runtime consumption is a phantom var that silently wastes user configuration time.

Common mistake: Vars used only during install (e.g., to write config files) belong in env_vars but NOT in mcp.env. Only vars the MCP server reads at runtime belong in mcp.env.

---

OAuth and Interactive Auth

When a plugin cannot hand the user a static token to paste, install.sh is the right place to walk them through the auth flow and cache the result in .env. Tokens written there are picked up by ATK on every subsequent command — no special handling needed downstream.

Three approaches, in order of preference: (1) static credential — user pastes an existing token at atk add, nothing special in install; (2) Device Authorization Flow (RFC 8628) — script shows the user a URL + code, polls for approval, writes the token to .env; (3) browser redirect relay (e.g. mcp-remote) — handled at MCP connect time, install does nothing for auth.

For tokens that install obtains on the user's behalf, declare them required: false in plugin.yaml so the user can also paste an existing token to skip the flow.

ATK_NONINTERACTIVE=1: any install.sh that prompts or opens a browser must exit 0 immediately when this var is set. Agents use it during testing. Hanging instead of respecting it is a bug.

---

Plugin Documentation Conventions

ATK uses two documentation files by convention. Neither is declared in plugin.yaml — they are discovered by filename. Both are content, not behavior.

README.md — Help file

Always include a README.md in your plugin directory. This is the canonical help file: atk help <plugin> reads and renders it in the terminal.

A good plugin README includes:

1. Name and one-line description — what this plugin is for
2. Overview — brief explanation of the upstream tool and why it's useful
3. Installation — the exact atk add command and any prerequisites (e.g., "requires Docker")
4. Environment variables — a table with names, defaults, and descriptions
5. Usage — how to interact with the plugin after install (e.g., atk mcp show <plugin>, atk logs, web UI URL)
6. MCP tools — if the plugin exposes MCP tools, list them with brief descriptions. REQUIRED: dump the live server's tool list and compare it against your README before committing. For stdio servers: start the server, send {"jsonrpc":"2.0","id":1,"method":"tools/list"}, record the output. Never copy tool names from upstream docs alone — the running server is the ground truth.
7. Links — upstream documentation, repository

Example structure:

# My Plugin

One-line description of what it does.

## Overview

Brief description of the upstream tool and its purpose.

## Installation

Requires: Docker, [any other prereqs]

```bash
atk add my-plugin

Environment Variables

Variable	Default	Description
MY_API_KEY	—	API key (required)
MY_OPTION	"value"	Optional setting

Usage

After install: http://localhost:8080 MCP config: atk mcp show my-plugin

Links

• Upstream repository

SKILL.md — Agent skill file

If your plugin exposes an MCP server, include a SKILL.md with instructions for AI agents on how to use it effectively. ATK injects this file into agent configuration when running atk mcp --claude (and future agent integrations).

A good SKILL.md includes:

• What this MCP is for and why it exists
• What the tools do (brief, usage-oriented — not a copy of the API docs)
• When to use it and when not to
• Any critical usage patterns or caveats

Keep it concise. Agents read this as system-level instruction, not documentation.

# My Plugin — Skill

Brief description of what this MCP provides and its purpose.

## Tools

- **tool_name**: What it does and when to use it
- **other_tool**: What it does and when to use it

## Usage Patterns

Key patterns or workflows an agent should know about.

## Notes

Any caveats, limitations, or non-obvious behaviors.

---

Common Plugin Patterns

Pattern: MCP-only (no service)

schema_version: "2026-01-23"
name: GitHub MCP
description: GitHub API integration via MCP

env_vars:
  - name: GITHUB_TOKEN
    required: true
    secret: true
    description: GitHub personal access token

mcp:
  transport: stdio
  command: npx
  args: [ "-y", "@github/mcp-server" ]
  env:
    - GITHUB_TOKEN

No service, no lifecycle — just atk setup then atk mcp show <name>. Warnings from atk start/stop are expected and harmless for MCP-only plugins.

Pattern: Docker service with MCP bridge

service:
  type: docker-compose
  compose_file: docker-compose.yml

lifecycle:
  install: docker compose pull && docker compose up -d
  uninstall: docker compose down --rmi local --volumes
  start: docker compose up -d
  stop: docker compose down
  status: docker compose ps --filter "status=running" --services | grep -q my-service
  logs: docker compose logs -f
  health_endpoint: http://localhost:8080/health

mcp:
  transport: stdio
  command: uv
  args: [ "run", "--directory", "$ATK_PLUGIN_DIR", "server.py" ]
  env:
    - MY_API_KEY

Pattern: Build from upstream source

When the plugin builds from a vendor repo (not pre-built images), use a custom install.sh:

#!/bin/bash
set -e
PLUGIN_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
VENDOR_URL="https://github.com/org/repo.git"
VENDOR_REF="v2.3.1"   # Pin to a specific tag or commit — NEVER use main or latest

rm -rf "$PLUGIN_DIR/vendor"
git clone --depth 1 --branch "$VENDOR_REF" "$VENDOR_URL" "$PLUGIN_DIR/vendor/Repo"
docker compose build
docker compose up -d

Always pin to a specific tag or commit. Using main or latest means upstream breaking changes silently break your plugin.

uninstall.sh must remove the vendor clone, built images, and volumes.

---

Custom Scripts (atk run)

Plugins can ship auxiliary scripts alongside their lifecycle commands. Any script placed in the plugin directory is runnable by users with atk run <plugin> <script>. ATK looks for:

1. plugins/<name>/<script>
2. plugins/<name>/<script>.sh

Example — a backup.sh shipped with a database plugin:

#!/bin/bash
docker compose exec my-plugin pg_dump mydb > "$ATK_PLUGIN_DIR/backup.sql"
echo "Backup saved to $ATK_PLUGIN_DIR/backup.sql"

Users run it with: atk run my-plugin backup

---

User Customization (custom/)

ATK supports user overrides — plugin authors do NOT need to create these:

• ~/.atk/plugins/<name>/custom/overrides.yaml — deep-merged into plugin.yaml
• ~/.atk/plugins/<name>/custom/docker-compose.override.yml — auto-injected into docker compose commands

---

Testing Protocol

Always test through ATK itself. Do not just validate YAML — run the full lifecycle:

# 1. Add plugin
atk add <source>          # see source-specific sections below

# 2. Verify initial state
atk status                # should show running

# 3. Test stop/start cycle
atk stop <name>
atk status                # should show stopped
atk start <name>
atk status                # should show running, ports healthy

# 4. Test MCP output
atk mcp show <name>       # verify JSON is correct

# 5. Test idempotency
atk uninstall <name> --force
# verify: no containers, no volumes, no vendor clone
atk install <name>
atk status                # should show running again

# 6. Clean up
atk remove <name> --force

Note: If atk add fails mid-install (files copied but manifest not written), the directory ~/.atk/plugins/<name>/ becomes an orphan. A subsequent atk add will fail with "Plugin directory already exists" even though atk remove reports success. Fix: rm -rf ~/.atk/plugins/<name>.

What to verify at each step

Command	Check
atk add	Exit 0, env var prompts work, install completes, health checks pass
atk status	Service plugins: shows running, all ports marked ✓, ENV ✓. MCP-only plugins (no service: block): shows mcp-only, no ports column — this is correct and expected, not an error.
atk stop	Exit 0, service actually stopped
atk start	Exit 0, service restarts cleanly
atk mcp show	Correct JSON: transport, command, args, env all match plugin.yaml
atk uninstall	Exit 0, all resources cleaned up (containers, volumes, vendor)
atk install	Exit 0, full re-setup from scratch works (idempotency)

Practical notes

• Port conflicts: Check that no other containers are using the same ports before testing.
• Health checks take time: Docker Compose health checks may need 5–30 seconds. Use --retry loops.
• set -e in scripts: Use in install.sh. Do NOT use in stop.sh or uninstall.sh.
• Lifecycle one-liners: For simple commands, put them inline in plugin.yaml instead of creating scripts.
• Unverified plugin prompt: Local and non-registry plugins show a ⚠ Unverified plugin confirmation on atk add. Pass -y to skip it non-interactively. Env var prompts follow: printf "VAR1\nVAR2\n" | atk add -y ./plugins/<name>.
• Destructive-command confirmation: atk uninstall and atk remove each prompt with a data-loss warning. Pass --force to skip the prompt — this is the uninstall/remove counterpart to atk add -y, and is required for scripted lifecycle tests.

---

Part 2: Installation Type — Local Path

Used when: Installing a plugin from the local filesystem — typically during plugin development, or for plugins not published anywhere.

Directory Structure

Point atk add at any directory containing plugin.yaml:

my-plugin/            ← atk add ./my-plugin
├── plugin.yaml       # Required
├── install.sh        # Optional
├── docker-compose.yml
└── README.md

Or, when adding ATK support to an existing project in-place:

project-root/
└── .atk/             ← atk add ./.atk  (from project root)
    ├── plugin.yaml
    └── ...

ATK also accepts a single YAML file: atk add ./plugin.yaml

How ATK Adds a Local Plugin

ATK copies the entire source directory to ~/.atk/plugins/<name>/. The full source directory becomes the plugin directory — all files inside it are available.

# From project root
atk add ./.atk

# From parent directory
atk add ./my-project/.atk

# From registry repo during development
atk add ./plugins/my-plugin

Development Workflow

Local source is ideal for iterating on a plugin:

# Edit files in .atk/ or my-plugin/
# Re-add to pick up changes
atk remove <name> --force
atk add -y ./.atk    # -y bypasses the unverified-plugin confirmation for local plugins

Troubleshooting — "Plugin directory already exists" after atk remove

Symptom: atk add fails with exit 5: Plugin directory '<name>' already exists, even though atk remove completed successfully (or reported nothing to remove).

Cause: atk remove only cleans up plugins that are tracked in the manifest (~/.atk/manifest.yaml). If a previous atk add failed after copying files but before writing the manifest entry, the directory ~/.atk/plugins/<name>/ remains as a stale orphan — invisible to atk remove, but still blocking the next atk add.

Fix: Manually remove the orphaned directory:

rm -rf ~/.atk/plugins/<name>

Then re-run atk add normally.

---

Part 3: Installation Type — Registry Plugin

Used when: Publishing a plugin to the ATK registry so users can install it with just atk add <name>.

Directory Structure

Plugin files live directly in atk-registry/plugins/<name>/ — no .atk/ subdirectory:

atk-registry/
└── plugins/
    └── my-plugin/        ← this entire directory is the plugin
        ├── plugin.yaml   # Required
        ├── install.sh    # Optional
        ├── docker-compose.yml
        └── README.md     # Required — enforced by `make validate`

When ATK fetches a registry plugin, it sparse-checkouts plugins/<name>/ and copies its contents to ~/.atk/plugins/<name>/ — same result as local and git installs, just sourced from the registry repo.

Self-Contained Requirement

Registry plugins must be completely self-contained. All lifecycle scripts, Dockerfiles, compose files, and config must be inside the plugin directory. No references to files outside plugins/<name>/.

index.yaml

Never edit index.yaml manually. CI auto-generates it by running scripts/generate_index.py on every push.

Testing a Registry Plugin Locally

cd atk-registry

# Test via local path (mirrors what users get)
atk add ./plugins/<name>

# Run full lifecycle test
atk status
atk stop <name>
atk start <name>
atk mcp show <name>
atk uninstall <name> --force
atk install <name>
atk remove <name> --force

Publishing

1. Place plugin files in atk-registry/plugins/<name>/
2. Validate: make validate
3. Commit and push — CI auto-generates index.yaml

---

Pre-Publish Validation Checklist

• Install command verified: npm view <package> (npx), uvx <package> --help (uvx), or docker pull <image> (Docker) returns successfully — package/image exists before users try to install
• MCP tool list in README.md verified against live tools/list response — no hallucinated or missing tools
• plugin.yaml has schema_version, name, description
• If lifecycle.install is defined, lifecycle.uninstall is also defined
• Port numbers match between plugin.yaml and docker-compose.yml
• Env vars use ${VAR:-default} syntax in docker-compose
• MCP server uses $ATK_PLUGIN_DIR for paths (not hardcoded paths)
• Lifecycle scripts are executable (chmod +x)
• install.sh uses set -e; stop.sh and uninstall.sh do NOT use set -e
• Health endpoint returns HTTP 200 when healthy
• README.md exists and covers: purpose, prerequisites, env vars, usage
• Tested: full lifecycle cycle (add → status → stop → start → uninstall → install → remove)
• Build-from-source plugins: pinned to a specific tag or commit (not main/latest)
• Registry plugins: make validate passes