@a5c-ai/babysitter-github

Babysitter orchestration plugin for GitHub Copilot. It supports both:

• GitHub Copilot CLI via the local plugin and hook model
• GitHub Copilot coding agent / cloud agent via repository-installed skills and instructions

This package ships a complete Copilot CLI plugin bundle -- skills, lifecycle hooks, and SDK integration -- that lets you run Babysitter's event-sourced, multi-step orchestration engine directly inside GitHub Copilot CLI sessions. It uses the Babysitter SDK CLI and the shared ~/.a5c process-library state. The installer registers the plugin bundle and materializes the active skills and hooks so Copilot CLI can execute Babysitter commands and hook scripts directly.

Prerequisites

• Node.js 22+
• GitHub Copilot CLI (copilot) -- requires an active GitHub Copilot subscription
• Babysitter SDK CLI (@a5c-ai/babysitter-sdk) -- installed globally

Installation

From marketplace (recommended)

Register the a5c.ai marketplace and install the plugin:

# Register the marketplace
copilot plugin marketplace add a5c-ai/babysitter

# Install the plugin
copilot plugin install babysitter

Direct GitHub install

Install directly from the Git repository using Copilot CLI. Copilot CLI discovers the plugin via .github/plugin/marketplace.json at the repo root:

copilot plugin install a5c-ai/babysitter

Alternative Installation (npm / development)

For development or environments where the Copilot CLI plugin system is not available, install via npm:

Install the SDK CLI first:

npm install -g @a5c-ai/babysitter-sdk

Then install the GitHub Copilot plugin globally:

npm install -g @a5c-ai/babysitter-github
babysitter-github install

Or install from source:

cd plugins/babysitter-github
node bin/install.js

Install into a specific workspace:

babysitter-github install --workspace /path/to/repo

GitHub Copilot cloud agent installation

For GitHub Copilot's cloud-hosted coding agent, install repository-scoped Babysitter support instead of the local ~/.copilot CLI plugin surface:

babysitter-github install --cloud-agent --workspace /path/to/repo

This installs:

• a mirrored Babysitter GitHub plugin bundle under .github/babysitter/github-plugin/
• Babysitter skills under .github/skills/
• a managed Babysitter block in AGENTS.md
• a managed Babysitter block in .github/copilot-instructions.md
• a copilot-setup-steps workflow, or a generated merge candidate if the repo already has one

If the repository already has a custom copilot-setup-steps.yml, the installer preserves it and writes a merge candidate to:

.github/workflows/copilot-setup-steps.babysitter.generated.yml

If the workspace does not already have an active process-library binding, the installer bootstraps the shared global SDK process library automatically:

babysitter process-library:active --json

Uninstallation

Via Copilot CLI:

copilot plugin uninstall babysitter

Via npm:

babysitter-github uninstall

Integration Model

The plugin provides:

• skills/babysit/SKILL.md as the core orchestration entrypoint
• Mode wrapper skills such as $call, $plan, and $resume
• Plugin-level lifecycle hooks for sessionStart, sessionEnd, and userPromptSubmitted

For Copilot cloud agent, the hook scripts are mirrored into the repository as part of the installed plugin bundle for reference and parity, but the hosted agent path is driven by repository instructions, skills, and setup workflow instead of local ~/.copilot/hooks.json.

The process library is fetched and bound through the SDK CLI in ~/.a5c/active/process-library.json.

Active Process-Library Model

Process discovery prefers active roots in this order:

1. .a5c/processes in the current workspace
2. The SDK-managed active process-library binding returned by babysitter process-library:active --json
3. The cloned process-library repo root from defaultSpec.cloneDir when adjacent reference material is needed
4. Installed extension content only as a compatibility fallback

Available Skills

The plugin registers ten skills that surface as slash commands within Copilot CLI:

| Skill | Description | |-------|-------------| | babysit | Core entrypoint. Orchestrate .a5c/runs/<runId>/ through iterative execution. Invoke when asked to babysit, orchestrate, or run a workflow. | | call | Start a new orchestration run. Everything after $call becomes the initial Babysitter request. Always creates an interactive run. | | plan | Design a process definition without executing it. Useful for reviewing or refining a workflow before committing to a run. | | resume | Resume an incomplete or paused orchestration run from where it left off. | | doctor | Diagnose run health -- journal integrity, state cache, effects, locks, sessions, logs, and disk usage. | | retrospect | Analyze a completed run: results, process quality, and suggestions for process improvements and optimizations. | | observe | Launch the real-time observer dashboard to watch active runs. | | assimilate | Assimilate an external methodology, harness, or specification into Babysitter process definitions. | | help | Show documentation for Babysitter command usage, processes, skills, agents, and methodologies. | | user-install | Set up Babysitter for yourself -- installs dependencies, interviews you about preferences, and configures user-level defaults. |

How the Hook-Driven Orchestration Loop Works

GitHub Copilot CLI supports plugin lifecycle hooks. This plugin registers three hooks that drive the orchestration loop:

SessionStart

Fires when a new Copilot CLI session begins. The hook:

1. Initializes a Babysitter session for the active Copilot session
2. Ensures the SDK CLI is installed at the correct version (pinned in versions.json)
3. Creates baseline session state in the .a5c state directory

SessionEnd

The orchestration loop driver. Registered as sessionEnd in hooks.json, this hook fires when the Copilot CLI session ends and:

1. Checks whether the active run has completed or emitted a completion proof
2. If the run is still in progress, re-injects the next orchestration step to continue iteration
3. Only allows the session to exit when the run finishes or reaches a breakpoint requiring human input

This is what keeps Babysitter iterating autonomously within the Copilot CLI session -- each turn performs one orchestration phase, and the Stop hook decides whether to loop or yield.

UserPromptSubmitted

Fires before a user prompt reaches the model. The hook applies density-filter compression to long user prompts to reduce token usage while preserving semantic content.

Configuration

AGENTS.md

The plugin uses AGENTS.md (the Copilot CLI equivalent of CLAUDE.md) for custom agent instructions. The cloud-agent installer appends a managed Babysitter section to the repository root AGENTS.md so the hosted agent can see the same orchestration guidance.

.github/copilot-instructions.md

The cloud-agent installer also appends a managed Babysitter block to .github/copilot-instructions.md. This gives GitHub-hosted Copilot sessions a repository-wide entrypoint for the Babysitter skills and setup workflow.

copilot-setup-steps workflow

The cloud-agent path seeds .github/workflows/copilot-setup-steps.yml with a copilot-setup-steps job that installs the Babysitter SDK and initializes the active process library before the cloud agent starts working.

Environment Variables

| Variable | Default | Description | |----------|---------|-------------| | CLAUDE_PROJECT_DIR | CWD | Project root directory (set by Copilot CLI) | | BABYSITTER_LOG_DIR | <plugin>/.a5c/logs | Log output directory | | BABYSITTER_STATE_DIR | <cwd>/.a5c | State directory for session data |

SDK Version Pinning

The plugin pins its required SDK version in versions.json. The SessionStart hook reads this file and ensures the correct version of @a5c-ai/babysitter-sdk is installed globally before proceeding.

Copilot CLI Plugin Structure

This section documents the Copilot CLI plugin format that this package conforms to. Understanding this structure is useful when extending the plugin or building new ones.

Plugin Manifest Location

Copilot CLI looks for the plugin manifest in these paths, checked in order:

1. .plugin/plugin.json
2. .github/plugin/plugin.json
3. .claude-plugin/plugin.json
4. plugin.json (repository root)

The first match wins. This plugin uses plugin.json at the package root.

For marketplace discovery, Copilot CLI looks for .github/plugin/marketplace.json at the repository root. This file lists all available plugins in the repo and is used when installing via copilot plugin install OWNER/REPO.

plugin.json Schema

The manifest declares metadata, skills, hooks, and optional integrations:

| Field | Required | Type | Description | |-------|----------|------|-------------| | name | Yes | string | Plugin identifier (e.g., "babysitter") | | description | No | string | Human-readable summary | | version | No | string | Semver version string | | author | No | object | Author info: { "name": "...", "email": "..." } | | license | No | string | SPDX license identifier | | keywords | No | string[] | Searchable tags for marketplace discovery | | agents | No | string | Path to agents directory | | skills | No | string | Path to skills directory (auto-discovers SKILL.md files in subdirectories) | | hooks | No | string | Path to hooks.json | | mcpServers | No | string | Path to .mcp.json for MCP server configuration |

Example from this plugin:

{
  "name": "babysitter",
  "version": "0.1.0",
  "description": "Orchestrate complex, multi-step workflows ...",
  "author": "a5c.ai",
  "license": "MIT",
  "skills": "skills/",
  "hooks": "hooks.json",
  "commands": [],
  "keywords": ["orchestration", "workflow", "automation"]
}

Skills Format

Each skill lives in its own directory under skills/ and is defined by a Markdown file with YAML frontmatter:

skills/
  babysit/
    SKILL.md
  call/
    SKILL.md
  plan/
    SKILL.md

The SKILL.md file uses frontmatter to declare metadata:

---
name: babysit
description: Orchestrate a multi-step workflow using the Babysitter SDK
---

Skill body with instructions for the agent...

The name and description fields in the frontmatter are required. The body of the Markdown file contains the instructions the agent follows when the skill is invoked.

hooks.json Format

The hooks.json file declares lifecycle hook handlers as an array of command descriptors per event type:

{
  "version": 1,
  "hooks": {
    "sessionStart": [
      {
        "type": "command",
        "bash": "./hooks/session-start.sh",
        "powershell": "./hooks/session-start.ps1",
        "timeoutSec": 30
      }
    ],
    "sessionEnd": [
      {
        "type": "command",
        "bash": "./hooks/session-end.sh",
        "powershell": "./hooks/session-end.ps1",
        "timeoutSec": 30
      }
    ],
    "userPromptSubmitted": [
      {
        "type": "command",
        "bash": "./hooks/user-prompt-submitted.sh",
        "powershell": "./hooks/user-prompt-submitted.ps1",
        "timeoutSec": 30
      }
    ],
    "preToolUse": [...],
    "postToolUse": [...],
    "errorOccurred": [...]
  }
}

Each hook entry specifies a bash and/or powershell command, a type (currently always "command"), and an optional timeoutSec.

Supported hook event types:

| Event | Description | |-------|-------------| | sessionStart | Fires when a new CLI session begins | | sessionEnd | Fires when a CLI session ends | | userPromptSubmitted | Fires before a user prompt reaches the model | | preToolUse | Fires before a tool is executed | | postToolUse | Fires after a tool has executed | | errorOccurred | Fires when an error is encountered |

Flow-control decisions: Only preToolUse hooks can return flow-control decisions via the permissionDecision field in stdout JSON. Valid values are "deny", "allow", and "ask". All other hook event outputs are ignored by the runtime.

Marketplace Distribution

Copilot CLI plugins can be distributed through marketplaces -- Git repositories that contain a manifest listing available plugins.

Creating a Marketplace

A marketplace is a Git repository with a marketplace.json file at the repository root in .github/plugin/marketplace.json:

{
  "name": "a5c.ai",
  "owner": {
    "name": "a5c.ai",
    "email": "[email protected]"
  },
  "metadata": {
    "description": "Babysitter orchestration plugins",
    "version": "1.0.0"
  },
  "plugins": [
    {
      "name": "babysitter",
      "description": "Multi-step workflow orchestration with event-sourced state",
      "version": "0.1.0",
      "source": "./plugins/babysitter-github"
    }
  ]
}

The source field points to the plugin directory relative to the marketplace repository root.

User Commands

Copilot CLI provides built-in commands for plugin and marketplace management:

Marketplace commands:

copilot plugin marketplace add OWNER/REPO        # Register a marketplace
copilot plugin marketplace list                   # List registered marketplaces
copilot plugin marketplace browse NAME            # Browse plugins in a marketplace

Plugin installation:

copilot plugin install PLUGIN@MARKETPLACE         # Install from a marketplace
copilot plugin install OWNER/REPO                 # Install directly from a GitHub repo
copilot plugin install ./PATH                     # Install from a local path

Plugin management:

copilot plugin list                               # List installed plugins
copilot plugin update PLUGIN                      # Update a plugin
copilot plugin uninstall PLUGIN                   # Remove a plugin

Plugin Storage

Installed plugins are stored under ~/.copilot/installed-plugins/:

• Marketplace installs: ~/.copilot/installed-plugins/MARKETPLACE/PLUGIN-NAME/
• Direct installs: ~/.copilot/installed-plugins/_direct/SOURCE-ID/

Default Registries

Copilot CLI ships with two built-in registries:

• copilot-plugins -- official first-party plugins
• awesome-copilot -- community-curated plugin collection

These registries are available without running marketplace add.

Plugin Structure (Directory Layout)

plugins/babysitter-github/
  plugin.json              # Plugin manifest (skills, hooks, metadata)
  .github/plugin.json      # Plugin manifest (alternate discovery path)
  hooks.json               # Hook configuration (sessionStart, sessionEnd, userPromptSubmitted)
  hooks/
    session-start.sh       # SessionStart lifecycle hook
    session-end.sh         # SessionEnd lifecycle hook
    user-prompt-submitted.sh  # UserPromptSubmitted hook (prompt compression)
  skills/
    babysit/SKILL.md       # Core orchestration skill
    call/SKILL.md          # Start a new run
    plan/SKILL.md          # Plan without executing
    resume/SKILL.md        # Resume an incomplete run
    doctor/SKILL.md        # Diagnose run health
    retrospect/SKILL.md    # Analyze completed runs
    observe/SKILL.md       # Observer dashboard
    assimilate/SKILL.md    # Assimilate external methodologies
    help/SKILL.md          # Help and documentation
    user-install/SKILL.md  # User setup
  bin/
    cli.js                 # CLI entry point (babysitter-github command)
    install.js             # Installation script
    uninstall.js           # Uninstallation script
  scripts/
    team-install.js        # Team-level installation
  versions.json            # SDK version pinning
  package.json             # npm package metadata
  AGENTS.md                # Custom instructions for Copilot CLI

Cloud-agent installation additionally writes into the target repository:

.github/
  babysitter/github-plugin/                # Mirrored plugin bundle for repo-local visibility
  skills/
    babysitter-babysit/SKILL.md            # Installed Babysitter cloud skills
    babysitter-call/SKILL.md
    ...
  copilot-instructions.md                  # Managed Babysitter block appended
  workflows/
    copilot-setup-steps.yml                # Managed workflow when no custom file exists
    copilot-setup-steps.babysitter.generated.yml  # Merge candidate when a custom file already exists
AGENTS.md                                  # Managed Babysitter block appended

Verification

Verify marketplace registration:

copilot plugin marketplace list

Verify the installed plugin:

npm ls -g @a5c-ai/babysitter-github --depth=0

Verify the active shared process-library binding:

babysitter process-library:active --json

Troubleshooting

Hook not firing

Run the doctor skill from within a Copilot CLI session to diagnose hook and session health:

$doctor

Run stuck or not progressing

Check the run status and diagnose:

$doctor [run-id]

You can also inspect the run directory directly:

babysitter run:status --run-id <runId> --json
babysitter run:events --run-id <runId> --json

SDK version mismatch

If the plugin reports version incompatibility, ensure the pinned SDK version is installed:

SDK_VERSION=$(node -e "console.log(JSON.parse(require('fs').readFileSync('versions.json','utf8')).sdkVersion)")
npm install -g @a5c-ai/babysitter-sdk@$SDK_VERSION

Windows limitations

On native Windows, Copilot CLI may not execute hook scripts depending on shell configuration. The plugin still installs correctly, but lifecycle hooks may not fire. Using WSL or Git Bash is recommended. The hooks.json file includes powershell entries alongside bash entries to improve Windows compatibility where PowerShell execution is available.

Development / Contributing

Local development

git clone https://github.com/a5c-ai/babysitter.git
cd babysitter
npm install
cd plugins/babysitter-github
node bin/install.js

Publishing

cd plugins/babysitter-github
npm run deploy            # Publish to npm (public)
npm run deploy:staging    # Publish to npm with staging tag

Team installation

cd plugins/babysitter-github
npm run team:install

This sets up the plugin for all team members in a shared workspace, writing team-level configuration to .a5c/team/.

License

MIT