Sentinel

What Sentinel is

Sentinel is a subagent published in the athola/claude-night-market repository on GitHub, which has about 339 stars. The repository describes itself as: “23 Claude Code plugins: TDD enforcement hooks, git/PR workflows, spec-driven development, code review, project lifecycle, fix-from-error, maintenance automation, context optimization, research, and multi-LLM delegation. 186 skills, 128 commands, 54 agents.”

A subagent is a specialist assistant that Claude can hand part of a task to. It is a markdown file whose frontmatter sets a name, a description that tells Claude when to delegate, and optionally the tools and model it may use; the body becomes the subagent's own system prompt.

Because a subagent works in its own context, it keeps the main conversation focused: Claude can send a narrow job, such as a review or a specialised analysis, to Sentinel and get back a compact result.

How to install Sentinel

New to extending Cowork? Our plugins guide and Customize guide explain how skills, plugins, and connectors fit together.

Inside the source file

An excerpt from plugins/egregore/agents/sentinel.md, shared under the repository's MIT license. Read the full file on GitHub.

{
  "status": "ok | warning | critical | exhausted",
  "utilization_pct": 42,
  "tokens_remaining": 58000,
  "cooldown_active": false,
  "cooldown_until": null,
  "recommendation": "continue"
}

Before you install

• Read the whole file first. Skills, commands, and subagents are instructions Claude will follow, so make sure they match what you want.
• Check which tools, scripts, or MCP servers it uses. Local servers and scripts run with your permissions.
• Try it in a test project or a copy of your files before pointing it at real work.
• Pin the version you tested, and review changes before updating.
• Watch for instructions that fetch web content or run shell commands; those are where prompt injection risks start. See our prompt injection guide.

FAQ