Agent Skill

The Yorker skill is a small set of Markdown instructions that teaches a coding agent how to work with Yorker: the yorker.config.yaml schema, the order to run commands in, what it must not do without asking, and how to investigate a failing monitor.

It follows the open Agent Skills format, so it works with any agent that supports skills. The agent loads the short main file when a task involves monitoring and pulls in the detailed references only when it needs them, which keeps your context window free for your code.

Install

From your project root:

npx @yorker/cli skills install

This writes the skill to .claude/skills/yorker/, where Claude Code looks for project skills. Commit the directory so everyone on the team, and every agent, gets the same instructions.

Flags

What is inside

yorker/
├── SKILL.md                      # when to use Yorker, the edit-validate-test-diff-deploy loop, hard rules
└── references/
    ├── config.md                 # monitor types, alerts, SLOs, channels, secrets, location IDs
    ├── browser-scripts.md        # Playwright scripts Yorker can run, step markers
    └── investigate.md            # finding out what is failing and why

The rules in SKILL.md are the part that matters most. They tell the agent to:

• validate after every edit and never deploy a config that has not validated,
• show you the yorker diff plan and wait for your go-ahead before deploying,
• never pass --prune or --force unless you ask,
• stop on drift and let you choose which side wins,
• keep secrets in environment variables and never ask you to paste a key,
• read assertions off the real response instead of guessing field names.

Use it

Once installed, you do not invoke the skill by name. Ask for the outcome and the agent picks it up:

Add monitoring for the new /api/payments endpoint.

Are any of our monitors failing? If so, work out why.

Turn tests/checkout.spec.ts into a Yorker browser monitor that runs every 10 minutes from the US and Europe.

See Agentic Workflows for what each of these produces.

Update

The skill ships inside the CLI, so it is always the version that matches the commands you have installed. After upgrading the CLI, refresh the copy in your repo:

npm install -g @yorker/cli@latest
yorker skills install --force

The skill also points the agent at the live Markdown docs and tells it that the docs win if the two disagree, so a slightly stale copy degrades gracefully.

Agents without skill support

Print the skill and paste it into whatever your agent reads on startup, such as AGENTS.md or a rules file:

yorker skills show >> AGENTS.md

Print a single reference the same way:

yorker skills show config
yorker skills show browser-scripts
yorker skills show investigate

With --json, skills show returns the content along with the list of available references, so an agent can discover and fetch them itself.

Related

• AI Agents & Coding Assistants: choosing between the skill, the CLI, and the REST API.
• CLI reference: every command the skill uses.
• Markdown & llms.txt: the docs the skill links to.