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Lesson 7 - Create and use a QA agent

Create a requirements-first QA profile that combines test coverage, the quality-checks skill, and direct browser evidence.

You’ve used the quality-checks skill to run automated checks and Playwright MCP to observe the filtering experience in a browser. Now you’ll bring those capabilities together in a custom agent with a clearly defined QA process.

In this lesson, you will:

  • explore how a custom agent works with instructions, skills, and MCP tools.
  • create and inspect a reusable quality assurance (QA) profile.
  • select the QA agent and review its findings against the filtering issue.

Scenario

Tailspin Toys wants a consistent review of requirements, code quality, automated checks, test coverage, and browser behavior before opening a pull request (PR). A custom agent can coordinate that QA process and provide a reusable report.

What is a custom agent?

A custom agent is a specialized version of Copilot defined in a Markdown profile. The profile describes the agent’s purpose, instructions, and available tools. For this workshop, you’ll define a QA role in .github/agents/qa.agent.md and select it in the app.

The customizations you’ve used have different jobs. Repository instructions describe the team’s standards. The quality-checks skill packages repeatable checks. Playwright MCP supplies browser tools. The QA profile tells Copilot how to use those capabilities to assess requirements and report findings. It doesn’t replace them or require another session.

Create the QA profile

Before opening the feature PR, you’ll ask Copilot to create a reusable QA profile. The profile will define both the checks QA performs and the boundaries it must follow.

  1. Confirm the session is in Interactive mode.

  2. Send the following prompt to Copilot to create the new custom agent:

    Create a custom agent named QA in .github/agents/qa.agent.md. It should check features against their issues and agreed requirements, follow the repository instructions, run the quality-checks skill, use Playwright MCP to verify behavior, and add tests when coverage is missing.

Have it report each requirement as pass, fail, or blocked with supporting evidence. It must ask before changing implementation code, and it must not commit changes or open pull requests. Use the current model and available tools. Just create the profile for now so I can review it.

Inspect the profile

Before using the new agent, review its profile to confirm Copilot captured the intended QA workflow and authority boundaries. This prevents an incomplete or overly broad agent from changing the feature when you only want it verified.

  1. Open Changes and select .github/agents/qa.agent.md.
  2. Read the frontmatter. The description is required; name is optional, but including it gives the agent a clear display name.
  3. Read the profile instructions and confirm that QA starts from requirements, follows repository instructions, runs the quality-checks skill, and uses Playwright MCP.
  4. Confirm that QA reports supporting evidence, asks before changing implementation code, and does not commit changes or open pull requests.
  5. If the generated profile misses any of these responsibilities or boundaries, ask the general Copilot agent to revise it before continuing.

Run QA against the issue

With the profile reviewed, select QA in the current session so it can use the filtering issue and planning decisions already in context. Confirm the active agent before asking it to begin the review.

  1. In the current session, open the agent picker in the prompt box.

  2. Select QA and verify that the app visibly identifies QA as the active agent before sending the run prompt.

  3. Send the following prompt to ask QA to review the feature:

    Review the filtering feature against the issue and the decisions in our plan. Is it ready for a PR?

  4. Confirm QA uses the correct issue and planning decisions. Provide the issue URL or any missing context if it asks.

  5. Read through the report it provides once it’s done doing its work!

Summary and next steps

You’ve added a reusable specialist role to the workflow and reviewed its work. In this lesson, you:

  • explored how a custom agent works with instructions, skills, and MCP tools.
  • created and inspected a reusable QA profile that starts from requirements.
  • selected the QA agent and reviewed its findings against the filtering issue.

You now have the implementation, skill update, QA profile, tests, and verification report ready for review. Next, you’ll bring them together in a feature PR and use Agent Merge.