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Marcel.L
Marcel.L

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Using GitHub Copilot Coding Agent for DevOps Automation

#github #devops #githubcopilot #automation

Using GitHub Copilot Coding Agent for DevOps Automation

What if you could assign a GitHub Issue to an AI teammate and come back to a ready-to-review pull request? That is exactly what GitHub Copilot Coding Agent does. It works autonomously inside an ephemeral GitHub Actions environment, analyses your codebase, makes changes, runs tests, and opens a PR for your approval.

In this post we will look at how the coding agent works, how to set it up for a DevOps repository, and walk through six practical use cases you can try straight away.

What Is GitHub Copilot Coding Agent?

Think of the coding agent as an async, pull-request-oriented developer. You describe the work, it does the coding in the background, and you review the result. Here is the flow:

  1. Assign the task via a GitHub Issue, PR comment, VS Code, or the GitHub CLI.
  2. The agent spins up in an isolated GitHub Actions container with your setup workflow.
  3. It explores, codes, and iterates, running builds, linters, and tests along the way.
  4. A pull request appears with all changes, ready for your review.
  5. You approve and merge. The agent can never merge its own work.

Security at a Glance

The agent is locked down by design:

  • Runs in ephemeral containers destroyed after each session.
  • Can only push to branches prefixed with copilot/, never to main or master.
  • Every PR is scanned by CodeQL for security issues, secret scanning for leaked credentials, and dependency checks against the GitHub Advisory Database.
  • The person who triggered the agent cannot approve the resulting PR, guaranteeing independent review.
  • Internet access is controlled by a default firewall. External services require explicit allow-listing.
  • Full audit trails of every action the agent took.

Key Limitations

Keep these in mind when planning tasks:

  • One repository, one PR per task. The agent cannot span multiple repos or open multiple PRs from a single issue.
  • Linux runners only (Ubuntu x64 GitHub Actions).
  • Read-only repo access within its sandbox. It writes to its copilot/ branch only.
  • No signed commits without a ruleset bypass for the agent.

For the full list of capabilities and constraints, see the official documentation.

Getting Set Up

You need a GitHub Copilot Pro, Pro+, Business, or Enterprise plan, write access to the repository, and GitHub Actions enabled. For organisations, an admin must enable the coding agent under Copilot settings.

Note: The coding agent uses both GitHub Actions minutes and Copilot premium requests. Keep an eye on usage through your billing settings.

1. Create the Setup Workflow

This workflow runs before the agent starts coding. It installs your project's dependencies so the agent can build and test. The job must be named copilot-setup-steps and live on your default branch:

# .github/workflows/copilot-setup-steps.yml
name: Copilot Setup Steps
on: workflow_dispatch

jobs:
  copilot-setup-steps:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4

      - name: Install dependencies
        run: |
          npm install
          # or: pip install -r requirements.txt
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Important: Only steps, permissions, runs-on, services, snapshot, and timeout-minutes are honoured inside this job. Everything else is ignored.

If your workflows need secrets, add them through the copilot environment in repository Settings > Environments.

2. Add Custom Instructions

Create a .github/copilot-instructions.md file to teach the agent your team's conventions. This is the single biggest lever for improving output quality:

# Copilot Instructions

## Code Standards

- Use Terraform 1.6+ syntax
- All infrastructure must include tags: Environment, Owner, CostCentre

## Testing

- Terraform modules require terratest validation
- CI/CD changes need a dry-run in dev first

## Documentation

- Update CHANGELOG.md for infrastructure changes
- Include deployment runbooks for new services
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You can also create scoped instruction files under .github/instructions/ with an applyTo glob, so rules only activate for matching files (for example, applyTo: "terraform/**").

3. Assign Your First Task

The simplest method: create a GitHub Issue, add @copilot as the assignee, and wait. The agent picks it up, works autonomously, and opens a PR when finished.

Other options:

  • PR comments: @copilot please add unit tests for this new module.
  • GitHub CLI: gh issue edit 42 --add-assignee @copilot
  • VS Code: Use the Copilot Chat panel or the GitHub sidebar to assign issues directly.

You can track progress through the Copilot Agents Panel on GitHub, which gives a real-time view of the session, including full logs of what the agent explored and changed.

DevOps Use Cases

Here is where things get interesting. These six scenarios show how the coding agent fits naturally into DevOps workflows.

Use Case 1: Fix a Broken CI/CD Pipeline

The problem: Your production deployment workflow failed overnight. Engineers are blocked.

Without the agent: Someone opens GitHub Actions, scrolls through hundreds of log lines, spots a missing environment variable, edits the YAML, pushes, waits for CI. Thirty to forty-five minutes gone.

With the agent: Create an issue like this:

Title: Fix failing production deployment workflow

Our deploy workflow failed on run #2847. The error appears to be in the AWS authentication step. Please investigate the logs, fix the workflow configuration, and validate the fix passes.

Assignee: @copilot
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The agent analyses the logs, finds the missing AWS_DEPLOYMENT_ROLE reference, checks similar workflows for the correct pattern, updates the YAML, runs a validation build, and opens a PR with the fix. Your involvement? A five-minute code review.

Use Case 2: Enhance Infrastructure as Code

The problem: You need to add cluster auto-scaling to your EKS infrastructure across dev, staging, and prod.

With the agent:

Title: Add cluster auto-scaling to EKS infrastructure

Add Kubernetes Cluster Autoscaler to all three environments.

Acceptance criteria:

- Update Terraform modules with autoscaler config
- Set appropriate min/max node counts per environment
- Add CloudWatch alarms for scaling events
- Update IAM roles with required permissions
- Add terratest validation
- Document the scaling policies

Assignee: @copilot
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The agent reads your existing modules, adds the autoscaler following AWS best practices, wires up environment-specific variables, writes tests, updates docs, and delivers one clean PR. You review, run terraform plan in your pipeline, and merge.

Use Case 3: Remediate Security Vulnerabilities

The problem: Dependabot flagged 15 vulnerabilities in your Node.js dependencies.

With the agent:

Title: Remediate active Dependabot security alerts

Please review all active security vulnerabilities, update dependencies to patched versions, and ensure all tests pass. Handle any breaking API changes from major version bumps and note them in the PR description.

Assignee: @copilot
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The agent analyses each alert, updates package.json, runs npm audit and the full test suite, fixes any breakage from API changes, and opens a single PR with a clear summary of what changed and why.

Tip: Because the agent opens exactly one PR per task, consider creating separate issues for "safe patch updates" and "major version bumps with breaking changes" if you want to review them independently.

Use Case 4: Keep Documentation in Sync

The problem: Your docs drift out of date every time infrastructure changes land.

Solution: Trigger a documentation update automatically after infrastructure PRs merge:

# .github/workflows/doc-update.yml
name: Update Documentation
on:
  pull_request:
    types: [closed]
    paths:
      - 'terraform/**'
      - 'kubernetes/**'
      - '.github/workflows/**'

jobs:
  update-docs:
    if: github.event.pull_request.merged == true
    runs-on: ubuntu-latest
    steps:
      - name: Create Documentation Issue
        run: |
          gh issue create \
            --title "Update docs for PR #${{ github.event.pull_request.number }}" \
            --body "PR #${{ github.event.pull_request.number }} modified infrastructure. Please review and update relevant documentation, architecture diagrams, and deployment runbooks." \
            --assignee @copilot \
            --label "documentation"
        env:
          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
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Every merged infrastructure PR spawns a documentation task that the agent handles. Your docs stay fresh without anyone having to remember.

Use Case 5: Boost Test Coverage on Autopilot

The problem: Your team knows test coverage is low, but writing tests for existing modules never makes it to the sprint.

With the agent: Create targeted issues for each area that needs coverage:

Title: Add unit tests for authentication module

The auth module at src/auth/ currently has minimal test coverage. Please:

1. Analyse the existing code and identify untested paths
2. Write comprehensive unit tests covering happy paths and edge cases
3. Ensure all tests pass and document any discovered bugs
4. Report the before/after coverage in the PR description

Assignee: @copilot
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The agent reads the module, generates tests that exercise both success and failure paths, runs them to confirm they pass, and opens a PR with a coverage summary. Repeat across modules with separate issues and you can steadily burn down test debt in the background.

Tip: GitHub's own experiments with this pattern took test coverage from roughly 5% to near 100% across 45 days, producing over 1,400 tests. Small, daily PRs kept reviews manageable. See the Continuous AI blog post for details.

Use Case 6: Remediate Security Alerts via Campaigns

The problem: Your organisation runs security campaigns to address CodeQL or Dependabot findings at scale, but engineers struggle to find time for the fixes.

With the agent: From the Security tab on GitHub, select alerts and assign them directly to Copilot as part of a campaign. The agent receives the alert context, analyses the vulnerable code path, applies a fix, validates the change passes your test suite, and opens a PR, all without anyone filing a separate issue.

This is a first-class integration, not a workaround. The coding agent understands the alert metadata (CVE, severity, affected file and line) and uses it to produce targeted patches. For large campaigns spanning dozens of alerts, you can assign batches to Copilot and review the resulting PRs as they arrive.

Note: Security campaigns require GitHub Advanced Security or GitHub Code Security. The coding agent's own built-in security scanning (CodeQL, secret scanning, dependency checks) does not require these licences.

Tips for Getting the Best Results

Write clear issues. The quality of the PR directly reflects the quality of the issue. Include a problem statement, acceptance criteria, relevant file paths, and any constraints. A vague "make it faster" will produce vague results.

Iterate via PR comments. If the first attempt is not quite right, leave a review comment:

@copilot please use SSM Parameter Store instead of environment variables and add retry logic with exponential backoff.
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The agent will push follow-up commits to the same PR.

Use custom instructions and scoped instruction files. The more context the agent has about your conventions (naming, tagging, testing patterns, preferred libraries), the better its output. This pays dividends across every task.

Always review thoroughly. The agent is a capable first-drafter, not an infallible engineer. Test changes in a non-production environment, verify security implications, and check for unintended side effects before merging.

Extending the Agent

MCP Servers

The coding agent ships with GitHub and Playwright MCP servers by default. You can add more through your repository settings or a .vscode/mcp.json file. For example, connecting an Azure MCP server gives the agent access to Bicep schema lookups:

{
  "mcpServers": {
    "AzureBicep": {
      "type": "local",
      "command": "npx",
      "args": [
        "-y",
        "@azure/mcp@latest",
        "server",
        "start",
        "--namespace",
        "bicepschema",
        "--read-only"
      ]
    }
  }
}
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Custom Agents, Hooks, and Skills

Beyond custom instructions, you can create custom agents specialised for different tasks (frontend, docs, testing), define hooks that run shell commands at key points during execution, and package reusable skills with instructions and scripts. See the official docs on customising the coding agent for details.

Scheduled Maintenance

Automate recurring toil with a cron workflow:

# .github/workflows/weekly-maintenance.yml
name: Weekly Maintenance
on:
  schedule:
    - cron: '0 10 * * 5' # Friday 10 AM

jobs:
  maintenance:
    runs-on: ubuntu-latest
    steps:
      - name: Weekly dependency updates
        run: |
          gh issue create \
            --title "Weekly dependency updates" \
            --body "Review and update all dependencies. Run full test suite." \
            --assignee @copilot
        env:
          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
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Try It Today

Pick one pain point in your current workflow and assign it to @copilot. Here is a template to get you started:

Title: Analyse and optimise CI/CD pipeline performance

@copilot please review our GitHub Actions workflows and:

1. Identify performance bottlenecks
2. Suggest and implement caching strategies
3. Add parallel job execution where possible
4. Summarise the improvements in the PR description

Assignee: @copilot
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Start small, review the PR carefully, and build trust over time. As your team sees the results, you will naturally expand to more complex tasks.

Additional Resources

Author

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Marcel.L

Microsoft MVP in DevTech - DevOps | DevOps Architect | Technical speaker focused on Microsoft technologies, Agentic AI, IaC & automation in Azure. Find me on GitHub: https://github.com/Pwd9000-ML

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