Lean Agentic Reviews & Lightweight Automation: Copilot Change Groups + Slim Actions Runner

[ebndev]

Two public preview features are here to streamline code review and trim automation costs. Copilot now groups related changes in pull requests, and GitHub Actions introduces a new 1 vCPU Linux "ubuntu-slim" runner for lightweight jobs.

🔍 Copilot Change Groups (public preview)

Copilot automatically analyzes a pull request and clusters related changes—refactors, config tweaks, test updates, etc.—into logical groups. This helps you:

• See intent behind each set of changes faster.
• Review large or noisy PRs with more confidence.
• Focus on meaningful logic instead of minor churn.

Try it: Opt in to the new Files changed preview by clicking Try the new experience (top-right of the tab). Groups appear inline where you'd normally scroll a flat list of files.

Feedback: Share thoughts in the community discussion → https://gh.io/change-group-feedback

Preview disclaimer: UI and behavior may evolve before GA.

🧪 1 vCPU Linux Runner for GitHub Actions (public preview)

Run lightweight automation jobs on cost-efficient ephemeral containers using the new ubuntu-slim runner type.

• 1 vCPU / 5 GB RAM
• Hypervisor-level isolation; container is decommissioned after the job
• 15 minute max runtime (auto-terminated if exceeded)
• Great for: issue/PR labeling, linting & formatting, light bundling (e.g. webpack), small build fragments, housekeeping tasks

🚀 Why this matters

• Faster cognitive parsing of complex PRs → lower review fatigue.
• Lower-cost automation for non-CI heavy tasks → better spend efficiency.
• Shared focus: precision review + intentional resource usage.

✅ Where to start

1. Enable the Files changed preview on a larger PR—note review time saved.
2. Migrate a few housekeeping workflows to ubuntu-slim and compare job durations/cost.
3. Pair change groups with required reviews to keep velocity + guardrails.
4. Audit existing runners: move lint/test-splitting jobs off heavyweight VMs.

💬 Join the conversation

Drop feedback on change groups or runner usage patterns. What grouping categories or runner sizes do you want next?

Let’s keep reviews sharp and automation lean. 🛠️

[fproulx-boostsecurity]

That's nice. Looking forward to see the delta in cold start time

[kenchan0130]

I think the addition of the 1 vCPU Linux Runner for GitHub Actions is a fantastic improvement!
However, for the intended use cases such as linting, many third-party actions rely on using: 'docker'.

Therefore, I believe Docker support should be enabled to ensure compatibility with these actions.