Add GitHub Actions and Codespaces Efficiency skill

[mutl3y]

Pull Request Checklist

• I have read and followed the CONTRIBUTING.md guidelines.
• I have read and followed the Guidance for submissions involving paid services.
• My contribution adds a new instruction, prompt, agent, skill, or workflow file in the correct directory.
• The file follows the required naming convention.
• The content is clearly structured and follows the example format.
• I have tested my instructions, prompt, agent, skill, or workflow with GitHub Copilot.
• I have run npm start and verified that README.md is up to date.
• I am targeting the staged branch for this pull request.

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Description

Adds a new github-actions-codespaces-efficiency skill focused on reducing GitHub Actions and Codespaces waste.

The skill provides:

• A lean SKILL.md entrypoint with scope, workflow, output shape, and review rubric.
• Focused references for Actions audits, Codespaces optimization, reporting, and concrete patterns.
• agents/openai.yaml metadata aligned to the full Actions + Codespaces scope.
• Updated generated skills documentation via npm run build.

Validation run locally:

• node ./eng/validate-skills.mjs
• npm run build

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Type of Contribution

• New skill file.
• Update to existing instruction, prompt, agent, plugin, skill, or workflow.

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Additional Notes

This PR targets staged and is opened from the contributor fork branch mutl3y:workflow_cost.

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By submitting this pull request, I confirm that my contribution abides by the Code of Conduct and will be licensed under the MIT License.

[github-actions]

🔍 Skill Validator Results

✅ All checks passed

Scope	Checked
Skills	1
Agents	1
Total	2
Severity	Count
---	---:
❌ Errors	0
⚠️ Warnings	0
ℹ️ Advisories	0

Summary

Level	Finding
ℹ️	Found 1 skill(s)
ℹ️	[github-actions-codespaces-efficiency] 📊 github-actions-codespaces-efficiency: 1,048 BPE tokens [chars/4: 1,262] (detailed ✓), 11 sections, 1 code blocks
ℹ️	✅ All checks passed (1 skill(s))

Full validator output

```text Found 1 skill(s) [github-actions-codespaces-efficiency] 📊 github-actions-codespaces-efficiency: 1,048 BPE tokens [chars/4: 1,262] (detailed ✓), 11 sections, 1 code blocks ✅ All checks passed (1 skill(s)) ```

[Copilot]

Pull request overview

Adds a new skill (github-actions-codespaces-efficiency) to guide audits and concrete improvements that reduce GitHub Actions runtime/cost and Codespaces waste, and registers it in the generated skills documentation.

Changes:

• Added a new skill entrypoint (SKILL.md) with a focused workflow, output shape, and review rubric for Actions + Codespaces efficiency work.
• Added supporting reference docs for Actions audits, Codespaces optimization, reporting, and reusable implementation patterns.
• Added agent metadata and updated docs/README.skills.md to include the new skill and its bundled assets.

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
skills/github-actions-codespaces-efficiency/SKILL.md	New skill entrypoint defining scope, workflow, output contract, and references.
skills/github-actions-codespaces-efficiency/references/actions.md	Reference guidance for auditing and improving GitHub Actions efficiency.
skills/github-actions-codespaces-efficiency/references/codespaces.md	Reference guidance for devcontainer/Codespaces sizing, prebuilds, and cost controls.
skills/github-actions-codespaces-efficiency/references/patterns.md	Concrete YAML/config patterns for caching, concurrency, trigger scoping, etc.
skills/github-actions-codespaces-efficiency/references/reporting.md	Guidance for before/after reporting and follow-up review passes.
skills/github-actions-codespaces-efficiency/agents/openai.yaml	Agent UI/prompt metadata for the skill.
docs/README.skills.md	Registers the new skill in the generated skills index with bundled assets.

[mutl3y]

Added a compact audit command block to SKILL.md to address the review comment about having no code blocks. This is included in commit cf55938.

[aaronpowell]

I think this would make more sense to exist as two separate skills, one that focuses on GitHub Actions and another that focuses on Codespaces/Devcontainers. While yes, it's likely people are using them together, they aren't really overlapping products in how they work, so having them in a single skill will overload the context window with (arguably) unhelpful tokens.

[aaronpowell]

can you drop this file.