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	2
Agents	1
Total	3
Severity	Count
---	---:
❌ Errors	0
⚠️ Warnings	0
ℹ️ Advisories	0

Summary

Level	Finding
ℹ️	Found 2 skill(s)
ℹ️	[github-actions-efficiency] 📊 github-actions-efficiency: 866 BPE tokens [chars/4: 1,051] (detailed ✓), 10 sections, 1 code blocks
ℹ️	[github-codespaces-efficiency] 📊 github-codespaces-efficiency: 734 BPE tokens [chars/4: 904] (detailed ✓), 10 sections, 1 code blocks
ℹ️	✅ All checks passed (2 skill(s))

Full validator output

```text Found 2 skill(s) [github-actions-efficiency] 📊 github-actions-efficiency: 866 BPE tokens [chars/4: 1,051] (detailed ✓), 10 sections, 1 code blocks [github-codespaces-efficiency] 📊 github-codespaces-efficiency: 734 BPE tokens [chars/4: 904] (detailed ✓), 10 sections, 1 code blocks ✅ All checks passed (2 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.

[mutl3y]

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.

I did look at its context use which is why I layered the specifics for workflows, codespaces and the reporting into reference's, happy to take another look and split it if you think its better, will drop the openai file

[aaronpowell]

Sorry, this PR is looking incredibly confused now, it's adding an external plugin which isn't following the process for submitting external plugins and it's deleted an MCP server we use.

Can you clean it up to be focused and then I'll review again.