Add harness engineering skill 🤖🤖🤖

[baskduf]

Pull Request Checklist

• I have read and followed the CONTRIBUTING.md guidelines.
• I have read and followed the Guidance for submissions involving paid services. No paid services are involved.
• 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 harness-engineering skill for adopting repository-level guardrails for coding agents.

The skill helps users turn repeated AI coding-agent mistakes into durable repository artifacts: agent instructions, enforceable checks, failure memory, drift checks, adoption reports, and review workflows. It is intentionally prompt-first and repository-specific, so it tells the agent to inspect the target repository before adding harness pieces instead of copying a generic template.

This is distinct from existing AI-readiness or AGENTS.md generation resources because it focuses on recurrence prevention after a concrete failure or repeated review pattern, and on tying every high-risk rule to a test, lint rule, CI gate, drift check, or manual review point.

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Type of Contribution

• New instruction file.
• New prompt file.
• New agent file.
• New plugin.
• New skill file.
• New agentic workflow.
• Update to existing instruction, prompt, agent, plugin, skill, or workflow.
• Other (please specify):

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Additional Notes

Validation run locally:

• npm ci
• npm run skill:validate
• npm run plugin:validate
• npm start
• git diff --check
• Markdown CRLF scan excluding node_modules
• gh skill install /tmp/awesome-copilot-pr-work harness-engineering --from-local --agent github-copilot --scope project --force in a temporary smoke-test repository
• copilot -p "Use the harness-engineering skill..." dry-run confirmed GitHub Copilot CLI loaded the skill and summarized the first three workflow steps without editing files

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

Summary

Level	Finding
ℹ️	Found 1 skill(s)
ℹ️	[harness-engineering] 📊 harness-engineering: 1,605 BPE tokens [chars/4: 1,971] (detailed ✓), 18 sections, 3 code blocks
ℹ️	✅ All checks passed (1 skill(s))

Full validator output

```text Found 1 skill(s) [harness-engineering] 📊 harness-engineering: 1,605 BPE tokens [chars/4: 1,971] (detailed ✓), 18 sections, 3 code blocks ✅ All checks passed (1 skill(s)) ```