Add browser investigation agents for performance, regressions, and ru…

[proflead]

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 three new specialized browser-focused agents for runtime investigation workflows:

• frontend-performance-investigator.agent.md
• devtools-regression-investigator.agent.md
• accessibility-runtime-tester.agent.md

These agents are intentionally narrower than existing general browser/testing/debug agents and focus on evidence-backed runtime analysis with Chrome DevTools MCP-
style workflows.

Summary of each agent:

• Frontend Performance Investigator: runtime web-performance diagnosis for Core Web Vitals, Lighthouse regressions, layout shifts, long tasks, and slow network
  paths.
• DevTools Regression Investigator: browser regression reproduction and triage for broken user flows, with console/network evidence and likely root-cause
  narrowing.
• Accessibility Runtime Tester: runtime accessibility validation for keyboard flows, focus management, dialog behavior, form errors, and browser-observed WCAG
  issues.

This also regenerates docs/README.agents.md so the new agents appear in the catalog.

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Type of Contribution

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

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Additional Notes

These are not intended to be generic browser testers.

The goal is to add more focused runtime investigation agents in areas that are valuable to users and explicitly in scope for the repository:

• performance optimization
• testing and quality assurance
• accessibility and inclusive design

I tried to keep overlap low by making each agent centered on a distinct investigation workflow rather than a general-purpose testing persona.

Validation performed:

• Ran npm ci
• Ran npm run build
• Ran bash scripts/fix-line-endings.sh

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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

4 resource(s) checked | ✅ All checks passed

Full output

No agents found in the specified paths: "/home/runner/work/awesome-copilot/awesome-copilot/agents/accessibility-runtime-tester.agent.md", "/home/runner/work/awesome-copilot/awesome-copilot/agents/devtools-regression-investigator.agent.md", "/home/runner/work/awesome-copilot/awesome-copilot/agents/frontend-performance-investigator.agent.md"

Note: Errors were found. These are currently reported as warnings and do not block merge. Please review and address when possible.

[Copilot]

Pull request overview

Adds three new narrowly scoped, browser-focused investigation agents to the repository’s agent catalog to support runtime evidence-based workflows (performance diagnosis, regression triage, and accessibility runtime testing), and updates the agents README so they appear in the published list.

Changes:

• Added Frontend Performance Investigator agent for DevTools-driven performance investigations (CWV/Lighthouse/trace-based analysis).
• Added DevTools Regression Investigator agent for reproducing browser regressions and collecting console/network evidence.
• Added Accessibility Runtime Tester agent for keyboard/focus/runtime accessibility validation, plus regenerated docs/README.agents.md to include all three.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated no comments.

File	Description
docs/README.agents.md	Adds the three new agents to the published agents catalog table.
agents/frontend-performance-investigator.agent.md	New agent definition focused on runtime web performance investigation workflows.
agents/devtools-regression-investigator.agent.md	New agent definition focused on browser regression reproduction and evidence collection.
agents/accessibility-runtime-tester.agent.md	New agent definition focused on runtime accessibility testing (keyboard/focus/forms/dynamic UI).