Align AGENTS.md with canonical sections

[glenn-jocher]

Standardizes this repo's AGENTS.md against the Ultralytics org conventions.

• Replaced the repo-local Core Principles rewrite with the canonical 5-principle version. The old text carried an Output gate requiring every PR body to contain a Deleted: line, which contradicts the canonical review gate ("a missing or thin PR description is never itself a finding").
• Replaced the drifted 4-step PR Workflow with the canonical 5-step version.
• Added the repo-specific intro paragraph that was missing.
• Commands, Architecture, and Conventions are preserved unchanged, including the HUB shutdown and Platform migration notices.

🛠️ PR Summary

_{Made with ❤️ by Ultralytics Actions}

🌟 Summary

Updated repository guidance to reflect HUB’s shutdown and promote simpler, owner-focused development practices. 🧭

📊 Key Changes

• Replaced the former HUB development principles with a notice that the repository is now historical and points users to Ultralytics Platform.
• Reworked the core principles to emphasize:
  • Deleting or modifying existing code before adding new code.
  • Solving issues in the code path that owns the behavior.
  • Searching for and reusing existing functionality.
  • Keeping changes minimal and avoiding speculative complexity.
  • Delivering thoroughly validated, zero-regression changes.
• Simplified the PR review process by removing the mandatory Deleted: PR-body requirement and external adversarial review-agent step.
• Updated review guidance to require a clean, cold full-diff review before merging.
• Retained safeguards against pushing directly to main, force-pushing, or overwriting other contributors’ work.

🎯 Purpose & Impact

• 🧹 Aligns contributor and AI-agent guidance with the repository’s reduced role after HUB’s shutdown.
• 🔗 Directs users toward Ultralytics Platform, the successor service.
• ⚙️ Encourages smaller, cleaner, and more maintainable changes by prioritizing deletion, reuse, and ownership.
• ✅ Streamlines the review workflow while preserving important safeguards against regressions and unsafe Git operations.
• 👥 Makes the instructions easier for contributors to follow across the remaining README, dataset, and workflow-focused repository content.

[UltralyticsAssistant]

👋 Hello @glenn-jocher, thank you for submitting a ultralytics/hub 🚀 PR! This is an automated message, and an engineer will assist with the review. To ensure a seamless integration of your work, please review the following checklist:

• ✅ Define a Purpose: Clearly explain the purpose of your fix or feature in your PR description, and link to any relevant issues. Ensure your commit messages are clear, concise, and adhere to the project's conventions.
• ✅ Synchronize with Source: Confirm your PR is synchronized with the ultralytics/hub main branch. If it's behind, update it by clicking the 'Update branch' button or by running git pull and git merge main locally.
• ✅ Ensure CI Checks Pass: Verify all Ultralytics Continuous Integration (CI) checks are passing. If any checks fail, please address the issues.
• ✅ Update Documentation: Update the relevant documentation for any new or modified features.
• ✅ Add Tests: If applicable, include or update tests to cover your changes, and confirm that all tests are passing.
• ✅ Sign the CLA: Please ensure you have signed our Contributor License Agreement if this is your first Ultralytics PR by writing "I have read the CLA Document and I sign the CLA" in a new message.
• ✅ Minimize Changes: Limit your changes to the minimum necessary for your bug fix or feature addition. "It is not daily increase but daily decrease, hack away the unessential. The closer to the source, the less wastage there is." — Bruce Lee

For more guidance, please refer to our Contributing Guide. Don't hesitate to leave a comment if you have any questions. Thank you for contributing to Ultralytics! 🚀

[UltralyticsAssistant]

🔍 PR Review

_{Made with ❤️ by Ultralytics Actions}

Clean PR. The updated AGENTS.md matches the provided canonical Core Principles and PR Workflow, adds the repository-specific introduction, and preserves the existing Commands, Architecture, and Conventions guidance.

[UltralyticsAssistant]

🎉 Thank you, @glenn-jocher, and congratulations on the merge!

“Simplicity is the ultimate sophistication.” — Leonardo da Vinci

This PR brings that principle to life by clarifying HUB’s historical status, directing users to Ultralytics Platform, and encouraging focused, owner-driven changes that reuse existing functionality and avoid unnecessary complexity. The streamlined review guidance also preserves strong safeguards while making contribution workflows clearer and more efficient.

Your thoughtful work helps keep the project maintainable and contributors aligned. Thank you!