AI Decision Drift After OBS Upgrade: A Postmortem

TL;DR

• Decision drift hit 23% after OBS v2.4.0 upgrade; consistency dropped from 99.2% to 76.8%
• Schema validation passed; root cause was changed priority weight calculation logic
• Version anchoring and decision equivalence verification are now mandatory pre-upgrade steps
• Snapshots must bind to OBS version; 72-hour rollback window enforced with auto-archival
• New ObsUpgradeValidator class (see obs_upgrade_validator.py) enforces these safeguards

Key Takeaways

If you upgrade the OBS knowledge infrastructure, you must first run ObsUpgradeValidator.verify_decision_equivalence against the current snapshot.

If you deploy AI Agents in production, you must bind every decision state snapshot to the exact OBS version string at capture time.

If you perform OBS upgrades without regression tests on the target version, you will not catch cognitive framework changes until they hit production.

If your testing environment runs a different OBS version than production, your test coverage is ineffective—maintain version parity or use versioned test fixtures.

If you skip decision equivalence validation, linear-to-geometric weighting changes will silently corrupt your agents’ reasoning chains.

Read the Full Article (Chinese)

This is an abstract. The full technical walkthrough, including the ObsUpgradeValidator class implementation and D-2026-0512-001 incident timeline, is available in Chinese at the original article.