diff --git a/.planning/PROJECT.md b/.planning/PROJECT.md
index 002b728..12ff484 100644
--- a/.planning/PROJECT.md
+++ b/.planning/PROJECT.md
@@ -79,6 +79,7 @@ The product uses debate/speech terminology throughout:
 - **Performance**: 3D UI must run at 60fps on mid-range hardware; 2D fallback for low-end devices
 - **Independence**: No upstream coordination with Omarchy - must be resilient to their changes
 - **Python tooling**: Use ruff for linting and formatting (replaces flake8, black, isort)
+- **Package versions**: Always use actual latest versions from PyPI/npm, not AI training data assumptions — verify with `pip index versions` or package registries
 
 ## Key Decisions
 
@@ -90,6 +91,7 @@ The product uses debate/speech terminology throughout:
 | Self-hosted infrastructure | Build server already available; full control over build environment | - Pending |
 | Greenfield implementation | No legacy constraints; can build architecture correctly from start | - Pending |
 | Ruff for Python tooling | Fast, replaces flake8+black+isort; better DX with single tool | - Pending |
+| Verify package versions | Always check actual latest from registries, never trust AI assumptions | - Pending |
 
 ---
 *Last updated: 2026-01-25 after initialization*