GDAL MCP

# 13️⃣ `13_mutable_defaults.md` # Mutable Defaults ### Principle Never use mutable objects (`[]`, `{}`) as default arguments. ### ✅ Prefer ```python def add_item(item, items=None): if items is None: items = [] items.append(item) return items ```` ### ❌ Avoid ```python def add_item(item, items=[]): # shared state bug items.append(item) return items ``` ### Why * Prevents shared state between calls * Avoids subtle, hard-to-debug behavior --- ### 🤝 Our Philosophy Predictability beats cleverness. Mutable defaults are almost never worth the surprise.