This directory contains expression implementations that are intentionally kept outside core exprs/.
Use exprs_ext/ for built-in expression extensions that need integration with higher BE modules such as storage, compute environment, execution runtime, or platform helpers. Keep reusable expression contracts, common scalar helpers, UDF runtime helpers, and aggregate registry mechanics in core exprs/ instead.
Read the nearest nested guide before changing a group:
dict/AGENTS.mdfor dictionary expression extensions.table_function/AGENTS.mdfor table-function expression extensions.utility/AGENTS.mdfor utility expression functions.
After changing module ownership or layering rules, edit be/module_boundary_manifest.json first, then run python3 build-support/render_be_agents.py --write.