Knowledge cutoff
Also called Training cutoff
The date after which a model's training text has little or nothing. Nothing tells it that time has passed, so it describes old versions and old APIs in the present tense unless the prompt says otherwise.
Agents reach for the version of a library that was common in their training text. The fix is cheap: make it read the installed version's types or docs instead of recalling them.
Say it to your agent
“You may be remembering an older version of this library. Read node_modules/zod/package.json and its type definitions before you write the schema, and name the file you checked.”