Project knowledge is the reference material attached to a project so the AI starts with useful context: the files, notes, examples, and background documents it can draw on while it works. For a client project that might mean the service agreement, brand rules, SOPs, meeting notes, and examples of good output. It works alongside project instructions: the instructions say how to behave, the knowledge says what to know.
An email with attachments is the everyday version. The email says what you want; the attachments give the material. Ask someone to review a contract without attaching it and they guess. Attach the contract, prior comments, and the client’s standards, and they can actually work.
Why you care
More isn’t always better. A messy pile makes the AI slower and likelier to pull the wrong thing, so good knowledge is curated: current sources, no stale drafts, concise files, and anything relevant only once goes in the prompt instead of becoming permanent. A vault is the larger living place where information compounds; project knowledge is the small attached set. The right reference material turns a generic helper into someone who has actually read the file.