Two things can happen to a document or prompt you send to an AI tool, and only one of them is reversible. Processing uses your data in real time to complete a task; when the task finishes, the data does not re-enter the system for future learning. Training feeds your content into a model so it becomes part of what the model knows, and there is no undo: getting your content back out means retraining, which nobody has budgeted for (Parseur).
That distinction drives everything else. Model inversion, the reconstruction of training data by querying a trained model, and cross-tenant contamination, where one customer's documents influence another customer's output, are the two failure modes that make training clauses worth negotiating (Parseur). Neither shows up in a vendor's security portal.
Insist on separate answers for each pillar. A comparison of typical vendor positions looks like this:
| Data type | Typical default retention | What to ask for in writing |
|---|---|---|
| Prompts and inputs | 30 days for abuse monitoring on some platforms | Named retention window, and whether zero data retention is available |
| Outputs | Often the same as prompts | Whether outputs are stored separately from your conversation history |
| System and metadata logs | Longer than content, often unstated | Log schema, fields captured, and retention period |
| Embeddings and vector indexes | Rarely disclosed | Whether vectors are derived from your tenant only and how they are purged |
| Backups | Usually the longest clock | Rotation schedule and whether deletion reaches backups |
| Support tickets and attachments | Handled outside the main product | Whether support copies are scrubbed and after how long |
The Future of Privacy Forum's internal policy checklist is a useful internal companion because it forces you to define, before you shop, which categories of company data may enter an AI tool at all (FPF).



