A model can return a well-formed object that still describes an unauthorized operation. A customer identifier can have the correct syntax while referring to the wrong customer. A payment amount can be a valid number while exceeding the amount the user is allowed to approve.
When generated content enters another system, security depends on how that receiving system interprets it. The relevant checks include format, meaning, permissions, and the state of the business transaction.
Format validation is one layer
OWASP's improper output handling category covers cases where generated content is passed to downstream systems without appropriate scrutiny. Examples include unsafe rendering and execution. The OWASP guidance treats model output as untrusted input to those systems.
A schema can establish that a proposed expense record contains a date, an amount, and a department identifier. It cannot establish that the receipt belongs to the claimant or that the department accepts the charge. Those are application decisions requiring authenticated context and business records.
Separate proposals from execution
An illustrative expense assistant can return a proposed classification for review. The application stores that proposal separately from an approved ledger entry. A transaction service then validates the claimant, permitted cost centers, currency, and approval state before recording a charge.
This separation gives each component a defined responsibility. The model extracts and suggests. The application identifies the user and controls the workflow. The ledger enforces accounting constraints. A request does not acquire additional authority because its explanation sounds consistent with the receipt.
Rendering is another interpretation boundary
Generated text may become HTML, Markdown, a spreadsheet, or a database query. Each destination has different interpretation rules. Content that is harmless as plain text can become active markup or a formula when exported. Use the destination's established encoding and parameterization controls rather than a single generic cleanup step.
For example, a report preview and its downloadable spreadsheet can require separate tests. The preview may display a synthetic string literally while the spreadsheet application interprets the same value. Testing only the browser would leave the export behavior unexamined.
Verify rejected as well as accepted proposals
Build controlled cases for a valid classification, an unknown cost center, a record from another test account, and an amount outside the configured approval limit. Also test missing fields and additional fields that the service does not accept. Record whether validation rejects the request without partially updating records.
The model may produce different wording across repeated runs. The service's acceptance conditions can remain stable. An assessment can therefore distinguish variability in extraction quality from a failure to enforce the business rule.
For release review, retain the input fixture, proposed object, validation result, and resulting state. This gives finance and engineering a shared explanation of what happened. It also supports regression checks when a model, prompt, schema, or export library changes.
Sources
OWASP: Input Validation. The expense workflow is an illustrative design and test example.
