DLP for AI: How Block, Alert, and Mask Modes Protect Sensitive Data

Every prompt an employee sends to an AI model can contain sensitive information: a customer's email address, a contract clause, an API key, or a financial figure. Data loss prevention (DLP) for AI checks prompts before they leave the organization and decides what happens to sensitive data.

What is DLP for AI?

Traditional DLP protects email, file sharing, and endpoints. DLP for AI applies the same idea to prompts. Before a request reaches a large language model, the DLP layer scans it for sensitive data such as personal information, credentials, or confidential business data, and then applies the action defined in the company's policy.

Three modes: Block, Alert, and Mask

Block

Block completely stops a request that contains sensitive data. The prompt never reaches the model. This mode suits the most critical data types, for example credentials, payment card data, or information that must never leave the company.

Alert

Alert lets the request through but warns about the detected data. It helps raise awareness without interrupting work and gives the security team visibility into how sensitive data is used. Alert is a good starting point when a company is still learning its usage patterns.

Mask

Mask replaces sensitive values with masked placeholders before the request is sent to the model. The employee still gets a useful answer, but the model never sees the original data. This mode works well for tasks like summarizing customer conversations or analyzing documents that contain personal information.

How to choose the right mode

• Use Block for data that must never be shared with external models under any circumstances.
• Use Mask when the task is legitimate but the specific values are not needed for a good answer.
• Use Alert for lower-risk data and during the first weeks of rollout, to understand real usage before tightening rules.

Many organizations combine modes: different data types get different actions, and policies become stricter as the team learns how AI is used.

DLP is one part of AI governance

DLP works best together with role-based access control, clear usage policies, and audit trails. Read our guides on AI data security when using LLMs and writing an enterprise AI usage policy to build the full picture.

DLP in Waibee

Waibee includes built-in DLP with Block, Alert, and Mask modes. Sensitive data is detected before a request reaches any of the 100 AI models available on the platform, and the action depends on the policy configured for your organization. Learn more on our solutions page.

Key takeaways

• DLP for AI scans prompts for sensitive data before they reach a model
• Block stops the request, Alert lets it through with a warning, Mask hides sensitive values
• The right mode depends on the data type and the task
• DLP is most effective as part of a wider AI governance setup