Recipe: tag PII in your schema

Time: 2 minutes · Audience: anyone shipping a contract with personally identifiable data

Problem

Your data product contains email, ssn, phone_number, or other PII. You need:

  1. The fields tagged so analysts know they're sensitive.
  2. Native cloud masking (BigQuery dynamic data masking / Snowflake masking policies) applied automatically.
  3. AI/LLM agents blocked from reading those columns.

Solution

Three small additions to the contract.

1. Tag the column with sensitivity: pii

exposes:
  - exposeId: customers
    contract:
      schema:
        - name: customer_id
          type: STRING
          required: true
        - name: name
          type: STRING
        - name: email
          type: STRING
          sensitivity: pii          # ← marks as PII
        - name: phone_number
          type: STRING
          sensitivity: pii
        - name: ssn
          type: STRING
          sensitivity: phi          # PHI = stricter than PII (HIPAA-class)

The schema field sensitivity is recognized by every provider that supports column masking (today: BigQuery, Snowflake — AWS Glue lineage tags coming).

2. Make it explicit at the access-policy layer

accessPolicy:
  grants:
    - principal: "group:analysts@company.com"
      permissions: ["read"]                 # gets masked PII (asterisks for email/phone, full for everything else)
    - principal: "group:fraud-team@company.com"
      permissions: ["read", "select"]       # cleared role; sees PII unmasked (verified by audit log)

The actual unmasking-vs-masking behavior is determined by the platform's masking policies; fluid policy apply deploys the policy attached to each principal.

3. Block AI agents from reading PII

agentPolicy:
  allowedModels: ["claude-3-opus"]
  allowedUseCases: ["analysis", "summarization"]
  deniedUseCases: ["training"]
  auditRequired: true

The combination of sensitivity: pii on columns + agentPolicy at the contract root tells the governance pipeline to mask PII columns from any read where the principal is tagged as an agent.

Verify before deploying

fluid policy-check contract.fluid.yaml                                  # validates the policy block
fluid plan contract.fluid.yaml                                          # shows which masks/grants will be applied
fluid policy compile contract.fluid.yaml --out runtime/policy/bindings.json  # contract → provider bindings
fluid policy apply runtime/policy/bindings.json                         # deploy the compiled IAM (dry-run; add --mode enforce)

See also