Data Protection
·IdenticAPI

PII and Secrets Leakage Checklist for AI Applications

A practical checklist to prevent PII and secrets from entering prompts, logs, retrieval indexes, and model outputs.

This PII and secrets leakage checklist is an actionable audit you can run before shipping—or monthly while operating—any LLM feature that accepts user text, indexes documents, calls tools, or logs prompts, so sensitive data is less likely to reach model providers, vector stores, observability backends, or other users. Work through each section, mark status, assign an owner, and track remediation; no checklist replaces legal review, but it catches the engineering gaps that cause most accidental exposures.

Use PII & Secrets Detection (POST /api/v1/security/pii-secrets) as your primary text scanner. Validate with PII Checker. Integration reference: docs.

How to use this checklist

  • Pass — Control implemented and verified in staging/production
  • Partial — Started but gaps remain (note them)
  • Fail — Not implemented; treat as blocker for production
  • N/A — Justify in writing (e.g., no RAG in v1)

Record request_id samples from test scans in your security ticket system for traceability.


1. Data inventory and scope

#ItemPass criteria
1.1List all text paths entering LLM contextDiagram covers user input, history, RAG, tools, system vars
1.2Classify which features may process PIIWritten policy per feature flag / SKU
1.3Identify regulated data types (PCI, PHI, etc.)Legal/compliance sign-off documented
1.4Map third parties receiving promptsProvider names, data processing terms reviewed
1.5Define retention for chat logsTTL configured; deletion tested

Related: LLM Data Leakage, What Is PII Detection?


2. Input boundary controls

#ItemPass criteria
2.1Server-side PII/secrets scan on every chat messageCannot reach LLM without scan
2.2Block on unsafe verdict (secrets)User sees non-echoing error; no provider call
2.3Redact on suspicious verdict (PII) when policy requiresredacted_text forwarded; see Redact PII Before LLM
2.4Scan full assembled prompt, not only latest turnHistory + RAG + tools included
2.5Privacy filter module documentedOwner team named; see LLM Privacy Filter
2.6Fail-closed behavior defined for scanner outageDocumented in runbook
2.7Max input length enforced (≤32,000 chars per API limit)Split or reject oversized payloads

3. Secrets-specific controls

#ItemPass criteria
3.1API keys never in system prompts or few-shot examplesPR review checklist
3.2.env / PEM uploads blocked or scanned in document chatFile type allowlist
3.3Paste-code UI warns on secret patternsManual UX test
3.4Rotation runbook for exposed keysLinked from on-call docs; see Prevent API Key Leak
3.5Private keys trigger block + incidentTest with synthetic PEM
3.6Credential pairs detected in formsSee Detect Credentials in User Input

Related: Secrets Detection for LLM Applications, Detect Private Keys and Tokens


4. RAG and document ingestion

#ItemPass criteria
4.1Chunks scanned before embeddingQuarantine or redact on findings
4.2PDF/HTML extraction re-scanned post-parseHidden text cases tested
4.3Internal wikis/repos secret-scanned before indexCI or ingestion job
4.4Retrieval results scanned before prompt assemblyOr pre-embedded clean store only
4.5Vector store access restrictedIAM / tenant isolation verified

5. Tool and agent paths

#ItemPass criteria
5.1Tool outputs minimized (least fields)Schema review
5.2Tool outputs scanned before model re-entryAutomated test
5.3Agents cannot exfiltrate env vars via promptsSandbox has no secret env
5.4Browser/fetch tools do not pull raw .env URLsBlocklist tested
5.5High-impact tools require human approvalDocumented exceptions

6. Logging and observability

#ItemPass criteria
6.1Raw prompts not logged at INFO in productionLog config audit
6.2Privacy scan logs request_id + categories onlyNo raw PII in SIEM
6.3Error traces strip Authorization headersSynthetic curl test
6.4Debug modes time-limited and gatedCannot enable via query param alone
6.5Third-party analytics exclude message bodiesTag manager / SDK review

7. Output and display

#ItemPass criteria
7.1Model output scanned before show (when PII echo risk)Optional but documented
7.2Multi-tenant session isolation testedUser A cannot see User B context
7.3Support admin views redacted by defaultRole-based access
7.4Export/download flows respect redactionCSV export test

8. Redaction strategy

#ItemPass criteria
8.1Redaction vs masking vs tokenization decidedSee comparison article
8.2Placeholder format consistent ([EMAIL], etc.)Matches API docs
8.3Stored chat history policy defined (raw vs redacted)DB column audit
8.4Credit card handling aligned with PCI scopePAN not in general chat; see Detect Credit Card Numbers

9. Enterprise alignment

#ItemPass criteria
9.1App-level scan complements corporate DLP (if any)Roles clear; see PII Detection vs DLP
9.2Vendor DPAs cover LLM subprocessorsLegal file current
9.3Employee AI acceptable-use policy publishedTraining completion tracked

10. Testing and CI

#ItemPass criteria
10.1Synthetic fixtures in CI (user@example.com, sk-test_...)Pipeline green
10.2Node or Python integration testsSee Node.js / Python guides
10.3Regression test for each leaked-secret incidentTicket → test case
10.4Staging uses distinct API keys from productionKey inventory
10.5Manual spot-check via PII Checker before major releasesRelease template

Synthetic test vectors (never use real data):

user@example.com
555-010-0200
4111111111111111
sk-test_abcdefghijklmnopqrstuvwxyz123456
AKIA0000000000000000
password=ExampleSyntheticPassword123!

Expected: appropriate verdict and findings per API docs.


11. Incident response

#ItemPass criteria
11.1Playbook for secret in promptRotation steps within 24h target
11.2Provider log inquiry process documentedContacts listed
11.3Customer notification criteria definedLegal involvement trigger
11.4Post-incident test added to CIClosed-loop verified

12. Limitations acknowledgment

#ItemPass criteria
12.1Team acknowledges regex limits (obfuscation, images)Documented in risk register
12.2No "100% secure" marketing claimsPublic copy review
12.3Periodic re-audit scheduled (e.g., quarterly)Calendar invite exists

Detection reduces risk; it does not guarantee zero leakage.


Quick scorecard

Count Pass items in sections 2–7 (core engineering):

ScoreInterpretation
90%+ PassStrong baseline for production
70–89%Ship with documented gaps and timeline
Below 70%High leakage risk—prioritize sections 2, 3, 4

Next steps after the audit

  1. Implement missing server-side scan — Detect PII in Text API
  2. Build privacy filter module — LLM Privacy Filter
  3. Train team on secrets in prompts — Prevent API Key Leak
  4. Add PII & Secrets Detection to staging and production with monitoring

Re-run this checklist after major feature launches (RAG, agents, new model provider).

Frequently asked questions

What is the PII and secrets leakage checklist for?

It is a structured audit of engineering, logging, RAG, tool, and incident-response controls to reduce accidental exposure of personal data and credentials in AI applications before and after launch.

How often should I run this checklist?

Run it before shipping LLM features and re-run after major changes such as adding RAG, agents, or a new model provider. Quarterly reviews help catch configuration drift in logs and retention.

What is the minimum bar for production?

At minimum: server-side scanning on every LLM path, block on unsafe secrets, redact or block PII per policy, scan full assembled prompts, and avoid logging raw message bodies in production.

Does passing the checklist guarantee zero leakage?

No. Detection has false negatives and obfuscated data may evade scanners. The checklist reduces common engineering gaps; it does not replace legal review or enterprise DLP where required.

What synthetic data should I use for checklist tests?

Use user@example.com, 555-010-0200, 4111111111111111, sk-test_ prefixes, AKIA0000000000000000, and password=ExampleSyntheticPassword123—never real customer data or live credentials.

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