Sensitive Data & PII

The sensitive data & PII discipline detects, redacts, and minimises the PII in the AI flows (L313) — the entities (the names, the emails, the phone numbers, the SSNs, L313), the detection (the recognizers: the patterns and the ML models, L313), and the redaction (the masking — name@***.com — and the blocking, L313) — with the minimization (the least PII in the prompt, L312) as the principle (L313).

The one-sentence interview answer: "The PII discipline is the detection, the redaction, and the minimization (L313). The entities (L313): the names, the emails, the phone numbers, the SSNs, the addresses (L313) — the data that identifies (L313). The detection (L313): the recognizers (L313) — the pattern matching for the emails and the SSNs (L313), the ML models for the names (L313). The redaction (L313): the masking (L313) — the value replaced (L313): name@***.com (L313) — or the blocking (L313) — the entity removed (L313). The placement (L313): the redaction before the prompt (L312) — the provider (L278) sees less (L313); before the log (L329) — the record (L329) holds less (L313); and before the training (L365) — the model (L365) learns less (L313). The minimization (L312): the least PII (L312) in the flow (L313) — the data not collected (L313) is the data not leaked (L312). The AI shape (L173): the prompts (L312) and the logs (L329) — the PII detected (L313) and redacted (L313) before the exits (L312) — the L313 discipline (L313) at each boundary (L312)."

Think of the PII as the labeled jewels in the castle. The jewels (the PII, L313) are labeled (the entities, L313): the rubies (the names, L313), the emeralds (the emails, L313), the diamonds (the SSNs, L313). The guards (the detection, L313) recognize the labels (L313) — the ruby's shape (the pattern, L313), the emerald's sparkle (the ML model, L313). Before the jewels leave the castle (the exits, L312), the clerk (the redaction, L313) replaces them with the replicas (the masking, L313) — the ruby-shaped glass (the ***, L313) — or keeps them in (the blocking, L313). And the castle's rule (the minimization, L312): the fewer jewels brought in (L313), the fewer lost (L312). The castle works because the labels are recognized, the replicas are sent, and the jewels are minimized (L313).

   the jewels (the PII, L313)
   ┌────────────────────────────────────────────────────────┐
   │ the labels (the entities, L313) — the names, the       │
   │ emails, the SSNs (L313)                                │
   │ the guards (the detection, L313) — the recognizers     │
   │ (L313)                                                 │
   │ the replicas (the redaction, L313) — the masks (L313)  │
   │ the rule (the minimization, L312) — the least jewels   │
   └────────────────────────────────────────────────────────┘

The mental model is the jewels: the labels, the guards, the replicas, and the rule (L313).

   the input (L313)
        │  "email me at john@example.com" (L313)
        ▼
   ┌────────────────────── THE DETECTION (L313) ────────────────────────┐
   │  the recognizers (L313) — the email's pattern (L313)              │
   │  the entity found: the EMAIL (L313)                               │
   └──────────────────────────┬───────────────────────────────────────┘
                              ▼
   ┌────────────────────── THE REDACTION (L313) ────────────────────────┐
   │  the masking (L313): "email me at ***@***.com" (L313)             │
   │  or the blocking (L313): "email me" (L313)                        │
   └──────────────────────────┬───────────────────────────────────────┘
                              ▼
   ┌────────────────────── THE EXIT (L312) ─────────────────────────────┐
   │  the prompt (L312) — the provider sees the masked (L313)          │
   │  the log (L329) — the record holds the masked (L313)              │
   └──────────────────────────────────────────────────────────────────┘

The flow is the PII's path: detect → redact → exit (L313).

• The entities (L313). The data that identifies (L313): the names, the emails, the phone numbers, the SSNs, the addresses (L313).
• The detection (L313). The recognizers (L313): the pattern matching (L313) — the emails and the SSNs (L313); the ML models (L313) — the names and the addresses (L313).
• The redaction (L313). The masking (L313) — the value replaced (L313): john@example.com → ***@***.com (L313); the blocking (L313) — the entity removed (L313).
• The placement (L313). The redaction before the exits (L312): the prompt (L312), the log (L329), the training (L365) (L313).
• The minimization (L312). The least PII (L312) in the flow (L313) — the data not collected (L313) is the data not leaked (L312).

• A chat product (L162). The prompts (L312) redacted (L313) — the provider (L278) sees the masked (L313).
• A RAG platform (L280). The documents (L316) — the PII (L313) redacted before the chunking (L178).
• An observability pipeline (L274). The logs (L329) — the PII (L313) redacted before the write (L329).
• A regulated workload (L371). The GDPR (L371) — the PII (L313) detected and redacted (L313), the records (L322) kept (L371).
• Anything AI (L313). The PII (L313) out of the prompts and the logs (L313) — the discipline (L313) at each exit (L312).

The through-line: the discipline is the PII's boundary — the detect, the redact, the minimize (L313).

Say it in four moves:

1. The entities. "The names, the emails, the SSNs (L313)."
2. The detection. "The recognizers — the patterns and the ML models (L313)."
3. The redaction. "The masking and the blocking (L313)."
4. The minimization. "The least PII in the flow (L312)."

• The redaction is the exit's guard (L313). The prompt (L312), the log (L329), and the training (L365) — the PII (L313) redacted at each (L313).
• The minimization is the first line (L312). The PII not collected (L313) — the data not leaked (L312) — the L312 principle (L312), PII-shaped (L313).
• The recognizers are the coverage (L313). The patterns (L313) and the ML (L313) — the coverage (L313) is the recognizers' (L313).
• The masked value is the flow's shape (L313). The *** (L313) — the flow (L313) keeps its shape (L313) without the value (L313).
• The compliance is the record (L371). The GDPR (L371) — the PII (L313) redacted and the consent (L312) recorded (L322).

• The raw prompt (L312). The PII (L313) to the provider (L278) — the redaction (L313) before the exit (L312).
• The raw logs (L329). The PII (L313) in the records (L329) — the redaction (L313) before the write (L329).
• The recognizers' gap (L313). The names (L313) un-detected (L313) — the ML recognizers (L313) added (L313).
• The collection-first (L313). The PII collected (L313) without the need (L313) — the minimization (L312) first (L313).
• The masked-then-revealed (L313). The PII (L313) redacted in the prompt (L312) but logged raw (L329) — the discipline (L313) at every exit (L312).

• Minimize the collection (L312) — the least PII (L313).
• Detect at the boundary (L313) — the recognizers (L313) before the exit (L312).
• Redact at every exit (L313) — the prompt (L312), the log (L329), the training (L365).
• Test the recognizers (L341) — the PII set (L342) in the eval (L341).
• Record the compliance (L322) — the GDPR (L371) evidence (L322).

Q: Walk me through the PII discipline.

A: The detect, the redact, the minimize (L313). The entities — the names, the emails, the SSNs (L313). The detection — the recognizers: the patterns and the ML models (L313). The redaction — the masking and the blocking (L313). And the minimization — the least PII in the flow (L312).

Q: Where do you redact?

A: At the exits (L312): before the prompt (L312) — the provider (L278) sees the masked (L313); before the log (L329) — the record (L329) holds the masked (L313); and before the training (L365) — the model (L365) learns the masked (L313). The discipline (L313) at every exit (L312).

Q: How do you detect the PII?

A: The recognizers (L313): the pattern matching (L313) for the structured entities — the emails, the SSNs, the phone numbers (L313); and the ML models (L313) for the unstructured — the names and the addresses (L313). The coverage (L313) is the recognizers' (L313).

Q: What's the minimization?

A: The first line (L312): the PII not collected (L313) is the PII not leaked (L312). The prompt (L312) asks for the least (L313), the flow (L173) keeps the least (L313) — and the redaction (L313) is the last line (L313).

• What are the entities (L313)?
• What's the detection (L313)?
• What's the redaction (L313)?
• Where do you redact (L313)?
• What's the minimization (L312)?

The senior read: the mask for the flow, the block for the risk (L313).

// The PII discipline (L313) — the detect, the redact (L313).
// 1 · THE DETECTION (L313) — the recognizers (L313).
const entities = await pii.detect(prompt, {
  recognizers: [
    { type: 'EMAIL', pattern: EMAIL_RE },      // the pattern (L313)
    { type: 'SSN',   pattern: SSN_RE },        // the pattern (L313)
    { type: 'NAME',  model: 'presidio-name' }, // the ML (L313)
  ],
});

// 2 · THE REDACTION (L313) — the masking and the blocking (L313).
const redacted = pii.redact(prompt, entities, {
  mode: 'mask',                                // the mask (L313)
  mask: (type) => (type === 'SSN' ? 'BLOCK' : `***`),  // the SSN blocked (L313)
});

// 3 · THE EXITS (L312) — the redacted everywhere (L313).
await model.invoke(redacted);                  // the prompt (L312)
logger.info({ prompt: redacted });             // the log (L329)
// the training dataset (L365) — the redacted only (L313)

// 4 · THE MINIMIZATION (L312) — the least PII collected (L313).
//   the form asks for the email only — not the SSN (L313)

What the reader must SEE — the discipline, applied:

  pii.detect + recognizers   → the detection (L313)
  mode: mask + SSN blocked   → the redaction (L313)
  the redacted in the prompt, the log, the training → every exit (L312)
  the form asks the least     → the minimization (L312)

  The detect, the redact, the minimize (L313).

• The detection is the latency's cost (L313). The recognizers (L313) — the milliseconds (L313) before the exit (L312).
• The redaction is the flow's cost (L313). The mask (L313) — the negligible (L313) cost (L313).
• The minimization is the cost's lever (L312). The least PII (L312) — the fewer tokens (L332), the lower the cost (L334) (L313).
• The compliance is the record's cost (L322). The GDPR (L371) — the records (L322) for the audit (L322).

• The PII = the data at risk (L313): the entities, the detection, the redaction, the minimization.
• The entities: the names, the emails, the SSNs (L313).
• The detection: the recognizers — the patterns and the ML (L313).
• The redaction: the masking and the blocking (L313).
• The minimization: the least PII (L312) — the first line (L313).

SENSITIVE DATA & PII = the detect, the redact, the minimize

THE ENTITIES (L313)
  the names (L313) · the emails (L313) · the phones (L313)
  the SSNs (L313) · the addresses (L313)

THE DETECTION (L313)
  the pattern matching (L313) — the emails, the SSNs (L313)
  the ML models (L313) — the names, the addresses (L313)

THE REDACTION (L313)
  the masking (L313) — the value replaced (L313)
  the blocking (L313) — the entity removed (L313)
  at every exit (L312): the prompt (L312), the log (L329),
  the training (L365)

THE MINIMIZATION (L312)
  the least PII in the flow (L312)
  the data not collected (L313) is the data not leaked (L312)

INTERVIEW, 4 MOVES
  1 entities  "the names, the emails, the SSNs (L313)"
  2 detection "the recognizers — the patterns and the ML (L313)"
  3 redaction "the masking and the blocking (L313)"
  4 minimize  "the least PII, the first line (L312)"

You now hold the discipline: the entities, the detection, the redaction, and the minimization — with the replicas at the gates. The labeled jewels stay in the castle — and the replicas go out (L313).

Next: the agent that can do too much — Excessive Agency (L314).