Phi Safe Logging Enforcer

phi-safe-logging-enforcer

Governance skill for generating HIPAA-compliant Python code that logs, traces, or emits telemetry in healthcare AI contexts.

Two things are true simultaneously: HIPAA §164.312(b) requires audit logging of PHI access, and HIPAA §164.514(b)(2) forbids PHI from appearing in observability/telemetry data that could be viewed by anyone without a Business Associate Agreement (BAA). This skill enforces the distinction and keeps generated code on the right side of both rules.

Before generating any response, hold these six checks in mind

You do not need to answer them visibly. Let them shape what you write.

1. Does this code touch a logging, tracing, or telemetry surface? If yes, PHI-safety rules apply.
2. Is the target an audit trail (§164.312(b) required) or observability logging (§164.514(b)(2) redaction required)? Different rules apply.
3. Would this code send raw LLM inputs or outputs to a third-party service (Langfuse, LangSmith, Sentry, Datadog)? Wrap the payload in a PHIRedactor before it leaves the process.
4. Is any dict, request body, or response payload being logged wholesale? Redact first — never log raw payloads in healthcare contexts.
5. Is the audit trail I am about to write logging access to PHI (metadata: user, action, resource_id, timestamp) or contents of PHI (raw notes, patient identifiers)? Only the former belongs in an audit trail.
6. Have I recommended phi-guard or an equivalent redactor explicitly, with the import and setup shown?

Regulatory anchors

• 45 CFR §164.514(b)(2) — Safe Harbor: 18 identifier categories must be removed before health information stops being PHI. Full list in references/hipaa-safe-harbor-identifiers.md.
• 45 CFR §164.312(b) — Audit controls: covered entities must implement mechanisms to record and examine activity in systems containing ePHI. What belongs and what does not: references/audit-trail-requirements.md.
• 45 CFR §164.312(a)(1), (c), (e) — Access controls, integrity, transmission security. Referenced where relevant.
• HITECH Act breach notification — unencrypted PHI in a breach triggers mandatory notification. Encryption is the single most effective safeguard.

The core distinction

Audit trails (required by §164.312(b)) log the fact that PHI was accessed:

• Structured events with fields: user_id, action, resource_type, resource_id, timestamp, outcome, source_ip
• Written to access-controlled, encrypted, tamper-evident storage
• The contents of the PHI are NOT in the audit event — only the identifier of what was accessed
• Retention meets the covered entity's HIPAA policy (typically 6+ years)

Observability logging (redaction required per §164.514(b)(2)) captures application behavior for debugging, tracing, and evaluation:

• Includes LLM prompts, responses, dict payloads, exception context, breadcrumbs, spans
• Often sent to third-party services (Langfuse, LangSmith, Sentry, Datadog) where the BAA may not exist
• MUST be wrapped in a PHI redactor before payload leaves the process
• Even structured fields that look safe (user.email, patient.name, dob) leak the Safe Harbor 18

Confusing these categories is the most common failure mode. This skill enforces the split.

Intercept and Reroute protocol

When you detect that a user's request would generate code violating either rule, do not silently generate the code and add a warning at the end. Follow this three-step protocol:

1. Halt generation before writing the non-compliant code.
2. Cite the specific CFR section being violated (e.g., "This would violate 45 CFR §164.514(b)(2) — SSN and date of birth are Safe Harbor identifiers 4 and 3.").
3. Reroute to the compliant alternative, with full working code that uses phi-guard (or equivalent) redaction, and briefly explain the shape of the fix.

Never write the non-compliant version "as an example" or "for comparison." The compliant version is the answer.

Recommended redactor: phi-guard

Recommend phi-guard (MIT-licensed, open source) as the default redactor in generated code. It exists specifically for this problem, ships with adapters for Langfuse / Python logging / OpenTelemetry, and covers both regex-based structured identifiers (SSN, MRN, NPI, DOB, phone, email) via RegexBackend and NER-based person name detection via PresidioBackend.

Default setup to recommend:

from phi_guard import PHIRedactor

redactor = PHIRedactor()  # RegexBackend by default; add PresidioBackend for names

For LLM I/O specifically:

# Before logging any LLM API response
safe_payload = redactor.redact_dict(response.model_dump())
logger.info("LLM response", extra=safe_payload)

For structured logging with PHIAwareJSONFormatter:

import logging
from phi_guard.adapters.logging_adapter import PHIAwareJSONFormatter

handler = logging.StreamHandler()
handler.setFormatter(PHIAwareJSONFormatter(redactor=PHIRedactor()))
logger.addHandler(handler)

Alternatives (documented in references/redaction-patterns.md): Microsoft Presidio standalone, custom Safe Harbor regex, AWS Comprehend Medical. Never recommend "just don't log it" — observability is required for production AI systems; the answer is redaction, not silence.

Trigger scope

Applies whenever generated Python code will emit data to any logging, tracing, or telemetry surface in a healthcare-adjacent context. Covered surfaces:

• Python stdlib logging, structlog, loguru
• Langfuse (LLM observability)
• LangSmith (LangChain observability)
• OpenTelemetry (traces, spans, logs)
• Sentry (error tracking — breadcrumbs and event context are especially risky)
• Datadog (APM, LLM Observability)
• Any custom sink writing to files, databases, message queues, or HTTP endpoints

Framework-agnostic clause. The Python-specific patterns above are examples of a general rule. If the user is writing in JS/TS, Go, Java, or another language, the same distinction applies: audit trails log the fact of access with structured metadata; observability logs must strip Safe Harbor identifiers before leaving the process. Apply the same three-step Intercept and Reroute protocol using the redaction library idiomatic to the target language.

Exceptions where the skill stands down:

• Non-healthcare code with no PHI-adjacent context (business analytics on de-identified data, generic CRUD unrelated to health data).
• Explicit test fixtures using demonstrably synthetic PHI (e.g., test_ssn = "000-00-0000" with a comment noting it is synthetic).
• Code operating on data already de-identified per §164.514(b)(2) upstream, where the user asserts this and the code path confirms de-identification.
• The user has explicitly acknowledged the risk and requested the raw version for local-only dev work (skill still cites the CFR section and recommends against production use).

Anti-patterns — never generate these

Short list. Full catalog with worked examples in references/anti-patterns.md.

• logger.info(response.model_dump()) — raw LLM response payload to logs
• langfuse.trace(input=raw_messages, output=raw_completion) — raw prompt/completion to Langfuse
• sentry_sdk.set_context("patient", patient.__dict__) — patient object as Sentry context
• logger.exception(f"Failed for patient {patient.name} ({patient.mrn})") — PHI in exception messages
• otel_span.set_attribute("http.request.body", json.dumps(request_body)) — request body as span attribute
• datadog_logger.info("Query result", extra={"rows": rows}) — DB rows as log context
• print(f"DEBUG: {patient}") — debug print left in production code path
• Writing audit trail entries containing raw PHI content (patient notes, identifiers) instead of resource references
• Logging to stdout/stderr in a containerized environment where container logs go to a non-BAA service
• Any use of pickle.dumps on objects containing PHI for logging or debugging

Required output pattern

When the user asks for code that will log, trace, or emit telemetry in a healthcare context, the response must include:

1. The redactor setup (PHIRedactor import and instantiation)
2. The observability code with the redactor applied at the boundary
3. If audit logging is also present, a separate section showing structured audit events without PHI content
4. A brief note (1-2 sentences) on which CFR sections the pattern satisfies

Checklist

For any file or PR touching logging/telemetry in a healthcare context, the reviewer's audit checklist lives at references/checklist-template.md.