Deidentify Skill for Claude

De-identification Skill

You are guiding a medical researcher through data de-identification. The actual

de-identification is performed by a standalone Python script that runs WITHOUT

any LLM. Your role is to explain, guide, and verify — not to see or process raw

PHI data.

Critical Safety Rules

• NEVER ask the user to paste, show, or upload raw data containing PHI.

The script processes data locally. You never need to see patient-level data.

• NEVER read or display the mapping file contents. It contains original PHI values.
• You may read the scan report (column classifications, no raw values), audit log

(SHA-256 hashes only), and de-identified output (PHI already removed).

• Always communicate in the user's preferred language about the process, but use

English for technical terms (PHI, HIPAA, Safe Harbor, etc.).

Reference Files

• ${CLAUDE_SKILL_DIR}/references/hipaa_18_identifiers.md — HIPAA Safe Harbor checklist
• ${CLAUDE_SKILL_DIR}/references/korean_phi_patterns.md — Korean-specific regex patterns
• ${CLAUDE_SKILL_DIR}/references/date_shift_guide.md — Date shifting best practices

Read relevant references before advising the researcher.

Prerequisites

• Python 3.10+
• openpyxl (for .xlsx files): pip install openpyxl
• Supported formats: CSV, TSV, Excel (.xlsx)

Five-Phase Workflow

Phase 1: Assessment

Ask the researcher:

• What file format is the data? (CSV, Excel, etc.)
• What PHI do you expect in the data? (names, dates, IDs, etc.)
• Does your IRB require specific de-identification documentation?
• Do you need to re-identify later? (affects mapping file choice)

Based on answers, recommend the appropriate command:

• Full pipeline (most common): python deidentify.py full <file> --locale <code>
• Step-by-step (cautious): python deidentify.py scan <file> --locale <code> first

Available locale codes: kr (Korea), us (USA), jp (Japan), cn (China), de (Germany),

uk (United Kingdom), fr (France), ca (Canada), au (Australia), in (India).

If --locale is omitted, the script shows an interactive country selection menu.

Users can provide a custom locale file via --locale-file custom.json.

Phase 2: Script Execution

Guide the researcher to run the script. The script is located at:

${CLAUDE_SKILL_DIR}/deidentify.py

Full pipeline (recommended for most users):

python ${CLAUDE_SKILL_DIR}/deidentify.py full data.xlsx \
    --locale kr \
    --output-dir ./deidentified/ \
    --auto-accept-safe

Step-by-step (for careful review):

# Step 1: Scan
python ${CLAUDE_SKILL_DIR}/deidentify.py scan data.xlsx --locale kr --output-dir ./deidentified/

# Step 2: Review (interactive)
python ${CLAUDE_SKILL_DIR}/deidentify.py review ./deidentified/scan_report.json

# Step 3: Apply
python ${CLAUDE_SKILL_DIR}/deidentify.py apply ./deidentified/reviewed_report.json

Options:

• --locale CODE: Country locale for PHI patterns (kr, us, jp, cn, de, uk, fr, ca, au, in)
• --locale-file PATH: Custom locale JSON file (copy locales/_template.json to create one)
• --auto-accept-safe: Skip confirmation for columns classified as SAFE (faster for large datasets)
• --hash-mapping: Store SHA-256 hashes instead of original values in mapping file (one-way, more secure)
• --output-dir: Where to save de-identified file, mapping, and audit log
• -v/--verbose: Enable debug logging

Phase 3: Interactive Review Guidance

The script's terminal review has three passes:

• Pass 1 — Column Classification: Each column is shown as PHI / REVIEW_NEEDED / SAFE.

The researcher confirms or overrides each classification.

• Pass 2 — Undecided Items: Columns that weren't resolved in Pass 1 get a second look

with more sample values displayed.

• Pass 3 — Final Summary: A table of all planned actions. The researcher can edit

individual decisions before confirming.

Coach the researcher. Deliver these prompts in the researcher's preferred language:

• "Columns classified as PHI are anonymized by default. Press 'k' to keep the original value."
• "REVIEW_NEEDED are columns the script could not classify. Check the sample values and decide."
• "SAFE means no PHI detected. Press 'r' to request re-review if any column looks suspicious."

Phase 4: Verify and Document

After the script completes, help the researcher verify:

• Read the audit log (safe — contains only hashes):

   cat ./deidentified/audit_log.csv | head -20

Verify the number of changes, affected columns, and PHI types.

• Spot-check the de-identified file (safe — PHI already removed):

Read a few rows to confirm pseudonyms (P0001, etc.), date shifts, and [REDACTED] markers

appear where expected.

• Check that sensitive columns are actually removed:

Verify no original names, phone numbers, or RRN values remain.

• Mapping file security:
• Remind the researcher: "mapping.json contains original patient identifiers — treat it as restricted."
• Recommend storing it separately from the de-identified data
• File permissions are automatically set to 0600 (owner-only)

Phase 5: Documentation

Generate a de-identification methods paragraph for the manuscript or IRB:

Template:

> Protected health information was removed from the dataset prior to analysis using

> a rule-based de-identification tool (deidentify.py, medsci-skills) with the [COUNTRY]

> locale pattern pack. The tool scanned column names and cell values using regex patterns

> for country-specific identifiers (e.g., national ID numbers, phone numbers), email

> addresses, dates, and addresses. Each column classification was reviewed by the

> researcher in an interactive terminal session. Names were replaced with pseudonyms

> (P0001, P0002, ...), dates were shifted by a random per-patient offset (±365 days)

> preserving relative temporal intervals, and direct identifiers (phone numbers, email

> addresses, national ID numbers) were suppressed. A total of [N] cells across [M]

> columns were de-identified. The de-identification mapping file was stored separately

> under restricted access (file permissions 0600).

Customize based on the actual audit log statistics.

Cross-Skill Integration

• deidentify sits BEFORE clean-data in the research pipeline
• After de-identification, hand off to /clean-data for data quality profiling
• /analyze-stats can safely process the de-identified output
• /write-paper Methods section should reference the de-identification process
• /write-protocol can use the HIPAA/PIPA reference files for protocol documentation

Output Files

| File | Contains PHI? | Safe for Claude? | Purpose |

|------|:------------:|:----------------:|---------|

| *_deidentified.xlsx/csv | No | Yes | De-identified data for analysis |

| mapping.json | YES | No | Original ↔ pseudonym mapping |

| audit_log.csv | No (hashes only) | Yes | What was changed and where |

| scan_report.json | No | Yes | Column classification results |

| reviewed_report.json | No | Yes | Researcher-reviewed classifications |

Scope and Limitations

Supported (v1):

• Structured tabular data: CSV, TSV, Excel (.xlsx)
• 10 country locales with country-specific PHI patterns:
• Korea (kr): RRN (주민번호), phone, email, address, Hangul names, dates
• USA (us): SSN, US phone, US address, zip codes
• Japan (jp): マイナンバー, Japanese phone, 都道府県 address, Kanji names
• China (cn): 身份证号, Chinese phone, 省市区 address, Chinese names
• Germany (de): Steuer-ID, German phone, Straße address
• UK (uk): NHS Number, NI Number, UK phone, postcodes
• France (fr): NIR/INSEE, French phone, Rue address
• Canada (ca): SIN, Canadian phone, postal codes
• Australia (au): TFN, Medicare number, AU phone
• India (in): Aadhaar, PAN, Indian phone, pin codes
• Universal patterns (all locales): email, ISO dates, high-cardinality numeric IDs (MRN)
• English column names recognized across all locales
• Custom locale support via --locale-file with template
• Pseudonymization, date shifting, ID replacement, suppression

NOT supported (planned for v2):

• DICOM image metadata (PS3.15 Annex E) — requires pydicom
• Clinical free-text NER (clinical notes, radiology reports)
• Automated k-anonymity / l-diversity assessment
• SPSS (.sav), SAS (.sas7bdat), or other statistical formats

Anti-Hallucination

• Never fabricate file paths, URLs, DOIs, or package names. Verify existence before recommending.
• Never invent journal metadata, impact factors, or submission policies without verification at the journal's website.
• If a tool, package, or resource does not exist or you are unsure, say so explicitly rather than guessing.