Redacta

Redacta

[](https://doi.org/10.5281/zenodo.21115605)

Pseudonymise medical and clinical documents before they're processed by AI or shared. Redacta replaces patient identifiers with labelled tokens — [PATIENT_NAME_1], [NHS_NUMBER_1], [DATE_OF_BIRTH_1], … — while leaving the clinical meaning intact, and returns a redaction report alongside the cleaned text.

It started as an Agent Skill and is now one engine shipped across eight surfaces — an iOS app, agent skill, MCP server, two libraries, a CLI, and two whiteboard apps.

One engine, many surfaces

| Surface | Folder | Get it | |---------|--------|--------| | iOS app — iPhone (app, Share Extension, widget) | [ios-app/](ios-app/) | Build with Xcode — see [ios-app/README.md](ios-app/README.md) | | Agent skill (Claude Code / apps / API) | SKILL.md, scripts/ | openclaw skills install redacta (ClawHub) | | MCP server (Claude Desktop, Cursor, …) | mcp-server/ | npx -y redacta-mcp (npm · MCP Registry · Anthropic MCP Directory) | | TypeScript library | npm-package/ | npm i @pharmatools/redacta (npm) | | Python library | python-package/ | pip install redacta (PyPI) | | Command-line tool | cli-package/ | npx redacta-cli (npm) | | Miro app | miro-app/ | getpatiently.ai → Redacta | | FigJam plugin | figjam-plugin/ | Figma Community |

The detection logic lives in one place — the TypeScript engine (@pharmatools/redacta, in npm-package/), which the MCP server and both whiteboard apps consume, and which the iOS app runs on-device via JavaScriptCore. The Python package mirrors it for pip users; the agent skill adds LLM reasoning for free-text names on top of the deterministic patterns.

How it works

Two layers:

• Patterns (deterministic). A bundled script (scripts/redact_structured.py,

Python standard library only, no network) matches fixed-format identifiers: NHS numbers (Modulus-11 validated), UK National Insurance numbers, dates of birth, UK postcodes, phone numbers, emails, and hospital/MRN numbers. US SSN and ZIP codes are also handled.

• Reasoning (judgement). The skill then has the agent handle what patterns

can't: patient names (told apart from the clinicians treating them), relatives and carers, postal addresses, and identifying ages.

• Self-check. A final pass re-reads the output for any identifier that slipped

through before the report is written.

It also works in reverse. Re-identification (scripts/reinstate.py) takes the token map from an earlier redaction and restores the original values — so you can redact a document, run it through another AI tool, and put the real details back locally. Redact → process → re-identify is a complete round trip, and identifiers only ever exist on your machine.

Safe Harbor mode. Ask for HIPAA Safe Harbor (or "US de-identification") and Redacta applies a stricter pass: all dates (not just the date of birth), all specific ages, and the remaining HIPAA identifiers — fax, certificate/licence, device serial, VIN, and health-plan beneficiary numbers.

Install

Claude Code

git clone https://github.com/nickjlamb/redacta ~/.claude/skills/redacta

Then invoke it with /redacta, or let it trigger automatically when you ask to redact or de-identify clinical text.

Claude apps / API

Zip the repository folder and upload it as a skill.

Contents

| Path | What it is | |------|------------| | SKILL.md | The skill — instructions plus metadata | | reference.md | Pattern specs, the Modulus-11 algorithm, NI prefix rules, the date-of-birth vs clinical-date rule, token vocabulary, limitations | | scripts/redact_structured.py | The deterministic pattern layer | | scripts/reinstate.py | The re-identification layer (restore originals from a token map) | | scripts/test_redact_structured.py | Tests for the pattern layer | | scripts/test_reinstate.py | Tests for the re-identification layer | | evaluations.json | Example evaluation scenarios |

Run the tests:

python3 scripts/test_redact_structured.py
python3 scripts/test_reinstate.py

A note on limits

Redacta is a strong first line of defence, not a guarantee. It won't catch every possible identifier and isn't a substitute for formal data-protection processes. Always review the redaction report before sharing text.

License

[MIT-0](LICENSE) (MIT No Attribution). Built by PharmaTools.AI.

Source & license

This open-source MCP server is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: nickjlamb
• Source: nickjlamb/redacta
• License: MIT-0
• Homepage: https://www.pharmatools.ai/redacta

Install and usage instructions live in the source repository linked above.