mloda-pii

mloda-pii is a Claude Code hook that replaces identifiers (emails, phone numbers, IBANs, IP addresses, your own dictionary entries) in tool results with tokens such as PII_EMAIL_... before the model sees them. Your local tools and Claude's replies on your screen keep the real values. Every token is a keyed HMAC-SHA256, computed through mloda. It guards against accidental exposure and does not see everything the model gets; see Limits below.

The package also ships a mloda FeatureGroup that tokenizes a string column the same way, without a license key.

Setup

uv tool install "mloda-pii[hook]"   # or: pip install "mloda-pii[hook]" into a virtualenv that stays in place
cd your-project
mloda-pii init invite.txt           # the invite file, '-' for stdin, or the token itself

Then restart Claude Code. init creates the master key, stores and verifies the license, runs the hook once on a test value, and only then registers it in .claude/settings.local.json. It also creates .mloda-pii/dictionary.txt for names and company-specific IDs to detect, kept out of git. Running it again is safe.

Ask for an invite at info@mloda.ai or via mloda.ai.

Modes

Both modes give the same tokens from the same master key; there is no fallback between them.

Back up your master key

The master key lives in ~/.config/mloda-pii/master.key. Back it up: every token depends on it, and a lost key changes all of them. init never overwrites an existing key.

Everyday commands

• mloda-pii status: the key, the license and its expiry, where the hook is registered, the last events. Exits 1 when something is missing.
• mloda-pii uninstall: removes the hook entries (same --user / --project flags). --purge also deletes the master key and the stored license, after asking (--yes skips it).
• mloda-pii license install | status | remove: manage the license alone.
• mloda-pii stats: per-day counts from the audit log, which never holds values.

A prompt that contains raw identifiers is blocked and a pseudonymized copy is shown to resubmit.

Command options: mloda-pii <command> --help.

The FeatureGroup

from mloda.user import Feature, Options

feature = Feature("email__pii_anonymized", Options(context={"pii_key_file_env": "KEY_FILE"}))

<column>__pii_anonymized returns the 64-hex keyed HMAC-SHA256 token of a string column. pii_key_file_env names the environment variable that holds the path to the master key file. It needs the anonymizer-rs binary, like the local mode.

Limits

• The hook guards against accidental exposure, not a model that tries to recover values: a Bash command gets the real value and can return it disguised, which detection misses.
• Hooks never see @file mentions, CLAUDE.md and memory files, the client's own reminders, images or compaction summaries; those reach the model unchanged.
• A crashed or timed-out hook on a tool result lets the original output through.
• The values of one event sit in a private temporary Parquet file (under $XDG_RUNTIME_DIR, else /dev/shm, else the temp dir) for the duration of the call.
• The license gate is a speed bump: the local mode makes the same tokens without one, by design.
• Tokens are still personal data under GDPR; whoever holds the key can recompute them.
• The local vault under ~/.local/state/mloda-pii/ (or $XDG_STATE_HOME) maps tokens back to raw values; nothing expires it, and uninstall --purge leaves it in place.

License

mloda-pii is proprietary and source-available, under the mloda-pii License in the LICENSE file of the package. Use in your daily work is permitted with a license key from mloda, also when the key is free, or in the local mode with an anonymizer binary mloda provided. The license text is binding over this summary.

Related

• mloda: declarative data and feature access, the framework mloda-pii runs on.
• mloda-registry: plugins and guides for mloda.