dsh-mask

Compatibility

What you get

dsh-mask anonymizes personal data at the model boundary — before a message reaches the model — and keeps a restore table host-side so placeholders stay reversible:

• Request-time masking — agent/pre-step messages are rewritten so phones, emails, ID cards, bank cards, and keys (on by default) and IPs (opt-in) become <PHONE_1>-style placeholders. The masked text is what gets logged and sent to the model.
• Restore table — the placeholder → original map lives only in memory and a controlled storage domain (dsh_mask); the plaintext never enters the session log.
• Audit, not plaintext — the mask/applied session event records only "replaced N values + type distribution", never the original text or the mapping.
• /mask command — status (counts + distribution), on/off (runtime toggle), restore <text> (unmap placeholders), help.
• mask_test tool — run a snippet through the detector and see the placeholder result; it never reveals the original values.

user message ──agent/pre-step──▶ placeholders ──model──▶ placeholders ──restore──▶ display
                                   ▲                                                    │
                                   └──────── restore table (memory + dsh_mask) ────────┘

Quick start

# 1. install the bundle into your profile
dsh plugin --profile web add "github:PerryLink/dsh-mask#main"

# or from npm (published releases)
dsh plugin --profile web add dsh-mask

# 2. verify the row mounts
dsh --profile web --dump-config | grep -A2 'id: mask'

Then tailor the entity list in your profile patch:

- insert:
    - id: mask
      name: dsh-mask
      config:
        entities: [phone, email, id-card, bank-card, key]

> /mask status
> /mask restore <PHONE_1>

Install & uninstall

• git channel (latest main): dsh plugin --profile web add "github:PerryLink/dsh-mask#main" (equivalent to installing from git+https://github.com/PerryLink/dsh-mask.git). No build step — index.mjs and lib/ are the shipped artifacts.
• npm channel (published releases): dsh plugin --profile web add dsh-mask.
• tarball channel: pnpm pack in this repo, then dsh plugin --profile web add ./dsh-mask-<version>.tgz.
• uninstall: dsh plugin --profile web remove dsh-mask (or remove the row from the profile patch).

dsh-mask no longer bundles the storage stack. Profiles that already compose it (the web profile does, via @deepseek-ai/dsh-web-app) provide storageDomain, so persistence works out of the box. On a bare profile without storage the plugin still mounts and masks, but the restore table is memory-only (lost on restart) — compose the storage stack in your profile patch, or set persistRestoreTable: false.

Configuration

All tunables are Schemastery Config fields (changeable from cordis.yml). An id-targeted override replaces the whole row — restate every key you need. cordis.patch.yml documents each key inline.

Example override in your profile patch:

- insert:
    - id: mask
      name: dsh-mask
      config:
        entities: [phone, email, id-card, bank-card, key, ip]
        persistRestoreTable: false
        registerCommand: true

Tools & surfaces

Permissions & data

• Permissions: dsh-mask performs no network requests and stores no credentials; it only reads the session at the agent/pre-step boundary and writes its own dsh_mask storage domain. The dshWorkshop manifest declares network:none and credentials:none.
• Data: the placeholder → original restore table lives in memory and, when persistRestoreTable: true, in the controlled dsh_mask storage domain — this is the only place plaintext PII is stored, and it is never written to the session log.
• Session log: mask/applied is declared in types.d.ts and appended only when the host records the type (see Known limitations). Its payload is counts + type distribution only.

Security boundaries

• Plaintext never enters the session log. The masked (placeholder) form is what gets logged and sent to the model, so model-visible content is reconstructable from the log in placeholder form; the originals stay in the restore table.
• Sanitize before display/log. lib/sanitize.mjs redacts PII, secrets, and URL credentials before any text reaches the model or the log; mask_test and /mask status never echo originals.
• Controlled restore. /mask restore is the single explicit reveal surface, and it only reads the mapping for the active session.
• Fail closed. Unimplemented mode (regex+ner), unknown scope values, NER-only entities, and out-of-bounds numbers all fail loudly at load.
• Registrations are effects. The listener, command, tool, and storage-domain close are all Cordis effects — stop/hot-reload removes them.

Known limitations

• Regex only. Name (person) and address (address) recognition needs an external NER recognizer, which the pure-host zero-dependency form does not bundle; mode: regex+ner and those entities fail loudly at load. The PII types covered out of the box are phone, email, ID card, bank card, key, and (opt-in) IP.
• Region-specific patterns. The phone and id-card detectors match mainland-China formats only: phone is 1[3-9] followed by nine digits, and id-card is an 18-character Chinese resident ID (17 digits plus a digit or X). Phone numbers and national identifiers from other countries are not detected. email, ip, and key are region-agnostic; bank-card accepts any 16-19 digit run at a lower confidence score.
• Display-layer restore needs a client half. Masking is fully host-side, but transparently un-masking the assistant bubbles in the client UI is a browser-half feature this pure-host form does not ship. The host side keeps the restore table and the exported RestoreStore seam (its methods take a session id), so a future client half would reach them through a host remote rather than directly; today the unmasking surface is the /mask restore <text> command, and the maskClientEnabled key is validated but read by no runtime code yet.
• Session events on 0.1.6-alpha.2. The harness records 58 session event types and none of them is mask/*; its Session.append also cannot stamp the ignorable envelope, so the session-log audit appends are skipped and sessions keep loading. The gate is not silent about it: the first refusal per session logs one visible warning naming the skipped type and this documented limitation. The plugin enables the append automatically once a host records the type or supports the ignorable envelope.

Development

pnpm install                                       # node ^22.19 || >=24
pnpm run typecheck && pnpm run typecheck:ci        # two rulers: checkout face (guarded; unverifiable without the checkout) + published-line face
pnpm test                                          # node --test
pnpm run verify:self-contained                     # dependency specs resolve from the registry
pnpm run verify:artifacts                          # shipped files present + index.mjs importable
pnpm run check:readmes                             # five-language README consistency
pnpm pack                                          # the published tarball

There is no build step: pure ESM, index.mjs and lib/ are the shipped artifacts.

Benchmark

The PII benchmark (per-type P/R/F1 over 108 synthetic samples) is published in benchmark/RESULTS.md; regenerate it with node benchmark/run.mjs (no build step, zero new dependencies).

Topics

dsh, dsh-plugin, deepseek-harness, deepseek, cordis, pii, mask, privacy, anonymization, security

Contributors

• @PerryLink — creator and maintainer: the regex PII detector ported from Pii-Stripper-Middleware, the agent/pre-step masking seam, the restore table, the /mask command and mask_test tool, and the five-language docs.

PerryLink DSH Plugin Family

This project is one of the 41 DeepSeek Harness plugins maintained by PerryLink. If this one helps you, the others likely will too:

Install from the DSH Desktop Market

All PerryLink plugins are browsable in the built-in DSH Desktop Market: Market → Sources → add source → paste https://perrylink-dsh-catalog.perrylink.workers.dev/catalog-source.json → select it. Installation still goes through the Market's npm-identity verification and your confirmation.

License

LICENSE (Apache License 2.0) © 2026 dsh-mask contributors