dsh-pii-gate

PII detection & exfiltration guard for DeepSeek Harness. Scans tool arguments (and optionally tool results) for personally identifiable information — emails, phone numbers, CN resident IDs, credit cards, API keys and more — audits every hit, and (in block mode) denies tool calls that would send PII out of the machine.

Plugin id: dsh-pii · npm: dsh-pii-gate

Install

dsh plugin --profile web add dsh-pii-gate
dsh --profile web --dump-config | grep -A3 'id: dsh-pii'   # verify

The plugin ships disabled. Set enabled: true in your profile patch to opt in.

Modes

mode	behavior
audit (default)	detect + audit + let the pipeline continue — pure observability
block	additionally deny calls on outbound tools (outboundTools globs) carrying ≥ minMatches PII hits

A denial reason tells the model exactly which PII types were found and how to proceed (scrub the input, or exempt the tool).

Detectors

id	default	notes
email	on
phone_cn	on	mainland mobile numbers
phone_intl	on	E.164-ish +… forms
cn_id	on	18-digit ID with mod-11 checksum validation — order numbers and timestamps don't trigger it
credit_card	on	13–19 digits with Luhn validation
api_key	on	sk-, ghp_, AKIA…, xox…, Bearer … shapes
ssn	on	US social security numbers
ipv4	off	opt-in; version strings like 1.2.3.4 are legitimate false-positive risks
iban	off	opt-in
custom	—	customPatterns: [{ name, pattern }], compiled as regex

Privacy invariants

• Audit entries carry PII type counts and an 8-hex evidence hash — the raw matched text never lands in logs, audit files or memory.
• The detector runs in-process; nothing is ever transmitted.

Honest limitations

tools/pre-execute is an approval-chain waterfall: it can short-circuit a call but cannot rewrite its arguments in place. In-place redaction of arguments is therefore out of scope for v1 — the gate blocks or observes, it does not silently edit tool input. If you need the arguments themselves scrubbed before they reach a backend, pair this plugin with your own tool wrapper or wait for a dsh mutation seam.

Config

- id: dsh-pii
  name: dsh-pii-gate
  config:
    enabled: false
    mode: audit                 # audit | block
    outboundTools: [bash, shell, "http*", "fetch*", "web*", "send*", "mail*", "email*", "upload*", "request*"]
    exemptTools: []
    detectors: { email: true, phone_cn: true, phone_intl: true, cn_id: true, credit_card: true, api_key: true, ssn: true, ipv4: false, iban: false }
    customPatterns: []          # - {name: mrn, pattern: 'MRN-\\d{8}'}
    minMatches: 1
    scanResults: true
    audit: { enabled: true }    # default file: <cwd>/.dsh-pii-gate/audit.jsonl

A profile-level patch targeting id: dsh-pii replaces the WHOLE config row (no deep merge) — restate every key you want to keep.

Audit format (JSONL)

{"ts":"2026-09-19T12:00:00.000Z","pii_version":"0.1.0","phase":"decision","tool":"http_request","args_hash":"9f2b…","verdict":"deny","matches":{"email":1,"phone_cn":1},"total":2,"reason":"PII on outbound tool (email, phone_cn)"}

Development

pnpm install && pnpm --filter dsh-pii-gate test   # build + node:test

MIT licensed. Part of the dsh-plugins monorepo.