four-opencode-anonymizer

OpenCode plugin: PII detection and anonymization before LLM calls. Reversible via in-memory session store — no disk, no persistence, zero cross-session bleed.

Installation

{
  "plugin": ["@four-bytes/four-opencode-anonymizer"]
}

Modes

Set via FOUR_ANON_MODE env (default: redact_for_llm):

Mode	Placeholder	Mapping	Reversible
redact_for_llm	<EMAIL_1>	✅ in-memory	✅
redact_for_logs	<EMAIL_1>	✅ in-memory	✅
redact_for_memory	<EMAIL_1>	✅ in-memory	✅
irreversible_export	[EMAIL]	❌	❌

Detected PII Types (10 total)

Regex Detector

• Email: john.doe@example.com → <EMAIL_1>
• IBAN (international): DE89370400440532013000, FR76 3000 6000 0112... → <IBAN_1>
• Phone (DE): +49 170 1234567 → <PHONE_1>
• Tax ID (keyword-triggered): Steuer-ID: 12 345 678 901, USt-IdNr.: DE123456789 → <TAX_ID_1>
• API Key: sk-proj-abc123... → <API_KEY_1>
• Credit Card (Luhn-validated): 4111 1111 1111 1111 → <CREDIT_CARD_1>
• Bank Account (keyword-triggered): Kontonummer: 1234567890, BLZ 37040044 → <BANK_ACCOUNT_1>
• Reference (keyword-triggered): Referenz: ABC-12345, Kundennummer: KD-98765 → <REFERENCE_1>

NER Detector

• Person names: Herr Müller, Frau Dr. Schmidt → <NAME_1>
• Cities: Berlin, München → <CITY_1>

Non-goals (not anonymized)

• Currency amounts: 1.234,67 €, $1,234.56, 12.345,00 EUR
• Bare numbers without keyword context (e.g. random 11-digit sequence)

Environment Variables

Variable	Default	Description
FOUR_ANON_MODE	redact_for_llm	Anonymization mode

Store (in-memory, per-session)

• No disk — mappings live in memory only, destroyed on process exit
• Session-scoped — each sessionID gets its own isolated Map
• Zero cross-session bleed — getOriginal() is scoped to the session's Map
• No encryption needed — data never leaves process memory
• Migration from v0.1.x: vault.db, vault.key, and FOUR_ANON_KEY are no longer used

Security Notes

• irreversible_export: No mappings stored — cannot be undone
• Session isolation: Each session has its own mappings, verified by cross-session bleed tests
• Placeholder leakage: Unknown placeholders (from other sessions/LLM hallucination) left as-is — never fabricated
• Loading order: Anonymizer MUST be loaded before other plugins (privacy gateway)

Development

bun install
bun test        # 101 tests, 0 failures
bun run typecheck
bun run build

License

Apache-2.0

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