@guardbee/guard-core

@guardbee/guard-core

🇬🇧 English | 🇹🇷 Türkçe | 🇨🇳 中文

Shared detectors used by other GuardBee MCP packages. Not an MCP server on its own, just a library — you don't need to install this package directly.

It exists so the same rule runs everywhere: a static scanner flagging a pattern and the runtime proxy blocking it use one implementation.

What's inside

Export	Used by	Purpose
maskPiiInText, maskPiiInValue, PII_PATTERNS	security-proxy	Mask TC Kimlik No, VKN, IBAN, card, phone, email, provider API keys, private keys, connection strings and JWTs in tool results; an optional replacer turns matches into tokens
SECRET_RULES	secret-scanner, security-proxy	38 secret rules (provider keys and tokens, private keys, connection strings, JWT). The scanner reports all of them; the proxy masks the 32 that are not marked broad
isValidTcKimlik, isValidVkn, isValidIban, isValidLuhn, isValidTrPhone	security-proxy, prompt-leak-scanner	Validation after a regex match
INJECTION_RULES, findInjections	prompt-injection-scanner, security-proxy	27 injection rules in English and Turkish, with base64-decoding; the scanner uses the 17 precise ones
scanForPromptInjection, scanToolResult	security-proxy	Block on a precise high/critical rule, warn on anything else
gatewayPolicySchema, validatePolicy, policyShape	security-proxy, app.guardbee.ai	The gateway policy document (labels, rules, taint, approval, defaults, interceptors). The dashboard validates an edit with it before saving, so a policy that saves is one the proxy accepts
classifyTool, CAPABILITY_RULES	toxic-flow-auditor, security-proxy	Label a tool as untrusted-content / sensitive-data / exfiltration / destructive (lethal trifecta)

Checksum-validated masking

A regex alone masks any 11-digit number as a TC Kimlik No and any 16-digit number as a card. Each match is now checked before it is masked:

Pattern	Check
TC Kimlik No	Official 10th/11th digit algorithm
VKN (tax number)	Gelir İdaresi check digit, and a VKN / Vergi No label before the number
IBAN	ISO 7064 MOD97-10
Card number	Luhn
Phone (TR)	Mobile (5xx), landline (2xx–4xx) or 850 code; written with a +90 / 0 prefix or grouped with spaces/dashes, and not part of a URL or id

A match that fails its check (an order number, a tracking code) is left unchanged.

Precise and broad rules

Injection and secret rules carry a broad flag for patterns that also match ordinary text: "act as", "developer mode", any 40-character base64 run, a publishable Stripe key. Static scanners that show a finding to a person skip broad injection rules; the runtime proxy never blocks or masks on a broad rule, because a false match there would also mark the session as holding sensitive data or stop a legitimate call.