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Layer 3 — Guardian

ToolGuard™ — The Function-Call Firewall

Every function call. Every MCP request. Classified, governed, and audited.

ToolGuard is WhiteFin's deny-by-default function-call firewall for AI agents. It intercepts every tool call and MCP request through a cost-ordered deterministic guard chain — pattern, schema, identity, taint, and policy stages — with sub-second total latency. Every authorization decision is a deterministic function of policy state and observed action — never a probabilistic LLM evaluation. First-block-wins architecture ensures the cheapest guard catches the threat first; early-deny calls clear in the low-millisecond range. Intent-analysis and behavioral detectors run as advisory Control Plane components that feed policy refinement and human review — they never gate real-time enforcement.

SCAN
BLOCK
DRY-RUN
PASS

7-Guard Pipeline

Every function call passes through all seven guards in sequence. Total pipeline latency: ~15ms.

01PII Filter
02Schema Validation
03Identity & Scope
04Taint & Provenance
05Adaptive Rate Limit
06Policy Adjudication

Deny by Default

If it's not in the policy, it doesn't execute. Zero exceptions. Every tool call requires an explicit allow rule. No implicit permissions. No fallback to open access.

Live Decision Feed

ToolGuard™ Live
delete_records(batch_7)
DRY-RUN
read_portfolio(user_42)
PASSED
execute_trade(AAPL, 500)
BLOCKED

One-Line Integration

No SDK. No wrapper. Just change the base URL.

# One line change
client = OpenAI(base_url="https://api.whitefin.ai/v1")

See ToolGuard Block a Live Attack

Try the interactive demo and watch every guard evaluate in real time.

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