Enterprise LLM Proxy, Reversible DLP and MCP Server Architecture: How We Deployed Secure B2B AI (Cord OS, Humi & ExpoProperty) With Zero Data Leaks

✦ Sponsored Engineering Case Study by Miscat.tech: Across our security audits of mid-market manufacturing, logistics, real estate, and B2B service firms, over 68% of sales, operations, and finance employees regularly paste confidential contract clauses, margin spreadsheets, and customer PII into personal ChatGPT accounts — a vulnerability known as Shadow AI. Below is the exact Enterprise LLM Proxy + Reversible DLP + MCP Server architecture we engineered and deployed in production across Cord OS (cordos.pl), Humi, and ExpoProperty (spisinwestycji.pl — 104 production MCP tools).

1. Why Workplace AI Bans Fail — and Consumer Chat Accounts vs. Zero-Retention Enterprise Gateways

Blocking AI via corporate firewall policies only pushes employees to use personal phones or consumer accounts where prompts may be retained for model training. Furthermore, leadership has zero audit visibility when an account manager uploads a master pricing sheet or M&A term sheet.

The engineering solution is deploying a centralized Enterprise LLM Proxy connected exclusively to zero-data-retention API endpoints (signed DPA, 0-day log retention) alongside self-hosted Open-Weights models.

2. Reversible In-Flight PII & Margin Anonymization (<9ms Overhead)

The core component of the Miscat.tech gateway is an in-memory bidirectional DLP (Data Loss Prevention) filter written in Go that intercepts every prompt before any network packet leaves your VPC or on-premise server:

1. Hybrid Entity Detection (NER + RegEx + ERP Dictionary): Within ~8ms, the gateway detects company names, tax IDs (VAT/EIN/NIP), IBANs, emails, phone numbers, and executive names synced from your ERP/CRM database.
2. Synthetic Token Substitution (Pseudonymization): Real identifiers are replaced with deterministic placeholders (e.g., ACME LOGISTICS LTD → [CLIENT_042], VAT DE123456789 → [TAX_ID_042]), storing the mapping strictly in local ephemeral Redis/RAM with TTL = 120s.
3. Real-Time Stream De-Anonymization: The external frontier model (Claude Sonnet or GPT) reasons over the contract structure or financial math using only [CLIENT_042]. As SSE chunks stream back through the Miscat.tech proxy, placeholders are swapped back to real names in flight. External cloud providers never see a single client name or tax ID.

// Miscat.tech Reversible DLP Dataflow (In-Flight Latency Overhead: < 9ms):
[Employee Prompt]:
"Check why the net margin on the freight contract for Trans-Euro GmbH (VAT DE812000112) dropped below 12%."

   │  (1. Local Go DLP Filter + Read-Only MCP ERP Lookup)
   ▼
[Outbound Payload to Zero-Retention LLM API]:
"Check why the net margin on the freight contract for [CLIENT_042] (VAT [TAX_ID_042]) dropped below 12%.
 Order ledger data: freight_rev=7100 EUR, carrier_cost=4200 EUR, fuel=1890 EUR, tolls=640 EUR."

   │  (2. On-the-fly SSE Stream De-Anonymization)
   ▼
[Displayed to Employee]:
"Net margin for Trans-Euro GmbH dropped to 5.21% due to unbilled toll surcharges (+180 EUR)..."

3. Three Production Deployments Built by Miscat.tech

• Cord OS (cordos.pl): A ground-up B2B operations platform backed by PostgreSQL with a native MCP server, allowing executives to query live operational KPIs from Claude and ChatGPT under strict Row-Level Security (RLS).
• Humi (AI Sales Onboarder & ERP Settlement Engine): A private voice-and-text AI simulation platform where new sales reps practice objection handling against an AI customer grounded in real company playbooks — cutting onboarding time by 60%.
• ExpoProperty (spisinwestycji.pl, prebooking.pl): A primary-market real estate & prebooking platform powered by one of Europe's largest production MCP servers exposing 104 specialized tools for inventory, pricing, and reservation workflows.

4. Financial & Security Comparison (25-Person Team): Per-Seat SaaS vs. Miscat.tech LLM Proxy

5. Deploy Your Private AI Gateway & MCP Infrastructure

Want to equip your team with frontier AI models (Claude, OpenAI, local Qwen) connected directly to your ERP and document repositories with 100% IP and GDPR/SOC2 control? Contact Miscat.tech for a free 15-minute engineering architecture review →