Fail Closed, Not Open: Designing an AI Gateway for Regulated Enterprises

Short summary

The article details the architecture of Aegis Gateway, an AI routing system for regulated enterprises that structurally prevents compliance breaches by making non-compliant fallback impossible. Its three-stage pipeline (policy filtering, ranking, fallback) ensures the fallback executor can only iterate over pre-filtered eligible models, so when none are available the request is refused rather than silently downgraded. Every decision carries a versioned audit trace distinguishing 'not allowed' from 'not needed,' enabling regulators to verify past routing decisions against the policies in force at the time.

• •Three-stage routing pipeline (policy → ranking → fallback) makes compliance violations structurally unreachable, not just discouraged
• •Fail-closed design refuses requests when no compliant model is available, prioritizing governance over availability
• •Every response includes a versioned decision trace with rejected models, specific rule violations, and scoring breakdowns for auditability

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