A Beginner's Guide to Per-Tenant AI Agent Model Version Pinning: How the March 2026 Foundation Model Release Wave Is Forcing Backend Engineers to Isolate Tenant Workloads from Upstream Behavior Drift

Imagine you ship a flawless AI-powered feature to your enterprise customers on a Tuesday. By Thursday, three tenants are filing support tickets because the agent's tone changed, its JSON output stopped conforming to the schema your parser expects, and one customer's carefully tuned classification workflow is