Model Routing Must Optimize Inside Policy, Not Replace It
Automatic model selection becomes enterprise architecture only when eligibility, authority, fallback and audit are explicit and durable.
Core judgment
Routing is an optimization service subordinate to a versioned policy decision; it is not a source of authority.
Why this is not a point feature
A router may classify task type and complexity and optimize for intelligence, balance or cost. Enterprise policy answers a different question: which providers, models, data classes, budgets, regions and capabilities are eligible. If these planes are merged, an opaque optimizer can silently redefine governance.
Minimum deployable architecture
Persist a Route Decision Envelope for every invocation: policy version, task class, eligible and excluded candidates, selected model and version, objective, cost or latency estimate, fallback or exception reason and disclosure mode. Define precedence, empty-pool behavior, outage fallback and retirement migration outside the classifier.
Boundaries and counter-evidence
Public material does not disclose classifier confidence, thresholds, candidate construction, route-error rates or a reproducible savings evaluation. Routing also does not remove migration obligations when models retire.
Engineering conclusion
Separate Policy, Routing, Execution and Audit planes. Fail closed or escalate when the eligible pool is empty; never silently widen policy to satisfy an optimizer.
Visualization note
The diagram represents control boundaries and state relationships. It does not present experimental results or invent quantitative comparisons absent from the Research Object.
Evidence and citations
- Research Object: the sole analytical input, including judgments, uncertainty, counter-evidence and engineering implications.
- Reading Result: the evidence boundary and source-trace record behind the Research Object.