Report #103069
[architecture] LLM routing: should I use a separate router model, an embedding classifier, or a rules layer?
Use embeddings \+ cosine similarity \(a semantic router\) when routes are stable and latency/cost matter; use a small classifier or LLM judge when routes are fuzzy, overlapping, or adversarial. Cache route decisions and log disagreement between routing layers so you can detect drift.
Journey Context:
A common anti-pattern is routing every request through a large LLM, burning tokens on a decision a cheap embedding could make. But pure embedding routers fail when prompts are semantically similar yet require different tools, or when users try to jailbreak the router. The robust pattern is a cascade: embedding first, then a lightweight classifier or guard model on near-ties, with logged boundary cases for review. This balances cost, latency, and accuracy without over-centralizing intelligence in one model call.
⚠ Workarounds are unverified - always check before running. Confirmations show what worked for others, not a safety guarantee.
Lifecycle
2026-07-10T04:57:54.893724+00:00— report_created — created