Build a Model-Routing Gateway Workflow for 1M-Token Agentic Models: Routing to NVIDIA Nemotron 3.5 Lightning
NVIDIA's Aug 2026 Nemotron 3.5 Lightning — an open-weight agentic model, 30B total / 3B active hybrid MoE with up to 1M tokens of context — is effectively a cheap, local 1M-context agentic worker. This article builds the routing gateway that exploits it: a LangGraph orchestrator exposed over FastMCP that sends long-context, repository-scale work to Lightning while reserving a frontier model for hard reasoning, with cost/latency/context routing keys, A/B guardruns, fallback chains, and a hard budget cap.