LLM Routing: What It Is and Why Your AI Stack Needs It
LLM routing is the practice of dynamically selecting which language model handles each request, based on factors like cost, latency, quality, and availability. Instead of hardcoding a single model, a router evaluates every request and picks the optimal model in real time.
Why LLM Routing Exists
The LLM landscape has fragmented. There are dozens of capable models across OpenAI, Anthropic, Google, Mistral, Meta, and others. Each has different strengths:
- GPT-5 excels at complex reasoning but costs more
- Claude Sonnet 4.5 handles nuanced writing well
- Gemini 2.5 Flash is extremely fast for simple tasks
- Llama 4 Maverick runs cheaply on open-source infrastructure
- DeepSeek V3.1 offers strong quality at ultra-low pricing
No single model is best for everything. A classification task doesn't need GPT-5. A legal analysis doesn't belong on a budget model. LLM routing solves this by matching each request to the right model automatically.
How LLM Routing Works
A typical LLM router sits between your application and the model providers:
- Request comes in — your agent or app sends a prompt
- Router scores candidates — each available model is scored against your optimization criteria (cost, speed, quality, carbon)
- Best model is selected — the router picks the winner and forwards the request
- Response returns with metadata — you get the response plus which model was used, what it cost, and how long it took
The entire routing step adds minimal overhead — typically under 100ms.
Static vs. Dynamic Model Selection
Most teams start with static selection: pick GPT-5, hardcode it everywhere, move on. This works until you look at the bill.
| Approach | Cost | Quality | Resilience |
|---|---|---|---|
| Static (one model) | Overpay on simple tasks | Consistent but not optimized | Single point of failure |
| Manual (model per endpoint) | Better but rigid | Requires constant tuning | Still fragile |
| Dynamic routing | 20–45% savings typical | Optimized per request | Automatic fallbacks |
Dynamic routing is the only approach that improves automatically as new models launch and prices change.
What to Look For in an LLM Router
Not all routers are equal. Key features to evaluate:
- Multi-dimensional scoring — cost alone isn't enough; you need speed and quality weights too
- Automatic fallbacks — if a provider is down, the router should try the next best option
- Per-workload configuration — support agents and code agents shouldn't use the same routing strategy
- Transparent metadata — every response should tell you what model was used and what it cost
- Drop-in compatibility — it should work with your existing stack without rewiring everything
LLM Routing with ClawPane
ClawPane implements LLM routing as a drop-in provider for OpenClaw. You add ClawPane as a model provider, configure your routing weights, and every agent request gets routed automatically.
No model names in your agent config. No manual tuning per request. Just set your optimization priorities and let the router handle the rest.