AI routing policies

The AI Gateway can choose the model for you. Send a request to the model chat-auto (or its alias zn-auto) and the gateway sends it to one of two tiers: Efficient, a cheaper model for short chats, summaries, and classification, or Frontier, a stronger model for hard reasoning, code, and long content. Sending simple prompts to the cheaper model can lower your AI spend.

Governance → Policies → AI Routing: routing posture, memory and cache, and where requests go.

Routing only happens when you ask for it. A request that names a specific model goes to that model and is never re-routed.

How the gateway chooses

For a request to chat-auto or zn-auto, the gateway checks these rules in order and uses the first one that matches:

A few things to know:

• Every message counts, including the system message and earlier turns of the chat, not just the latest question.
• Rule 4 matches inside longer words, so “improve”, “approve”, and “reasoning” also go to Frontier.
• Any other header value is ignored, and the other rules apply.
• The choice is made by these fixed rules, not by calling another model, so routing adds no extra cost.

Choose the tier yourself

When you already know a request needs the stronger model, or never does, add the X-ZN-Tier header. It overrides the other rules.

curl "$GATEWAY_URL/chat/completions" \
  -H "Authorization: Bearer $INFERENCE_KEY" \
  -H "X-ZN-Tier: strong" \
  -H "Content-Type: application/json" \
  -d '{"model": "chat-auto", "messages": [{"role": "user", "content": "Review this contract clause"}]}'

Your gateway address and key are shown in the usage guide when you create an inference key under AI Estate → Inference Keys. Use them in place of $GATEWAY_URL and $INFERENCE_KEY.

Test where a prompt would go

To see which tier a prompt would get without sending it to a model, use the dry run:

curl -X POST "$ZOPNIGHT_API/orgs/$ORG_ID/ai/routing/evaluations" \
  -H "Authorization: Bearer $ZOPNIGHT_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{"prompt": "Summarise this ticket", "maxTokens": 300}'

It answers with a tier (cheap means Efficient, strong means Frontier) and the gateway’s model name (chat-cheap or chat-strong). It looks only at the prompt and maxTokens you send. Add "tier": "strong" to see the effect of the header. GET /orgs/$ORG_ID/ai/routing shows the rules; they’re the same for every organisation. Every built-in role can call both. See Authentication for tokens.

The AI Routing page

Governance → Policies → AI Routing is a planning view for routing:

• Routing posture: Cost-saver (Efficient by default; only the hardest, image, or document requests reach Frontier), Balanced (route by how complex the task is; code, analysis, images, and documents go to Frontier), or Quality-first (Frontier by default; only simple chat and low-budget requests go to Efficient). All three also send requests with personal data to Frontier, and Balanced sends long answers (max_tokens of 2,000 or more) there too. Changing a routing condition or a tier’s model switches the posture to Custom; changing Memory & cache keeps it.
• Memory & cache: reuse answers to similar questions, and connect a knowledge base.
• Where requests go: which model would serve Efficient and which would serve Frontier.
• Conditions: how complex the task is, a cost cap per request, requests that need a fast answer, images, documents, long answers, sensitive data, fitting the model’s context window, falling back to another provider, and task types (coding, analysis, extraction, chit-chat).
• Test routing: type a prompt (optionally attach a file or mark it as containing personal data) and see which tier these settings would pick.

Only the built-in Admin role (or a custom role that can update AI models) can change the page’s settings. Everyone else sees it read-only.

Related

• AI Gateway: connect providers, issue inference keys, and see AI spend.
• Policies overview: the other kinds of policy.