Traffic Model
Routes
Routes are the main traffic entrypoint in Arc. They let you attach policy and observability to a named request path without changing your application protocol.
Route Key
Pass X-Arc-Route with a slug such as customer-support. Arc resolves that route and applies its configured model, prompt, rollout, and traffic control settings.
Request Path
Application
Your existing OpenAI-compatible request.
Arc Proxy
Auth, route policy, logging, memory, limits, and routing.
Provider
OpenAI, Anthropic, or another configured upstream.
What A Route Can Own
Primary model
The default model injected when the request body omits model.
Fallback models
Secondary model options if you want redundancy at the route level.
System prompt
A route-level prompt injected ahead of user messages unless bypassed.
Shadow mode
Background comparison traffic that does not affect the user-facing response.
Canary state
Controlled rollout of a candidate model to a small percentage of traffic.
Rate limit
Warn or reject when a route exceeds the configured request window.
Memory pool
Optional connection to long-lived conversation memory.
Smart tier
Complexity-based model selection for the route.
Direct Traffic
If a request does not include X-Arc-Route, Arc still proxies it. The request appears as Direct in logs and does not inherit route-level policy.
Practical recommendation