docs: clarify circuit breakers do not handle concurrency

aigw/product/ai-gateway/circuit-breaker.mdx

@@ -76,3 +76,15 @@ flowchart TD
 
 - Unhealthy targets removed from routing
 - If all targets are OPEN, circuit breaker is bypassed
+
+## Where Circuit Breakers Fit
+
+Circuit breakers protect your setup from unhealthy targets. They watch for failures and open when a target stops responding reliably, so the gateway can route around it until it recovers. Circuit breakers are failure-based. They open when failures cross your configured thresholds, and they don't limit how many requests run in parallel.
+
+If your goal is to shape traffic or manage load, for example handling bursts of parallel requests, these work well alongside circuit breakers in a config:
+
+- [Rate limits](/aigw/product/ai-gateway/virtual-keys/rate-limits) to cap requests or tokens on a provider or integration
+- [Load balancing](/aigw/product/ai-gateway/load-balancing) to spread traffic across targets by weight
+- [Fallbacks](/aigw/product/ai-gateway/fallbacks) to route to a backup target when a request fails
+
+Each handles its own part. For example, if a provider returns `429` under heavy load and `429` is in `failure_status_codes`, the circuit breaker counts those responses as failures and can open the circuit, while your fallback or load balancing strategy decides where traffic goes next.

product/ai-gateway/circuit-breaker.mdx

@@ -81,6 +81,17 @@ flowchart TD
 - Unhealthy targets removed from routing
 - If all targets are OPEN, circuit breaker is bypassed
 
+## Where Circuit Breakers Fit
+
+Circuit breakers protect your setup from unhealthy targets. They watch for failures and open when a target stops responding reliably, so the gateway can route around it until it recovers. Circuit breakers are failure-based. They open when failures cross your configured thresholds, and they don't limit how many requests run in parallel.
+
+If your goal is to shape traffic or manage load, for example handling bursts of parallel requests, these work well alongside circuit breakers in a config:
+
+- [Rate limits](/product/ai-gateway/virtual-keys/rate-limits) to cap requests or tokens on a provider or integration
+- [Load balancing](/product/ai-gateway/load-balancing) to spread traffic across targets by weight
+- [Fallbacks](/product/ai-gateway/fallbacks) to route to a backup target when a request fails
+
+Each handles its own part. For example, if a provider returns `429` under heavy load and `429` is in `failure_status_codes`, the circuit breaker counts those responses as failures and can open the circuit, while your fallback or load balancing strategy decides where traffic goes next.
 
 import PrismaAirsCta from "/snippets/prisma-airs-cta.mdx";