Guides
OpenAI-Compatible Gateway Patterns for Agent Fleets
Base URL design, model aliases, logging, and failure modes when many agents share one gateway in front of multiple providers.
gatewaylitellmagentsarchitecturemulti-provider
Verified 17 days ago
OpenAI-Compatible Gateway Patterns for Agent Fleets
Agent codebases converge on one client shape: OpenAI-compatible chat completions and tool calls. Gateways let you keep that shape while swapping providers.
Common patterns
1. Alias router
cheap,smart,coder-localaliases in config- Agents never hardcode vendor model strings
2. Shadow logging
- Gateway logs prompts, tool calls, latency, cost
- Agent broker still owns approval policy
3. Local + cloud hybrid
- Local vLLM for private or bulk tasks
- Cloud flagship for hard reasoning
- Explicit allowlists for which tasks may leave the machine
Failure modes
| Failure | Symptom | Mitigation |
|---|---|---|
| Silent fallback | Wrong model answers | Fail closed on missing route |
| Dual spend | Retries hit two providers | Idempotency keys / broker locks |
| Tool schema drift | One provider fails tools | Per-provider tool tests |
| Key leakage | Keys in agent prompts | Env injection only |
Minimal architecture
Agent -> Broker (policy) -> Gateway (route/log) -> Provider/Local server
Do not make the gateway your only security boundary.
Practical checklist
- Model aliases documented
- Per-route timeouts
- Spend dashboards by agent and task
- Tool-call eval on each provider you route to
- Kill switch to force local-only mode
Bottom line
Gateways are infrastructure glue. Keep them thin, observable, and boring — put judgment in the agent broker and verification harness.