Guides

Guides for choosing the agent backend layer

Decision-first pages for teams comparing model routers, LLM gateways, OpenRouter, and the agent backend layer.

Decision guides

These guides are for architecture and product-positioning decisions. Integration steps live in docs; harness details live in the catalog.

4 guides

What an AI agent API needs beyond a model response: sessions, tools, streaming, files, artifacts, routing, and production controls.

AI agent APIagent APIAI agent platformagent runtime

How to choose between a Codex-optimized model API and a complete Codex agent run when adding coding work to a product.

Codex APICodex agent APICodex SDKCodex integration

Where HarnessRouter, OpenRouter, TokenRouter, and model routers fit in an AI product stack.

agent backendmodel routerOpenRouterTokenRouter

How OpenRouter fits with HarnessRouter when a product needs both model routing and agent-backed work.

OpenRouter vs HarnessRouterOpenRouter alternative for agentsuse OpenRouter with agentsmodel routing for AI agents