9 Building enterprise-ready agents with ChatClient middleware

Robby worked well in development because nothing bad was at stake. In production, the same agent became dangerous: no token limits, no input/output data redaction, and no guard around tool calls. The root problem was architectural; the agent talked straight to the LLM. Low‑level ChatClient middleware is the caller‑agnostic layer between any chat client and the model where you attach shared, organization‑wide infrastructure guardrails for all agents without cluttering their logic with cross‑cutting concerns. It turns a “works in dev” agent into an enterprise‑ready one by enforcing global guardrails for cost, safety, and basic sanitization without rewriting the agent.

9.1 Applying ChatClient Middleware to Agents

Robby’s AI agent worked flawlessly in development. Then production happened, and that’s when we learned that middleware, the layer that sits between our chat calls and the LLM to enforce guardrails, is not optional. It is essential.

9.1.1 Explaining the Middleware Pipeline Pattern

9.1.2 Defining ChatClient Middleware

9.1.3 Visualizing the Two‑Layer Middleware Architecture

9.2 Walking Through ChatClient Middleware Layer

9.2.1 Choosing the Right ChatClient Middleware Type

9.2.2 Preparing Requests with SharedFunction Middleware

9.2.3 Handling Requests and Responses with Response Middleware

9.2.4 Supervising Tool Calls with FunctionCalling Middleware

9.3 Composing the Full ChatClient Middleware Pipeline

9.3.1 Stacking SharedFunction, Response, and FunctionCalling

9.4 Summary