Introduction
The gap between an AI agent demo and a production system is enormous. We've seen countless teams build impressive prototypes in a weekend, only to spend months trying to make them reliable enough for real users. After deploying AI agents for 85+ enterprise clients, we've identified the patterns that separate toys from tools.
This guide distills our learnings into actionable architecture decisions. Whether you're building customer support automation, internal knowledge assistants, or sales intelligence systems, these principles apply.
Key Takeaways
- Structured Outputs Are Non-Negotiable — Never trust raw LLM responses. Always use JSON mode, function calling, or structured extraction to get predictable outputs.
- Design for Failure — LLMs will fail. Rate limits hit. Responses timeout. Build graceful degradation into every interaction.
- State Management is the Hard Part — Conversation context, user preferences, and session state require careful architecture. This is where most agents break.
- Observe Everything — You cannot debug what you cannot see. Comprehensive logging and tracing are essential from day one.
The Production Agent Architecture
A production-ready agent isn't just an LLM wrapper. It's a system with multiple components working in harmony. Here's the architecture we use across most deployments:
1. Input Processing Layer
Before any message reaches the LLM, it passes through validation, sanitization, and enrichment. This layer handles:
- Input length validation and truncation
- PII detection and redaction
- Context injection (user profile, session history)
- Intent classification for routing
2. Orchestration Layer
This is the brain of the agent. It decides which tools to invoke, manages conversation flow, and handles multi-turn interactions. We typically use a state machine pattern here rather than free-form agent loops.
"The most reliable agents are the ones with the least autonomy. Constrain the action space ruthlessly."
3. Tool Execution Layer
Tools (APIs, databases, external services) are where agents actually do useful work. Each tool needs:
- Strict input validation via JSON Schema
- Timeout handling with sensible defaults
- Retry logic with exponential backoff
- Clear error messages that the LLM can understand
4. Output Processing Layer
Before responses reach users, they pass through final validation, formatting, and safety checks. This includes:
- Response length limits
- Hallucination detection (when possible)
- Brand voice consistency checks
- Link validation
Structured Outputs: The Foundation
Free-form text responses are a liability in production. They're unpredictable, hard to parse, and impossible to validate reliably. Here's how we handle structured outputs:
// Define your output schema explicitly
const AgentResponse = z.object({
thinking: z.string().describe("Internal reasoning - not shown to user"),
response: z.string().max(2000).describe("User-facing response"),
action: z.enum(["continue", "escalate", "close"]).optional(),
confidence: z.number().min(0).max(1),
citations: z.array(z.string()).optional()
});
// Force structured output from the model
const result = await model.generate({
messages: conversation,
response_format: { type: "json_object" },
schema: AgentResponse
});
This pattern ensures every response is predictable and validatable. If the model returns invalid JSON or doesn't match the schema, you catch it immediately rather than discovering it through broken downstream logic.
Error Handling That Actually Works
In production, everything that can fail will fail. Here's our error handling hierarchy:
- Retry with backoff — Most transient errors resolve themselves
- Fallback to simpler models — If GPT-4 is slow, try GPT-3.5
- Graceful degradation — Acknowledge limitations, offer alternatives
- Human escalation — Some things require people
async function robustCompletion(messages, options = {}) {
const models = ["gpt-4-turbo", "gpt-4", "gpt-3.5-turbo"];
for (const model of models) {
try {
return await withRetry(
() => complete(model, messages),
{ maxRetries: 3, backoff: "exponential" }
);
} catch (e) {
logger.warn(`Model ${model} failed, trying next`, { error: e });
}
}
// All models failed - graceful degradation
return {
response: "I'm experiencing some difficulties. Let me connect you with a team member.",
action: "escalate"
};
}
Observability: Debug in Production
You will have bugs in production. The question is whether you can find and fix them. We log:
- Every LLM request and response (with cost tracking)
- Tool invocations and results
- State transitions in the conversation
- User feedback signals
- Latency at every step
Use distributed tracing (we like OpenTelemetry) to connect these events across a conversation. When something goes wrong, you can reconstruct exactly what happened.
Conclusion
Building production AI agents is engineering, not magic. The LLM is just one component in a larger system that handles the messy reality of user interactions, network failures, and edge cases. Focus on structured outputs, comprehensive error handling, and observability from day one.
The patterns in this guide have been battle-tested across dozens of enterprise deployments. They work. The hard part isn't knowing what to do — it's having the discipline to do it consistently.
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