Most AI agent demos look impressive for exactly one reason: they were never asked to handle anything unexpected.
A single-turn GPT wrapper with a couple of tools attached is not an agent. It's a function call with a marketing budget. Real autonomous agents operate across time, across failures, and across ambiguity — without a human catching every edge case.
The Core Problem
The failure mode I see most often is what I call hallucination propagation. Agent A generates output. Agent B consumes it as ground truth. Agent C acts on B's interpretation. By the time anything surfaces, the original error has mutated into something completely unrecoverable.
The fix isn't better prompts. It's architecture.
What Actually Works
1. Structured inter-agent contracts. Every agent should output a validated schema, not free text. When agent boundaries have typed contracts, errors stay local and recoverable.
2. Explicit failure modes. Each sub-agent should have a defined failure policy: retry with backoff, escalate to orchestrator, or halt. Leaving this implicit means every failure becomes a mystery.
3. State that outlives the context window. Real tasks take longer than one inference. You need external state — a task store, a checkpoint system — so agents can resume rather than restart.
4. Observability from day one. You cannot debug what you cannot see. Every agent action should emit a structured trace: inputs, outputs, latency, token cost, and result classification.
The Orchestration Layer
The orchestrator's job is decomposition, delegation, and synthesis — not intelligence. Keep it dumb. The moment your orchestrator starts reasoning, you've built a second agent in disguise and doubled your failure surface.
The planner decomposes. Specialists execute. The orchestrator routes and collects. That separation is what makes the system debuggable.
Production Checklist
Before calling any agent system production-ready, verify:
- Every inter-agent message is schema-validated
- Every agent has a defined timeout and failure path
- State is persisted externally and checkpointed
- A full trace is emitted for every run
- The system degrades gracefully — partial results are better than silent failures
This isn't glamorous. But it's the difference between a demo and a system that runs when you're asleep.