Pitfalls · 7 min · Updated 2026-06-14 · Atlas Editorial
The four guardrails every first-time agent builder skips and regrets.
TL;DR
§01
An agent is a loop: think → act → observe → repeat. Each loop is a full LLM call. A buggy stop condition means the agent loops forever. We've seen first-time builders ship a $180 bill in a single weekend because their agent kept "retrying" a broken tool call.
Set a hard max-iterations (start at 8) and a hard max-tokens-per-run (start at 50k). Refuse to ship without both.
Watch out
Don't trust 'I'll add limits later'. The first runaway loop happens in dev, not prod.
§02
Every tool you give the agent doubles the number of paths it can take, which quadruples your debugging surface. The teams who ship working agents start with ONE tool — usually web search or a single internal API — and only add a second when the first is rock-solid.
Multi-tool, multi-step agents are the bait of every framework demo. They're rarely the right starting point.
§03
The agent went off the rails on step 14 of a 22-step trace. You have no logs. You're done.
Pick a logging library (Langfuse, Helicone, or just print-to-database) and wire it BEFORE the first run. Every prompt in, every response out, every tool call, every cost. The first time something weird happens, you'll have the receipts.
§04
Send an email. Delete a row. Charge a card. Post to a public channel.
Any irreversible action needs a human approval gate in v1. Yes, it breaks the "fully autonomous" pitch. It also stops your agent from emailing 800 customers the wrong invoice at 3am.
Still curious?
Ask anything about this guide — clarifications, examples, what to do next.
Coding · Claude 4.5
Paste a diff. Get the review your staff engineer would write.