What is a Prerequisite Gate? — Plain-Language AI Definition

What is a Prerequisite Gate?

A prerequisite gate is a hard-coded check in an agentic system that prevents an action from executing until specific conditions are met. Unlike a soft suggestion in a prompt, a gate is enforced in code and cannot be skipped by the model.

Why It Matters

Language models are probabilistic. Even with clear instructions, they occasionally skip steps. Prerequisite gates remove that risk for critical operations by making the check deterministic.

How It Works

1. The model requests a tool call
2. Your application code intercepts the call
3. It checks prerequisite conditions
4. If all gates pass, the tool executes
5. If any gate fails, the tool returns an error message explaining what is missing

Key Takeaway

Prerequisite gates are the seatbelts of agentic systems. They enforce critical checks in code where prompt instructions alone are not reliable enough.