Conditional Logic — Build AI Agents That Make Real Decisions

A workflow without conditional logic is a straight line. Real-world tasks rarely travel in straight lines. Here is how to add branches, routers and decision trees to your AI agent workflows.

Most beginner AI agent workflows follow a single path: trigger fires, AI processes, action executes. This works for simple tasks. But as soon as your workflow needs to handle different types of input differently — different email categories, different lead qualities, different document types — you need conditional logic.

The Router Pattern

The most useful conditional structure in AI agent building is the Router. One trigger fires, the AI classifies the input, and the Router sends it to the correct path based on that classification. Make.com calls this the Router module. n8n calls it the Switch node. Zapier calls it Paths. Same concept, different names.

The classifier prompt is the most important element. It must return an exact, predictable value that your routing condition can match. If your prompt says "classify as URGENT or NORMAL" but sometimes returns "URGENT — high priority" instead of just "URGENT", the router breaks on those cases.

Classify the email below as EXACTLY ONE of: URGENT | REPLY | FYI | SPAM. Return ONLY the category name — nothing else. No explanation. No punctuation.

Building the Router in Make.com

Add an OpenAI module with your classification prompt and temperature set to 0. Add a Router module immediately after. Create one route per possible output. In each route's filter condition, set: Text — Contains exactly — URGENT (or REPLY, FYI, SPAM). Always add a catch-all route at the end to handle any unexpected classifier output.

Handling Edge Cases

Every workflow eventually receives an input it was not designed for — an email in Italian, a form submission in the wrong format, an unusually short document. How your workflow handles these determines whether it is a professional system or a fragile prototype.

Add a pre-classification check as the first step: "Is this input in English and appropriate for processing? Answer YES or NO." Route NO inputs to a separate handling path — either a translation step or a human review notification — before the main classification runs.

The Decision Tree Pattern

For more complex logic — where the first decision determines which second-level decision to make — chain your routers. After the first router classifies the email type, each branch can have its own sub-classification. URGENT emails get classified by requester (VIP vs standard). REPLY emails get classified by subject (support vs sales vs partnership). Each sub-classification routes to its own specific action.