$ man variable

Variable

A placeholder in a template that gets replaced with dynamic content. Same as merge field, but "variable" is the Clay/AI terminology. {icebreaker}, {pain_point}, {company_name}.

Variables let you scale personalization. You write the structure once, the AI generates the content per contact, and the platform merges it in. Without variables, you're writing 500 unique emails. With variables, you're writing one template and filling 500 blanks intelligently.

I define variables in my campaign research prompts. Each prompt outputs a JSON array with fields like icebreaker, pain_point, service_fit, confidence. Those become columns in Clay. Then I map them to merge fields in Instantly or HeyReach. The variable names have to match exactly — if the prompt outputs pain_point but the email references {pain_signal}, the merge breaks. Naming consistency matters.