Prompt Hidden Required Input

---
title: prompt.hidden_required_input
---

## What it checks

Crux emits this finding when a prompt effectively requires an input field because an injected context or injectable requires it, but the field is not required by the prompt's authored input schema.

## Why it matters

Prompt callers, eval cases, replay, and generated devtools forms usually start from the prompt contract. If a required field is only visible through composition, callers can miss it.

## How to fix

Add the field to the prompt input schema, make the injected source optional, or document why the injected requirement is intentionally owned by the context or injectable.

## When to suppress

Suppress only when the hidden requirement is intentional and the calling boundary always supplies the field: