Before revision: In pattern-forming developmental systems, cells commonly interpret graded input signals, known as morphogens.
After revision: Information theory is gaining popularity as a tool to characterize performance of biological systems. However, information is commonly quantified without reference to whether or how a system could extract and use it; as a result, information-theoretic quantities are easily misinterpreted. Here we take the example of pattern-forming developmental systems, cells commonly interpret graded input signals, known as morphogens.