What should API documentation for maintainers emphasize?

• A. Hide implementation details and avoid examples.
• B. Document every line of code with comments.
• C. Provide clear API documentation, usage examples, input/output contracts, and edge-case notes.
• D. Only the function signatures and parameter names.

Answer: (C)

APIs that will be maintained over time need documentation that is actionable and precise: it should describe how to call the interface, what it does, what inputs and outputs look like, and how it behaves in edge cases. Providing clear API documentation, usage examples, input/output contracts, and edge-case notes gives maintainers a reliable guide to implement, test, and troubleshoot.

Usage examples show real-world patterns you’re aiming to support, so developers can reproduce common flows quickly. Input/output contracts spell out types, required versus optional fields, formats, and validation rules, which helps prevent integration errors and clarifies expectations. Edge-case notes prepare maintainers for unusual or boundary conditions, performance considerations, error handling, and limits, reducing confusion when things don’t go as expected.

Why the other approaches don’t fit as well: hiding implementation details and avoiding examples leaves important questions unanswered and makes integration harder. documenting every line of code with comments adds noise and isn’t the right vehicle for describing how to use the API. providing only function signatures and parameter names omits behavior, constraints, and error conditions, leaving maintainers guessing about how the API will behave in practice.