codespecified

Codespecified is an umbrella term used in software engineering to describe a practice in which the specifications of a software system are defined or enforced primarily in code rather than in separate prose documents. In a codespecified approach, the codebase itself serves as the primary source of truth about expected behavior; executable artifacts such as unit tests, property-based tests, type signatures, and runtime contracts encode the system’s requirements. Documentation may be generated from the code or kept minimal, with behavior traceable to specific modules, functions, or interfaces.

Applications include API design through interface types and contracts, test-driven development, and languages that support formal or runtime contracts; code-derived specifications can also be used in model-driven development where models are compiled into executable code. In practice, codespecified methods are common in agile environments, continuous integration pipelines, and DevOps cultures, where living documentation and automated checks help reduce drift between what is described and what is implemented.

Origins lie in the broader movement toward executable specifications and living documentation; the term is not standardized but is discussed alongside concepts such as design by contract, property-based testing, and literate or executable documentation.

Benefits include improved consistency, faster feedback, and easier verification of software behavior; challenges include potential accessibility barriers for non-developers, the risk of overreliance on tests as documentation, and maintenance overhead when code evolves without parallel updates to human-facing materials.

Related concepts include executable specification, design by contract, live documentation, and test-driven development.