Live Spec
A machine-readable, deterministic contract that defines what to build, why it matters, and how to verify it works.
Definition
A Live Spec is a version-controlled, modular blueprint that replaces traditional user stories with a machine-readable contract precise enough for an agent to implement without clarifying questions. Unlike informal ticket descriptions, a Live Spec leaves no room for interpretation and includes everything an agent needs to verify its own work against acceptance criteria.
Every Live Spec contains three minimum assets:
- Behavioral Contract — the precise description of what the system should do, including inputs, outputs, edge cases, and error handling.
- System Constitution — the architectural rules, coding standards, and constraints the implementation must respect.
- Actionable Task Map — the decomposed steps an agent follows to implement the spec, ordered by dependency.
A Live Spec is not a static document. It evolves alongside the codebase, is stored under version control, and is updated whenever requirements change or new constraints emerge. This living nature distinguishes it from traditional requirements documents that become stale after initial creation.