What is spec-driven development?

Spec-driven development is a software development workflow where a written specification defines the intended behavior, constraints, edge cases, and verification criteria before implementation begins. In AI-assisted development, the spec becomes the source of truth for coding agents, tests, reviews, and implementation tasks.

How is spec-driven development different from vibe coding?

Vibe coding starts with informal prompts and improves the result after code appears. Spec-driven development starts with explicit scope, non-goals, user flows, data rules, UI states, and verification checks before an AI coding agent writes code.

What should a spec include for AI coding agents?

An agent-ready spec should include the goal, non-goals, user roles, user flows, data rules, API or server function contracts, UI states, acceptance criteria, edge cases, technical constraints, and verification commands.

Is spec-driven development the same as TDD or BDD?

No. TDD starts from tests, and BDD starts from shared behavior examples. Spec-driven development starts one layer earlier by defining the product and implementation intent that tests, tasks, and code should follow.

When should you not use spec-driven development?

Do not use a heavy spec-driven process for throwaway experiments, one-hour prototypes, tiny copy changes, or situations where the goal is still pure exploration. Use SDD when the feature must survive review, integrate with existing systems, or be delegated to an AI coding agent safely.

All posts

Spec-Driven Development2026/06/01

Spec-Driven Development (SDD): The Practical 2026 Guide for AI Coding Agents

A practical guide to spec-driven development for AI coding agents: definition, workflow, scorecard, templates, tool comparison, and when not to use SDD.

Related IdeaPico resources

AI PRD Generator Agent-Ready Spec PRD for Cursor

All posts