protologue

Spec-Driven Development

Also called SDD.

Spec-driven development is an approach to building software with AI coding agents in which a written specification of what the software should do, and why, is created and refined first, and the agent then derives a technical plan, a task list and the code from it, with the specification kept as the source of truth.

Description

GitHub's open-source Spec Kit, released in September 2025, structures the process in four phases. The developer describes what they are building and why, and the agent expands it into a detailed specification. The developer then supplies technical direction, and the agent writes an implementation plan. The agent breaks the specification and plan into small, independently testable tasks, then implements them while the developer reviews focused changes. The specification acts as a contract that agents and tools use to generate, test and validate code. In vibe coding, by contrast, intent lives only in the chat prompts.

Sources

  1. Delimarsky (GitHub) (2025). Spec-driven development with AI: Get started with a new open source toolkit.

Cite this entry

Protologue. (2026). Spec-Driven Development. In Protologue: A Taxonomy of Prompting and LLM Techniques (v1.4.0, PTL-0226). https://protologue.com/t/spec-driven-development/

BibTeX
@misc{protologue_spec_driven_development,
  title = {Spec-Driven Development},
  author = {{Protologue}},
  year = {2026},
  howpublished = {Protologue: A Taxonomy of Prompting and LLM Techniques, v1.4.0},
  note = {Entry PTL-0226},
  url = {https://protologue.com/t/spec-driven-development/}
}

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