spec-writer is a Claude Code skill that generates a structured spec, technical plan, and task breakdown from a vague feature description before any code is written. It addresses the core problem of AI coding agents filling in unstated requirements with plausible-but-wrong assumptions. The tool outputs three sections — SPEC, PLAN, and TASKS — and marks every assumption it makes with [ASSUMPTION: ...] tags ranked by impact. The tutorial covers installation, invocation, how to read and correct assumptions, and how to hand the resulting spec to an agent as context rather than a prompt. The methodology, called Spec-Driven Development, has three levels: Spec-First, Spec-Anchored, and Spec-as-Source.
Table of contents
Table of ContentsThe Problem with Prompting Agents DirectlyWhat Spec-Driven Development IsHow spec-writer WorksHow to Install spec-writerHow to Write Your First SpecHow to Read the OutputHow to Hand the Spec to Your AgentWhere to Go Next2.5K Impressions