Spec Driven Development — Chapter 02 Memory: 0 - Why SDD is essential in the age of AI

Stage: Complete
Next Step: None (frozen). Next chapter is Chapter 03.
Reading Span: PDF pages 13–19
Source Text: /library/Spec Driven Development/Chapter-02-Why-SDD-is-essential-in-the-age-of-AI/Chapter-02-source-text.md (the chapter's own words; read instead of the PDF)
Full Record: /library/Spec Driven Development/Chapter-02-Why-SDD-is-essential-in-the-age-of-AI/Chapter-02-chapter-notes.md (read only if needed)
Last Updated: 2026-10-01

Carried-in Context (from earlier chapters)

Ch1: Ködel offers his experience (VB6 ERP, Basel II systems, mobile apps, long-run ownership of Meu Cronograma Capilar) as the reason to examine his approach. Reader trusts him and wants to see the method; credibility is not evidence of general effectiveness.

Core Question: Why does a specification matter more when AI generates code quickly?
Core Thesis: As AI makes code generation fast, Ködel argues that a clear specification becomes more valuable because people must decide what to build, judge the result, and remain accountable for it.
Key Concepts: Vibe-coding; specification as a reference; judge, decide, answer; the illustrative 70/30 framing.
Notable Arguments / Evidence Limits: Hypothetical permission, offline, scale, and product-specific edge cases. No measured comparison establishes the 70/30 split or SDD's general effectiveness.
Action Item: Write a five-line mini-spec for one small feature: problem, intended user outcome, one rule, one edge case, and a check that would show it works.

Pending Questions: None
Reader's Answers (paraphrase): Identified vague agent prompting, the human duties to judge/decide/answer, edge cases, and the purpose of the 70/30 framing.
Misconceptions / Feedback Given: A specification supplies the evaluation target; the percentages are illustrative, not measured.
Personal Threads: None

70/30 split and SDD effectiveness remain unsupported by measurement; watch for evidence later.