# Spec Driven Development — Chapter 03 Memory: 0b - Trilogy map: what lives in each volume
- **Stage**: Complete
- **Next Step**: None (frozen). Next chapter is Chapter 04.
- **Reading Span**: PDF pages 20–22
- **Source Text**: /library/Spec Driven Development/Chapter-03-Trilogy-map-what-lives-in-each-volume/Chapter-03-source-text.md (the chapter's own words; read instead of the PDF)
- **Full Record**: /library/Spec Driven Development/Chapter-03-Trilogy-map-what-lives-in-each-volume/Chapter-03-chapter-notes.md (read only if needed)
- **Last Updated**: 2026-10-01

## Carried-in Context (from earlier chapters)
- Ch1: Ködel's experience is offered as credibility, not proof; reader trusts him but wants to see the method.
- Ch2: With fast AI code generation, a specification becomes the target for judging output; humans must judge, decide, answer. 70/30 framing is illustrative, not measured. Vibe-coding = vague prompting without a target.

## This Chapter
- **Core Question**: How does Ködel divide the work of building software with AI across his three books?
- **Core Thesis**: Specification, architecture, and AI context are three connected concerns—what and why to build, where rules belong, and what information the model sees—while this volume is promised to remain usable on its own.
- **Key Concepts**: SDD = what and why (verifiable target); *FOCUS Architecture* = where (rules located, dependencies point inward); *Context Engineering* = what the agent sees (selection and cost per call); stand-alone volume = cross-references explain the idea in place, with name and link.
- **Notable Arguments / Evidence Limits**: Organizing map and a promise, not an empirical comparison. The stand-alone claim can be checked as cross-references appear.
- **Action Item**: For one small feature, write three short lines: intended behavior and how to verify it; where its rule belongs in code; which specification and code excerpts an AI agent would need.

## Reader State
- **Pending Questions**: None
- **Reader's Answers (paraphrase)**: Accurately recalled the three questions and order (what/why, where, what the agent sees/selection/cost). Proposed testing the author's practical claims against own experience. Follow-up: a cross-reference should include a small explanation of the concept it refers to.
- **Misconceptions / Feedback Given**: Reader's "test it in my experience" is valuable but differs from the narrower stand-alone-volume promise; clarified the promise (name, link, summary in place).
- **Personal Threads**: Reader has also started *FOCUS Architecture* and *Context Engineering*.

## Open Threads
- Check later cross-references to FOCUS / Context Engineering for in-place explanation (stand-alone promise).