A structured codebook for scoring participant testimony against Längle's 12 Fundamental Existential Prerequisites (12FEP) framework, designed for use with Large Language Models as a research instrument. Built by multi-LLM cross-validation against two primary Längle sources (2002, 2011b). Every code traces to a verbatim quote with citation. Companion to the WCET4 (2026) paper "Do You Understand?! Best Practices using Artificial Intelligence in Research (and Life)" by Graham Nelson-Zutter. Methodological refinement of the predecessor EA 4FM Codebook (built first, Oct 25–29, 2025); this 12FEP codebook simplifies the build protocol (parallel start + cross-LLM merges + LLM jury vote, vs the per-LLM iteration + self-merge + multi-LLM cross-merge + researcher selection used by 4FM) and reduces the source set (2 vs 4 Längle papers), while decomposing the four Fundamental Motivations into 12 Existential Prerequisites for finer-grained scoring. Note: LLMs (ChatGPT, Gemini, Claude) used in the methodology that produced this codebook are research instruments, not co-authors. See README and docs/lineage.md for details.

LLMs used during the methodology of producing this codebook (ChatGPT 5 Thinking, Gemini 2.5 Turbo, Claude Sonnet 4.5) are research instruments, not co-authors. They are not listed in the `creators` field, in keeping with the position of Nature, Science, JAMA, ICMJE, and WAME that AI systems cannot meet authorship criteria.