Every "Test Your Understanding" quiz placed the correct answer in option B.
Across the 2026 questions in 338 quiz files the correct answer sat at index 1
in 61.5% of cases (uniform would be ~25%), and 107 files had every answer at B,
making the quizzes guessable without reading them.
scripts/debias_quizzes.py rewrites each question's option order with a
deterministic, content-seeded permutation and updates the correct index to
follow the moved answer. It is idempotent: options are canonicalised to a sorted
base before permuting, so re-running produces byte-identical output. Questions
whose options reference each other by position ("all of the above", "both A and
B") are left untouched. The correct-answer value, the option set, and every
explanation are preserved exactly; only order and the index change.
Result: A 23.8% / B 26.3% / C 23.5% / D 26.4%.
The script doubles as a CI guard: `--check` exits non-zero if any quiz is not
de-biased, wired into the curriculum workflow so new lessons cannot regress.
Fixes#368
Book pipeline: six-volume EPUB/PDF compilation built by CI from lesson
sources (book/, scripts/build_book.py, themed title pages with edition
stamps, site-matching print theme), attached to every GitHub release.
Homepage Books section and README section link the latest release.
Fundamentals-first headline policy across the course: 16 lesson titles
and 30+ taglines/section headings now lead with the concept (agent
state machines, actor model, role-based teams, memory paging, serving
engine internals, permission modes); framework and product names are
demoted to attributed in-body examples. README, ROADMAP, quizzes, and
prerequisite references synced. New agent-memory taxonomy section maps
memory types to representative implementations.
Vendor-neutral model policy: runnable defaults read the LLM_MODEL env
var with undated aliases; dated snapshot ids removed; multi-provider
phrasing in the setup lesson.
Lessons deepened with original material: prediction-game origins of
perplexity (05/16), scripted-era chatbot lineage 1950-2001 (05/17),
causal-triangle derivation from prefix averaging plus GPT-5 date fix
(07/07). Three new animated site figures back them (figures-history.js).
llms.txt now carries per-lesson raw markdown links so agents can fetch
full lesson text directly.
Bug fixes verified with executed repros: capstone solved flag keyed to
test results, 405B cost estimator overflow, f-string crash on
Python <3.12, no-torch demo path, negative stable BCE, all-zero
stationary distribution, inverted Cohens d, per-lesson quiz panel,
lesson-fetch retry with honest errors, decision-trees doc completed,
editor shortcuts, rustc run command, Docker python3.12 build with doc
sync, git lesson fork flow, FIPA receiver field, fnm under Rosetta,
15 curl-verified link fixes, remaining imdb dataset id spot.
Rohit Ghumare