Printed in the book
Companion code
This address is printed in the book, so it keeps working. It explains what is public, what needs verification, and how to get help.
The address for this page is printed in the book. It will keep working, and it will keep meaning the same thing, through any redesign of the rest of this site. If it ever stops resolving, that is a defect worth reporting, because a printed path cannot be corrected after printing.
Get the companion code
The working code for the book lives in a private GitHub repository. Readers get read access in three steps: sign in with GitHub, answer one question that needs the book open, and accept the invitation GitHub sends you.
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Step 1 of 3. Sign in with your GitHub account. This site sees only your public GitHub username and account number. It cannot post, read your repositories or act on your account, and it does not keep the sign-in token.
No GitHub account? Create one free, then come back.
Signed in as .
Too many incorrect answers today. Please try again tomorrow, with the book open.
Step 3 of 3. GitHub has sent an
invitation to . Accept it, then the repository is yours to read and clone.
Accept the invitation on GitHub Open the repository
Invitations expire after 7 days.
What this checks, honestly
It checks that you have a GitHub account and had the book open. It cannot check that you bought it: Amazon does not tell authors who their buyers are, and every printed copy is identical, so a barcode or ISBN identifies the edition, not your copy. If you are borrowing a copy, the question will not stop you — and that is fine.
What is kept: your GitHub account number and username, when you passed, and which question you answered — so access can be restored or removed. No email address, no password. See the privacy notice.
What is public
The companion repository address printed in the book is public and needs no sign-in:
Why enterprise-digital-brain? Enterprise Digital Brain is the
name of the book's companion implementation: the runnable reference build of the
Contextual Agentic Enterprise, described in Chapter 25. The GitHub organisation is named
after it, and every repository in it starts with edb-.
What needs verification
Some material is tied to a specific printing: full listings, release archives and anything under licence. Access to those is checked on the server for every request — a hidden button is not access control, and a printed address is navigation, not entitlement.
A single code printed in every copy would not be purchase verification: it would be one shared secret in tens of thousands of hands. Amazon does not pass buyer identities or per-copy codes to this site, so verification cannot be automatic.
Editions and versions
No release has been published against a printed edition yet. When one is, it appears here with its version, compatibility note, licence and checksum.
If something does not work
A printed path cannot be corrected after printing, so if an address in the book does not resolve, that is a defect worth reporting. Use the contact form and choose “The book or companion resources”, or check the errata first.