What a codex is, and whether you need one

The idea

A codex is the bible of your world: the characters, places, things, factions, rules, events and maps, each with a page of its own, and each page knowing what is true where and when. Write keeps one per universe, so every series set in that world reads from the same book of facts—and so does any AI you've connected, which is where a codex really starts to pay for itself.

If you've ever kept a spreadsheet of eye colours, or scrolled back three books to check which hand a character lost, this is that, kept for you.

Do you need one?

Not right away, and maybe not at all. A standalone novel with a dozen characters does fine with the notes panel—and notes have tags now, so they can be a small codex of their own (see Notes that become codex entries). A codex earns its keep when:

• you write a series, or several series in the same world;
• facts change over time—a city falls, a captain is promoted, a name changes—and you need to know what was true in this book;
• you want an AI to check your continuity or draft with the world in mind;
• you've lost track of something you invented, and it was important.

Start with notes. When a note wants to be shared across books, turn it into an entry; the rest of the codex can grow from there.

How it's put together

• A universe is the world. It belongs to a pen name, and series join it. One universe, one codex.
• An entry is one thing in the world: Tanis Richards, the Intrepid, Transcend. Every entry has a type—character, place, item, faction, rule, event, map, or one you've added yourself.
• Each entry has a summary (one line), a body (as much as you like), and at-a-glance information: the fields on the right-hand side of its page, like the box on a Wikipedia article. Fields can hold general information, or information that applies only to one book, one series, or a stretch of time.
• Calendars let a fact have a when. The codex starts with an ordinary Gregorian calendar; a science-fiction universe can add its own, with its own way of writing dates.
• Mentions search your books for an entry's name and aliases, so you can see every scene a character walks through.

Where to find it

From the Library, Manage → Codexes lists your universes, each with an Open codex button. From inside a book, the Codex button in the editor's toolbar opens a rail that shows who and what the scene you're writing mentions, with a link to the whole codex framed to that book—see The codex while you write.