The weft book

Weft is a language and a runtime for programs that combine AI models, people and tools.

Running an agent puts one model in charge of the whole job, and you wait while it works. Weft goes the other way. You break the job into a graph of small steps, called nodes. A node can run a model, open a webhook, ask a person, call an API or keep a database. Each one sees only what you wired to it, and the graph does the coordinating. The compiler checks every connection before the run, and every value that passes between nodes is written down where you can read it afterwards.

Let Tangle show you

Two things are yours to do, and both are quick. Install weft, which is mostly waiting, and decide which services you want weft to keep keys for. Then make a project:

weft new hello --assistant claude-code

That puts Tangle in the project. Tangle is our weft specialist: it knows the language, reads the catalog on your disk before it wires anything, writes any step you are missing, and will build you a web frontend if you ask for one. It also tests what it builds. It runs one piece at a time on a real input, looks at what came out, and goes back to fix the step that got it wrong. You can hand it a job and find the program working when you come back.

Open the project in your assistant and ask it to show you around, or just say what you want built. It walks you through everything below, pointing at your own screen while it does. You do not need the rest of this book.

Or read it yourself

If you would rather build with your own hands, or you just prefer reading, two sections get you to the same place.

Set it up gets you to a running program: install, your first project, the three things in a weft project that are alive on their own clocks, and how to talk to Tangle.

Build something real is where you take the wheel: editing the graph with a mouse, running one part of it on its own, connecting an account, giving your machine an address the internet can reach, and putting a person in the middle of a run.

After that the book stops being a path and becomes a reference. The language, writing your own nodes, connections, and what the runtime is doing underneath. Read a section when you need it.

The last part, why it is shaped this way, is the thinking behind the design: what weft handles for you, and how we decide what belongs in the language.

If something here is wrong

These docs are AI-written and the code moves fast, so mistakes get through. If you find one, or an explanation you cannot follow, tell us or come and say so on Discord. You do not need the correction worked out before you raise it.