Where it ends, and where it plugs in

This is the whole loop, and it is deliberately one machine, one GitHub account, one harness, and at most one Linear workspace. That floor is where most of the value is, and it is not everywhere somebody will want to take it.

So there are four places a factory calls out to something it does not ship, and each of them is a path rather than a plugin API. Three are optional, and the factory does the local thing when the file is absent:

• runtimes/<name>.sh runs a beat somewhere other than this Mac.
• identity/<role> prints a token, so the gaffer and a worker act as different accounts instead of as you.
• scripts/notify.sh is wherever you want the status block sent.

The fourth is always there. contracts/factory-loop.md is what the gaffer actually does, written out in prose, and editing it is how you change the loop.

None of this is a registry or an API, because a seam that needs one is a seam nobody can ship against. One page: contracts/extending.md.

contracts/ is the layer beneath this one, starting with what-is-a-factory.md, the normative definition every other document here should be explainable in terms of. Everything in that directory changes what the machine does when you edit it, and nothing else in the repo has that property.