# AGENTS.md — internal/config

**Three files: what this project is, who this machine is, and what was last
written into the project's agent-harness tree.** The only package in the tree
that imports yaml.

| file | what is in it |
|---|---|
| `config.go` | `Project`, `Logins` and `Scaffold` (the three files), `Resolve`/`ResolveOutsideAProject`/`Require`, `Resolved` with `Complete` and `Redacted`, the `KETTLE_*` overrides, and the 0600 write |

## The split is the whole design

```
<project>/.kettle/config.yaml     login: noodles          a NAME, never a token
                                  repo:  owner/name

~/.config/kettle/logins.yaml      logins: [{name, url, user, scopes, token}]
                                                                      mode 0600

<project>/.kettle/scaffold.yaml   version: v1.4.0         a note, load-bearing
                                  out:     .claude        for nothing
```

The third file is the newest and the least important, which is exactly why it is
a file of its own — see *Unknown keys are an error* below. It records what
`kettle gen scaffold` last wrote into the project and which build wrote it, so
`kettle config` can say when a project's skills are four releases behind the
binary reading them. **Nothing resolves from it.** Delete it and you lose the
warning and nothing else.

`user` and `scopes` are **documentation and nothing else** — nothing is checked
against either, and no request is refused because of one. `scopes` is what the
token was minted with, as Gitea spells it (`write:issue`, `write:repository`),
and it is written down because the instance will not answer the question:
`GET /user/tokens` needs basic auth rather than token auth, so a token cannot be
asked what it may do. What it buys is a 403 that can be read — `kettle auth list`
and `kettle config` show what was recorded, and an empty list means "nobody wrote
it down", never "none".

**A token in a file inside a working tree ends up in a commit.** Not always, not
immediately, and not by anyone careless — but a project config is exactly the file
somebody eventually decides to share, and a secret that has ever been pushed has to
be rotated. So the project pins a login by **name**, and the name is worth nothing
on its own, which is what makes it safe to keep in a repository.

Which tokens this computer holds is a fact about the computer, the way which issues
a tree holds is a fact about the tree. `SaveLogins` writes 0600 into a 0700
directory; nothing else on the machine has any business reading it. `$KETTLE_CONFIG_HOME`
relocates it — the test suite sets it, so a run can neither read nor overwrite the
developer's own tokens — and `$XDG_CONFIG_HOME` is honoured too.

**Nothing prints a token.** `Redacted` is what a receipt gets; `kettle config` shows
`(set)`.

## Resolution, and why it fails early

`Resolve` merges three sources — the project config, the machine's login file, and
the environment — into `Resolved`, which is everything the transport needs.

**Every failure names the file it read and the command that fixes it.**
"401 Unauthorized" is what happens when this function is allowed to return a
half-filled struct, and a 401 names nothing an operator can act on.

The same discipline splits the two "missing" answers: a missing `config.yaml` is
`ErrNoConfig`, not an empty config, because "this project has not been told which
tracker it belongs to" and "it belongs to no tracker" are different answers and only
one is fixed by running `init`. A missing login file, by contrast, **is** an empty
list — a machine with no logins yet is an ordinary machine.

`Complete` is that assertion on its own, as a method, because the two questions are
different: `kettle config` wants to **show** a half-filled configuration and
everything that dials wants to **refuse** one. `Require` is `Resolve` plus
`Complete`; [`gitea.New`](../gitea/AGENTS.md) and `cmd/release` call `Complete`
themselves, so a client can never be built from a struct that is missing a field.

`ResolveOutsideAProject` is for the one caller that legitimately stands nowhere near
a project: [`cmd/release`](../../cmd/release/AGENTS.md), run from a fresh clone. The
marker is gitignored, so a clone has none and a build tool must not create one — and
with no marker there is nothing to merge, so the **environment is** the
configuration. A marker that is there is read as always, so the same command run
from a maintainer's own checkout picks up the login pinned in it. Every other caller
wants `Resolve`, where "no project" is the answer rather than a state to work
around: a push that quietly ran against whatever was in the environment would be a
push into somebody else's repository.

`ReadProjectFile` exists for exactly one caller: `kettle init`, which is creating
the marker `LoadProject` walks for, and on a dry run may not have created it at all.

## Overrides

| variable | shadows |
|---|---|
| `KETTLE_LOGIN` | `login:` in the project config |
| `KETTLE_REPO` | `repo:` in the project config |
| `KETTLE_URL` | the login's `url` |
| `KETTLE_TOKEN` | the login's `token` |
| `KETTLE_CONFIG_HOME` | the directory holding `logins.yaml` |

Each wins over the file it shadows. They exist for CI, for a one-off run against
another instance, and for anyone who would rather not have a token on disk at all.

## Unknown keys are an error

Not a silent drop. An older binary reading a newer config would otherwise delete the
setting it did not recognize the next time it wrote the file — which is a data-loss
bug that only shows up on the machine running the older build.

**The price is that a field added here is a one-way door for the file that holds
it.** `scopes:` was the first one to prove it: a login file written by a binary
that has the field cannot be read by one that does not — the older build stops
with "unknown field" rather than dropping the line. That is acceptable for
`logins.yaml`, which is machine-local and whose reader is the one binary the
operator upgrades; it would **not** be acceptable for `config.yaml`, which is
committed and read by whatever version each machine happens to have. Adding a
field to the project file means answering that first, out loud, here.

`scaffold.yaml` exists because that answer came back "no". Recording which build
wrote a project's `.claude/` tree wanted two keys, and putting them in
`config.yaml` would have made every older `kettle` in the world stop reading a
committed file. A separate file written and read by one binary about one
directory carries the same cost for nothing: an older build never opens it.

## What does not belong here

A request, a store path, an issue. This package reads and writes three files and
answers "who am I and where am I pointed"; [`gitea`](../gitea/AGENTS.md) takes the
answer and dials, and the paths themselves come from
[`project`](../project/AGENTS.md).

## Keeping this file true

- **Scope:** `config.go` — the three files, their fields, the overrides, the file modes.
- **Update it when** a field is added to any of them (the block above is the
  contract), an override is added or renamed, the location or mode of the login file
  changes, or the unknown-key policy changes.
- **Do not** move a credential into the project file, and if that ever changes, the
  argument above is what has to be answered first.