# Tools — where the scripts are, and which ones can stop you

```
Status: Current
Owner: _null
Last reviewed: 2026-08-18
Governs: scripts/**, .githooks/**
Review trigger: Any script added to, removed from or repurposed in scripts/; any
                change to which of them gates a commit or a release
```

> A signpost, deliberately. Every project that adopts this template has a
> `docs/TOOLS.md`, so "read `docs/TOOLS.md` first" is an instruction that works
> without knowing anything about the project — which is the whole reason this
> file exists at a fixed path.

## The list is not here

**[`architecture/README.md`](architecture/README.md)** holds the table of what
this project has and what each script is. That is the one copy.

A second table here would be two records of one fact, and the other one would
never hear that a script was renamed. So this file answers the questions that
table does not, and points at it for everything else.

## This project has seven of them, and that is deliberate

The template this repository adopted ships around twenty scripts. Privacy:
Period Tracker took six of them and wrote one of its own. `scaffold.sh` copies
none of them on purpose — *"an unconfigured `release.sh` landing in every new
repository is a loaded gun, not a head start"* — so each one is taken having been
read and configured.

**The ones not taken were not forgotten.** `release.sh`, `deploy.py`,
`backup.sh`, `restore-check.sh`, `preflight.sh`, `healthcheck.sh`, `migrate.sh`,
`status.sh`, `dev.sh`, `audit-gate.mjs` and `release-notes.mjs` all assume a
deployed Node or Postgres service with an npm dependency tree and a URL.
Privacy: Period Tracker is an Android app that ships through Google Play and has
no server at all. A release here is an AAB and a Play Console submission, so
[`security/SECURITY_CHECKLIST.md`](security/SECURITY_CHECKLIST.md) carries what
`release.sh` would have gated.

`duplication.py` and `dead-code.py` need no server, but both read a JavaScript or
TypeScript source tree: `dead-code.py` walks an export graph and excludes
Next.js entry points, and `duplication.py` does not scan `.kt` at all. Either
would have to be adapted before it said anything true about Kotlin, so neither is
taken yet.

`controls.sh` reports which operational controls a project has — backups, a
proven restore, somewhere errors go, an environment that is not production — and
exits `2` until some are declared expected. An app with nothing running has none
to declare, so taking it would install a check that could only report that it did
not run.

Two were deferred rather than declined:

- **`verify.sh`** — worth having once there is a real check suite to aggregate.
  Today `./gradlew check` is the whole answer and wrapping it would add a layer
  that could only be wrong.
- **`check-env.sh`** — its SPEC ships empty and exits `2` until it has entries,
  and this project has no environment variables yet. It gets taken with the first
  signing or Play credential, which is exactly the moment it becomes worth
  running.

**The seventh is `schema-guard.sh`, and it is this project's own.** It clears
the bar in *Adding one* below the hard way: it exists because the check it
replaces was proved green over exactly the failure it claimed to catch. Its
header carries that proof.

If this project later grows a script the template already has, take that one
rather than writing a new one — the arguments in its header are the part that
took the longest.

## Which ones can stop you

Not in a table, because the honest answer lives in each script's own header and
would go stale here. The rule that matters:

**Exit code `2` is never a pass.** These scripts distinguish "the check ran and
found nothing" from "the check did not run", because those look identical from
the outside and only one of them is evidence. A hook or a CI step that treats a
`2` as success has quietly turned the check off. Each script states its codes at
the top; read them there.

**And a `2` is not automatically a failure either — it is a question.** The
pre-commit hook learned this the hard way: `secrets.sh` exits `2` on a commit
that only *deletes* files, because a deletion has no added lines to scan, and
that is the correct answer. The hook treated every non-zero as a refusal and
printed *"possible credential in the staged changes"* over a plain `git rm`, so
deletion-only commits were impossible and the reason given was a security
problem that did not exist.

The rule that came out of it: **on a `2`, ask whether the check could have had
anything to look at.** The hook now refuses a `2` whenever the staged diff adds
lines — because then the scanner did have input and checking nothing is exactly
the failure `2` reports — and accepts it, saying so, when the diff only removes
content. Both directions are proved with `prove-guard.sh`-style injections
before either is believed.

The hooks are the other place work gets stopped:
[`architecture/githooks/README.md`](architecture/githooks/README.md) has the one
install command and the table of what each hook runs. Note that **`post-commit`
pushes**, and that `pre-commit` here runs Gradle rather than the template's
TypeScript typecheck.

## Where to start in a fresh clone

1. `git config core.hooksPath .githooks` — per clone, every time, and an
   uninstalled hook fails silently.
2. `bash scripts/secrets.sh --tracked` — the one-time audit of what is already
   committed. The staged-diff mode is for the hook; this mode is for the day you
   clone.
3. `./gradlew test` — the prediction acceptance tests run on the JVM, so this
   needs no emulator and should be fast.
4. [`architecture/GUARDS.md`](architecture/GUARDS.md) — how to write a check that
   can actually fail, before you write one. `scripts/prove-guard.sh` performs its
   first rule.

## Adding one

Put it in `scripts/`, give it a header saying what it does and **which incident
motivated it**, state its exit codes, and add a row to
[`architecture/README.md`](architecture/README.md)'s table — this file's
`Review trigger` fires on exactly that.

The bar, from the scripts that are already here: **done by hand three times, or
once with a consequence.** A script written before either of those has no
failure to describe in its header, which is the part that stops the next person
deleting it.
