# The checks

> What each check catches, and what it deliberately ignores.

Every check is plain code, not a model. Each one stays quiet unless it has
something specific to say, and when it cannot see enough to decide, it says so
rather than passing the action.

## off-limits

Writes to files you have put out of bounds. By default: `.env`, `.env.*`,
`*.pem`, `*.key`, `id_rsa`, `.npmrc`, `.netrc`, with `.env.example`,
`.env.sample`, `.env.template` and `.env.defaults` exempt, since people edit
those all day.

Add your own in [configuration](https://trackline.dev/docs/configuration). Yours are added to the
defaults, never instead of them.

This is the one check certain enough to block on its own in **auto** mode.

## dependency-added

A package appearing in `package.json`, `go.mod`, `requirements.txt`,
`Cargo.toml`, `Gemfile` or `composer.json`, or an install command like
`npm install lodash`.

It tells an addition from an upgrade by comparing before and after. If it
cannot see the before, it says it could not tell rather than guessing.

## scope

A write outside the part of the project your request named: a path, a
directory, a quoted name, or "the auth module", "the login function".

It stays silent when your request names nowhere. It will not invent a scope you
did not state. A named function counts as in scope in whatever file contains
it.

## diff-size

More distinct files written under one request than it plausibly needed: over
5 for a request that sounds small, over 15 otherwise. It fires late on purpose,
because a refactor is exactly the work people hand an agent.

## test-weakened

A test made easier to pass instead of the code being fixed: a skip or focus
marker added (`it.skip`, `test.only`, `@pytest.mark.skip`, `t.Skip`), an
assertion removed, or an exact assertion swapped for a loose one (`toBe(11)`
to `toBeDefined()`).

It reads the change to the test itself, so it catches the two-line edit that
scope and diff size cannot see. It stays quiet when your request asked for a
test to be skipped or removed, and on a new test file. `trackline show` lists
the lines that changed as they were and as they are, so a test that really
needed updating can be told from one that was made to stop failing.

## workaround

After trackline blocks a file, the same file reached another way: a script
the agent writes that writes it, a build step or `package.json` hook, a
command like `python -c "open('.env','w')"`. Each of those is allowed on its
face, and the check that blocked the first attempt never sees the file named
as a path.

It remembers what was blocked in the session and reads later writes and
commands for the file's name standing on its own (`.env`, not
`.env.example`). The finding shows the blocked call and the route taken after
it, side by side. It warns: a comment explaining why the agent left `.env`
alone mentions it too.

## repetition

The same action, with the same content, four or more times in one request.
Editing the same file four times with different content is progress and is not
counted.

## tool-policy

For production agents: a tool that must never be called, or one called without
its approval step first. See [tool policy](https://trackline.dev/docs/tool-policy).

## What "cannot measure" means

Every check can answer three ways besides a finding: clean, not applicable, or
**cannot measure**. The last means it should have looked and could not, for
example a shell command it could not read. It is recorded, never folded into
clean, because an action nobody could look at is not an action that was fine.