Scope checks per package in a monorepo

Every rule in Straitjacket looks at one file at a time. Nothing compares a file against the rest of the tree, so a monorepo needs no boundary markers and no special mode — a scan from the root is just a scan of every file under it.

What a monorepo does want is different settings per package, and that falls out of how configuration is discovered.

One config per package

Straitjacket looks for straitjacket.toml in the current directory and walks up to the filesystem root, using the first one it finds. So a package with its own file gets its own settings when you scan from inside it:

straitjacket.toml                  # repo-wide defaults
packages/web/straitjacket.toml     # stricter: the design system lives here
packages/legacy/straitjacket.toml  # looser: grandfathered

cd packages/web && straitjacket

That picks up packages/web/straitjacket.toml and never sees the root one. The files do not merge — the nearest config wins outright — so a package config should be complete rather than a delta.

# packages/legacy/straitjacket.toml
skip = ["motion", "inline-font"]
max-lines = 4000

Scanning the whole tree

Run from the root and you get the root config for everything:

straitjacket

Per-package configs are not consulted in that pass — discovery starts from the working directory, not from each file. If you want each package checked under its own rules, scan them separately, which in CI is a matrix job or a loop:

for pkg in packages/*/; do (cd "$pkg" && straitjacket) || fail=1; done

Narrowing from the root

For the common case — one root config, but only some directories worth scanning — set paths and skip the loop entirely:

# straitjacket.toml
paths = ["packages/web/src", "packages/api/src"]

Or pass them per-run:

straitjacket packages/web packages/api

Excluding by prefix

Two rules take path prefixes directly, which is usually cleaner than carving up the scan:

file-size-exclude = ["packages/generated/", "notes/"]
todo-exclude = ["packages/legacy/"]

The suppression markers still cover the one-off exceptions that no amount of scoping should.