Blast Radius — blueprint deps

blueprint deps answers one question before you touch a module: who gets hit if I change this? It is read-only, needs no setup beyond the blueprint itself, and never writes a file.

It is the day-to-day companion to blueprint inspect: inspect judges the architecture (violations, cycles, exit 1), deps only describes it — fan-in and fan-out per module, no verdict attached.

How to run it

npx @kekkai/blueprint deps                      # leaderboard: every module by fan-in
npx @kekkai/blueprint deps hooks/useCart        # one module, by module key
npx @kekkai/blueprint deps src/hooks/useCart/useCart.ts   # same query, by file path

All three input forms resolve to the same module key — with or without the src/ prefix, with or without the file extension.

Flag	Effect
--json	Machine-readable output (for tooling or an AI agent)
--framework vue|react	Force the preset when no config exists and detection is ambiguous

What you will see

Without a target — the blast-radius leaderboard, every module sorted by how many modules import it. The most dangerous file to touch sits on top:

Blast radius (imported-by count):
  2 ← hooks/useCart
  1 ← services/api
  0 ← containers/Cart
  0 ← pages/Home
  (not under a declared layer, invisible to deps: legacy/)

With a target — both directions at once. imported by is the blast radius of changing it; imports is what it stands on:

hooks/useCart
  imported by (2):
    ← containers/Cart
    ← pages/Home
  imports (1):
    → services/api

With --json — the same data, structured. The leaderboard payload is { modules, skipped }; a target query returns a single module object:

{
  "module": "hooks/useCart",
  "importedBy": ["containers/Cart", "pages/Home"],
  "imports": ["services/api"]
}

An unknown target exits 1 with a pointer back to the leaderboard; every successful query exits 0.

Granularity — set by module.layout

The unit of every answer is the module, and what counts as a module follows the blueprint's module.layout (per layer, via layer.module):

• folder layout — each direct child of the layer is one module (hooks/useCart, components/HelloWorld). Direct files drop their extension, so deps components/HelloWorld and components/HelloWorld.vue name the same module.
• flat layout — the whole layer collapses to one node. This fits layers whose nested folders are not modules — a Next.js route tree, for example, where app/(marketing)/pricing/page.tsx is a route, not a feature folder. Deps says so explicitly rather than silently switching granularity:

app (flat layer — answers at layer granularity)

What is in the graph — and what is not

• Declared layers only. Folders outside architecture.layers are not scanned into the graph; the leaderboard lists them as skipped (see legacy/ above) so a zero fan-in is never misread as "nobody imports this". Querying into one fails with the reason: ✗ "legacy/" is not a declared layer.
• Test files are excluded (architecture.testFiles) — a test importing a module adds nothing to its blast radius, matching the lint side.
• Only alias and relative imports form edges. Package imports (axios, vue) are not part of the module graph — package ownership is inspect's job.
• Cycles are listed, not judged. Two modules importing each other simply show up in each other's fan-in and fan-out; the verdict belongs to inspect.

Config validation

A hand-written blueprint.config.mjs that skips defineBlueprint is validated on load anyway. A structural mistake fails immediately with a precise message instead of crashing mid-command:

✗ blueprint.config.mjs: architecture.module.private must be an array.