Exorcist: a ghost hunter for your package.json

This is a submission for the Hacktoberfest Open-Source AI Challenge Week 4: Ghost in the Machine

What I Built

Exorcist is a dependency health scanner for package.json — the checks
npm audit doesn't run. Drop in a file (or paste a GitHub repo URL) and it
finds the slow rot every Node project accumulates: deprecated packages,
functional duplicates nobody noticed they installed twice, packages a major
version or more behind, oversized bundles, copyleft licenses hiding in a
permissive project, and dependencies with no publish in two years. It rolls
everything into a single 0–100 health score and tells you what to do about
each finding.

For the theme — Ghost in the Machine — I leaned all the way in: a Victorian
broadside-poster UI, a blood-drip ceiling, flickering candles, a lantern that
follows your cursor, and a results screen presented as a morgue toe-tag.
Findings are "spirits" (Dead, Dormant, Cursed, Ancient, Bloated, Possessed,
and Resurrection for the alternatives it suggests). It's a bit much. That was
the point.

Demo

Live: https://exorcist-hf26-wk4.onrender.com

Click "Try a demo tome" on the landing page to scan a deliberately haunted
package.json — it has lodash+underscore duplicates, deprecated left-pad
and request, and a few other dependency sins, so you can see every check
fire without hunting down a real cursed project first.

No login, no setup, no data leaves your browser — see Privacy below.

Code

ibrahim-iqbal / exorcist-hf26-wk4

Dependency health scanner powered by EmbeddingGemma — Hacktoberfest Week 4

Exorcist

Drop your package.json. See what lurks within.

Live demo · DEV write-up · Design spec

More screenshots

Dark results	Light landing	Light results

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Every Node.js project accumulates ghosts: deprecated packages nobody noticed, duplicates doing the same job, bloated bundles dragging down load times, licenses that conflict with yours, and ancient major versions three generations behind. These spirits hide in plain sight inside package.json, haunting your build long after anyone remembers inviting them in.

The invoicing-app fix is npm audit, which covers CVEs but not the slow rot — the functional duplicate you installed because you forgot you already had one, the 200kB library you pulled in for a function that ships with Node, the package whose last commit was in 2022. Exorcist catches those.

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Features

• Fully local. Your package.json never leaves your machine. The ML model downloads once and runs in the browser tab via WebAssembly. No…

View on GitHub

git clone https://github.com/ibrahim-iqbal/exorcist-hf26-wk4.git
cd exorcist-hf26-wk4
npm install
npm run dev

MIT licensed. Architecture and the full scan pipeline are written up in
docs/DESIGN.md
if you want the "how it actually works" version instead of the pitch.

How I Built It

The stack: React 19, TypeScript, Vite 8, Tailwind v4 for utility spots, and a
hand-built CSS theming layer (custom properties, no CSS-in-JS) for the poster
UI. Framer Motion and plain CSS keyframes handle the atmosphere — drips,
embers, the cursor-following lantern.

The scan pipeline

The scan runs entirely in the browser in seven stages:

Each stage reports progress so the UI can animate the summoning circle in
real time. If any stage fails (model can't load, registry unreachable), the
pipeline degrades gracefully — the checks that needed that data are skipped,
and the rest still run.

The open-source AI piece

EmbeddingGemma 300M
— Google's open-weight embedding model from the Gemma family, running
entirely in-browser via Transformers.js
on ONNX Runtime WebAssembly. No API key, no inference server, no per-request
cost. It does two genuine jobs that keyword matching can't:

1. Duplicate detection. lodash and underscore share almost no words in their descriptions, but they're functionally the same thing. Exorcist embeds every package's npm description and flags pairs above an 82% cosine-similarity threshold.
2. Alternative suggestions. When a package is dead or dormant, Exorcist finds the closest healthy package by embedding distance instead of consulting a hardcoded lookup table — if request is deprecated, it can surface axios or node-fetch based on what the package actually does.

If the model can't load — offline, low memory, an older browser without
WebAssembly SIMD — the scan degrades gracefully. Those two checks get skipped
and the other five still run. No crash, no blank screen.

The rest of the pipeline (npm registry lookups, Bundlephobia bundle-size
checks, the scoring model) is plain TypeScript with no AI involved — the
model earns its place for the two checks that genuinely need semantic
understanding, not because "AI" sounded good on a feature list.

Why Does Open Innovation Matter?

Because package.json is basically a map of your stack, your exposure, and
how far behind you are on patches — and I didn't want to ask anyone to upload
that to a server to find out if their dependencies were rotten.

An open-weight model running client-side means:

• Privacy by construction, not by policy. There's no backend that could see your file even if I wanted it to. The claim "your data never leaves your browser" is checkable in the network tab, not just written in a privacy policy.
• No per-scan cost. A closed embedding API would do the same duplicate detection, but every scan would mean a network call, a cost, and a dependency on that endpoint staying up. EmbeddingGemma is a file, not a service — run it on every project, every day, for free.
• Works offline once cached. After the first load, the full scan (minus the npm/Bundlephobia lookups, which are public and anonymous anyway) works without internet.
• Inspectable. The 82% similarity threshold, the severity weights, the category caps on the health score — all of it is in the source, and all of it is a number someone can disagree with and change. That's a different relationship to the tool than a black-box API returning a score.

Open-weight models made this flow possible without those tradeoffs. That's
the whole pitch for "open innovation" here: the intelligence lives where the
data already is, instead of the data having to travel to where the
intelligence is.

The Spirit of It

The moment Exorcist stopped feeling like a side project and started feeling
like a real tool was the first time I ran it on one of my own production
package.json files — not the demo, not a test fixture, a project I
actually ship.

It found request. Deprecated since 2020. Still in my dependencies. I knew
request was deprecated — I'd read the notice years ago — but it was still
there, still being installed, still adding weight to every npm install,
because no scan I normally run flags "deprecated but functional." I'd walked
past that ghost every day without seeing it.

Then it found that lodash and underscore were both installed. Different
parts of the codebase pulled them in at different times. They do essentially
the same thing. Nobody noticed because the duplicate isn't visible in a
lockfile diff or a bundle report — you only see it if you compare what the
packages do, not what they're named. That's the check that needs
embeddings, and that's why I built it.

Exorcist is a tool for the kind of technical debt that hides in plain sight:
not security vulnerabilities or breaking changes, but the slow accumulation
of things that stopped being the right choice sometime between when you
installed them and now. The ghosts in your dependency tree aren't dramatic.
They're just quietly making everything a little heavier, a little slower, a
little harder to maintain — and nobody exorcises them because nobody looks.

Now something does.

Prize Categories

• Best Use of Gemma — EmbeddingGemma 300M (from the Gemma family) runs entirely in-browser via Transformers.js/ONNX for semantic duplicate detection and alternative package suggestions. No API, no server, no cost.
• Best Use of Render — The live demo at exorcist-hf26-wk4.onrender.com is deployed as a Render static site from render.yaml, building from source on every push.

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Built for Hacktoberfest 2026, Week 4: Ghost in the Machine.