Polymorph

September 20, 2026 · View on GitHub

Chrome extension that collapses posts matching English rules you wrote, replacing them with your own images or GIFs. TypeSafe Jev (via OpenRouter Decisions, typesafe/jev-1.13) is the judge; nothing is deleted—Show original restores the post.

At a glance	Details
Source	Source
Tags	`Open source` · `Free source build` · `BYOK`
Product homepage	Project homepage
Pricing and access	Build and load unpacked; no app purchase fee. Bring an OpenRouter API key; each judged post can incur provider charges. Not on the Chrome Web Store. Reviewed 2026-09-20.
Jev evidence	`src/jev/client.ts` and `src/defaults.ts` POST Choice questions to `https://openrouter.ai/api/alpha/decisions` with model `typesafe/jev-1.13`; gate thresholds in code.
Disclosure	AI-assisted catalog review; no affiliation with the maintainer. Listing is not an endorsement. Source inspected; Chrome installation and live feed judging were not tested.
Maintainer	moomooskycow. Independently curated.
Format	TypeScript Manifest V3 Chrome extension (0.3.0), Vite build, Vitest suite.
Platform and availability	Source-built Chromium extension (Developer mode → Load unpacked → `dist/`). Default allowlist: X, Reddit, Hacker News, YouTube.
Jev's role	Judges whether a post's visible text matches an enabled English rule; extension UI hides/replaces matches. Fail-open on errors.
Requirements	Chromium; Node/pnpm to build; OpenRouter API key in extension Options.
License	MIT.

When to use

Use it as a personal filter that turns matching posts into your media while keeping one-click restore. Prefer Unclutter for broader page-clutter hide rules, or TypeSafe Fun AdBlocker for experimental ad-shaped DOM judgments. Example rules ship off.

How it works

Content script observes allowlisted feeds and extracts visible post text (capped; no author ids/HTML/cookies in the default state builder).
Background worker calls OpenRouter Decisions with typesafe/jev-1.13 Choice questions per enabled rule (src/jev/).
On a match above gate probability/confidence, the extension swaps in a replacement card (your IndexedDB media library or a compact collapse card). Failures leave the post visible.

Get started

git clone https://github.com/moomooskycow/polymorph.git
cd polymorph
git checkout 3290af04a0aadca0c8841bd27cdaeb92e8c837fa
pnpm install
pnpm build
pnpm test

Chrome → chrome://extensions → Developer mode → Load unpacked → dist/. Options: paste OpenRouter key, enable a rule, optional media. Live judging sends post text to OpenRouter and can incur charges. This listing did not load the extension in Chrome or call live Decisions.

Examples and demos

Three example rules in Options (disabled by default).
Offline Vitest coverage under src/jev/*.test.ts and pnpm test.

Limits and data handling

Visible post text (bounded) goes to OpenRouter for Jev judgments; the key stays in chrome.storage.local and is used only against openrouter.ai per upstream. Replacement media stays in IndexedDB locally. Not a store-listed product; personal daily-driver framing. Upstream accuracy claims were not reproduced here.

Review and maintenance

Reviewed on 2026-09-20 at commit 3290af0: 0.3.0, MIT. AI-assisted source review of README, src/defaults.ts, src/jev/client.ts, package metadata, and license. pnpm test / Chrome load / live OpenRouter were not executed on the review host.