A free, open-source browser extension that turns answers from ChatGPT, Claude, Gemini, and Grok
into numbered steps, formulas, diagrams and quick checks, right beside your chat.
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Chat assistants explain STEM problems well, but the explanation arrives as one long reply. stemLM puts the study work beside the chat:
- Ask. Type a question or attach a photo or PDF in your AI chat. Press the orange stemLM + beside the chat box, then send.
- Study. Read numbered steps with working, formulas and diagrams beside your chat. Open Solution to see them all at once.
- Check. Try a quick check, then reveal the answer. Ask in chat adds the step's context to your follow-up question.
- Save. Save a solution with one click. Search Saved questions by subject or date to reopen it.
- Export. Download the full solution as a PDF, with formulas and diagrams, or merge saved questions into one revision file.
It covers physics, chemistry, maths, biology, computer science, and electrical, mechanical, civil and chemical engineering. The AI works out the subject from your question.
Important
The steps come from your AI model, and models make mistakes. stemLM makes reasoning easier to follow, but it does not verify it. Check important results, and check diagrams against the problem.
| Chat service | Address |
|---|---|
| ChatGPT | chatgpt.com |
| Claude | claude.ai |
| Gemini | gemini.google.com |
| Grok | grok.com |
stemLM runs in desktop Google Chrome 116 or newer and Microsoft Edge. It does not run on phones or tablets. You use your own account with the chat service, so that service's plan, usage limits and terms still apply.
From GitHub (v2.0.0). Download stemlm-2.0.0-chrome.zip from the latest release, extract it, and load the folder containing manifest.json with Load unpacked at chrome://extensions or edge://extensions (enable Developer mode first). See INSTALL.md for installation, updating without losing saved work, and checksum verification. Read what's new in v2.0.0.
From the Chrome Web Store. Open the Chrome Web Store, choose Add to Chrome, and pin stemLM from the puzzle-piece menu so its toolbar button is always handy. Open a supported chat and the orange + appears beside the chat box. Refresh any chat tab that was already open.
From source. See Development to build the extension and load it unpacked.
- No stemLM account. No login, subscription or payment details.
- Your study library stays in your browser. stemLM reads the question and answer on the chat page to build the study view on your computer. It has no server that receives your questions, answers or saved solutions.
- No extension telemetry in v2.0.0. This build disables analytics and ships no telemetry endpoint or credential. It has no analytics toggle. The published privacy policy also describes behavior in other releases.
- You press Send. The + prepares instructions in your chat; stemLM never sends a message for you. Your chat provider receives what you send, under its own policies.
- Open source. Every line of the extension is in this repository under the MIT licence.
The full Privacy Policy and Terms and Conditions are Markdown copies of the versions published at stemlm.app/privacy and stemlm.app/terms. The website versions apply if the two ever differ.
Pressing the + attaches a plain-text instruction file to your message. It teaches the model one answer format: a single fenced stemlm capsule holding the steps, formulas, quick checks and takeaways. Figures inside the capsule are not pictures. They are short, typed key: value specs in a small language, for example:
@diagram id=f1 type=plot
fn: x^2 - 4
domain: -3 3
xlabel: x
ylabel: y
eq: y=x^2-4
@enddiagram
The extension parses the capsule and compiles every figure spec to SVG in your browser. There is no language model in the render path: layout, validation, sanitization and drawing all happen locally and deterministically.
flowchart LR
A["Chat page<br/>(ChatGPT, Claude, Gemini, Grok)"] -->|answer text| B["Content script<br/>platform adapter"]
B --> C["Capsule parser<br/>src/protocol"]
C --> D["Study panel<br/>React in a shadow root"]
C -->|figure specs| E["Figure compiler<br/>src/lib/figure"]
E -->|sanitized SVG| D
D --> F["Saved questions<br/>extension storage"]
D --> G["PDF export"]
The figure compiler goes catalog → engine → Scene IR → layout kernel → SVG. Five core engines (plots, scenes, graphs, tables and circuits) sit beside about 60 template families. Examples:
| Area | Figures |
|---|---|
| Physics and mechanics | free-body diagrams, ray optics, fields around point charges, gas-state and thermodynamic diagrams, trusses, shear and moment diagrams, Mohr's circle, cams |
| Electrical and computing | circuits with BJT, MOSFET and op-amp stages, hybrid-π models, two-ports, transmission lines, transformers, motors, phasors, Smith charts, PWM and timing diagrams, K-maps, datapaths and pipelines |
| Chemistry | skeletal structures from SMILES, VSEPR shapes, Newman, Fischer and Haworth projections, MO, crystal-field and Jablonski diagrams, NMR splitting trees, electrochemical cells |
| Chemical and civil engineering | McCabe–Thiele diagrams, reactors, heat exchangers, process flow diagrams, soil phase diagrams, retaining walls, frames |
| Biology | membranes, gel electrophoresis, operons, PCR, neurons, cell division, Ramachandran plots, phylogenetic trees |
| Computer science | flowcharts, state machines and automata, arrays, linked lists, stacks, hash tables, Gantt charts |
| Tables | matrices, dynamic-programming tables, ICE tables, Punnett squares |
Figures fail closed. When a spec is incomplete, unsupported, or fails validation, the entire figure section is hidden while the explanation stays readable. The panel does not display raw specs or a figure-repair button. Validation checks supported drawing structure; it cannot guarantee that the model understood the question correctly.
git clone https://github.com/chayprabs/stemlm-app.git
cd stemlm-app
pnpm install
pnpm build # production build in .output/chrome-mv3Open chrome://extensions (or edge://extensions), turn on Developer mode, choose Load unpacked, and select .output/chrome-mv3. A "How to use stemLM" page opens after the first install.
For day-to-day work, pnpm dev starts a development build with hot reload in a separate browser profile.
After rebuilding an unpacked install, press the extension's Reload control. Open chat tabs pick up the new version automatically; refresh any tab that does not show the +. Reloading closes an open study panel; choose Load conversation in the panel to bring the answer back. Keep the extension installed between builds to keep its saved questions.
| Command | What it does |
|---|---|
pnpm dev |
Development build with hot reload (Chrome) |
pnpm build |
Production build in .output/chrome-mv3 |
pnpm compile |
Type-check with tsc --noEmit |
pnpm test |
Run the full Vitest suite (happy-dom) |
pnpm test:watch |
Run Vitest in watch mode |
pnpm verify |
Type-check, test and build: run this before opening a pull request |
pnpm zip |
Package the build for the Chrome Web Store |
pnpm release:chrome |
Type-check, test, build and create the release ZIP |
npx vitest run src/lib/figure |
Run only the figure-compiler tests |
pnpm dev:firefox and pnpm build:firefox exist, but Firefox is not tested or supported.
See RELEASING.md for the release process and CHANGELOG.md for version history.
entrypoints/ MV3 entry points: background worker, content script, study panel,
toolbar popup, settings, saved-questions library, PDF export, welcome page
src/platforms/ one adapter per chat site: find the composer, attach, read answers
src/content/ the controller that runs in the chat tab and drives the panel
src/protocol/ the instruction file, capsule parser, subject playbooks, quality checks
src/lib/figure/ figure catalog, engines, Scene IR, layout kernel, SVG compiler
src/lib/ storage, settings, PDF export, math rendering, tab and session plumbing
src/components/ study panel UI: steps, solution view, figures, quick checks, reports
src/state/ the panel's state store
assets/ design tokens, shipped styles, bundled IBM Plex fonts
public/ extension icons and welcome-page images
scripts/ icon generation and the study-panel bundle split
temp-icon/ source artwork for the logo and toolbar icons
The content script stays small on chat pages. The study panel, with Markdown, KaTeX and the figure engines, is a separate bundle that loads the first time you open the panel. Fonts ship inside the extension; nothing is fetched from a font CDN.
Bug reports, wrong figures, chat-site breakages and pull requests are all welcome. Read CONTRIBUTING.md before you start: it covers setup, the project's rules for figures and protocol changes, and how to test. Everyone taking part follows the Code of Conduct.
Found a security issue? Please don't open a public issue; follow SECURITY.md.
stemLM's code and original assets are released under the MIT licence.
- IBM Plex Sans and IBM Plex Mono are bundled under the SIL Open Font License 1.1 (
assets/fonts/ibm-plex/OFL.txt). - KaTeX and its fonts are MIT-licensed. Every runtime dependency uses a permissive licence (MIT, ISC, BSD, Apache-2.0, Zlib or 0BSD; DOMPurify is dual-licensed MPL-2.0 or Apache-2.0). Run
pnpm licenses list --prodto check. - No textbook figure or corpus image is included in this repository.
ChatGPT, Claude, Gemini and Grok are trademarks of OpenAI, Anthropic, Google and xAI, respectively. Their marks are used only to show compatibility. stemLM is an independent project and is not affiliated with or endorsed by them.
stemLM is built by Chaitanya Prabuddha, Rohit Gupta and Abhishek Dogra. Feedback, a bug, or a subject we handle badly? Email founders@stemlm.app. We read everything.