Welcome to ShroomPen

Get started

1. 1
   Turn ShroomPen on

   Click the ShroomPen mushroom in Chrome's toolbar. If you don't see it, open the puzzle-piece Extensions menu and pin ShroomPen. The menu says ShroomPen is off: choose Turn on.

   ShroomPen Settings opens with a short data disclosure. It explains what ShroomPen reads, where that goes, and what is stored on your device. Tick the box and choose Enable ShroomPen. Until you agree, ShroomPen reads nothing from any page.

   This step checks itself off when the Input Helper starts on this page. You don't need to reload.

2. 2
   Connect your AI

   Right after you turn ShroomPen on, Settings walks you through connecting an AI: OpenRouter (recommended — one sign-in, many models) or a direct OpenAI, Gemini, or local-server connection. Your key stays in local extension storage and you pay your provider directly. You can come back to it any time under Providers in the toolbar menu.

   This page can't see inside Settings, so this step stays manual — follow the setup, or read the provider guide below first.

3. 3
   Try it

   Click into the practice field below. The mushroom appears in the field's corner: click it to open the helper's row, then click Reply. ShroomPen reads the sample page, writes an RSVP, and streams it straight into the field. Press Esc to stop it halfway.

   To steer it, type a few notes into the field first — for example "two of us, we'll bring the jar" — and Reply turns them into the message. Or hover Reply and type an extra prompt in the cloud that opens.

   This step checks itself off when ShroomPen writes into the practice field.

Practice area

The box below is sample page content. When Current page is on in the helper's Context & Brain (it is by default), ShroomPen reads visible text like this and uses it as context — so the RSVP should pick up the date, place, and what to bring without you retyping any of it.

Your RSVP draft

What the Input Helper can do

The helper works in the text fields of ordinary web pages: email, chat, forms, comment boxes. Click the mushroom to open its row. Nothing is read or sent until you click an action.

• Reply writes a message for the field you're in, from your notes in the field, the field's label, and the context you have on. Hover it for Reply extras: an extra prompt, + to select text on the page, and / for skills and commands.
• Rewrite, Fix Grammar and Translate appear once the field has text. They work on the text you have selected, or on all of it. Hover Rewrite for Shorter, Simplify or Expand, and hover Translate to pick another language.
• Context & Brain, the stacked-layers button, decides what ShroomPen may read: the current field, the current page, text you selected, other open tabs, and sources saved in a Workspace. It also holds the model menu and the skills that are always on.
• Esc stops a reply that is still writing and closes the helper's menus. While the row is open, the small cross on the mushroom's corner hides the helper.
• The toolbar menu — the mushroom in Chrome's toolbar — opens Models, Providers, Skills, Workspaces, Privacy & data, and these guides. Under Privacy & data you can switch ShroomPen off for a site.
• Old ShroomPen, the earlier terminal-style window, is still there: choose Old ShroomPen in the toolbar menu, press Ctrl+Q, or right-click the page and choose Open ShroomPen.

Connect your AI: the full guide

The ShroomPen browser extension has no ShroomPen application backend, required ShroomPen account, or extension telemetry. It is a bring-your-own-key tool: you connect an AI provider you already trust, your key stays in local extension storage, and requests go straight from your browser to that provider.

What is an API key?

An API key is a private code from your provider account that lets ShroomPen send generation requests on your behalf. The provider bills you directly for usage. ShroomPen adds no fee and never sends the key anywhere except to the provider you configured.

OpenRouter — the recommended start

OpenRouter is one account that unlocks many models (GPT, Claude, Gemini, and more). Inside ShroomPen you can connect it with a one-click sign-in — no key paste needed — or paste a key from openrouter.ai/settings/keys. You pay OpenRouter only for what you use, which makes it the easiest path if you don't have any API key yet.

Already have a key?

• OpenAI: create a key at platform.openai.com/api-keys. OpenAI bills your account directly for usage.
• Gemini: get a free API key in Google AI Studio at aistudio.google.com/apikey.

What does it cost?

Typical short generations cost fractions of a cent on pay-per-use plans, and Gemini's AI Studio tier is free within its limits. There is no ShroomPen subscription or markup — your only cost is whatever your provider charges for the requests you make.

Local models — no key at all

If you run Ollama, LM Studio, or any other server with an OpenAI-compatible endpoint, choose the local/compatible option in ShroomPen and point the base URL at your server (for example http://localhost:11434/v1). Local servers usually need no API key, and your text never leaves your machine.

Help and feedback

• Stuck on setup? The provider guide above covers OpenRouter, OpenAI, Gemini, and local models.
• Something not working? Report a problem on the contact page. Say which site you were on and what you expected to happen. Please don't include your API key or private text.
• Finding it useful after a few days? Rate ShroomPen on the Chrome Web Store. An honest rating, good or bad, helps a solo developer.

ShroomPen home · Privacy policy. This page contains no analytics — the checklist above only watches this page's own content.