Welcome to ShroomPen

ShroomPen is already working on this page. Walk through the three steps below — the first and last tick themselves when the extension does its job here.

Get started

Open ShroomPen
Press Ctrl+Q, or right-click anywhere on this page and choose Open ShroomPen. A small overlay appears on top of the page.

The very first time, ShroomPen shows a short data disclosure instead of the overlay. It explains what ShroomPen reads, where that goes, and what is stored on your device. Tick the box and choose Enable ShroomPen to continue, or Not now to leave it switched off. Until you agree, ShroomPen reads nothing from this page.

This step checks itself off once the overlay itself opens — the disclosure alone does not count.
Connect your AI
The first time you open ShroomPen, a short setup wizard offers 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.

This page can't see inside the overlay, so this step stays manual — follow the wizard, or read the provider guide below first.
Try it
Click into the practice field below, open ShroomPen, and ask for a draft that uses the current page — for example: "Write a short RSVP for two people using the current page." Press Enter to generate, then choose Insert to place the draft into the field.

This step checks itself off when text lands in the practice field.

Practice area

The box below is sample page content. When the Current page source is enabled, ShroomPen reads visible text like this and uses it as context — so a generated RSVP should pick up the date, place, and what to bring without you retyping any of it.

Sample page content

Community workshop: growing oyster mushrooms at home

Join us on Saturday, June 27 at 10:00 in Greenhouse 3 at the city garden. Beginners are welcome — we cover substrate prep, inoculation, and fruiting at home.

Bring a clean 2-liter glass jar; everything else is provided.
Spots are limited to 18 people.
RSVP with your name and the number of guests.

Your RSVP draft

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.