ShroomPen is a free AI writing extension for the Chrome browser, with its core positioning being "write, reply, and rewrite directly in the browser using your own API key." It does not provide its own AI model service, but instead lets users connect to third-party or local models, so it does not require users to register a ShroomPen account.
Purpose
ShroomPen is suitable for generating text directly in input boxes on any web page. It can reply to messages, rewrite content, fix grammar, or translate, and it can use factual information from the tab you currently have open and selected (such as names, order numbers, tracking, dates, etc.) to enrich the reply content. Typical uses include customer service replies, email writing, form filling, chat replies, and more.
Main capabilities
- Reply: Generate a reply based on the message in front of you and your rough notes.
- Rewrite, Fix Grammar, Translate: Operate on text already in the input box.
- Tab fact extraction: Check the tabs containing details (such as invoices, documents, notes, CRM pages), and ShroomPen will extract information from them to build the text; unchecking them removes the information unique to that tab.
- Supports multiple AI providers: OpenRouter, OpenAI, Anthropic, Gemini, or use Ollama or LM Studio through a local server.
How to use
- Install the ShroomPen extension from the Chrome Web Store.
- Connect a model: sign in with OpenRouter, paste an API key, or point to a local server.
- Click in any input box, ShroomPen appears in the corner, and click the button to write.
Use cases
- Customer service or support teams: combine tickets and tracking tabs to quickly generate accurate replies.
- Everyday office work: write and edit content on regular websites such as Gmail, LinkedIn, and Google Docs.
- Writing that needs factual grounding: extract information from multiple tabs and avoid manual searching.
Limitations and privacy design
- Does not automatically modify text: it writes only when you press the Reply, Rewrite, Fix Grammar, or Translate button, and only in the input field you are currently in.
- Does not read all pages: on first use it prompts that it can read content and waits for your consent; after that it reads only when you actively attach a pageor tab.
- Skips sensitive fields: password, bank card, banking, and one-time verification code fields are ignored; the extension can be disabled on any website.
- Communicates only with the provider you set: requests are sent directly from Chrome to the provider or local model you configured; there is no ShroomPen server and no extension telemetry.
- Sent content is visible: you can view the exact content that will be sent to the provider before the request is made (keys hidden).
- Avoids Chrome reserved pages: such as settings pages and the Web Store, the extension will not open on these pages.
- Local model note: when using Ollama, you need to set OLLAMA_ORIGINS to allow the extension, otherwise it will return a 403 error.
Cost
ShroomPen itself is free, with no ShroomPen account. You only pay the model fees to the provider you choose; when using local models or OpenRouter's free models, the model cost is $0.
