Optional local companion
ChatGPT, inside Readlet.
Readlet Companion is the small bridge that lets Readlet AI use the ChatGPT account you already have. No Readlet account, pasted API key, or terminal setup.
Version 2.4.0 · Signed with Apple Developer ID and notarized by Apple.
Windows support is currently a preview. The download includes its own installer and runtime.
Renewable generation rose while operational emissions fell. The largest shift came from the new solar portfolio, which supplied nearly a third of the added capacity (p. 14).
The report also identifies network resilience as the main area requiring continued investment (p. 31).
Three steps. Then back to your PDF.
The installer handles Chrome’s native bridge for you. There are no commands to copy and no configuration files to edit.
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01
Download Companion
Choose the installer for this computer. Readlet detects Mac or Windows automatically, but you can switch platforms above.
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02
Install it once
Open
Readlet Companion.pkgand follow the standard macOS installer. Enter your Mac password when asked.Unzip the download and open
Install Readlet Companion.cmd. Windows may ask you to approve the preview installer. -
03
Return to Readlet AI
Readlet reconnects automatically. Choose “Sign in with ChatGPT” if prompted, approve the browser sign-in, and continue your conversation.
A bridge, not another account.
Companion runs on this computer and gives the Chrome extension a safe route to your ChatGPT sign-in. The core PDF reader never depends on it.
- Stays on your device
- Your PDFs, reading history, vault, saved signatures, and local chat history remain in Readlet.
- Shared when you ask
- Your question and the relevant text, page image, visual crop, or edited detail are sent for that AI request.
- Where it goes
- The request goes through Companion to OpenAI using your connected ChatGPT account. It does not pass through Readlet-owned servers.
Good to know.
The practical details are here when you need them, without turning installation into a technical manual.
Why is a separate companion needed?
Chrome extensions cannot directly use your existing ChatGPT or Codex sign-in. Chrome’s supported solution is a native messaging host installed on your computer. Companion provides that bridge and bundles the runtime Readlet AI needs.
Will I reinstall it for every Readlet update?
No. Most Readlet interface, reader, and AI experience updates arrive with the extension or web app. A new Companion installer is only needed when the native bridge, bundled AI engine, or its security boundary changes. Readlet checks for Companion updates and tells you when one is available.
What does ChatGPT receive?
Readlet selects context for the question you asked: relevant PDF text and, when needed, the current page image, an enlarged visual detail, recent conversation context, or values required for an approved form action. It does not upload your entire signature vault.
Can I remove Companion later?
Yes. Removing Companion disables Readlet AI until you install it again, but it does not affect reading, search, OCR, editing, forms, signatures, or exports.
Release installers recognise the published Readlet extension automatically. Developer builds may require an extension ID.