primer.

Getting started with Primer

Open a sample book and start reading. You can browse all seven samples without an account. Sign in to save your reading progress, notes and conversations, or to add your own reading. Conversations use CAP’s shared AI allowance.

Read and ask a question

  1. Open a book from the library and choose a chapter.
  2. To chat, sign in with CAP. See AI through CAP for allowance, costs and privacy.
  3. Select a passage, then write your question in the companion. Your selected words are kept with the question when you send it.
  4. Follow a passage citation in a response to return to its source. Check the text yourself: a model can misunderstand a book or give an incorrect answer.
  5. Start another conversation for a different question. Primer adds a topic to new chapter-based conversation titles after a successful reply; you can rename them yourself.

On a narrow screen, switch between Read and Conversation. On desktop, drag the divider to adjust their widths or hide the companion to focus on reading.

Add your own reading

Sign in and open Add a reading. Your saved imports belong to your account and are not added to the public sample shelf. Import only material you have permission to use this way; a downloadable file is not automatically licensed for hosted storage or AI processing.

EPUB: Choose a DRM-free .epub file, inspect the conversion preview and warnings, then save it. Conversion runs on your device. The original EPUB stays local; saving uploads the converted reading package to private storage. You can download a .primer.json copy and import that file later. EPUBs are limited to 20 MB and converted packages to 6 MB.

Primer preserves text, headings, emphasis, lists and linked notes when the EPUB provides suitable markup. Open a note reference to read its text. Check important notes against your original. Supported embedded illustrations and simple tables are retained; original styling is omitted, merged-cell tables are flattened, and unrecognized note links may remain ordinary text. Image descriptions may inform chat, but image pixels are not sent to the text model. Publisher sections do not always correspond exactly to chapters. Closing the tab or canceling stops conversion.

Essay or other text: Paste text or Markdown, or choose a UTF-8 .md or .txt file up to 400 KB. The filename suggests an editable title. If you already have a draft, review the file and explicitly choose whether to replace the draft. Check the preview, then save. Rich pasted text can retain headings, emphasis, lists, links and quotations. Images and embeds are omitted. The limit is 100,000 characters and 1,000 parsed blocks. For a public article, paste its URL at the top and choose Add & start reading. Jina Reader extracts the text, saves it to your private library, and opens the reader directly. No Jina account or API key is needed. Subscriber-only text may be missing. Primer saves copies of supported images with the article. Choose Download backup (.zip) beside the original source in the reader to keep the Markdown and image files on your computer. Keep the images folder alongside article.md; sources.json records original URLs. A notice in the reader and archive reports any images that could not be saved. Up to 50 public HTTPS PNG, JPEG, GIF or WebP images are supported, limited to 1.5 MB each and 3 MB total. Slow or inaccessible images may be missing. Articles saved before this feature need to be imported again to acquire image copies. The source URL records attribution.

Markdown is plain text with simple formatting marks. For example:

# A question about the essay

What does the author mean by **freedom**?

- An individual choice
- A shared responsibility

You do not need to learn Markdown to paste ordinary text. PDF import and OCR are not available in this version.

See Finding books for download sources and format guidance.

What the companion sees

For both sample and imported books, Primer starts with bounded nearby text and can search for more passages, linked notes and your saved discussions about this book. Lookups stop at the current chapter unless you enable Allow lookups in later chapters. Earlier conversations may contain spoilers. Select a passage when asking a specific question; the companion can retrieve more context as needed.

Open Saved conversations above the current discussion to return to a previous chat. During a reply, a small lookup line shows activity as it happens; expand it to see what completed or was unavailable. These summaries remain with the saved reply. Additional model steps use CAP allowance and appear in Usage.

In Reading notes, edit Book context to give the companion a short overview of the book, separate from your personal goals. Primer starts it from available book metadata. Save your changes to apply them to future messages. Optional Draft with AI uses your selected model and CAP allowance, sending metadata and up to 16,000 characters of opening text. Review the proposal, move it into the editor, then save; generating alone never replaces your saved brief. The draft may be incomplete or wrong, and does not replace passages as evidence.

Your account context, book preferences and relevant conversation excerpts may also inform a reply. When you chat, text goes through Primer to CAP’s AI proxy and the selected model provider. Private library storage does not mean your text stays only on your device. See connection and privacy details.