
Garry Tan just added book-mirror to gbrain and called it an "infinite personal Blinkist."
The framing is accurate. Here's the actual design:
Feed any EPUB or PDF into the CLI. It splits the book by chapter, spins up one read-only Claude Opus subagent per chapter — all in parallel — and each subagent outputs a two-column markdown section. Left column: original text, frameworks, data, direct quotes. Right column: your notes, your words, your people, your dates mapped to every idea.
Main process assembles everything into media/books/-personalized.md. Permanent archive, fully greppable.
Three design constraints that matter:
1. CLI-first, batch pipeline — not a chat prompt, not a SaaS dashboard
2. Every subagent is read-only — no repo writes, no state changes, pure output. This is Garry's own token-max philosophy running in practice: parallel subagents, each with full chapter context, thin harness doing only orchestration
3. The right column has a hard rule: it must quote you — your actual words, specific names, specific dates. No reader history = generic summary. With it = a book read specifically for your life
20 chapters costs roughly $6 at current Claude Opus API rates.
Compare that: a paid ghostwriter writing custom reading notes runs $200–2000. Blinkist gives you a generic 15-minute summary with zero personalization. book-mirror gives you deep + personalized in minutes, and the output is markdown you own forever.
The cost inflection is real. But the personalization is the actual moat — you can't fake it, you can't shortcut it.
Which is why this lands differently for me personally.
My Memory Palace — years of decision journals, project retrospectives, notes on specific people like Patrick, Tom, Paco, Garry Tan, the whole crew — is exactly the right-column context source book-mirror needs. Feed those paths to book-mirror and the right column has real citations. Not AI-generated approximations. Actual things I wrote, actual names from my projects, actual timestamps.
This is the same thread as doc-index, claude-code-telegram-deploy, and single-html-dashboard: use AI to bring high-quality personalized work down to the cost of a coffee. The pattern isn't "AI replaces X." It's "the personalization floor just moved."
Garry isn't just describing this philosophy — he's dogfooding it in every skill he ships.
Repo: github.com/garrytan/gbrain
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