Plain

Ancient philosophy, stripped to its core, in words anyone can understand.

Plain turns classic Stoic philosophy books into bite-sized cards written in plain English — so you can actually read them and finish them.

The Three Voices

Three men. Three completely different lives. The same philosophy.

• Epictetus (The Slave) — Born into slavery. Found freedom in his own mind.
• Marcus Aurelius (The Emperor) — Ruled Rome. Wrote a private journal to keep himself sane.
• Seneca (The Senator) — One of the richest men alive. Forced to kill himself by the emperor he served.

They all arrived at the same answers. Plain lets you read those answers in words that don't require a philosophy degree.

Launch Books

Author	Book	Cards
Epictetus	The Enchiridion	72
Epictetus	Discourses	294
Marcus Aurelius	Meditations	522
Seneca	On the Shortness of Life	69
Seneca	On the Happy Life	79
Seneca	On Peace of Mind	79
Seneca	On Anger	193

Every card has two layers: a plain English translation (8th-grade reading level) and the original text shown below it. Cards are tagged with 8 themes — tap a tag to see how a slave, an emperor, and a senator each approached the same idea.

Tag	Cards
Knowing Yourself	494
Freedom & Control	407
What Matters Most	387
Human Nature	382
Calm Your Mind	357
Doing The Right Thing	266
Facing Hardship	221
Death & Mortality	167

Tech Stack

SvelteKit + Vercel (free tier). No database. No auth. All content is static JSON. Progress tracking uses localStorage.

• Structural pages pre-rendered at build time
• Card pages use ISR (Incremental Static Regeneration) — cached at the edge after first visit
• OG images generated on-demand via @vercel/og for card sharing
• Self-hosted serif font for a book-like reading experience

Local Development

npm install

# Start the dev server (http://localhost:5173)
npm run dev --prefix web

# Expose to local network for mobile testing
npm run dev --prefix web -- --host

Deploy

Deploys are manual via the Vercel CLI:

vercel          # preview deploy
vercel --prod   # production deploy

Content Pipeline

TypeScript CLI that turns plain-text source books into card JSON via the Anthropic Batch API. Source texts live in content/source/, pipeline cache in content/pipeline/, and finished card JSON is written to content/output/.

Pipeline: parse → refine → translate → assemble

1. Parse — Split source text into sections by Roman numeral markers
2. Refine — AI reviews each section: splits multi-idea sections into separate chunks, merges sections that can't stand alone
3. Translate — Plain English translation + tagging, with built-in meaning preservation verification
4. Assemble — Generate card IDs, reading time, source refs, write to content/output/

# Run full pipeline for one book (requires ANTHROPIC_API_KEY)
ANTHROPIC_API_KEY=... npx tsx scripts/generate.ts --book shortness-of-life

# Run individual phases against persisted intermediates
npx tsx scripts/generate.ts --book shortness-of-life --phase parse         # no AI calls
ANTHROPIC_API_KEY=... npx tsx scripts/generate.ts --book shortness-of-life --phase refine
ANTHROPIC_API_KEY=... npx tsx scripts/generate.ts --book shortness-of-life --phase translate
npx tsx scripts/generate.ts --book shortness-of-life --phase assemble      # no AI calls

# Verbose mode — stream pipeline log messages to stderr
ANTHROPIC_API_KEY=... npx tsx scripts/generate.ts --book shortness-of-life --verbose

Flags: --book <slug> (required), --phase <parse|refine|translate|assemble>, --verbose, --output <dir> (default: content/output), --help.

Each run writes a diagnostic log to content/pipeline/<slug>/pipeline.log with LLM decisions, validation errors, retries, and cache status. Use --verbose to also print these to stderr.

Testing

npm test          # runs both pipeline and web unit tests

npm test runs two suites in sequence:

1. Pipeline tests (186 tests) — parser, chunker, refine, translator, cache, batch, validator, and assembler (scripts/lib/__tests__/)
2. Web unit tests (36 tests) — content utilities and tag logic (web/tests/unit/)

Playwright e2e tests are separate and require a built app:

npm run build --prefix web
npm run test:e2e --prefix web

Documentation

• docs/ARCHITECTURE.md — Data models, route structure, rendering strategy, and full project architecture
• docs/BRANDING.md — Brand guide covering voice, visual identity, motion, sound, and brand rules
• docs/CONTENT_STRATEGY.md — Book selection, card writing guidelines, tag taxonomy, and content pipeline
• docs/ANALYTICS.md — Analytics strategy and event tracking