The words you actually needed

Your own Quizlet, Duolingo and Memrise, on one machine. The drills are the ones you already know — a flashcard pile, four-choice learn mode, matching, a graded test, a daily goal, a streak, typed production before anything counts as learned. The cards are generated from your Claude Code sessions — the words you actually reached for, in the wording you reached for them. Out of those the trainer assembles a study plan no one else could be handed: unique to you, unrepeatable, and impossible to buy.

A Claude Code plugin. It captures the language you reach for while you work, turns those words into flashcards, and schedules them with FSRS.

• Cards are written by the Claude you already pay for — no API key.
• No server, no account, no telemetry. The trainer binds 127.0.0.1.
• One deck per language pair, several capturing at once.
• 35 languages in 13 scripts: Latin, Cyrillic, Greek, Hebrew, Arabic, Devanagari, Bengali, Thai, Ethiopic, Armenian, Georgian, Han, Hangul.

See it work

The whole tour, 98 seconds, with a player you can scrub →

How it works

1. A UserPromptSubmit hook collects the phrases you reached for. Code, diffs and tool output are never captured.
2. At session end Claude turns the queue into cards — word, meaning, example, CEFR level, category, topic. A gate checks each one and sends the broken ones back once for repair.
3. You open the trainer and review. FSRS decides when a card comes back.

Install

/plugin marketplace add MarcSky/loanword
/plugin install loanword

Asks for your native language, the language you are learning and the capture mode. Needs Node 22.13 or newer.

Inside Claude Code

Command	What it does
/loanword:start	Opens the trainer at localhost:4747
/loanword:stats	Progress: learned, streak, hardest words
/loanword:ticker	Claude Code widget with flashcards in the status line under your prompt

No build command. The Overview says how many records are waiting, and Build now opens the list first: one row per captured phrase, per language, so you throw away what you already know before it costs a model call. Turn on Make cards automatically in Settings if you would rather a session ending with ten or more records build them by itself. loanword build forces it, and the very first run — an empty deck with a full queue — builds without asking so the trainer has something to show.

Ticker

/loanword:ticker puts the open deck into Claude Code's status line: one card under the prompt, weakest first, a new one every ticker_every seconds. You watch the words you actually reached for go by while Claude works — no tab to open, no session to start. /loanword:ticker off takes it back out.

The trainer

Six screens, served off disk, no build step, no framework, no network.

Screen	What it holds
Overview	What is due, the daily-goal ring, categories, eight weeks of rhythm, the build queue
Practice	Flashcards, Learn mode, and a graded Test — none of them touch the FSRS schedule
Deck	Search, filters, edit in place, star, remove with undo; Chapters groups by category and topic
Study	A planned session; a new card is shown once with both sides, then returns as a typed question
Analytics	Your review log, a table behind every chart, Markdown or CSV export
Settings	Languages, categories, capture, study, appearance, your data

Every screen, one at a time →

Many languages at once

• One queue per language — queue.<code>.jsonl, all appended in the same hook pass, so two languages cost the same keystrokes as one.
• One switch per language — Settings → Collect words for pauses a language without deleting its deck or schedule.
• One schedule per deck — studying en → de never moves a card in en → es.
• Builds run side by side — one lane per target; loanword build --target=ka narrows it to one.
• Decks seed each other — Sync copies the concepts you already learned and asks the builder for the new side. The schedule is never copied.
• Offline speech only — the browser's local voices, then Piper, macOS say or eSpeak NG. loanword speech --lang=ka prints the one command that fetches a voice.

Interface language is separate from the pair you learn: English, Spanish, French, Portuguese, Russian, Hindi and Chinese ship in the box — see ui/i18n/README.md to add one.

Your level

One CEFR estimate per deck, Elo over the first graded answer to each card. No model call, no placement test. A band is named after a hundred first answers, never above the hardest band the deck has tested ten times. A floor set in Settings beats the arithmetic.

What the cards cost

• claude -p on this machine, as a bare completion: no tools, no project context, no session history.
• Sonnet writes cards by default; Haiku and Opus are in Settings. Filing always runs on Haiku.
• The Claude subscription you are already signed into pays for it. Settings → Use my API key takes an Anthropic key instead; it is kept beside your deck in settings.json, and the trainer only ever shows its first and last characters.
• Every call's tokens and cost are logged, per model, over 1, 7 or 30 days.
• Nothing is asked twice: only cards the gate marked go back, one call a batch.
• A call over MAX_CALL_USD (3, or LOANWORD_MAX_CALL_USD) halves its batch instead of retrying. scripts/tune.mjs answers a failure with one change and remembers what worked in tuning.json.

Two hooks, and nothing else

Hook	Runs	Budget
UserPromptSubmit	scripts/capture.mjs --source=prompt	10 s
SessionEnd	scripts/capture.mjs --source=session	30 s

Declared in hooks/hooks.json. The prompt hook scrubs secrets, splits the text against the stop-list and a snapshot of what you know, and appends one line per active language — it never opens SQLite. At session end only candidate words are taken from the assistant's replies, never the sentences, and tool results and code blocks are skipped. A queue over 4 MB stops accepting until loanword build drains it.

Privacy

• Data lives in ~/.claude/plugins/data/loanword*, or CLAUDE_PLUGIN_DATA.
• Code, diffs and tool output are never captured.
• Secrets are stripped before anything is written (scripts/scrub.mjs); removed text leaves a ▮.
• To keep client repositories out: install at user scope and claude plugin disable loanword where it does not belong, or set mode: active.

Found a leak in queue.jsonl? That is a P0. Open an issue.

Settings

Set at install time, changeable from the trainer. Stored in settings.json in the plugin data directory; the stored value wins.

Option	Default	Meaning
native_lang	es	The language you write prompts in
target_lang	en	The language you are learning
mode	both	active: your prompts; passive: assistant replies
daily_limit	15	New cards per day, 3 to 100. Reviews are never capped
auto_build	false	Build cards when a session ends, without asking
echo	off	line: open every reply with the native phrasing of your prompt; weave: also work your ten weakest words into the answer
level	—	A1…C2: words below this level never become cards
peek	false	Print one card into the session while you wait for an answer
peek_pick	—	Which cards may appear: starred, slipping, leech, new, and any CEFR levels
peek_every	15	Minutes between those cards, 1 to 120
ticker_every	30	Seconds a word stays in the status line, 5 to 300

node scripts/store.mjs config    # effective settings

Language detection is local: different scripts by script, same-script pairs by a function-word vote, Japanese and Chinese by kana, in scripts/lang.mjs. Writing systems without spaces are queued as short sentences rather than split into words.

The loanword command

npm link                  # once, from the plugin folder; puts `loanword` on PATH

Command	What it does
loanword	Serves the trainer and opens the browser
loanword stop	Closes it and releases the port
loanword build	Turns the queue into cards now
loanword build --target=ka	Builds one language instead of all of them
loanword clone --from=en --to=ka	Queues the concepts of one deck for another
loanword vet	Which cards break the lexis rules; --apply repairs them
loanword speech --lang=ka	Says which offline voice would speak, and how to get one
loanword peek	Prints one card the way the hook does; --pick=starred,B1 narrows it
loanword tidy	Lists migrated leftovers and old backups; --remove deletes them
loanword migrate	Moves a JSONL deck into SQLite; --dry-run shows what would happen
loanword --stats	Progress as JSON, for scripts
loanword --where	Which plugin copy and which deck it reads

Flag	Meaning
--no-open	Do not open the browser
--host=lan	Bind every interface and print a URL with a one-off token. Without it, loopback only
--idle=<minutes>	Close after that long without a request. Default 30, 0 never. LOANWORD_IDLE_MINUTES sets the same thing
LOANWORD_PORT=<port>	Move off 4747
NO_COLOR=1	Plain startup banner

Ctrl+C, SIGTERM or loanword stop close it cleanly: connections finished, database closed, port released.

Export to Anki

The Export to Anki button in Settings downloads a CSV, and every build writes export/loanword.csv into the data directory.

1. Anki → File → Import
2. Field separator: semicolon ;
3. Fields in order: front, back, reading, example, tags
4. Treat the first line as a header

Tags look like loanword lang:en from:es cefr:B1 cat:process type:word topic:code_review, plus project:<repo> when the card knows where it was met.

Stop-lists

Words from the stop-list never become cards. Every language in the picker ships with one, in data/freq/ — see the README there for where they came from and how to swap in a counted frequency list.

Development

npm ci
npm test                             # unit, storage, migration, analytics, HTTP
npm run test:perf                    # 50k cards, 500k reviews, against the budget
npm run i18n                         # dictionaries complete and well-formed
npm run tokens                       # export the palette as design tokens
npm run icons                        # regenerate ui/icons.svg from the Phosphor map
npm run vendor                       # regenerate ui/vendor/ from node_modules
npm run stem                         # regenerate the Snowball stemmers
claude plugin validate . --strict

See CONTRIBUTING.md before opening a pull request.

Storage is one SQLite file, loanword.db. Copy it while the trainer is closed and you have a backup. Older decks migrate themselves on first start; node scripts/migrate.mjs --rollback puts the old files back. Schema changes go through the numbered ladder in scripts/db.mjs: the deck is copied into backup/ first, and every step is its own transaction.

Assets are vendored so the trainer works with zero network: Phosphor icons (MIT) in ui/icons.svg, General Sans by Indian Type Foundry (ITF Free Font License) in ui/fonts/, and three Web Awesome components (MIT) in ui/vendor/.

MIT.