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Docs · MCP connector

Nihontekini for Claude

Connect Claude to your Japanese flashcards. It can build decks for you, fix cards, see what you keep forgetting and quiz you on it.

Server URL

https://api.nihontekini.app/mcp

Remote MCP over Streamable HTTP, with OAuth sign-in.

What it does

Nihontekini is a Japanese flashcard app for iPhone with spaced repetition. The connector lets Claude work with your account in the same way you would in the app:

  • Add words to your decks from a topic, a JLPT level, a text you paste, song lyrics or a photo of a menu. Readings, meanings and example sentences you leave out are filled in from open dictionaries.
  • Fix a wrong reading or meaning, move cards between decks, suspend or delete them.
  • Tell you how your study is going and which words you keep forgetting.
  • Quiz you on those words, and save the score to the app.

Cards Claude adds reach your phone on its next sync.

Connect it

You need a free Nihontekini account, which you create in the app.

  • claude.ai and the Claude apps: open Customize > Connectors and add Nihontekini, or add a custom connector with the server URL above. If you use the Nihontekini plugin, connect it from the plugin’s Connectors tab. Then turn it on for a chat from the tools menu.
  • Claude Code: run claude mcp add --transport http nihontekini https://api.nihontekini.app/mcp, then type /mcp and pick Nihontekini to sign in.

The app’s Me > AI agents screen has steps for Claude, ChatGPT, Gemini and Grok.

Sign-in and access

Connecting opens a Nihontekini sign-in page (OAuth 2.1 with PKCE and dynamic client registration). Enter the email you use in the app, then the 6-digit code we email you, and tap Allow. Claude never sees your email code; it gets an access token for your account only.

Every connection is listed in the app under Me > AI agents, with when it was last used. Disconnect it there at any time: its token stops working at once. Deleting your account revokes every connection.

Tools

Thirteen tools. Read tools change nothing. Write tools change only your own Nihontekini data, and none of them reach anything outside Nihontekini.

Tool What it does Access
search_dictionary Looks up Japanese words in JMdict by spelling, reading or English meaning. Read
list_decks Lists your own decks and the ready-made decks you study, with card counts. Read
get_learned_words Words you have studied, as learning or known, most recently reviewed first. Read
get_weak_words Words you keep forgetting, for targeted practice. Read
find_cards Searches your cards by term, reading or meaning. Read
get_progress Words started and known, and reviews due now and in the last 7 days. Read
get_plan Your plan, and what is left of the free monthly allowance. Read
add_cards Adds cards to one of your decks, or to a new deck. Gaps are filled from the dictionary. Write
edit_card Fixes a card’s term, reading, meanings, notes, examples or tags, or moves it to another deck. Write
suspend_cards Takes cards out of study, or brings them back, keeping their progress. Write
make_quiz Makes a multiple-choice quiz on your weakest words and saves it as an unfinished test. Write
record_quiz_answers Grades the quiz from your answers and saves the score to the app. Write
delete_cards Deletes cards from your own decks, with their progress. Claude is told to ask you first. Write, destructive

Ready-made decks are shared, so their cards can be suspended but never edited or deleted.

Your data

Through the connector, Claude can read your decks, cards, study progress, review history summaries, quizzes and plan. It can change only what the write tools above allow: your cards, decks and quizzes.

What Claude reads is sent to Claude so it can answer you, and Anthropic’s own policy covers it from there. On our side we keep the data you create, and a record of which connection added or changed it, until you delete it or your account. We do not sell it or use it for advertising. The details are in our privacy policy.

Limits

  • Free plan: Claude can add 50 cards and make 3 quizzes a month. The allowance resets on the 1st (UTC). Reading your decks and progress is never limited.
  • Plus: no monthly limit. You can buy it in the app under Me > Nihontekini Plus.
  • Rate limit: 60 tool calls a minute per connection, on every plan.
  • One call adds up to 200 cards, and a quiz has up to 30 questions.

Help and links