What is flashcards-mcp CLAUDE.md?

A set of instructions for developing a flashcard MCP server, a service that lets AI assistants use flashcard data. It documents the build process, server entry point, architecture, storage, authentication, and available project and flashcard operations.

Use it when installing dependencies, building the TypeScript project, understanding its Vercel deployment and Firebase sign-in, or working with its user-scoped flashcard and project storage.

It gives a coding agent the repository-specific information needed to build and run the service without guessing how its parts fit together.

How louislva/flashcards-mcp configures Claude Code

Reuse

Borrowing it

Nothing to install: this file belongs to louislva/flashcards-mcp. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file

curl -O https://raw.githubusercontent.com/louislva/flashcards-mcp/master/CLAUDE.md

Clone the repo

git clone --depth 1 https://github.com/louislva/flashcards-mcp

Made for: Claude Code.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

README.md

[![agentmods](https://agentmods.dev/badge/instructions/louislva/flashcards-mcp/claude-md.svg)](https://agentmods.dev/instructions/louislva/flashcards-mcp/claude-md)

Your own site

<a href="https://agentmods.dev/instructions/louislva/flashcards-mcp/claude-md"><img src="https://agentmods.dev/badge/instructions/louislva/flashcards-mcp/claude-md.svg" alt="Measured on agentmods" height="20"></a>

Per session 864 This file is loaded in full into every session.

When invoked 864 The same file — it is already loaded in full.

Security scan A 0 findings. Scan, not verified.

Origin original No closer match found in the catalogue.

Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

Model	Per session	Once invoked
Fable 5.1	$0.00864	$0.00864
Opus 5	$0.00432	$0.00432
Sonnet 5	$0.00173	$0.00173
Haiku 4.5	$0.00086	$0.00086

Measured 6d ago against content hash 811fddbeabcd, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

flashcards-mcp CLAUDE.md scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 6d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

CLAUDE.md · 74 lines

How it starts

The opening of the file, as written. The whole thing — 74 lines — stays where its author put it; the contents beside it link to each section on GitHub.

CLAUDE.md

This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.

Build & Run

npm install
npm run build    # tsc → dist/

Deployed as Vercel serverless functions. No local stdio mode.

No test framework is configured.

Architecture

This is an MCP (Model Context Protocol) flashcard server deployed as Vercel serverless functions over HTTP, with OAuth 2.1 auth and Firebase Google Sign-In. Each user's data is isolated by Firebase UID.

Entry point

api/mcp.ts — HTTP mode. Uses KVStore (Upstash Redis). Deployed as a Vercel serverless function with OAuth 2.1 Bearer token validation. Extracts user ID from the access token and scopes all data access to that user.

Storage abstraction

StoreBackend interface (src/store.ts) abstracts persistence. One implementation:

KVStore (src/kv-store.ts) — Upstash Redis via @upstash/redis, keyed per-user as user:{uid}:flashcards

Stores the shape: { projects: Project[], flashcards: Flashcard[] }.

Tool registration

src/tools.ts exports registerTools(server, store) which wires up all MCP tools (CRUD for projects/flashcards, due card retrieval, review recording). The tools are framework-agnostic — they take a StoreBackend and work identically regardless of backing store.

Spaced repetition

src/sr.ts uses ts-fsrs to schedule cards with FSRS. Review quality maps to Anki-style ratings: 1 = Again, 2 = Hard, 3 = Good, 4 = Easy. Cards store FSRS memory state (stability, difficulty, fsrs_state, review/lapse counts, learning step, and last_review) instead of SM-2 ease/repetition fields.

Authentication: Firebase + OAuth 2.1

PKCE-only OAuth 2.1 flow for public MCP clients, with Firebase Google Sign-In as the identity provider.

Flow:

MCP client redirects to GET /api/authorize → renders "Sign in with Google" page
User signs in via Firebase popup → client-side JS gets Firebase ID token
POST /api/authorize with ID token → server verifies via Firebase Admin SDK → creates auth code with user_id
POST /api/token → exchanges code for access token (stored in Redis with user_id)
POST /api/mcp with Bearer token → validates token → extracts userId → creates KVStore(userId)

Read the full file on GitHub · 74 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

6d ago First seen · 74 lines · 864 tokens per session scan A 811fddbeabcd

Subscribe to this mod's changes

flashcards-mcp CLAUDE.md is an instructions file published in the GitHub repository louislva/flashcards-mcp (2 stars, last pushed 3mo ago), licensed MIT. It adds 864 tokens to every session, about $0.0043 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

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flashcards-mcp: Instructions file for Claude Code