Quizlar MCP Server

Voice-led, FSRS-scheduled flashcards from YouTube, PDFs, web, or text. Auto-graded quizzes.

Quizlar's MCP server lets Claude, Cursor, Cline, Windsurf, or any MCP-compatible client:

• Create flashcard decks from YouTube videos, PDFs, web pages, or pasted text
• Run auto-graded quizzes with the same tier-1-exact-match → phonetic → LLM grading pipeline that powers the voice product
• Track memory with FSRS spaced repetition — Quizlar is the scheduler of record, every answer updates real memory state

This repo is the public discovery surface (server.json for the Official MCP Registry + a stdio bundle for clients that need it). The hosted MCP server itself is closed-source and runs at https://mcp.quizlar.app/mcp/.

Listings

• Official MCP Registry — io.github.quizlar/mcp-server v1.0.0
• Smithery — https://smithery.ai/servers/quizlar/quizlar

Setup

1. Mint an API key at https://quizlar.app/settings/api-keys (format: sk-qz-<32 chars>).
2. Pick your client below and paste the snippet.

Cursor

~/.cursor/mcp.json:

{
  "mcpServers": {
    "quizlar": {
      "command": "npx",
      "args": [
        "-y",
        "mcp-remote",
        "https://mcp.quizlar.app/mcp/",
        "--header",
        "Authorization:Bearer ${QUIZLAR_API_KEY}"
      ],
      "env": { "QUIZLAR_API_KEY": "sk-qz-..." }
    }
  }
}

Windsurf

~/.codeium/windsurf/mcp_config.json — Windsurf supports Streamable HTTP natively, no wrapper needed:

{
  "mcpServers": {
    "quizlar": {
      "serverUrl": "https://mcp.quizlar.app/mcp/",
      "headers": { "Authorization": "Bearer ${QUIZLAR_API_KEY}" }
    }
  }
}

Then export QUIZLAR_API_KEY=sk-qz-... in your shell.

Claude Desktop

Open Settings → Connectors → "Add custom connector":

• Name: Quizlar
• URL: https://mcp.quizlar.app/mcp/
• Add header → Name: Authorization, Value: Bearer sk-qz-...

Or edit claude_desktop_config.json directly using mcp-remote:

{
  "mcpServers": {
    "quizlar": {
      "command": "npx",
      "args": [
        "-y",
        "mcp-remote",
        "https://mcp.quizlar.app/mcp/",
        "--header",
        "Authorization:Bearer ${QUIZLAR_API_KEY}"
      ],
      "env": { "QUIZLAR_API_KEY": "sk-qz-..." }
    }
  }
}

Cline

Edit cline_mcp_settings.json (Cline → Settings → MCP Servers → "Edit JSON"):

{
  "mcpServers": {
    "quizlar": {
      "command": "npx",
      "args": [
        "-y",
        "mcp-remote",
        "https://mcp.quizlar.app/mcp/",
        "--header",
        "Authorization:Bearer ${QUIZLAR_API_KEY}"
      ],
      "env": { "QUIZLAR_API_KEY": "sk-qz-..." }
    }
  }
}

Detailed steps in llms-install.md.

Smithery

npx -y @smithery/cli@latest install @quizlar/quizlar --client claude

Replace claude with cursor, windsurf, etc. Smithery walks you through pasting your API key.

Tools

22 tools mapped 1:1 to learner verbs:

• Build decks: create_deck, create_deck_from_text, create_deck_from_youtube, create_cards_batch, get_job_status
• Quiz: quiz_me (composite: build + start in one call), start_quiz, submit_answer, skip_question, end_quiz
• Browse: list_decks, get_deck, list_cards, search_decks, search_cards, list_sessions
• Analytics: get_progress, get_study_recommendations, get_learning_velocity, get_knowledge_gaps, get_retention_curves, get_card_difficulty_stats

Auth

Bearer API key (sk-qz-<32 chars>) is the simplest path and works in every client snippet above. Quizlar also exposes full OAuth 2.1 with Dynamic Client Registration + PKCE at https://mcp.quizlar.app/.well-known/oauth-authorization-server for clients that prefer a browser flow.

Troubleshooting

• 401 Unauthorized on every tool call — API key is missing, mistyped, or revoked. Re-mint at https://quizlar.app/settings/api-keys and paste the full sk-qz-… value, including the prefix, into the Authorization: Bearer … header.
• Client doesn't see Quizlar tools after editing config — fully restart the client (most don't hot-reload MCP config). For Claude Desktop, quit from the menu bar; for Cursor / Windsurf / Cline, close all windows.
• mcp-remote fails to launch — usually a Node.js / npx path issue. Run npx -y mcp-remote --help in a terminal to verify it resolves; if behind a corporate proxy, set HTTPS_PROXY in the client's env block or install mcp-remote globally with npm i -g mcp-remote.
• 429 / quota errors mid-quiz — free-tier daily limits reached. Quotas reset at midnight UTC; or upgrade at https://quizlar.app/settings/billing.
• OAuth callback never returns to the client — your loopback port may be blocked. Fall back to the API-key flow above; it bypasses OAuth entirely.

For anything not covered here, file an issue at https://github.com/quizlar/mcp-server/issues or email support@quizlar.app.

Links

• App: https://quizlar.app
• Issues: https://github.com/quizlar/mcp-server/issues
• Stdio bundle source: bundle/ (used to publish to Smithery + any other stdio-only client)

License

MIT for this configuration repo. The hosted MCP server itself is proprietary.