feat: initial implementation of anki-mcp MCP server

Implements a FastMCP server that wraps AnkiConnect (localhost:8765)
to expose Anki flashcard management as Claude MCP tools.

Tools provided:
- list_decks: list all deck names
- create_deck: create nested decks (:: separator)
- add_card: add Basic flashcard with optional tags
- get_due_cards: fetch today's due cards with optional deck filter
- update_card: edit front/back of existing note
- update_deck: rename deck (move-cards approach)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/server.py

@@ -0,0 +1,106 @@
+"""Anki MCP server — manage Anki flashcards via AnkiConnect."""
+
+import os
+import sys
+
+# sys.path injection for `mcp dev` compatibility
+_root = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
+if _root not in sys.path:
+    sys.path.insert(0, _root)
+
+from dotenv import load_dotenv
+
+load_dotenv(os.path.join(_root, ".env"))
+
+from mcp.server.fastmcp import FastMCP
+
+from src import anki
+
+mcp = FastMCP(
+    name="anki",
+    instructions=(
+        "Anki flashcard manager via AnkiConnect. "
+        "Add cards to decks, review due cards, manage categories. "
+        "Requires Anki to be running with the AnkiConnect add-on (code: 2055492159)."
+    ),
+)
+
+
+@mcp.tool()
+def list_decks() -> list[str]:
+    """List all Anki deck names."""
+    return anki.list_decks()
+
+
+@mcp.tool()
+def create_deck(deck_name: str) -> dict:
+    """Create a new Anki deck (or return existing deck ID).
+
+    Args:
+        deck_name: Deck name. Use '::' separator for nested decks (e.g. 'Korean::Vocabulary').
+    """
+    deck_id = anki.create_deck(deck_name)
+    return {"deck_name": deck_name, "deck_id": deck_id}
+
+
+@mcp.tool()
+def add_card(
+    deck_name: str,
+    front: str,
+    back: str,
+    tags: list[str] = [],
+) -> dict:
+    """Add a Basic flashcard to a deck.
+
+    Args:
+        deck_name: Target deck name (must already exist or be created first).
+        front: Front (question) side of the card.
+        back: Back (answer) side of the card.
+        tags: Optional list of tags to attach to the card.
+    """
+    note_id = anki.add_note(deck_name, front, back, tags)
+    return {"note_id": note_id, "deck_name": deck_name, "front": front, "back": back}
+
+
+@mcp.tool()
+def get_due_cards(deck_name: str = "", limit: int = 20) -> list[dict]:
+    """Get today's due cards for review.
+
+    Args:
+        deck_name: Filter by deck name. Leave empty to get due cards from all decks.
+        limit: Maximum number of cards to return (default 20).
+    """
+    return anki.find_due_cards(deck_name, limit)
+
+
+@mcp.tool()
+def update_card(note_id: int, front: str = "", back: str = "") -> dict:
+    """Edit an existing card's Front and/or Back content.
+
+    Args:
+        note_id: The note ID to update (obtained from add_card or get_due_cards).
+        front: New front text. Leave empty to keep existing.
+        back: New back text. Leave empty to keep existing.
+    """
+    anki.update_note_fields(note_id, front, back)
+    return {"note_id": note_id, "updated": {"front": bool(front), "back": bool(back)}}
+
+
+@mcp.tool()
+def update_deck(deck_name: str, new_name: str) -> dict:
+    """Rename an existing deck.
+
+    Args:
+        deck_name: Current deck name.
+        new_name: New deck name.
+    """
+    anki.rename_deck(deck_name, new_name)
+    return {"old_name": deck_name, "new_name": new_name}
+
+
+def main() -> None:
+    mcp.run()
+
+
+if __name__ == "__main__":
+    main()