Calculate the damage one Pokémon deals to another with a given move in Pokémon Champions (VGC-style, defaults to Doubles). Wraps the trusted @smogon/calc engine, so abilities (Contrary, Intimidate, ...), items, weather, terrain, Tera, crits, multi-hit, screens and Doubles spread reduction are all handled correctly. For moves whose power builds up over a battle — Rage Fist (per hit taken), Last Respects (per fainted ally) — pass moveContext so the base power scales correctly; or pin any variable-power move with moveContext.basePowerOverride. Answers questions like "does my Choice Band Staraptor-Mega OHKO that Garchomp?". Returns the damage range, percent range, hits-to-KO, and the human-readable calc string.

Given an attacking type and 1 or 2 defending types, return the damage multiplier (0, 0.25, 0.5, 1, 2, or 4) and a short explanation, for Pokémon Champions. Derived from the type chart bundled in @smogon/calc. Answers "how effective is Fighting vs a Flying/Psychic Pokémon?".

Look up a Pokémon by name (Mega forms accepted, e.g. "Staraptor-Mega" or "Mega Staraptor") in Pokémon Champions: returns base stats, typing, abilities, and weight. Data comes from the Champions Pokédex (Serebii) so game-original Mega Evolutions are accurate — e.g. Mega Staraptor has Contrary, which @smogon/calc gets wrong. Also returns the Pokémon's full learnable movelist ("moves"). The "source" field shows whether the answer came from the Champions dex or the @smogon/calc fallback. Optionally pass a regulation id (e.g. "m-b") to also get whether the Pokémon is legal there and its regulation-legal moves.

Check whether a Pokémon — and optionally specific moves and/or held items — is legal in a given Pokémon Champions regulation (e.g. "m-b"). Reads purely from local regulation JSON (fully offline). If the regulation file is missing, returns an error telling you to run the scraper. If the regulation has no per-move or per-item legality data, that is stated explicitly rather than guessed.

List the Pokémon Champions regulations currently available locally (the JSON files in regulations/), with each one's metadata (name, date range, source URL, last-scraped timestamp) and counts of legal Pokémon/moves. Cheap way to know what legality data this server has before calling check_legality.

Browse the items a Pokémon can hold in Pokémon Champions: Hold Items (Choice Scarf, Life Orb, Leftovers, ...), Mega Stones (Garchompite, Charizardite X, ...), and Berries (Sitrus, Lum, type-resist berries, ...). Each item includes its in-game effect, how to obtain it, and its category. Data is scraped from the Champions items page (Serebii). Optionally filter by category or a name substring, and pass a regulation id (e.g. "m-b") to mark which items are legal there. Answers "what berries can I hold?" or "which Mega Stones exist in Champions?".

Look up a single Pokémon Champions held item by name (e.g. "Choice Scarf", "Garchompite", "Sitrus Berry"): returns its in-game effect, how to obtain it, its category (Hold Item / Mega Stone / Berry), and whether it can be held in battle. Data comes from the Champions items page (Serebii). The "source" field shows whether the answer came from the Champions catalog or the @smogon/calc fallback (which lacks effect/location text). Optionally pass a regulation id (e.g. "m-b") to also get whether the item is legal there.

Given a move and a Pokémon Champions regulation (e.g. "m-b"), list every Pokémon that is legal in that regulation AND can learn the move. Answers "who can run Fake Out in M-B?" or "which legal mons get Spore?". Learnsets come from the Champions dex; the move's type/category/base power are included when the engine knows the move. NOTE: Champions publishes no per-move bans, so "legal move" means a legal Pokémon can learn it. Defaults to regulation "m-b".

List the moves available in a Pokémon Champions regulation (e.g. "m-b") — i.e. every move learnable by at least one legal Pokémon — each with its type, category (Physical/Special/Status), base power, and how many legal Pokémon can learn it. Optionally filter by name substring, move type (e.g. "Fire"), or category. Answers "what Fairy moves are usable in M-B?" or "is Glacial Lance legal here?". NOTE: Champions publishes no per-move bans, so this is the pool of learnable moves, not a separate curated allowlist. Defaults to regulation "m-b".

List the Pokémon legal in a Pokémon Champions regulation (e.g. "m-b") — the regulation's legal pool — each enriched with its National Dex number, typing, base stats, and abilities from the Champions dex. Optionally filter by name substring or by type (e.g. "Dragon"). Answers "what Fairy types are legal in M-B?" or "show me the M-B roster". Reads the regulation's legal-Pokémon allowlist directly (the complement to list_legal_moves). Defaults to regulation "m-b".