Clauses

File: config/frontier/clauses.conf

Clauses define battle rules and restrictions. Each clause is enforced at a specific point — before battle (team validation), during battle (in-battle), or by the Showdown engine (native). Formats reference clauses by ID.

Quick Example

clauses {
    species_clause {
        displayName = "Species Clause"
        description = "A player cannot have two of the same species of Pokemon on their team."
        type = "TEAM_VALIDATION"
        showdownRule = "Species Clause"
        perPokemon = false
        molangExpression = ["!query.has_duplicate_species"]
        failureMessage = "Species Clause: Your team has duplicate species"
    }
}

Fields

Field	Type	Default	Description
displayName	String	""	Human-readable name shown in GUIs.
description	String	""	What this clause does.
type	ClauseType	"SHOWDOWN_NATIVE"	When and how the clause is enforced.
showdownRule	String?	null	Showdown rule string (for SHOWDOWN_NATIVE clauses).
molangExpression	List<String>?	null	MoLang expressions for validation. Each entry is a separate expression.
perPokemon	Boolean	true	If true, expression runs once per Pokemon. If false, once for the whole team.
failureMessage	String?	null	Message shown when validation fails. Placeholders: {pokemon} (per-Pokemon only), {clause}.

Clause Types

Type	Description
TEAM_VALIDATION	Checked during team validation before the battle starts. Uses MoLang expressions.
SHOWDOWN_NATIVE	Passed directly to the Showdown battle engine as a rule string.
IN_BATTLE	Enforced during battle by Frontier (gimmick bans).

Enforcement Flow

1. Queue Join — TEAM_VALIDATION clauses run against the player’s team. If any fail, the player can’t join the queue and sees the failure message.
2. Battle Start — SHOWDOWN_NATIVE clauses are passed to the Showdown engine. Format-level bans (species, moves, abilities, items) also apply here.
3. During Battle — IN_BATTLE clauses (gimmick bans) fire when players attempt banned mechanics.

Default Clauses

Frontier ships with 13 clauses across all three types.

Team Validation Clauses

ID	Name	Per-Pokemon	Expression	Description
species_clause	Species Clause	No	!query.has_duplicate_species	No duplicate species on a team.
item_clause	Item Clause	No	!query.has_duplicate_items	No duplicate held items.
evasion_clause	Evasion Clause	Yes	!query.pokemon.has_any_move('doubleteam,minimize')	Bans evasion-boosting moves.
ohko_clause	OHKO Clause	Yes	!query.pokemon.has_any_move('fissure,sheercold,horndrill,guillotine')	Bans one-hit KO moves.
monotype	Monotype	No	query.team_shares_type	All team members must share a type.
level_cap	Level Cap	Yes	query.format_target_level == 0 || query.pokemon.level <= query.format_target_level	Pokemon must be at or below the format’s target level.
no_legendaries	No Legendaries	Yes	!query.pokemon.species.has_label('legendary')	Legendary Pokemon are banned.
nfe_only	NFE Only	Yes	query.pokemon.can_evolve	Only unevolved Pokemon (Little Cup).

Showdown Native Clauses

ID	Name	Showdown Rule	Description
sleep_clause	Sleep Clause	"Sleep Clause Mod"	Only one opposing Pokemon can be asleep at a time.

In-Battle Clauses (Gimmick Bans)

ID	Name	What It Bans
gimmick_ban	Gimmick Ban	Mega Evolution, Ultra Burst, Z-Moves, Dynamax, Terastallization
ban_mega	Mega Evolution Ban	Mega Evolution, Ultra Burst
ban_tera	Terastallization Ban	Terastallization
ban_dynamax	Dynamax Ban	Dynamax
ban_zmoves	Z-Moves Ban	Z-Moves

MoLang Query API

Frontier exposes custom MoLang queries for use in clause expressions.

Per-Pokemon Queries

Available when perPokemon = true. Access through query.pokemon.

Query	Returns	Description
query.pokemon.level	Double	Pokemon’s current level.
query.pokemon.can_evolve	1.0/0.0	Whether the Pokemon can still evolve.
query.pokemon.has_move('name')	1.0/0.0	Whether the Pokemon knows a specific move (Showdown ID).
query.pokemon.has_any_move('m1,m2,...')	1.0/0.0	Whether the Pokemon knows any of the listed moves.
query.pokemon.species.has_label('label')	1.0/0.0	Whether the species has a label (e.g., legendary).

Team-Wide Queries

Available in both per-Pokemon and team mode.

Query	Returns	Description
query.team_size	Double	Number of Pokemon on the team.
query.has_duplicate_species	1.0/0.0	Whether the team has duplicate species.
query.has_duplicate_items	1.0/0.0	Whether the team has duplicate held items.
query.team_shares_type	1.0/0.0	Whether all team members share at least one type.
query.format_target_level	Double	Format’s target level (0 if none).
query.format_team_size	Double	Format’s max team size.

Custom Clauses

You can define your own clauses with MoLang expressions. Here are two examples:

clauses {
    no_uber_abilities {
        displayName = "No Uber Abilities"
        description = "Bans Shadow Tag and Arena Trap."
        type = "TEAM_VALIDATION"
        perPokemon = true
        molangExpression = [
            "query.pokemon.ability.name != 'shadowtag' && query.pokemon.ability.name != 'arenatrap'"
        ]
        failureMessage = "{pokemon} has a banned ability"
    }
    max_level_50 {
        displayName = "Level 50 Cap"
        description = "All Pokemon must be level 50 or below."
        type = "TEAM_VALIDATION"
        perPokemon = true
        molangExpression = ["query.pokemon.level <= 50"]
        failureMessage = "{pokemon} exceeds the level 50 cap"
    }
}

Note

Custom clauses only work with TEAM_VALIDATION type. IN_BATTLE clauses are hardcoded for gimmick bans, and SHOWDOWN_NATIVE clauses just pass a rule string to the engine.