Verifiers

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Base Verifier Class

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Verifier

public abstract class Verifier
{
    protected abstract CheckIdentifier Identifier { get; }
    
    public abstract void Verify(LegalityAnalysis data);
    
    // Helper methods for creating CheckResults
    protected CheckResult GetValid(LegalityCheckResultCode msg);
    protected CheckResult GetInvalid(LegalityCheckResultCode msg);
    protected CheckResult Get(Severity s, LegalityCheckResultCode msg);
}

​

CheckResult

public readonly struct CheckResult
{
    public Severity Severity { get; }           // Valid, Invalid, Fishy
    public CheckIdentifier Identifier { get; }  // Which aspect was checked
    public LegalityCheckResultCode Code { get; } // Result code
}

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Core Verifiers

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AbilityVerifier

public sealed class AbilityVerifier : Verifier
{
    protected override CheckIdentifier Identifier => CheckIdentifier.Ability;
    
    public override void Verify(LegalityAnalysis data)
    {
        var result = VerifyAbility(data);
        data.AddLine(result);
    }
}

• Ability is within valid range for species/form
• AbilityNumber (1/2/4) matches ability slot
• Ability matches encounter constraints
• Ability Capsule usage validity (Gen 6+)
• Ability Patch usage validity (Gen 8+)
• Hidden ability availability
• PID-ability correlation (Gen 3-5)

// Gen 8 Hidden Ability validation
if (pk.AbilityNumber == 4 && enc.Ability.CanBeHidden())
    return VALID;

// Ability Patch usage check
if (pk.AbilityNumber == 4)
{
    if (AbilityChangeRules.IsAbilityPatchPossible(evoChainsAllGens))
        return GetValid(AbilityPatchUsed);
}

​

BallVerifier

public sealed class BallVerifier : Verifier
{
    protected override CheckIdentifier Identifier => CheckIdentifier.Ball;
    
    public static BallVerificationResult VerifyBall(
        IEncounterTemplate enc, 
        Ball current, 
        PKM pk
    );
}

• Ball matches encounter type (wild, static, trade)
• Ball inheritance rules (eggs, Gen 6+)
• Beast Ball restrictions (Ultra Beasts)
• Cherish/Master Ball restrictions
• Dream Ball availability (Dream World)
• Apricorn Ball restrictions (HGSS, Gen 7+)
• Heavy Ball catch rate restrictions (Gen 7)

private static BallVerificationResult VerifyBallEgg(IEncounterEgg enc, Ball ball, PKM pk)
{
    if (enc.Generation < 6)
        return VerifyBallEquals(ball, Poke); // Must be Poké Ball
    
    return ball switch
    {
        Master => BadInheritMaster,   // Cannot inherit
        Cherish => BadInheritCherish, // Cannot inherit
        _ => VerifyBallInherited(enc, ball, pk),
    };
}

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MoveVerifiers

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LearnVerifier

internal static class LearnVerifier
{
    public static void Verify(
        Span<MoveResult> result, 
        PKM pk, 
        IEncounterTemplate enc, 
        EvolutionHistory history
    );
}

• Move can be learned by species/form
• Move learned at valid level/method
• No duplicate moves
• No empty slots between moves
• First move slot not empty
• Form-exclusive moves (Hoopa, Kyurem)

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MovePPVerifier

• PP is within valid range
• PP Ups count is valid (0-3)
• Current PP ≤ Max PP

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LearnVerifierEgg

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LevelVerifier

• Current level ≥ met level
• Level matches experience
• Met level valid for encounter
• Evolution level requirements

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FormVerifier

• Form exists for species
• Form available in generation
• Form changeable/unchangeable
• Gender-form relationships (Meowstic, Indeedee)
• Battle-only forms (Mega, Primal)
• Time-based forms (Shaymin, Hoopa)

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GenderVerifier

• Gender valid for species (genderless, male-only, female-only)
• Gender matches PID (Gen 3-5)
• Gender matches encounter constraint
• Gender-locked evolutions

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NicknameVerifier

• Nickname length within limits
• Invalid characters
• Nickname language matches
• Species name detection
• Nicknamed flag correctness

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TrainerVerifiers

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TrainerIDVerifier

• ID format for generation
• ID matches encounter (trades, events)
• Shiny-ID correlation

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TrainerNameVerifier

• Name length and characters
• Language-specific restrictions
• Special character bans

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MemoryVerifier

• Memory intensity/feeling/variable valid
• Memory available for context
• OT/HT memory conflicts
• Memory contradictions with encounter

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RibbonVerifiers

• Ribbon available in generation
• Ribbon requirements met
• Ribbon conflicts
• Event/competition ribbons

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MarkVerifier

• Mark available for encounter type
• Weather-dependent marks
• Time-of-day marks
• Fishing/curry marks
• Ribbon marks (Tower, Master)

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Game-Specific Verifiers

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LegendsArceusVerifier

• Height/Weight alpha values
• Move shop moves
• Grit items (EV equivalent)
• Research level
• Alpha/Noble flags

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LegendsZAVerifier

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CXDVerifier

• Shadow Pokémon purification
• XD exclusive properties

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Statistical Verifiers

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IndividualValueVerifier

• IVs in range (0-31)
• Fixed IVs match encounter
• Flawless IV count
• Hyper Training validity

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EffortValueVerifier

• EVs in range (0-252 per stat, 510 total for Gen 3+)
• Gen 1/2 EV limits (0-65535)
• EV reset items used

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AwakenedValueVerifier

• AVs in range (0-200)
• AVs only on LGPE format

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Special Verifiers

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PIDVerifier

• Shiny-PID correlation
• Nature-PID correlation
• Gender-PID correlation (Gen 3-5)
• Ability-PID correlation (Gen 3-5)
• IV-PID correlation (Gen 3-4 methods)
• Encryption constant relationships

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TransferVerifier

• Valid transfer path
• Transfer-only moves removed
• Format-specific restrictions
• HOME tracker presence
• GO origin validation

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HistoryVerifier

• Current handler correctness
• HT name/gender/language
• Affection/friendship values
• Contest stats

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Verification Flow

public sealed class LegalityAnalysis
{
    public LegalityAnalysis(PKM pk)
    {
        // 1. Parse encounter type
        EncounterFinder.FindVerifiedEncounter(pk);
        
        // 2. Build evolution chains
        EvolutionChain.GetEvolutionChainsAllGens(pk, encounter);
        
        // 3. Run all verifiers
        foreach (var verifier in Verifiers)
            verifier.Verify(this);
        
        // 4. Compile results
        Valid = !Results.Any(r => r.Severity == Severity.Invalid);
    }
}

​

Custom Verification

public class CustomVerifier : Verifier
{
    protected override CheckIdentifier Identifier => CheckIdentifier.Misc;
    
    public override void Verify(LegalityAnalysis data)
    {
        var pk = data.Entity;
        
        // Custom validation logic
        if (SomeCondition(pk))
            data.AddLine(GetInvalid(LegalityCheckResultCode.InvalidCustomCheck));
        else
            data.AddLine(GetValid(LegalityCheckResultCode.ValidCustomCheck));
    }
}

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Verifier Organization

Legality/Verifiers/
├── Ability/
│   ├── AbilityVerifier.cs
│   ├── AbilityChangeRules.cs
│   └── AbilityBreedLegality.cs
├── Ball/
│   ├── BallVerifier.cs
│   ├── BallContext6.cs
│   └── BallUseLegality.cs
├── Egg/
├── Misc/
├── Ribbons/
└── Verifier.cs

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Related Documentation

• Encounters - Encounter matching
• Evolutions - Evolution chains
• Moves - Move validation