diff --git a/cloud-minecraft/cloud-fabric/src/main/java/cloud/commandframework/fabric/FabricClientCommandManager.java b/cloud-minecraft/cloud-fabric/src/main/java/cloud/commandframework/fabric/FabricClientCommandManager.java
index dca9fe3b..370dad7b 100644
--- a/cloud-minecraft/cloud-fabric/src/main/java/cloud/commandframework/fabric/FabricClientCommandManager.java
+++ b/cloud-minecraft/cloud-fabric/src/main/java/cloud/commandframework/fabric/FabricClientCommandManager.java
@@ -55,8 +55,9 @@ public final class FabricClientCommandManager<C> extends FabricCommandManager<C,
      * @see #FabricClientCommandManager(Function, Function, Function) for a more thorough explanation
      * @since 1.5.0
      */
-    public static FabricClientCommandManager<FabricClientCommandSource> createNative(
-            final Function<CommandTree<FabricClientCommandSource>, CommandExecutionCoordinator<FabricClientCommandSource>> execCoordinator
+    public static @NonNull FabricClientCommandManager<@NonNull FabricClientCommandSource> createNative(
+            final @NonNull Function<@NonNull CommandTree<@NonNull FabricClientCommandSource>,
+                    @NonNull CommandExecutionCoordinator<@NonNull FabricClientCommandSource>> execCoordinator
     ) {
         return new FabricClientCommandManager<>(execCoordinator, Function.identity(), Function.identity());
     }
@@ -76,11 +77,11 @@ public final class FabricClientCommandManager<C> extends FabricCommandManager<C,
      * @param backwardsCommandSourceMapper Function that maps the command sender type to {@link FabricClientCommandSource}
      * @since 1.5.0
      */
-    @SuppressWarnings("unchecked")
     public FabricClientCommandManager(
-            final @NonNull Function<@NonNull CommandTree<C>, @NonNull CommandExecutionCoordinator<C>> commandExecutionCoordinator,
-            final Function<FabricClientCommandSource, C> commandSourceMapper,
-            final Function<C, FabricClientCommandSource> backwardsCommandSourceMapper
+            final @NonNull Function<@NonNull CommandTree<@NonNull C>,
+                    @NonNull CommandExecutionCoordinator<@NonNull C>> commandExecutionCoordinator,
+            final @NonNull Function<@NonNull FabricClientCommandSource, @NonNull C> commandSourceMapper,
+            final @NonNull Function<@NonNull C, @NonNull FabricClientCommandSource> backwardsCommandSourceMapper
     ) {
         super(
                 commandExecutionCoordinator,
@@ -110,7 +111,7 @@ public final class FabricClientCommandManager<C> extends FabricCommandManager<C,
      * @since 1.5.0
      */
     @Override
-    public boolean hasPermission(@NonNull final C sender, @NonNull final String permission) {
+    public boolean hasPermission(final @NonNull C sender, final @NonNull String permission) {
         return true;
     }
 
diff --git a/cloud-minecraft/cloud-fabric/src/main/java/cloud/commandframework/fabric/FabricCommandManager.java b/cloud-minecraft/cloud-fabric/src/main/java/cloud/commandframework/fabric/FabricCommandManager.java
index f264ca50..9f31ddc2 100644
--- a/cloud-minecraft/cloud-fabric/src/main/java/cloud/commandframework/fabric/FabricCommandManager.java
+++ b/cloud-minecraft/cloud-fabric/src/main/java/cloud/commandframework/fabric/FabricCommandManager.java
@@ -139,10 +139,10 @@ public abstract class FabricCommandManager<C, S extends CommandSource> extends C
     @SuppressWarnings("unchecked")
     FabricCommandManager(
             final @NonNull Function<@NonNull CommandTree<C>, @NonNull CommandExecutionCoordinator<C>> commandExecutionCoordinator,
-            final Function<S, C> commandSourceMapper,
-            final Function<C, S> backwardsCommandSourceMapper,
-            final FabricCommandRegistrationHandler<C, S> registrationHandler,
-            final Supplier<S> dummyCommandSourceProvider
+            final @NonNull Function<S, C> commandSourceMapper,
+            final @NonNull Function<C, S> backwardsCommandSourceMapper,
+            final @NonNull FabricCommandRegistrationHandler<C, S> registrationHandler,
+            final @NonNull Supplier<S> dummyCommandSourceProvider
     ) {
         super(commandExecutionCoordinator, registrationHandler);
         this.commandSourceMapper = commandSourceMapper;
@@ -164,11 +164,13 @@ public abstract class FabricCommandManager<C, S extends CommandSource> extends C
         ((FabricCommandRegistrationHandler<C, S>) this.getCommandRegistrationHandler()).initialize(this);
     }
 
-    private void registerNativeBrigadierMappings(final CloudBrigadierManager<C, S> brigadier) {
+    private void registerNativeBrigadierMappings(final @NonNull CloudBrigadierManager<C, S> brigadier) {
         /* Cloud-native argument types */
-        brigadier.registerMapping(new TypeToken<UUIDArgument.UUIDParser<C>>() {}, builder -> builder.toConstant(UuidArgumentType.uuid()));
+        brigadier.registerMapping(new TypeToken<UUIDArgument.UUIDParser<C>>() {
+        }, builder -> builder.toConstant(UuidArgumentType.uuid()));
         this.registerRegistryEntryMappings();
-        brigadier.registerMapping(new TypeToken<TeamArgument.TeamParser<C>>() {}, builder -> builder.toConstant(TeamArgumentType.team()));
+        brigadier.registerMapping(new TypeToken<TeamArgument.TeamParser<C>>() {
+        }, builder -> builder.toConstant(TeamArgumentType.team()));
         this.getParserRegistry().registerParserSupplier(TypeToken.get(Team.class), params -> new TeamArgument.TeamParser<>());
 
         /* Wrapped/Constant Brigadier types, native value type */
@@ -180,9 +182,13 @@ public abstract class FabricCommandManager<C, S extends CommandSource> extends C
         this.registerConstantNativeParserSupplier(OperationArgumentType.Operation.class, OperationArgumentType.operation());
         this.registerConstantNativeParserSupplier(ParticleEffect.class, ParticleArgumentType.particle());
         this.registerConstantNativeParserSupplier(AngleArgumentType.Angle.class, AngleArgumentType.angle());
-        this.registerConstantNativeParserSupplier(new TypeToken<EnumSet<Direction.Axis>>() {}, SwizzleArgumentType.swizzle());
+        this.registerConstantNativeParserSupplier(new TypeToken<EnumSet<Direction.Axis>>() {
+        }, SwizzleArgumentType.swizzle());
         this.registerConstantNativeParserSupplier(Identifier.class, IdentifierArgumentType.identifier());
-        this.registerConstantNativeParserSupplier(EntityAnchorArgumentType.EntityAnchor.class, EntityAnchorArgumentType.entityAnchor());
+        this.registerConstantNativeParserSupplier(
+                EntityAnchorArgumentType.EntityAnchor.class,
+                EntityAnchorArgumentType.entityAnchor()
+        );
         this.registerConstantNativeParserSupplier(NumberRange.IntRange.class, NumberRangeArgumentType.numberRange());
         this.registerConstantNativeParserSupplier(NumberRange.FloatRange.class, NumberRangeArgumentType.method_30918());
         // todo: can we add a compound argument -- MC `ItemStackArgument` is just type and tag, and count is separate
@@ -207,7 +213,10 @@ public abstract class FabricCommandManager<C, S extends CommandSource> extends C
         this.registerConstantNativeParserSupplier(Team.class, TeamArgumentType.team());
         this.registerConstantNativeParserSupplier(/* slot *, ItemSlotArgumentType.itemSlot());
         this.registerConstantNativeParserSupplier(CommandFunction.class, FunctionArgumentType.function()); */
-        this.getParserRegistry().registerParserSupplier(TypeToken.get(MinecraftTime.class), params -> FabricArgumentParsers.time());
+        this.getParserRegistry().registerParserSupplier(
+                TypeToken.get(MinecraftTime.class),
+                params -> FabricArgumentParsers.time()
+        );
 
         /* Wrapped brigadier requiring parameters */
         // score holder: single vs multiple
@@ -310,7 +319,7 @@ public abstract class FabricCommandManager<C, S extends CommandSource> extends C
      * @param <T>      value type
      * @since 1.5.0
      */
-    final <T> void registerConstantNativeParserSupplier(final Class<T> type, final ArgumentType<T> argument) {
+    final <T> void registerConstantNativeParserSupplier(final @NonNull Class<T> type, final @NonNull ArgumentType<T> argument) {
         this.registerConstantNativeParserSupplier(TypeToken.get(type), argument);
     }
 
@@ -322,7 +331,10 @@ public abstract class FabricCommandManager<C, S extends CommandSource> extends C
      * @param <T>      value type
      * @since 1.5.0
      */
-    final <T> void registerConstantNativeParserSupplier(final TypeToken<T> type, final ArgumentType<T> argument) {
+    final <T> void registerConstantNativeParserSupplier(
+            final @NonNull TypeToken<T> type,
+            final @NonNull ArgumentType<T> argument
+    ) {
         this.getParserRegistry().registerParserSupplier(type, params -> new WrappedBrigadierParser<>(argument));
     }
 
diff --git a/cloud-minecraft/cloud-fabric/src/main/java/cloud/commandframework/fabric/FabricServerCommandManager.java b/cloud-minecraft/cloud-fabric/src/main/java/cloud/commandframework/fabric/FabricServerCommandManager.java
index faf458e5..8dfaa0b1 100644
--- a/cloud-minecraft/cloud-fabric/src/main/java/cloud/commandframework/fabric/FabricServerCommandManager.java
+++ b/cloud-minecraft/cloud-fabric/src/main/java/cloud/commandframework/fabric/FabricServerCommandManager.java
@@ -79,8 +79,9 @@ public final class FabricServerCommandManager<C> extends FabricCommandManager<C,
      * @see #FabricServerCommandManager(Function, Function, Function) for a more thorough explanation
      * @since 1.5.0
      */
-    public static FabricServerCommandManager<ServerCommandSource> createNative(
-            final Function<CommandTree<ServerCommandSource>, CommandExecutionCoordinator<ServerCommandSource>> execCoordinator
+    public static @NonNull FabricServerCommandManager<@NonNull ServerCommandSource> createNative(
+            final @NonNull Function<@NonNull CommandTree<@NonNull ServerCommandSource>,
+                    @NonNull CommandExecutionCoordinator<@NonNull ServerCommandSource>> execCoordinator
     ) {
         return new FabricServerCommandManager<>(execCoordinator, Function.identity(), Function.identity());
     }
@@ -101,9 +102,10 @@ public final class FabricServerCommandManager<C> extends FabricCommandManager<C,
      * @since 1.5.0
      */
     public FabricServerCommandManager(
-            final @NonNull Function<@NonNull CommandTree<C>, @NonNull CommandExecutionCoordinator<C>> commandExecutionCoordinator,
-            final Function<ServerCommandSource, C> commandSourceMapper,
-            final Function<C, ServerCommandSource> backwardsCommandSourceMapper
+            final @NonNull Function<@NonNull CommandTree<@NonNull C>,
+                    @NonNull CommandExecutionCoordinator<@NonNull C>> commandExecutionCoordinator,
+            final @NonNull Function<@NonNull ServerCommandSource, @NonNull C> commandSourceMapper,
+            final @NonNull Function<@NonNull C, @NonNull ServerCommandSource> backwardsCommandSourceMapper
     ) {
         super(
                 commandExecutionCoordinator,
@@ -159,7 +161,7 @@ public final class FabricServerCommandManager<C> extends FabricCommandManager<C,
      * @since 1.5.0
      */
     @Override
-    public boolean hasPermission(@NonNull final C sender, @NonNull final String permission) {
+    public boolean hasPermission(final @NonNull C sender, final @NonNull String permission) {
         final ServerCommandSource source = this.getBackwardsCommandSourceMapper().apply(sender);
         return Permissions.check(source, permission, source.getMinecraftServer().getOpPermissionLevel());
     }
diff --git a/cloud-minecraft/cloud-fabric/src/main/java/cloud/commandframework/fabric/argument/FabricArgumentParsers.java b/cloud-minecraft/cloud-fabric/src/main/java/cloud/commandframework/fabric/argument/FabricArgumentParsers.java
index a54acbdf..1c47f1c5 100644
--- a/cloud-minecraft/cloud-fabric/src/main/java/cloud/commandframework/fabric/argument/FabricArgumentParsers.java
+++ b/cloud-minecraft/cloud-fabric/src/main/java/cloud/commandframework/fabric/argument/FabricArgumentParsers.java
@@ -69,7 +69,7 @@ public final class FabricArgumentParsers {
      * @return a parser instance
      * @since 1.5.0
      */
-    public static <C> ArgumentParser<C, MinecraftTime> time() {
+    public static <C> @NonNull ArgumentParser<C, MinecraftTime> time() {
         return new WrappedBrigadierParser<C, Integer>(TimeArgumentType.time())
                 .map((ctx, val) -> ArgumentParseResult.success(MinecraftTime.of(val)));
     }
@@ -81,7 +81,7 @@ public final class FabricArgumentParsers {
      * @return a parser instance
      * @since 1.5.0
      */
-    public static <C> ArgumentParser<C, SinglePlayerSelector> singlePlayerSelector() {
+    public static <C> @NonNull ArgumentParser<C, SinglePlayerSelector> singlePlayerSelector() {
         return new WrappedBrigadierParser<C, EntitySelector>(EntityArgumentType.player())
                 .map((ctx, entitySelector) -> {
                     final CommandSource either = ctx.get(FabricCommandContextKeys.NATIVE_COMMAND_SOURCE);
@@ -107,7 +107,7 @@ public final class FabricArgumentParsers {
      * @return a parser instance
      * @since 1.5.0
      */
-    public static <C> ArgumentParser<C, MultiplePlayerSelector> multiplePlayerSelector() {
+    public static <C> @NonNull ArgumentParser<C, MultiplePlayerSelector> multiplePlayerSelector() {
         return new WrappedBrigadierParser<C, EntitySelector>(EntityArgumentType.players())
                 .map((ctx, entitySelector) -> {
                     final CommandSource either = ctx.get(FabricCommandContextKeys.NATIVE_COMMAND_SOURCE);
@@ -133,7 +133,7 @@ public final class FabricArgumentParsers {
      * @return a parser instance
      * @since 1.5.0
      */
-    public static <C> ArgumentParser<C, SingleEntitySelector> singleEntitySelector() {
+    public static <C> @NonNull ArgumentParser<C, SingleEntitySelector> singleEntitySelector() {
         return new WrappedBrigadierParser<C, EntitySelector>(EntityArgumentType.entity())
                 .map((ctx, entitySelector) -> {
                     final CommandSource either = ctx.get(FabricCommandContextKeys.NATIVE_COMMAND_SOURCE);
@@ -159,7 +159,7 @@ public final class FabricArgumentParsers {
      * @return a parser instance
      * @since 1.5.0
      */
-    public static <C> ArgumentParser<C, MultipleEntitySelector> multipleEntitySelector() {
+    public static <C> @NonNull ArgumentParser<C, MultipleEntitySelector> multipleEntitySelector() {
         return new WrappedBrigadierParser<C, EntitySelector>(EntityArgumentType.entities())
                 .map((ctx, entitySelector) -> {
                     final CommandSource either = ctx.get(FabricCommandContextKeys.NATIVE_COMMAND_SOURCE);
@@ -185,7 +185,7 @@ public final class FabricArgumentParsers {
      * @return a parser instance
      * @since 1.5.0
      */
-    public static <C> ArgumentParser<C, Message> message() {
+    public static <C> @NonNull ArgumentParser<C, Message> message() {
         return new WrappedBrigadierParser<C, MessageArgumentType.MessageFormat>(MessageArgumentType.message())
                 .map((ctx, format) -> {
                     final CommandSource either = ctx.get(FabricCommandContextKeys.NATIVE_COMMAND_SOURCE);
@@ -213,8 +213,8 @@ public final class FabricArgumentParsers {
         private final Text contents;
 
         static MessageImpl from(
-                final ServerCommandSource source,
-                final MessageArgumentType.MessageFormat message,
+                final @NonNull ServerCommandSource source,
+                final MessageArgumentType.@NonNull MessageFormat message,
                 final boolean useSelectors
         ) throws CommandSyntaxException {
             final Text contents = message.format(source,  useSelectors);
diff --git a/cloud-minecraft/cloud-fabric/src/main/java/cloud/commandframework/fabric/argument/IntRangeArgument.java b/cloud-minecraft/cloud-fabric/src/main/java/cloud/commandframework/fabric/argument/IntRangeArgument.java
index 555a5136..d8f5577f 100644
--- a/cloud-minecraft/cloud-fabric/src/main/java/cloud/commandframework/fabric/argument/IntRangeArgument.java
+++ b/cloud-minecraft/cloud-fabric/src/main/java/cloud/commandframework/fabric/argument/IntRangeArgument.java
@@ -107,7 +107,7 @@ public final class IntRangeArgument<C> extends CommandArgument<C, NumberRange.In
      */
     public static <C> @NonNull IntRangeArgument<C> optional(
             final @NonNull String name,
-            final NumberRange.IntRange defaultValue
+            final NumberRange.@NonNull IntRange defaultValue
     ) {
         final StringBuilder value = new StringBuilder(6);
         if (defaultValue.getMin() != null) {
diff --git a/cloud-minecraft/cloud-fabric/src/main/java/cloud/commandframework/fabric/argument/ScoreboardCriterionArgument.java b/cloud-minecraft/cloud-fabric/src/main/java/cloud/commandframework/fabric/argument/ScoreboardCriterionArgument.java
index 881dabd1..b58f7d3d 100644
--- a/cloud-minecraft/cloud-fabric/src/main/java/cloud/commandframework/fabric/argument/ScoreboardCriterionArgument.java
+++ b/cloud-minecraft/cloud-fabric/src/main/java/cloud/commandframework/fabric/argument/ScoreboardCriterionArgument.java
@@ -106,7 +106,7 @@ public final class ScoreboardCriterionArgument<C> extends CommandArgument<C, Sco
      */
     public static <C> @NonNull ScoreboardCriterionArgument<C> optional(
             final @NonNull String name,
-            final ScoreboardCriterion defaultCriterion
+            final @NonNull ScoreboardCriterion defaultCriterion
     ) {
         return ScoreboardCriterionArgument.<C>newBuilder(name).asOptionalWithDefault(defaultCriterion.getName()).build();
     }
diff --git a/cloud-minecraft/cloud-fabric/src/main/java/cloud/commandframework/fabric/argument/SidedArgumentParser.java b/cloud-minecraft/cloud-fabric/src/main/java/cloud/commandframework/fabric/argument/SidedArgumentParser.java
index a7a63c73..e73a64f4 100644
--- a/cloud-minecraft/cloud-fabric/src/main/java/cloud/commandframework/fabric/argument/SidedArgumentParser.java
+++ b/cloud-minecraft/cloud-fabric/src/main/java/cloud/commandframework/fabric/argument/SidedArgumentParser.java
@@ -65,7 +65,7 @@ abstract class SidedArgumentParser<C, I, R> implements ArgumentParser<C, R> {
         });
     }
 
-    protected abstract ArgumentParseResult<I> parseIntermediate(
+    protected abstract @NonNull ArgumentParseResult<@NonNull I> parseIntermediate(
             @NonNull CommandContext<@NonNull C> commandContext,
             @NonNull Queue<@NonNull String> inputQueue
     );
@@ -79,7 +79,11 @@ abstract class SidedArgumentParser<C, I, R> implements ArgumentParser<C, R> {
      * @return a resolved value
      * @since 1.5.0
      */
-    protected abstract ArgumentParseResult<R> resolveClient(CommandContext<C> context, CommandSource source, I value);
+    protected abstract @NonNull ArgumentParseResult<@NonNull R> resolveClient(
+            @NonNull CommandContext<@NonNull C> context,
+            @NonNull CommandSource source,
+            @NonNull I value
+    );
 
     /**
      * Resolve the final value for this argument when running on the server.
@@ -90,6 +94,10 @@ abstract class SidedArgumentParser<C, I, R> implements ArgumentParser<C, R> {
      * @return a resolved value
      * @since 1.5.0
      */
-    protected abstract ArgumentParseResult<R> resolveServer(CommandContext<C> context, CommandSource source, I value);
+    protected abstract @NonNull ArgumentParseResult<@NonNull R> resolveServer(
+            @NonNull CommandContext<@NonNull C> context,
+            @NonNull CommandSource source,
+            @NonNull I value
+    );
 
 }
diff --git a/cloud-minecraft/cloud-fabric/src/main/java/cloud/commandframework/fabric/argument/TeamArgument.java b/cloud-minecraft/cloud-fabric/src/main/java/cloud/commandframework/fabric/argument/TeamArgument.java
index ceebb758..6bd85035 100644
--- a/cloud-minecraft/cloud-fabric/src/main/java/cloud/commandframework/fabric/argument/TeamArgument.java
+++ b/cloud-minecraft/cloud-fabric/src/main/java/cloud/commandframework/fabric/argument/TeamArgument.java
@@ -138,7 +138,7 @@ public final class TeamArgument<C> extends CommandArgument<C, Team> {
         }
 
         @Override
-        protected ArgumentParseResult<String> parseIntermediate(
+        protected @NonNull ArgumentParseResult<String> parseIntermediate(
                 @NonNull final CommandContext<@NonNull C> commandContext,
                 @NonNull final Queue<@NonNull String> inputQueue
         ) {
@@ -150,7 +150,7 @@ public final class TeamArgument<C> extends CommandArgument<C, Team> {
         }
 
         @Override
-        protected ArgumentParseResult<Team> resolveClient(
+        protected @NonNull ArgumentParseResult<Team> resolveClient(
                 final @NonNull CommandContext<C> context,
                 final @NonNull CommandSource source,
                 final @NonNull String value
@@ -163,7 +163,7 @@ public final class TeamArgument<C> extends CommandArgument<C, Team> {
         }
 
         @Override
-        protected ArgumentParseResult<Team> resolveServer(
+        protected @NonNull ArgumentParseResult<Team> resolveServer(
                 final @NonNull CommandContext<C> context,
                 final @NonNull CommandSource source,
                 final @NonNull String value
diff --git a/cloud-minecraft/cloud-fabric/src/main/java/cloud/commandframework/fabric/argument/TimeArgument.java b/cloud-minecraft/cloud-fabric/src/main/java/cloud/commandframework/fabric/argument/TimeArgument.java
index 69529d6e..60af1b46 100644
--- a/cloud-minecraft/cloud-fabric/src/main/java/cloud/commandframework/fabric/argument/TimeArgument.java
+++ b/cloud-minecraft/cloud-fabric/src/main/java/cloud/commandframework/fabric/argument/TimeArgument.java
@@ -104,7 +104,7 @@ public final class TimeArgument<C> extends CommandArgument<C, MinecraftTime> {
      */
     public static <C> @NonNull TimeArgument<C> optional(
             final @NonNull String name,
-            final MinecraftTime defaultTime
+            final @NonNull MinecraftTime defaultTime
     ) {
         return TimeArgument.<C>newBuilder(name).asOptionalWithDefault(defaultTime.toString()).build();
     }
diff --git a/cloud-minecraft/cloud-fabric/src/main/java/cloud/commandframework/fabric/data/MinecraftTime.java b/cloud-minecraft/cloud-fabric/src/main/java/cloud/commandframework/fabric/data/MinecraftTime.java
index 4e1fb36c..4bdbb894 100644
--- a/cloud-minecraft/cloud-fabric/src/main/java/cloud/commandframework/fabric/data/MinecraftTime.java
+++ b/cloud-minecraft/cloud-fabric/src/main/java/cloud/commandframework/fabric/data/MinecraftTime.java
@@ -24,6 +24,8 @@
 
 package cloud.commandframework.fabric.data;
 
+import org.checkerframework.checker.nullness.qual.NonNull;
+
 import java.time.temporal.TemporalUnit;
 import java.util.Objects;
 import java.util.concurrent.TimeUnit;
@@ -50,7 +52,7 @@ public final class MinecraftTime {
      * @return a time holder
      * @since 1.5.0
      */
-    public static MinecraftTime of(final long ticks) {
+    public static @NonNull MinecraftTime of(final long ticks) {
         return ticks == 0 ? ZERO : new MinecraftTime(ticks);
     }
 
@@ -62,7 +64,7 @@ public final class MinecraftTime {
      * @return a time holder
      * @since 1.5.0
      */
-    public static MinecraftTime of(final long amount, final TemporalUnit unit) {
+    public static @NonNull MinecraftTime of(final long amount, final @NonNull TemporalUnit unit) {
         requireNonNull(unit, "unit");
         return new MinecraftTime(Math.round(amount / 50d * unit.getDuration().toMillis()));
     }
@@ -75,7 +77,7 @@ public final class MinecraftTime {
      * @return a time holder
      * @since 1.5.0
      */
-    public static MinecraftTime of(final long amount, final TimeUnit unit) {
+    public static @NonNull MinecraftTime of(final long amount, final @NonNull TimeUnit unit) {
         requireNonNull(unit, "unit");
         return amount == 0 ? ZERO : new MinecraftTime(TimeUnit.MILLISECONDS.convert(amount, unit) / 50);
     }
@@ -114,7 +116,7 @@ public final class MinecraftTime {
      * @return the target duration, as represented by the provided unit
      * @since 1.5.0
      */
-    public long convertTo(final TemporalUnit unit) {
+    public long convertTo(final @NonNull TemporalUnit unit) {
         return this.ticks * 50 / unit.getDuration().toMillis();
     }
 
@@ -125,7 +127,7 @@ public final class MinecraftTime {
      * @return the target duration, as represented by the provided unit
      * @since 1.5.0
      */
-    public long convertTo(final TimeUnit unit) {
+    public long convertTo(final @NonNull TimeUnit unit) {
         return unit.convert(this.ticks * 50, TimeUnit.MILLISECONDS);
     }
 
diff --git a/cloud-minecraft/cloud-fabric/src/main/java/cloud/commandframework/fabric/data/Selector.java b/cloud-minecraft/cloud-fabric/src/main/java/cloud/commandframework/fabric/data/Selector.java
index 45e295c2..58ba8ec9 100644
--- a/cloud-minecraft/cloud-fabric/src/main/java/cloud/commandframework/fabric/data/Selector.java
+++ b/cloud-minecraft/cloud-fabric/src/main/java/cloud/commandframework/fabric/data/Selector.java
@@ -25,6 +25,7 @@
 package cloud.commandframework.fabric.data;
 
 import net.minecraft.command.EntitySelector;
+import org.checkerframework.checker.nullness.qual.NonNull;
 import org.checkerframework.checker.nullness.qual.Nullable;
 
 import java.util.Collection;
@@ -44,7 +45,7 @@ public interface Selector<V> {
      * @return the input
      * @since 1.5.0
      */
-    String getInput();
+    @NonNull String getInput();
 
     /**
      * If this value came from a parsed selector, this will provide the details of that selector.
@@ -62,7 +63,7 @@ public interface Selector<V> {
      * @return all matched entities
      * @since 1.5.0
      */
-    Collection<V> get();
+    @NonNull Collection<V> get();
 
     /**
      * A specialized selector that can only return one value.
@@ -73,7 +74,7 @@ public interface Selector<V> {
     interface Single<V> extends Selector<V> {
 
         @Override
-        default Collection<V> get() {
+        default @NonNull Collection<V> get() {
             return Collections.singletonList(this.getSingle());
         }
 
@@ -83,7 +84,7 @@ public interface Selector<V> {
          * @return the value
          * @since 1.5.0
          */
-        V getSingle();
+        @NonNull V getSingle();
 
     }