diff --git a/kobby-generator-kotlin/src/test/kotlin/io/github/ermadmi78/kobby/generator/kotlin/SchemaValidationTest.kt b/kobby-generator-kotlin/src/test/kotlin/io/github/ermadmi78/kobby/generator/kotlin/SchemaValidationTest.kt
index 891b3921..28b0dc6d 100644
--- a/kobby-generator-kotlin/src/test/kotlin/io/github/ermadmi78/kobby/generator/kotlin/SchemaValidationTest.kt
+++ b/kobby-generator-kotlin/src/test/kotlin/io/github/ermadmi78/kobby/generator/kotlin/SchemaValidationTest.kt
@@ -9,6 +9,7 @@ import io.github.ermadmi78.kobby.model.parseSchema
 import org.junit.jupiter.api.Test
 import java.io.InputStreamReader
 import kotlin.test.assertEquals
+import kotlin.test.assertTrue
 import kotlin.test.fail
 
 /**
@@ -19,7 +20,7 @@ import kotlin.test.fail
 class SchemaValidationTest {
     private val layout = KotlinLayout(
         KotlinTypes.PREDEFINED_SCALARS + mapOf(
-            "DateTime" to KotlinType("java.time", "OffsetDateTime"),
+            "Date" to KotlinType("java.time", "LocalDate"),
             "JSON" to MAP.parameterize(STRING, ANY.nullable())
         ),
         KotlinContextLayout(
@@ -100,6 +101,11 @@ class SchemaValidationTest {
             emptyMap(),
             InputStreamReader(this.javaClass.getResourceAsStream("kobby.graphqls")!!)
         )
+
+        schema.validate().forEach {
+            println(it)
+        }
+
         val files = generateKotlin(schema, layout)
 
         files.forEach {
@@ -116,6 +122,8 @@ class SchemaValidationTest {
             InputStreamReader(this.javaClass.getResourceAsStream("unknown_scalar.graphqls.txt")!!)
         )
 
+        assertTrue(schema.validate().isEmpty())
+
         val expected = "Kotlin data type for scalar 'DummyScalar' not found. " +
                 "Please, configure it by means of 'kobby' extension. https://github.com/ermadmi78/kobby"
         try {
@@ -133,6 +141,8 @@ class SchemaValidationTest {
             InputStreamReader(this.javaClass.getResourceAsStream("unknown_type.graphqls.txt")!!)
         )
 
+        assertTrue(schema.validate().isEmpty())
+
         val expected = "Unknown type \"DummyType\""
         try {
             generateKotlin(schema, layout)
@@ -149,6 +159,8 @@ class SchemaValidationTest {
             InputStreamReader(this.javaClass.getResourceAsStream("unknown_arg_type.graphqls.txt")!!)
         )
 
+        assertTrue(schema.validate().isEmpty())
+
         val expected = "Unknown type \"DummyArg\""
         try {
             generateKotlin(schema, layout)
@@ -165,6 +177,8 @@ class SchemaValidationTest {
             InputStreamReader(this.javaClass.getResourceAsStream("unknown_parent.graphqls.txt")!!)
         )
 
+        assertTrue(schema.validate().isEmpty())
+
         val expected = "Unknown type \"DummyParent\""
         try {
             generateKotlin(schema, layout)
@@ -173,4 +187,20 @@ class SchemaValidationTest {
             assertEquals(expected, e.message)
         }
     }
+
+    @Test
+    fun testUnknownParentWithDefault() {
+        val schema = parseSchema(
+            emptyMap(),
+            InputStreamReader(this.javaClass.getResourceAsStream("unknown_parent_with_default.graphqls.txt")!!)
+        )
+
+        val expected = "Unknown type \"DummyParentWithDefault\""
+        try {
+            schema.validate()
+            fail("Must throw: $expected")
+        } catch (e: KobbyInvalidSchemaException) {
+            assertEquals(expected, e.message)
+        }
+    }
 }
\ No newline at end of file
diff --git a/kobby-generator-kotlin/src/test/resources/io/github/ermadmi78/kobby/generator/kotlin/unknown_parent_with_default.graphqls.txt b/kobby-generator-kotlin/src/test/resources/io/github/ermadmi78/kobby/generator/kotlin/unknown_parent_with_default.graphqls.txt
new file mode 100644
index 00000000..1045f644
--- /dev/null
+++ b/kobby-generator-kotlin/src/test/resources/io/github/ermadmi78/kobby/generator/kotlin/unknown_parent_with_default.graphqls.txt
@@ -0,0 +1,9 @@
+directive @default on FIELD_DEFINITION
+
+type Query {
+    temp: Film
+}
+
+type Film implements DummyParentWithDefault {
+    title: String! @default
+}
\ No newline at end of file
diff --git a/kobby-gradle-plugin/src/main/kotlin/io/github/ermadmi78/kobby/task/KobbyKotlin.kt b/kobby-gradle-plugin/src/main/kotlin/io/github/ermadmi78/kobby/task/KobbyKotlin.kt
index f1acdf19..1ca472fa 100644
--- a/kobby-gradle-plugin/src/main/kotlin/io/github/ermadmi78/kobby/task/KobbyKotlin.kt
+++ b/kobby-gradle-plugin/src/main/kotlin/io/github/ermadmi78/kobby/task/KobbyKotlin.kt
@@ -924,6 +924,14 @@ open class KobbyKotlin : DefaultTask() {
             "Schema parsing failed.".throwIt(e)
         }
 
+        try {
+            schema.validate().forEach { warning ->
+                logger.warn(warning)
+            }
+        } catch (e: Exception) {
+            "Schema validation failed.".throwIt(e)
+        }
+
         val output = try {
             generateKotlin(schema, layout)
         } catch (e: Exception) {
diff --git a/kobby-maven-plugin/src/main/kotlin/io/github/ermadmi78/kobby/GenerateKotlinMojo.kt b/kobby-maven-plugin/src/main/kotlin/io/github/ermadmi78/kobby/GenerateKotlinMojo.kt
index 86752750..dc23928a 100644
--- a/kobby-maven-plugin/src/main/kotlin/io/github/ermadmi78/kobby/GenerateKotlinMojo.kt
+++ b/kobby-maven-plugin/src/main/kotlin/io/github/ermadmi78/kobby/GenerateKotlinMojo.kt
@@ -290,6 +290,14 @@ class GenerateKotlinMojo : AbstractMojo() {
             "Schema parsing failed.".throwIt(e)
         }
 
+        try {
+            schema.validate().forEach { warning ->
+                log.warn(warning)
+            }
+        } catch (e: Exception) {
+            "Schema validation failed.".throwIt(e)
+        }
+
         val output = try {
             generateKotlin(schema, layout)
         } catch (e: Exception) {
diff --git a/kobby-model/build.gradle.kts b/kobby-model/build.gradle.kts
index 54eca996..a23f660e 100644
--- a/kobby-model/build.gradle.kts
+++ b/kobby-model/build.gradle.kts
@@ -34,4 +34,8 @@ tasks {
         minimize()
         configurations = listOf(shadowImplementation)
     }
+
+    test {
+        dependsOn(":resolveIntegrationTestDependencies")
+    }
 }
diff --git a/kobby-model/src/main/kotlin/io/github/ermadmi78/kobby/model/KobbyField.kt b/kobby-model/src/main/kotlin/io/github/ermadmi78/kobby/model/KobbyField.kt
index 734544cc..a0e511f9 100644
--- a/kobby-model/src/main/kotlin/io/github/ermadmi78/kobby/model/KobbyField.kt
+++ b/kobby-model/src/main/kotlin/io/github/ermadmi78/kobby/model/KobbyField.kt
@@ -62,6 +62,85 @@ class KobbyField internal constructor(
         node.isOperation || (overriddenField?.isResolve ?: (resolve || arguments.isNotEmpty()))
     }
 
+    internal fun validate(warnings: MutableList<String>) {
+        if (!primaryKey && !required && !default && !selection && !resolve) {
+            return
+        }
+        val topOverriddenField = findTopOverriddenField(node)
+
+        var counter = 0
+        if (primaryKey) {
+            counter++
+            warnings.addPropertyWarning(KobbyDirective.PRIMARY_KEY)
+            topOverriddenField?.takeIf { !it.primaryKey }?.also {
+                warnings.addOverriddenWarning(KobbyDirective.PRIMARY_KEY, it)
+            }
+        }
+
+        if (required) {
+            counter++
+            warnings.addPropertyWarning(KobbyDirective.REQUIRED)
+            topOverriddenField?.takeIf { !it.required }?.also {
+                warnings.addOverriddenWarning(KobbyDirective.REQUIRED, it)
+            }
+        }
+
+        if (default) {
+            counter++
+            warnings.addPropertyWarning(KobbyDirective.DEFAULT)
+            topOverriddenField?.takeIf { !it.default }?.also {
+                warnings.addOverriddenWarning(KobbyDirective.DEFAULT, it)
+            }
+        }
+
+        if (counter > 1) {
+            warnings += "Restriction violated [${node.name}.$name]: " +
+                    "The field is marked with several directives at once - " +
+                    "@${KobbyDirective.DEFAULT}, @${KobbyDirective.REQUIRED}, @${KobbyDirective.PRIMARY_KEY}, " +
+                    "the behavior of the Kobby Plugin is undefined!"
+        }
+
+        if (selection) {
+            if (!arguments.values.any { it.isInitialized }) {
+                warnings += "Restriction violated [${node.name}.$name]: " +
+                        "The @${KobbyDirective.SELECTION} directive can only be applied to a field that " +
+                        "contains optional arguments - nullable arguments or arguments with default value."
+            }
+            topOverriddenField?.takeIf { !it.selection }?.also {
+                warnings.addOverriddenWarning(KobbyDirective.SELECTION, it)
+            }
+        }
+
+        if (resolve && !node.isOperation) {
+            topOverriddenField?.takeIf { !it.resolve }?.also {
+                warnings.addOverriddenWarning(KobbyDirective.RESOLVE, it)
+            }
+        }
+    }
+
+    private fun findTopOverriddenField(startNode: KobbyNode): KobbyField? =
+        overriddenField?.takeIf { it.node != startNode }?.let {
+            it.findTopOverriddenField(startNode) ?: it
+        }
+
+    private fun MutableList<String>.addPropertyWarning(directive: String) {
+        if (arguments.isNotEmpty()) {
+            this += "Restriction violated [${node.name}.$name]: " +
+                    "The [@$directive] directive can only be applied to a field with no arguments."
+        }
+
+        if (type.node.kind != SCALAR && type.node.kind != ENUM) {
+            this += "Restriction violated [${node.name}.$name]: " +
+                    "The [@$directive] directive can only be applied to a field that returns a scalar or enum type."
+        }
+    }
+
+    private fun MutableList<String>.addOverriddenWarning(directive: String, topField: KobbyField) {
+        this += "Restriction violated [${node.name}.$name]: " +
+                "The [@$directive] directive cannot be applied to overridden fields. " +
+                "Please, apply [@$directive] directive to [${topField.node.name}.${topField.name}] field."
+    }
+
     override fun equals(other: Any?): Boolean {
         if (this === other) {
             return true
diff --git a/kobby-model/src/main/kotlin/io/github/ermadmi78/kobby/model/KobbySchema.kt b/kobby-model/src/main/kotlin/io/github/ermadmi78/kobby/model/KobbySchema.kt
index 83ef3f71..089797a2 100644
--- a/kobby-model/src/main/kotlin/io/github/ermadmi78/kobby/model/KobbySchema.kt
+++ b/kobby-model/src/main/kotlin/io/github/ermadmi78/kobby/model/KobbySchema.kt
@@ -36,6 +36,24 @@ class KobbySchema internal constructor(
     fun unions(action: (KobbyNode) -> Unit) = unions.values.forEach(action)
     fun enums(action: (KobbyNode) -> Unit) = enums.values.forEach(action)
     fun inputs(action: (KobbyNode) -> Unit) = inputs.values.forEach(action)
+
+    fun validate(): List<String> {
+        val warnings = mutableListOf<String>()
+
+        interfaces { node ->
+            node.fields { field ->
+                field.validate(warnings)
+            }
+        }
+
+        objects { node ->
+            node.fields { field ->
+                field.validate(warnings)
+            }
+        }
+
+        return warnings
+    }
 }
 
 fun KobbySchema(block: KobbySchemaScope.() -> Unit): KobbySchema =
diff --git a/kobby-model/src/test/kotlin/io/github/ermadmi78/kobby/model/DirectiveValidationTest.kt b/kobby-model/src/test/kotlin/io/github/ermadmi78/kobby/model/DirectiveValidationTest.kt
new file mode 100644
index 00000000..bca295a3
--- /dev/null
+++ b/kobby-model/src/test/kotlin/io/github/ermadmi78/kobby/model/DirectiveValidationTest.kt
@@ -0,0 +1,70 @@
+package io.github.ermadmi78.kobby.model
+
+import org.junit.jupiter.api.Test
+import java.io.InputStreamReader
+import kotlin.test.assertEquals
+
+/**
+ * Created on 30.08.2021
+ *
+ * @author Dmitry Ermakov (ermadmi78@gmail.com)
+ */
+class DirectiveValidationTest {
+    @Test
+    fun testDirectiveRestrictions() {
+        "default_arguments_and_return_type".shouldViolate(
+            "Restriction violated [Query.first]: The [@primaryKey] directive can only be applied to a field with no arguments.",
+            "Restriction violated [Query.first]: The [@primaryKey] directive can only be applied to a field that returns a scalar or enum type.",
+            "Restriction violated [Query.second]: The [@required] directive can only be applied to a field with no arguments.",
+            "Restriction violated [Query.second]: The [@required] directive can only be applied to a field that returns a scalar or enum type.",
+            "Restriction violated [Query.third]: The [@default] directive can only be applied to a field with no arguments.",
+            "Restriction violated [Query.third]: The [@default] directive can only be applied to a field that returns a scalar or enum type."
+        )
+
+        "default_cannot_override".shouldViolate(
+            "Restriction violated [Country.id]: The [@primaryKey] directive cannot be applied to overridden fields. Please, apply [@primaryKey] directive to [IBase.id] field.",
+            "Restriction violated [Country.name]: The [@required] directive cannot be applied to overridden fields. Please, apply [@required] directive to [IBase.name] field.",
+            "Restriction violated [Country.description]: The [@default] directive cannot be applied to overridden fields. Please, apply [@default] directive to [IBase.description] field."
+        )
+
+        "default_can_override".shouldViolate()
+        "default_override".shouldViolate()
+        "default_enum".shouldViolate()
+
+        "default_mix".shouldViolate(
+            "Restriction violated [Query.first]: The field is marked with several directives at once - @default, @required, @primaryKey, the behavior of the Kobby Plugin is undefined!",
+            "Restriction violated [Query.second]: The field is marked with several directives at once - @default, @required, @primaryKey, the behavior of the Kobby Plugin is undefined!",
+            "Restriction violated [Query.third]: The field is marked with several directives at once - @default, @required, @primaryKey, the behavior of the Kobby Plugin is undefined!",
+            "Restriction violated [Query.fourth]: The field is marked with several directives at once - @default, @required, @primaryKey, the behavior of the Kobby Plugin is undefined!"
+        )
+
+        "selection_no_optional".shouldViolate(
+            "Restriction violated [Query.first]: The @selection directive can only be applied to a field that contains optional arguments - nullable arguments or arguments with default value.",
+            "Restriction violated [Query.second]: The @selection directive can only be applied to a field that contains optional arguments - nullable arguments or arguments with default value.",
+            "Restriction violated [Query.fourth]: The @selection directive can only be applied to a field that contains optional arguments - nullable arguments or arguments with default value."
+        )
+
+        "selection_optional".shouldViolate()
+
+        "selection_cannot_override".shouldViolate(
+            "Restriction violated [Country.base]: The [@selection] directive cannot be applied to overridden fields. Please, apply [@selection] directive to [Base.base] field."
+        )
+        "selection_can_override".shouldViolate()
+        "selection_override".shouldViolate()
+
+        "resolve_cannot_override".shouldViolate(
+            "Restriction violated [Country.base]: The [@resolve] directive cannot be applied to overridden fields. Please, apply [@resolve] directive to [Base.base] field."
+        )
+        "resolve_can_override".shouldViolate()
+        "resolve_override".shouldViolate()
+    }
+
+    private fun String.shouldViolate(vararg warnings: String) {
+        val schema = parseSchema(
+            emptyMap(),
+            InputStreamReader(this@DirectiveValidationTest.javaClass.getResourceAsStream("$this.graphqls.txt")!!)
+        )
+
+        assertEquals(listOf(*warnings), schema.validate())
+    }
+}
\ No newline at end of file
diff --git a/kobby-model/src/test/resources/io/github/ermadmi78/kobby/model/default_arguments_and_return_type.graphqls.txt b/kobby-model/src/test/resources/io/github/ermadmi78/kobby/model/default_arguments_and_return_type.graphqls.txt
new file mode 100644
index 00000000..3e7462ab
--- /dev/null
+++ b/kobby-model/src/test/resources/io/github/ermadmi78/kobby/model/default_arguments_and_return_type.graphqls.txt
@@ -0,0 +1,14 @@
+directive @primaryKey on FIELD_DEFINITION
+directive @required on FIELD_DEFINITION
+directive @default on FIELD_DEFINITION
+
+type Query {
+    first(arg: Int): [Country!]! @primaryKey
+    second(arg: Boolean! = false): Country! @required
+    third(arg: String!): Country @default
+}
+
+type Country {
+    id: ID!
+    name: String!
+}
\ No newline at end of file
diff --git a/kobby-model/src/test/resources/io/github/ermadmi78/kobby/model/default_can_override.graphqls.txt b/kobby-model/src/test/resources/io/github/ermadmi78/kobby/model/default_can_override.graphqls.txt
new file mode 100644
index 00000000..d6e8a386
--- /dev/null
+++ b/kobby-model/src/test/resources/io/github/ermadmi78/kobby/model/default_can_override.graphqls.txt
@@ -0,0 +1,25 @@
+directive @primaryKey on FIELD_DEFINITION
+directive @required on FIELD_DEFINITION
+directive @default on FIELD_DEFINITION
+
+type Query {
+    countries: [Country!]!
+}
+
+interface IBase {
+    id: ID! @primaryKey
+    name: String! @required
+    description: String @default
+}
+
+interface ICountry implements IBase {
+    id: ID!
+    name: String!
+    description: String
+}
+
+type Country implements ICountry & IBase {
+    id: ID! @primaryKey
+    name: String! @required
+    description: String @default
+}
\ No newline at end of file
diff --git a/kobby-model/src/test/resources/io/github/ermadmi78/kobby/model/default_cannot_override.graphqls.txt b/kobby-model/src/test/resources/io/github/ermadmi78/kobby/model/default_cannot_override.graphqls.txt
new file mode 100644
index 00000000..2ca4ccd3
--- /dev/null
+++ b/kobby-model/src/test/resources/io/github/ermadmi78/kobby/model/default_cannot_override.graphqls.txt
@@ -0,0 +1,25 @@
+directive @primaryKey on FIELD_DEFINITION
+directive @required on FIELD_DEFINITION
+directive @default on FIELD_DEFINITION
+
+type Query {
+    countries: [Country!]!
+}
+
+interface IBase {
+    id: ID!
+    name: String!
+    description: String
+}
+
+interface ICountry implements IBase {
+    id: ID!
+    name: String!
+    description: String
+}
+
+type Country implements ICountry & IBase {
+    id: ID! @primaryKey
+    name: String! @required
+    description: String @default
+}
\ No newline at end of file
diff --git a/kobby-model/src/test/resources/io/github/ermadmi78/kobby/model/default_enum.graphqls.txt b/kobby-model/src/test/resources/io/github/ermadmi78/kobby/model/default_enum.graphqls.txt
new file mode 100644
index 00000000..619b4a47
--- /dev/null
+++ b/kobby-model/src/test/resources/io/github/ermadmi78/kobby/model/default_enum.graphqls.txt
@@ -0,0 +1,15 @@
+directive @primaryKey on FIELD_DEFINITION
+directive @required on FIELD_DEFINITION
+directive @default on FIELD_DEFINITION
+
+type Query {
+    first: [MyEnum!]! @primaryKey
+    second: MyEnum! @required
+    third: MyEnum @default
+}
+
+enum MyEnum {
+    FIRST,
+    SECOND,
+    THIRD
+}
\ No newline at end of file
diff --git a/kobby-model/src/test/resources/io/github/ermadmi78/kobby/model/default_mix.graphqls.txt b/kobby-model/src/test/resources/io/github/ermadmi78/kobby/model/default_mix.graphqls.txt
new file mode 100644
index 00000000..1c68c5e0
--- /dev/null
+++ b/kobby-model/src/test/resources/io/github/ermadmi78/kobby/model/default_mix.graphqls.txt
@@ -0,0 +1,16 @@
+directive @primaryKey on FIELD_DEFINITION
+directive @required on FIELD_DEFINITION
+directive @default on FIELD_DEFINITION
+
+type Query {
+    first: Int! @primaryKey @required
+    second: String! @primaryKey @default
+    third: Boolean @required @default
+    fourth: MyEnum! @primaryKey @required @default
+}
+
+enum MyEnum {
+    FIRST,
+    SECOND,
+    THIRD
+}
\ No newline at end of file
diff --git a/kobby-model/src/test/resources/io/github/ermadmi78/kobby/model/default_override.graphqls.txt b/kobby-model/src/test/resources/io/github/ermadmi78/kobby/model/default_override.graphqls.txt
new file mode 100644
index 00000000..39b6dd86
--- /dev/null
+++ b/kobby-model/src/test/resources/io/github/ermadmi78/kobby/model/default_override.graphqls.txt
@@ -0,0 +1,25 @@
+directive @primaryKey on FIELD_DEFINITION
+directive @required on FIELD_DEFINITION
+directive @default on FIELD_DEFINITION
+
+type Query {
+    countries: [Country!]!
+}
+
+interface IBase {
+    id: ID! @primaryKey
+    name: String! @required
+    description: String @default
+}
+
+interface ICountry implements IBase {
+    id: ID!
+    name: String!
+    description: String
+}
+
+type Country implements ICountry & IBase {
+    id: ID!
+    name: String!
+    description: String
+}
\ No newline at end of file
diff --git a/kobby-model/src/test/resources/io/github/ermadmi78/kobby/model/resolve_can_override.graphqls.txt b/kobby-model/src/test/resources/io/github/ermadmi78/kobby/model/resolve_can_override.graphqls.txt
new file mode 100644
index 00000000..cc93662e
--- /dev/null
+++ b/kobby-model/src/test/resources/io/github/ermadmi78/kobby/model/resolve_can_override.graphqls.txt
@@ -0,0 +1,14 @@
+directive @resolve on FIELD_DEFINITION
+
+type Query {
+    countries: [Country!]!
+}
+
+interface Base {
+    base: String @resolve
+}
+
+type Country implements Base{
+    id: ID! @resolve
+    base: String @resolve
+}
\ No newline at end of file
diff --git a/kobby-model/src/test/resources/io/github/ermadmi78/kobby/model/resolve_cannot_override.graphqls.txt b/kobby-model/src/test/resources/io/github/ermadmi78/kobby/model/resolve_cannot_override.graphqls.txt
new file mode 100644
index 00000000..097c9a2a
--- /dev/null
+++ b/kobby-model/src/test/resources/io/github/ermadmi78/kobby/model/resolve_cannot_override.graphqls.txt
@@ -0,0 +1,14 @@
+directive @resolve on FIELD_DEFINITION
+
+type Query {
+    countries: [Country!]!
+}
+
+interface Base {
+    base: String
+}
+
+type Country implements Base{
+    id: ID! @resolve
+    base: String @resolve
+}
\ No newline at end of file
diff --git a/kobby-model/src/test/resources/io/github/ermadmi78/kobby/model/resolve_override.graphqls.txt b/kobby-model/src/test/resources/io/github/ermadmi78/kobby/model/resolve_override.graphqls.txt
new file mode 100644
index 00000000..6901ef0d
--- /dev/null
+++ b/kobby-model/src/test/resources/io/github/ermadmi78/kobby/model/resolve_override.graphqls.txt
@@ -0,0 +1,14 @@
+directive @resolve on FIELD_DEFINITION
+
+type Query {
+    countries: [Country!]!
+}
+
+interface Base {
+    base: String @resolve
+}
+
+type Country implements Base{
+    id: ID! @resolve
+    base: String
+}
\ No newline at end of file
diff --git a/kobby-model/src/test/resources/io/github/ermadmi78/kobby/model/selection_can_override.graphqls.txt b/kobby-model/src/test/resources/io/github/ermadmi78/kobby/model/selection_can_override.graphqls.txt
new file mode 100644
index 00000000..6fa88990
--- /dev/null
+++ b/kobby-model/src/test/resources/io/github/ermadmi78/kobby/model/selection_can_override.graphqls.txt
@@ -0,0 +1,14 @@
+directive @selection on FIELD_DEFINITION
+
+type Query {
+    countries: [Country!]!
+}
+
+interface Base {
+    base(arg0: Int!, arg1: String! = "test"): String @selection
+}
+
+type Country implements Base{
+    id: ID!
+    base(arg0: Int!, arg1: String! = "test"): String @selection
+}
\ No newline at end of file
diff --git a/kobby-model/src/test/resources/io/github/ermadmi78/kobby/model/selection_cannot_override.graphqls.txt b/kobby-model/src/test/resources/io/github/ermadmi78/kobby/model/selection_cannot_override.graphqls.txt
new file mode 100644
index 00000000..00022f10
--- /dev/null
+++ b/kobby-model/src/test/resources/io/github/ermadmi78/kobby/model/selection_cannot_override.graphqls.txt
@@ -0,0 +1,14 @@
+directive @selection on FIELD_DEFINITION
+
+type Query {
+    countries: [Country!]!
+}
+
+interface Base {
+    base(arg0: Int!, arg1: String! = "test"): String
+}
+
+type Country implements Base{
+    id: ID!
+    base(arg0: Int!, arg1: String! = "test"): String @selection
+}
\ No newline at end of file
diff --git a/kobby-model/src/test/resources/io/github/ermadmi78/kobby/model/selection_no_optional.graphqls.txt b/kobby-model/src/test/resources/io/github/ermadmi78/kobby/model/selection_no_optional.graphqls.txt
new file mode 100644
index 00000000..93e847ae
--- /dev/null
+++ b/kobby-model/src/test/resources/io/github/ermadmi78/kobby/model/selection_no_optional.graphqls.txt
@@ -0,0 +1,11 @@
+directive @selection on FIELD_DEFINITION
+
+type Query {
+    first: Int! @selection
+    second(arg0: Int!, arg1: String!): String! @selection
+    fourth(arg0: Int!, arg1: String!): Country! @selection
+}
+
+type Country {
+    id: ID!
+}
\ No newline at end of file
diff --git a/kobby-model/src/test/resources/io/github/ermadmi78/kobby/model/selection_optional.graphqls.txt b/kobby-model/src/test/resources/io/github/ermadmi78/kobby/model/selection_optional.graphqls.txt
new file mode 100644
index 00000000..462d1ca1
--- /dev/null
+++ b/kobby-model/src/test/resources/io/github/ermadmi78/kobby/model/selection_optional.graphqls.txt
@@ -0,0 +1,11 @@
+directive @selection on FIELD_DEFINITION
+
+type Query {
+    first(arg0: ID): Int! @selection
+    second(arg0: Int!, arg1: String): String! @selection
+    fourth(arg0: Int!, arg1: String! = "test"): Country! @selection
+}
+
+type Country {
+    id: ID!
+}
\ No newline at end of file
diff --git a/kobby-model/src/test/resources/io/github/ermadmi78/kobby/model/selection_override.graphqls.txt b/kobby-model/src/test/resources/io/github/ermadmi78/kobby/model/selection_override.graphqls.txt
new file mode 100644
index 00000000..c26e408e
--- /dev/null
+++ b/kobby-model/src/test/resources/io/github/ermadmi78/kobby/model/selection_override.graphqls.txt
@@ -0,0 +1,14 @@
+directive @selection on FIELD_DEFINITION
+
+type Query {
+    countries: [Country!]!
+}
+
+interface Base {
+    base(arg0: Int!, arg1: String! = "test"): String @selection
+}
+
+type Country implements Base{
+    id: ID!
+    base(arg0: Int!, arg1: String! = "test"): String
+}
\ No newline at end of file