diff --git a/gradle-plugin/src/test/kotlin/io/spine/tools/prototap/gradle/PluginSpec.kt b/gradle-plugin/src/test/kotlin/io/spine/tools/prototap/gradle/PluginSpec.kt
index 6b43228..391ada7 100644
--- a/gradle-plugin/src/test/kotlin/io/spine/tools/prototap/gradle/PluginSpec.kt
+++ b/gradle-plugin/src/test/kotlin/io/spine/tools/prototap/gradle/PluginSpec.kt
@@ -82,6 +82,14 @@ internal class PluginSpec {
         assertDescriptorSetFileExits()
     }
 
+    @Test
+    fun `work as a 'classpath' dependency of 'buildscript'`() {
+        createProject("via-classpath")
+        runBuild()
+        assertJavaCodeGenerated()
+        assertRequestFileExits()
+    }
+
     private fun assertJavaCodeGenerated() {
         val javaDir = resultDir.resolve("java")
         javaDir.countFiles() shouldNotBe 0
diff --git a/gradle-plugin/src/test/resources/via-classpath/build.gradle.kts b/gradle-plugin/src/test/resources/via-classpath/build.gradle.kts
new file mode 100644
index 0000000..e6b9afc
--- /dev/null
+++ b/gradle-plugin/src/test/resources/via-classpath/build.gradle.kts
@@ -0,0 +1,62 @@
+/*
+ * Copyright 2024, TeamDev. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Redistribution and use in source and/or binary forms, with or without
+ * modification, must retain the above copyright notice and the following
+ * disclaimer.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+import com.google.protobuf.gradle.protobuf
+import io.spine.internal.dependency.Protobuf
+import io.spine.internal.dependency.GoogleApis
+import io.spine.internal.gradle.standardToSpineSdk
+
+buildscript {
+    standardSpineSdkRepositories()
+    dependencies {
+        classpath("io.spine.tools:prototap-gradle-plugin:@PROTOTAP_VERSION@")
+    }
+}
+
+plugins {
+    java
+    `java-test-fixtures`
+    id("com.google.protobuf")
+}
+
+apply(plugin = "@PROTOTAP_PLUGIN_ID@")
+
+repositories {
+    mavenLocal()
+    standardToSpineSdk()
+}
+
+protobuf {
+    protoc {
+        artifact = io.spine.internal.dependency.Protobuf.compiler
+    }
+}
+
+dependencies {
+    testFixturesImplementation(Protobuf.javaLib)
+    // For `google/type/` proto types used in stub domains.
+    testFixturesImplementation(GoogleApis.commonProtos)
+}
diff --git a/gradle-plugin/src/test/resources/via-classpath/settings.gradle.kts b/gradle-plugin/src/test/resources/via-classpath/settings.gradle.kts
new file mode 100644
index 0000000..4aadfdd
--- /dev/null
+++ b/gradle-plugin/src/test/resources/via-classpath/settings.gradle.kts
@@ -0,0 +1,31 @@
+/*
+ * Copyright 2024, TeamDev. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Redistribution and use in source and/or binary forms, with or without
+ * modification, must retain the above copyright notice and the following
+ * disclaimer.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+pluginManagement {
+    repositories {
+        mavenLocal()
+    }
+}
diff --git a/gradle-plugin/src/test/resources/via-classpath/src/testFixtures/proto/given/domain/gas_transportation.proto b/gradle-plugin/src/test/resources/via-classpath/src/testFixtures/proto/given/domain/gas_transportation.proto
new file mode 100644
index 0000000..a796651
--- /dev/null
+++ b/gradle-plugin/src/test/resources/via-classpath/src/testFixtures/proto/given/domain/gas_transportation.proto
@@ -0,0 +1,65 @@
+/*
+* Copyright 2024, TeamDev. All rights reserved.
+*
+* Redistribution and use in source and/or binary forms, with or without
+* modification, must retain the above copyright notice and the following
+* disclaimer.
+*
+* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+syntax = "proto3";
+
+package given.domain;
+
+//
+// This is a "vanilla" Protobuf file, which does not use Spine-specific features like
+// custom options such as `type_url_prefix` or validation constraints.
+// We also use "pure" Protobuf Java `protoc` plugin to process these files so that
+// we recreate conditions we have before ProtoData gets into play after `protoc`
+// finishes its work.
+//
+
+option java_package = "io.spine.given.domain.gas";
+option java_outer_classname = "GasTransportationProto";
+option java_multiple_files = true;
+
+import "google/type/latlng.proto";
+
+message OilAndGasWell {
+    google.type.LatLng location = 1;
+}
+
+message Pipe {
+    google.type.LatLng from = 1;
+    google.type.LatLng to = 2;
+}
+
+message GasProcessingPlant {
+    string name = 1;
+    google.type.LatLng location = 2;
+    repeated Pipe inbound = 3;
+    repeated Pipe outbound = 4;
+}
+
+message CompressorStation {
+    google.type.LatLng location = 1;
+    repeated Pipe inbound = 2;
+    repeated Pipe outbound = 3;
+}
+
+message LngStorage {
+    string name = 1;
+    google.type.LatLng location = 2;
+    Pipe inbound = 3;
+    Pipe outbound = 4;
+}
diff --git a/gradle-plugin/src/test/resources/via-classpath/src/testFixtures/proto/given/domain/oil_refinery.proto b/gradle-plugin/src/test/resources/via-classpath/src/testFixtures/proto/given/domain/oil_refinery.proto
new file mode 100644
index 0000000..c85fa31
--- /dev/null
+++ b/gradle-plugin/src/test/resources/via-classpath/src/testFixtures/proto/given/domain/oil_refinery.proto
@@ -0,0 +1,56 @@
+/*
+* Copyright 2024, TeamDev. All rights reserved.
+*
+* Redistribution and use in source and/or binary forms, with or without
+* modification, must retain the above copyright notice and the following
+* disclaimer.
+*
+* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+syntax = "proto3";
+
+package given.domain;
+
+//
+// This is a "vanilla" Protobuf file, which does not use Spine-specific features like
+// custom options such as `type_url_prefix` or validation constraints.
+// We also use "pure" Protobuf Java `protoc` plugin to process these files so that
+// we recreate conditions we have before ProtoData gets into play after `protoc`
+// finishes its work.
+//
+
+option java_package = "io.spine.given.domain.oil";
+option java_outer_classname = "OilRefineryProto";
+option java_multiple_files = true;
+
+enum ProductType {
+    PT_UNKNOWN = 0;
+    PETROL = 1;
+    KEROSENE = 2;
+    DIESEL = 3;
+    FUEL_OIL = 4;
+    LUBRICATING_OIL = 5;
+    PARAFFIN_WAX = 6;
+    ASPHALT_BASE = 7;
+}
+
+message Product {
+    ProductType type = 1;
+    float volume = 2;
+}
+
+message Refinery {
+    string name = 1;
+    float input = 2;
+    repeated Product output = 3;
+}