diff --git a/springio-platform-plugin/README.asciidoc b/springio-platform-plugin/README.asciidoc
index f95b8e3..94f3e5a 100644
--- a/springio-platform-plugin/README.asciidoc
+++ b/springio-platform-plugin/README.asciidoc
@@ -14,9 +14,8 @@ Provides additional checks to ensure springio platform compatibility
 
 == Quick Start
 
-See http://repo.spring.io/repo/org/springframework/build/gradle/springio-platform-plugin/[repo.spring.io] to determine the
-latest available version. Then configure the plugin in your project as
-follows:
+See http://repo.spring.io/repo/org/springframework/build/gradle/springio-platform-plugin/[repo.spring.io] to determine
+the latest available version. Then configure the plugin in your project as follows:
 
 [source,groovy]
 ----
@@ -41,7 +40,9 @@ configure(allprojects) {
 }
 ----
 
-NOTE: It is unlikely you will want to apply the plugin or snapshot repository to all projects. This is particularly true if you have sample projects within your project. Instead, you should limit the plugin to modules that are part of the Spring IO platform.
+NOTE: It is unlikely you will want to apply the plugin or snapshot repository to all projects. This is particularly
+true if you have sample projects within your project. Instead, you should limit the plugin to modules that are part of
+the Spring IO platform.
 
 Now you can run the following:
 
@@ -52,11 +53,17 @@ $ ./gradlew clean springioCheck -PJDK8_HOME=<jdk8-home> -PJDK7_HOME=<jdk7-home>
 
 This will:
 
-* Assist with running tests against your compiled code using JDK7 and JDK8 and the SpringIO dependency versions. For more information refer to <<additional-tests>>
-* Ensure that all dependency exclusions use both the group and the module. For more information refer to <<incompleteexcludestask>>
-* Verify that certain dependencies are not used and suggest alternatives. For more information refer to <<alternativedependenciestask>>
+* Check that Spring IO contains versions for all direct dependencies, all transitive dependencies, or both. For more
+  information refer to <<spring-io-dependencies>>
+* Assist with running tests against your compiled code using JDK7 and JDK8 and the Spring IO dependency versions. For
+  more information refer to <<additional-tests>>
+* Ensure that all dependency exclusions use both the group and the module. For more information refer to
+  <<incompleteexcludestask>>
+* Verify that certain dependencies are not used and suggest alternatives. For more information refer to
+  <<alternativedependenciestask>>
 
-If you would like springioCheck to be invoked when you run `./gradlew build`, then you can make the check task depend on springioCheck as shown below:
+If you would like springioCheck to be invoked when you run `./gradlew build`, then you can make the check task depend
+on springioCheck as shown below:
 
 [source,groovy]
 ----
@@ -71,23 +78,45 @@ configure(allprojects) {
 
 Typically users will keep the springioCheck task separate so as to only run the springioCheck task on the CI server.
 
+== Spring IO dependencies
+
+The plugin creates a new configuration, `springioTestRuntime`, that contains all of the project's dependencies with
+their versions mapped to those that are in the platform. This configuration is used when running the additional
+tests. By default, if a direct dependency is encountered that is not part of the platform the build will fail. This
+can be configured using the `springIoPlatform` extension. For example:
+
+[source,groovy]
+springioPlatform {
+    failOnUnmappedDirectDependency = true
+    failOnUnmappedTransitiveDependency = true
+}
+
+`failOnUnmappedDirectDependency` controls whether or not the build will fail if a direct dependency is encountered that
+is not part of the Spring IO plaform. The default is `true`. `failOnUnmappedTransitiveDependency` controls whether or
+not the build will fail if a transitive dependency is encountered that is not part of the Spring IO platform. The
+default is `false`.
+
 == Additional Tests
 
-One of the goals of the Spring IO platform is to ensure modules work with JDK7 and JDK8 and that they run with specific versions of dependencies. Applying the plugin will create tests that:
+One of the goals of the Spring IO platform is to ensure modules work with JDK7 and JDK8 and that they run with specific
+versions of dependencies. Applying the plugin will create tests that:
 
-* Nothing changes for how your code is actually compiled or consumed by users (dependency changes and JDK changes only impact the additional tests)
+* Nothing changes for how your code is actually compiled or consumed by users (dependency changes and JDK changes only
+  impact the additional tests)
 * Ensure that the Spring IO versions of dependencies are used at runtime for the additional test tasks
 * Tests are ran against the specified JDKs
 * If JDK7_HOME and JDK8_HOME is omitted, then no additional test tasks will be created 
 
-For example, the following will compile the project with the declared dependency versions and JDK. It will then run all the tests against JDK7 and JDK8 with the Spring IO dependency versions.
+For example, the following will compile the project with the declared dependency versions and JDK. It will then run all
+the tests against JDK7 and JDK8 with the Spring IO dependency versions.
 
 [source,bash]
 ----
 $ ./gradlew springioCheck -PJDK7_HOME=/opt/java/jdk/Sun/7.0 -PJDK8_HOME=/opt/java/jdk/Sun/8.0
 ----
 
-Where `JDK8_HOME` is the absolute path to the JDK8 Home and `JDK7_HOME` is the absolute path to the JDK7 Home. The example above works with the Spring Bamboo environment.
+Where `JDK8_HOME` is the absolute path to the JDK8 Home and `JDK7_HOME` is the absolute path to the JDK7 Home. The
+example above works with the Spring Bamboo environment.
 
 [source,bash]
 ----
@@ -98,7 +127,9 @@ NOTE: You can also place JDK8_HOME and JDK7_HOME in your gradle.properties
 
 == IncompleteExcludesTask
 
-This task ensures that any dependency exclusions that are done use both the group and the module because otherwise the dependency will not be excluded in the generated pom.xml file. For example the following is not allowed because it only excludes the module:
+This task ensures that any dependency exclusions that are done use both the group and the module because otherwise the
+dependency will not be excluded in the generated pom.xml file. For example the following is not allowed because it only
+excludes the module:
 
 [source,groovy]
 ----
@@ -133,4 +164,5 @@ dependencies {
 
 == AlternativeDependenciesTask
 
-This task will ensure certain dependencies are not used and suggest alternatives. For example, intead of using asm:asm it is preferred to use spring-core's repackages asm dependencies.
+This task will ensure certain dependencies are not used and suggest alternatives. For example, intead of using asm:asm
+it is preferred to use spring-core's repackages asm dependencies.
diff --git a/springio-platform-plugin/src/main/groovy/org/springframework/build/gradle/springio/platform/PlatformDependenciesBeforeResolveAction.groovy b/springio-platform-plugin/src/main/groovy/org/springframework/build/gradle/springio/platform/PlatformDependenciesBeforeResolveAction.groovy
index 9ffbecc..a54b40c 100644
--- a/springio-platform-plugin/src/main/groovy/org/springframework/build/gradle/springio/platform/PlatformDependenciesBeforeResolveAction.groovy
+++ b/springio-platform-plugin/src/main/groovy/org/springframework/build/gradle/springio/platform/PlatformDependenciesBeforeResolveAction.groovy
@@ -1,8 +1,10 @@
 package org.springframework.build.gradle.springio.platform;
 
 import org.gradle.api.Action
+import org.gradle.api.InvalidUserDataException
 import org.gradle.api.Project
 import org.gradle.api.artifacts.Configuration
+import org.gradle.api.artifacts.Dependency;
 import org.gradle.api.artifacts.DependencyResolveDetails
 import org.gradle.api.artifacts.ModuleVersionSelector
 import org.gradle.api.artifacts.ResolvableDependencies
@@ -22,10 +24,28 @@ class PlatformDependenciesBeforeResolveAction implements Action<ResolvableDepend
 	public void execute(ResolvableDependencies resolvableDependencies) {
 		def action = project.springioPlatform.dependencyResolutionAction;
 		if (!action) {
-			action = createDefaultActionFromStream(project,getClass().getResourceAsStream('springio-dependencies')) 
+			action = createDefaultActionFromStream(project, configuration, getClass().getResourceAsStream('springio-dependencies'))
 		}
 		
 		configuration.resolutionStrategy.eachDependency action
+
+		configuration.incoming.afterResolve {
+			if (action instanceof MappingDependencyResolveDetailsAction) {
+				String message
+				if (project.springioPlatform.failOnUnmappedDirectDependency && action.unmappedDirectDependencies) {
+					message = "The following direct dependencies do not have Spring IO versions: " + action.unmappedDirectDependencies.collect { "$it.group:$it.name" }.join(", ")
+				}
+
+				if (project.springioPlatform.failOnUnmappedTransitiveDependency && action.unmappedTransitiveDependencies) {
+					message = message ? message + ". " : ""
+					message += "The following transitive dependencies do not have Spring IO versions: " + action.unmappedTransitiveDependencies.collect { "$it.group:$it.name" }.join(", ")
+				}
+
+				if (message) {
+					throw new InvalidUserDataException(message)
+				}
+			}
+		}
 	}
 
 	/**
@@ -34,7 +54,7 @@ class PlatformDependenciesBeforeResolveAction implements Action<ResolvableDepend
 	 *
 	 * @return
 	 */
-	private static MappingDependencyResolveDetailsAction createDefaultActionFromStream(Project project, InputStream stream) {
+	private static MappingDependencyResolveDetailsAction createDefaultActionFromStream(Project project, Configuration configuration, InputStream stream) {
 		Map<String,ModuleVersionSelector> depToSelector = [:]
 		stream.eachLine { line ->
 			if(line && !line.startsWith('#')) {
@@ -44,11 +64,19 @@ class PlatformDependenciesBeforeResolveAction implements Action<ResolvableDepend
 			}
 		}
 		Set<String> ignoredGroupAndNames = project.rootProject.allprojects.collect { "$it.group:$it.name" }
-		new MappingDependencyResolveDetailsAction(depToSelector : depToSelector, ignoredGroupAndNames : ignoredGroupAndNames)
+		new MappingDependencyResolveDetailsAction(depToSelector : depToSelector, ignoredGroupAndNames : ignoredGroupAndNames, configuration : configuration)
 	}
 
 	private static class MappingDependencyResolveDetailsAction implements Action<DependencyResolveDetails> {
+
+		Configuration configuration
+
 		Map<String,ModuleVersionSelector> depToSelector = [:]
+
+		List<ModuleVersionSelector> unmappedDirectDependencies = []
+
+		List<ModuleVersionSelector> unmappedTransitiveDependencies = []
+
 		/**
 		 * In the format of group:name
 		 */
@@ -64,13 +92,27 @@ class PlatformDependenciesBeforeResolveAction implements Action<ResolvableDepend
 			ModuleVersionSelector mapping = getMapping("$requested.group:$requested.name") ?: (getMapping("$requested.group:") ?: getMapping(":$requested.name"))
 
 			if(!mapping) {
-				//logger.debug("Did NOT find mapping for $requested.group:$requested.name")
+				if (isDirectDependency(requested)) {
+					unmappedDirectDependencies << requested
+				} else {
+					unmappedTransitiveDependencies << requested
+				}
+
 				return
 			}
 
 			details.useTarget new DefaultModuleVersionSelector( mapping.group ?: requested.group, mapping.name ?: requested.name, mapping.version ?: requested.version)
 		}
 
+		private boolean isDirectDependency(ModuleVersionSelector selector) {
+			for (Dependency dependency: configuration.allDependencies) {
+				if (dependency.group == selector.group && dependency.name == selector.name) {
+					return true
+				}
+			}
+			return false
+		}
+
 		private ModuleVersionSelector getMapping(String id) {
 			depToSelector[id]
 		}
diff --git a/springio-platform-plugin/src/main/groovy/org/springframework/build/gradle/springio/platform/SpringioPlatformExtension.groovy b/springio-platform-plugin/src/main/groovy/org/springframework/build/gradle/springio/platform/SpringioPlatformExtension.groovy
index 3aec860..ba5033c 100644
--- a/springio-platform-plugin/src/main/groovy/org/springframework/build/gradle/springio/platform/SpringioPlatformExtension.groovy
+++ b/springio-platform-plugin/src/main/groovy/org/springframework/build/gradle/springio/platform/SpringioPlatformExtension.groovy
@@ -16,4 +16,16 @@ class SpringioPlatformExtension {
 	 * @see ResolutionStrategy#eachDependency
 	 */
 	def dependencyResolutionAction
+
+	/**
+	 * Controls whether or not the build will fail when a direct dependency that does not
+	 * have a Spring IO version mapping is encountered. Defaults to {@code true}.
+	 */
+	def failOnUnmappedDirectDependency = true
+
+	/**
+	 * Controls whether or not the build will fail when a transitive dependency that does
+	 * not have a Spring IO version mapping is encountered. Defaults to {@code false}.
+	 */
+	def failOnUnmappedTransitiveDependency = false
 }
diff --git a/springio-platform-plugin/src/test/groovy/org/springframework/build/gradle/springio/platform/PlatformDependenciesBeforeResolveActionTests.groovy b/springio-platform-plugin/src/test/groovy/org/springframework/build/gradle/springio/platform/PlatformDependenciesBeforeResolveActionTests.groovy
index 2833a69..4ccad9f 100644
--- a/springio-platform-plugin/src/test/groovy/org/springframework/build/gradle/springio/platform/PlatformDependenciesBeforeResolveActionTests.groovy
+++ b/springio-platform-plugin/src/test/groovy/org/springframework/build/gradle/springio/platform/PlatformDependenciesBeforeResolveActionTests.groovy
@@ -1,6 +1,7 @@
 package org.springframework.build.gradle.springio.platform
 
 import org.gradle.api.Action
+import org.gradle.api.InvalidUserDataException;
 import org.gradle.api.Project
 import org.gradle.api.artifacts.Configuration
 import org.gradle.api.artifacts.DependencyResolveDetails
@@ -29,7 +30,7 @@ class PlatformDependenciesBeforeResolveActionTests extends Specification {
 		parent.version = 'nochange'
 
 		config = parent.configurations.create('configuration')
-		action = new PlatformDependenciesBeforeResolveAction(project:parent, configuration: config)
+		action = new PlatformDependenciesBeforeResolveAction(project: parent, configuration: config)
 
 		child = ProjectBuilder.builder().withName('child').withParent(parent).build()
 		child.group = parent.group
@@ -65,7 +66,7 @@ class PlatformDependenciesBeforeResolveActionTests extends Specification {
 	def "default dependency resolution action supports group only"() {
 		setup:
 			DependencyResolveDetails details = details('grouponly:notdefined:changeme')
-			configureDefaultDependencyResolutionAction(parent)
+			configureDefaultDependencyResolutionAction(parent, config)
 		when:
 			action.execute(Mock(ResolvableDependencies))
 			config.resolutionStrategy.dependencyResolveRule.execute(details)
@@ -78,7 +79,7 @@ class PlatformDependenciesBeforeResolveActionTests extends Specification {
 	def "default dependency resolution action supports name only"() {
 		setup:
 			DependencyResolveDetails details = details('notdefined:nameonly:changeme')
-			configureDefaultDependencyResolutionAction(parent)
+			configureDefaultDependencyResolutionAction(parent, config)
 		when:
 			action.execute(Mock(ResolvableDependencies))
 			config.resolutionStrategy.dependencyResolveRule.execute(details)
@@ -91,7 +92,7 @@ class PlatformDependenciesBeforeResolveActionTests extends Specification {
 	def "default dependency resolution action supports name and group"() {
 		setup:
 			DependencyResolveDetails details = details('standardgroup:standardname:changeme')
-			configureDefaultDependencyResolutionAction(parent)
+			configureDefaultDependencyResolutionAction(parent, config)
 		when:
 			action.execute(Mock(ResolvableDependencies))
 			config.resolutionStrategy.dependencyResolveRule.execute(details)
@@ -104,7 +105,7 @@ class PlatformDependenciesBeforeResolveActionTests extends Specification {
 	def "default dependency resolution action prioritizes both group and name highest"() {
 		setup:
 			DependencyResolveDetails details = details('prioritygroup:priorityname:changeme')
-			configureDefaultDependencyResolutionAction(parent)
+			configureDefaultDependencyResolutionAction(parent, config)
 		when:
 			action.execute(Mock(ResolvableDependencies))
 			config.resolutionStrategy.dependencyResolveRule.execute(details)
@@ -117,7 +118,7 @@ class PlatformDependenciesBeforeResolveActionTests extends Specification {
 	def "default dependency resolution action prioritizes group only second highest"() {
 		setup:
 			DependencyResolveDetails details = details('priority2group:notfound:changeme')
-			configureDefaultDependencyResolutionAction(parent)
+			configureDefaultDependencyResolutionAction(parent, config)
 		when:
 			action.execute(Mock(ResolvableDependencies))
 			config.resolutionStrategy.dependencyResolveRule.execute(details)
@@ -130,7 +131,7 @@ class PlatformDependenciesBeforeResolveActionTests extends Specification {
 	def "default dependency resolution action prioritizes name only second highest"() {
 		setup:
 			DependencyResolveDetails details = details('notfound:priority3name:changeme')
-			configureDefaultDependencyResolutionAction(parent)
+			configureDefaultDependencyResolutionAction(parent, config)
 		when:
 			action.execute(Mock(ResolvableDependencies))
 			config.resolutionStrategy.dependencyResolveRule.execute(details)
@@ -138,22 +139,64 @@ class PlatformDependenciesBeforeResolveActionTests extends Specification {
 			details.target.version == 'priority3nameversion'
 	}
 	
-	def "default dependency resolution action supports notfound"() {
+	def "default dependency resolution action fails with unmapped direct dependency"() {
+		setup:
+			parent.dependencies {
+				configuration "notfound:notfound:nochange"
+			}
+			configureDefaultDependencyResolutionAction(parent, config)
+		when:
+			action.execute(Mock(ResolvableDependencies))
+			config.resolvedConfiguration
+		then:
+			thrown InvalidUserDataException
+	}
+
+	def "default dependency resolution action succeeds with unmapped transitive dependency"() {
 		setup:
 			DependencyResolveDetails details = details('notfound:notfound:nochange')
-			configureDefaultDependencyResolutionAction(parent)
+			configureDefaultDependencyResolutionAction(parent, config)
 		when:
 			action.execute(Mock(ResolvableDependencies))
 			config.resolutionStrategy.dependencyResolveRule.execute(details)
+		then: 'resolution will succeed'
+			config.resolvedConfiguration
+	}
+
+	def "default dependency resolution action can be configured to fail with unmapped transitive dependency"() {
+		setup:
+			DependencyResolveDetails details = details('notfound:notfound:nochange')
+			configureDefaultDependencyResolutionAction(parent, config)
+			parent.springioPlatform {
+				failOnUnmappedTransitiveDependency = true
+			}
+		when:
+			action.execute(Mock(ResolvableDependencies))
+			config.resolutionStrategy.dependencyResolveRule.execute(details)
+			config.resolvedConfiguration
 		then:
-			details.target.version == 'nochange'
-			details.target.name == 'notfound'
-			details.target.group == 'notfound'
+			thrown InvalidUserDataException
+	}
+
+	def "default dependency resolution action can be configured to succeed with unmapped direct dependency"() {
+		setup:
+			parent.dependencies {
+				configuration "notfound:notfound:nochange"
+			}
+			parent.springioPlatform {
+				failOnUnmappedDirectDependency = false
+			}
+			configureDefaultDependencyResolutionAction(parent, config)
+		when:
+			action.execute(Mock(ResolvableDependencies))
+
+		then: 'resolution will succeeed'
+			config.resolvedConfiguration
 	}
 	
-	void configureDefaultDependencyResolutionAction(Project project) {
+	void configureDefaultDependencyResolutionAction(Project project, Configuration configuration) {
 		project.springioPlatform {
-			dependencyResolutionAction = PlatformDependenciesBeforeResolveAction.createDefaultActionFromStream(parent, getClass().getResourceAsStream('test-springio-dependencies'))
+			dependencyResolutionAction = PlatformDependenciesBeforeResolveAction.createDefaultActionFromStream(parent, configuration, getClass().getResourceAsStream('test-springio-dependencies'))
 		}
 	}