diff --git a/src/resources/init-scripts/build-result-capture-service.plugin.groovy b/src/resources/init-scripts/build-result-capture-service.plugin.groovy
index e8ea40c..8eaf7fa 100644
--- a/src/resources/init-scripts/build-result-capture-service.plugin.groovy
+++ b/src/resources/init-scripts/build-result-capture-service.plugin.groovy
@@ -45,9 +45,15 @@ abstract class BuildResultsRecorder implements BuildService<BuildResultsRecorder
             buildScanFailed: false
         ]
 
-        def buildResultsDir = new File(System.getenv("RUNNER_TEMP"), ".build-results")
+        def runnerTempDir = System.getenv("RUNNER_TEMP")
+        def githubActionStep = System.getenv("GITHUB_ACTION")
+        if (!runnerTempDir || !githubActionStep) {
+            return
+        }
+        
+        def buildResultsDir = new File(runnerTempDir, ".build-results")
         buildResultsDir.mkdirs()
-        def buildResultsFile = new File(buildResultsDir, System.getenv("GITHUB_ACTION") + getParameters().getInvocationId().get() + ".json")
+        def buildResultsFile = new File(buildResultsDir, githubActionStep + getParameters().getInvocationId().get() + ".json")
         buildResultsFile << groovy.json.JsonOutput.toJson(buildResults)
     }
 }
diff --git a/src/resources/init-scripts/build-result-capture.init.gradle b/src/resources/init-scripts/build-result-capture.init.gradle
index c7c9013..fa7c428 100644
--- a/src/resources/init-scripts/build-result-capture.init.gradle
+++ b/src/resources/init-scripts/build-result-capture.init.gradle
@@ -106,9 +106,15 @@ class BuildResults {
     }
 
     def writeToResultsFile(boolean overwrite) {
-        def buildResultsDir = new File(System.getenv("RUNNER_TEMP"), ".build-results")
+        def runnerTempDir = System.getenv("RUNNER_TEMP")
+        def githubActionStep = System.getenv("GITHUB_ACTION")
+        if (!runnerTempDir || !githubActionStep) {
+            return
+        }
+        
+        def buildResultsDir = new File(runnerTempDir, ".build-results")
         buildResultsDir.mkdirs()
-        def buildResultsFile = new File(buildResultsDir, System.getenv("GITHUB_ACTION") + invocationId + ".json")
+        def buildResultsFile = new File(buildResultsDir, githubActionStep + invocationId + ".json")
 
         // Overwrite any contents written by buildFinished or build service, since this result is a superset.
         if (buildResultsFile.exists()) {
diff --git a/test/init-scripts/src/test/groovy/com/gradle/gradlebuildaction/BaseInitScriptTest.groovy b/test/init-scripts/src/test/groovy/com/gradle/gradlebuildaction/BaseInitScriptTest.groovy
index 4f62235..2b8f155 100644
--- a/test/init-scripts/src/test/groovy/com/gradle/gradlebuildaction/BaseInitScriptTest.groovy
+++ b/test/init-scripts/src/test/groovy/com/gradle/gradlebuildaction/BaseInitScriptTest.groovy
@@ -200,20 +200,17 @@ task expectFailure {
         File initScriptsDir = new File(testProjectDir, "initScripts")
         args << '-I' << new File(initScriptsDir, initScript).absolutePath
 
-        envVars['RUNNER_TEMP'] = testProjectDir.absolutePath
-        envVars['GITHUB_ACTION'] = 'github-step-id'
+        envVars.putIfAbsent('RUNNER_TEMP', testProjectDir.absolutePath)
+        envVars.putIfAbsent('GITHUB_ACTION', 'github-step-id')
 
         def runner = ((DefaultGradleRunner) GradleRunner.create())
             .withJvmArguments(jvmArgs)
             .withGradleVersion(gradleVersion.version)
             .withProjectDir(testProjectDir)
             .withArguments(args)
+            .withEnvironment(envVars)
             .forwardOutput()
 
-        if (envVars) {
-            runner.withEnvironment(envVars)
-        }
-
         runner
     }
 
diff --git a/test/init-scripts/src/test/groovy/com/gradle/gradlebuildaction/TestBuildResultRecorder.groovy b/test/init-scripts/src/test/groovy/com/gradle/gradlebuildaction/TestBuildResultRecorder.groovy
index 48baa2d..d815202 100644
--- a/test/init-scripts/src/test/groovy/com/gradle/gradlebuildaction/TestBuildResultRecorder.groovy
+++ b/test/init-scripts/src/test/groovy/com/gradle/gradlebuildaction/TestBuildResultRecorder.groovy
@@ -134,6 +134,20 @@ class TestBuildResultRecorder extends BaseInitScriptTest {
         testGradleVersion << ALL_VERSIONS
     }
 
+    def "produces no build results file when GitHub env vars not set with #testGradleVersion"() {
+        assumeTrue testGradleVersion.compatibleWithCurrentJvm
+
+        when:
+        run(['help'], initScript, testGradleVersion.gradleVersion, [], [RUNNER_TEMP: '', GITHUB_ACTION: ''])
+
+        then:
+        def buildResultsDir = new File(testProjectDir, '.build-results')
+        assert !buildResultsDir.exists()
+
+        where:
+        testGradleVersion << ALL_VERSIONS
+    }
+
     void assertResults(String task, TestGradleVersion testGradleVersion, boolean hasFailure, boolean hasBuildScan, boolean scanUploadFailed = false) {
         def results = new JsonSlurper().parse(buildResultFile)
         assert results['rootProjectName'] == ROOT_PROJECT_NAME