diff --git a/build.gradle.kts b/build.gradle.kts
index 9b21b01b..60ca4e8d 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -33,6 +33,7 @@ plugins {
   id("org.jetbrains.intellij.platform") version "2.19.0"
   id("org.jetbrains.grammarkit") version "2023.3.0.4"
   id("checkstyle")
+  id("jacoco")
   id("com.avast.gradle.docker-compose") version "0.17.21"
   id("org.jetbrains.kotlin.jvm") version "2.4.21"
   id("idea")
@@ -147,6 +148,26 @@ tasks {
      // Forward the experimental grammar-engine flag so CI can run the whole suite twice: once on the
      // original engine and once with -Dsystemd.unit.grammarParseEngine=true (see GrammarOptionValue).
      systemProperty("systemd.unit.grammarParseEngine", System.getProperty("systemd.unit.grammarParseEngine", "false"))
+     // Coverage for CI trends. The IntelliJ test framework loads classes through its own class loaders, which
+     // JaCoCo only records with includeNoLocationClasses; jdk.internal is excluded because instrumenting it
+     // breaks the JVM.
+     configure<JacocoTaskExtension> {
+       isIncludeNoLocationClasses = true
+       excludes = listOf("jdk.internal.*")
+     }
+   }
+
+   jacocoTestReport {
+     // Only reports on existing execution data (run `test` first); CI publishes the XML with the Coverage plugin.
+     reports {
+       xml.required = true
+       html.required = true
+       csv.required = false
+     }
+     // Generated lexer/parser/PSI code would only dilute the numbers.
+     classDirectories.setFrom(files(classDirectories.files.map {
+       fileTree(it) { exclude("**/generated/**", "**/psi/impl/**") }
+     }))
    }
 }
 
diff --git a/ci/release.Jenkinsfile b/ci/release.Jenkinsfile
index 0e168df8..c98ae7ca 100644
--- a/ci/release.Jenkinsfile
+++ b/ci/release.Jenkinsfile
@@ -414,7 +414,7 @@ pipeline {
             sh("""
               mkdir -p ./build
               ./generate-changelog  > build/CHANGELOG
-              ./gradlew --no-daemon -I ./build-cache-init.gradle.kts -I ./repo-cache-init.gradle.kts --build-cache build buildPlugin -PbuildScan
+              ./gradlew --no-daemon -I ./build-cache-init.gradle.kts -I ./repo-cache-init.gradle.kts --build-cache build buildPlugin jacocoTestReport -PbuildScan
               """)
             script {
               if (env.BRANCH_NAME ==~ /^([0-9][0-9][0-9]\.x)$/) {
@@ -452,6 +452,22 @@ pipeline {
             archiveArtifacts artifacts: 'build/reports/**'
           }
         }
+      }
+      post {
+        // Runs even when tests fail, so failing tests and coverage still land in the trends.
+        always {
+          junit testResults: 'build/test-results/test/*.xml', allowEmptyResults: true
+          // Coverage is informational: a reporting problem marks the build unstable rather than failing it
+          // (and blocking the release).
+          catchError(buildResult: 'UNSTABLE', stageResult: 'UNSTABLE') {
+            script {
+              if (fileExists('build/reports/jacoco/test/jacocoTestReport.xml')) {
+                recordCoverage(tools: [[parser: 'JACOCO', pattern: 'build/reports/jacoco/test/jacocoTestReport.xml']],
+                               sourceDirectories: [[path: 'src/main/kotlin'], [path: 'src/main/java']])
+              }
+            }
+          }
+        }
       }
         }
         stage("Unit Tests (new grammar engine)") {
@@ -472,6 +488,11 @@ pipeline {
               ./gradlew --no-daemon -I ./build-cache-init.gradle.kts -I ./repo-cache-init.gradle.kts --build-cache test -Dsystemd.unit.grammarParseEngine=true
               """)
           }
+          post {
+            always {
+              junit testResults: 'build/test-results/test/*.xml', allowEmptyResults: true
+            }
+          }
         }
       }
     }