diff --git a/src/main/java/com/google/devtools/build/lib/worker/ErrorMessage.java b/src/main/java/com/google/devtools/build/lib/worker/ErrorMessage.java
index d02d3f36c84a4d..46d32985cb45bd 100644
--- a/src/main/java/com/google/devtools/build/lib/worker/ErrorMessage.java
+++ b/src/main/java/com/google/devtools/build/lib/worker/ErrorMessage.java
@@ -42,6 +42,7 @@ public static final class Builder {
     private Path logFile;
     private String logText = "";
     private int logSizeLimit = Integer.MAX_VALUE;
+    private Exception exception;
 
     private Builder() {}
 
@@ -90,9 +91,22 @@ public Builder logSizeLimit(int logSizeLimit) {
       return this;
     }
 
+    /** Lets the error message contain the details of an exception. */
+    public Builder exception(Exception e) {
+      this.exception = e;
+      return this;
+    }
+
     /** Builds and returns the formatted error message. */
     public ErrorMessage build() {
       StringBuilder sb = new StringBuilder(message);
+
+      if (exception != null) {
+        sb.append("\n\n---8<---8<--- Exception details ---8<---8<---\n");
+        sb.append(Throwables.getStackTraceAsString(exception).trim());
+        sb.append("\n---8<---8<--- End of exception details ---8<---8<---");
+      }
+
       if (!logText.isEmpty()) {
         sb.append("\n\n---8<---8<--- Start of log");
         if (logText.length() > logSizeLimit) {
diff --git a/src/main/java/com/google/devtools/build/lib/worker/WorkerSpawnStrategy.java b/src/main/java/com/google/devtools/build/lib/worker/WorkerSpawnStrategy.java
index a912d1e56fc522..9a681ab5ea83fa 100644
--- a/src/main/java/com/google/devtools/build/lib/worker/WorkerSpawnStrategy.java
+++ b/src/main/java/com/google/devtools/build/lib/worker/WorkerSpawnStrategy.java
@@ -193,7 +193,8 @@ private void actuallyExec(
       String message =
           CommandFailureUtils.describeCommandFailure(
               verboseFailures, spawn.getArguments(), env, execRoot.getPathString());
-      throw new UserExecException(ErrorMessage.builder().message(message).build().toString());
+      throw new UserExecException(
+          ErrorMessage.builder().message(message).exception(e).build().toString());
     }
   }
 
@@ -296,6 +297,7 @@ private WorkResponse execInWorker(
         throw new UserExecException(
             ErrorMessage.builder()
                 .message("IOException while borrowing a worker from the pool:")
+                .exception(e)
                 .build()
                 .toString());
       }
@@ -307,6 +309,7 @@ private WorkResponse execInWorker(
             ErrorMessage.builder()
                 .message("IOException while preparing the execution environment of a worker:")
                 .logFile(worker.getLogFile())
+                .exception(e)
                 .build()
                 .toString());
       }
@@ -321,6 +324,7 @@ private WorkResponse execInWorker(
                     "Worker process quit or closed its stdin stream when we tried to send a"
                         + " WorkRequest:")
                 .logFile(worker.getLogFile())
+                .exception(e)
                 .build()
                 .toString());
       }
@@ -340,6 +344,7 @@ private WorkResponse execInWorker(
             ErrorMessage.builder()
                 .message("Worker process returned an unparseable WorkResponse:")
                 .logText(recordingStream.getRecordedDataAsString())
+                .exception(e)
                 .build()
                 .toString());
       }
@@ -365,6 +370,7 @@ private WorkResponse execInWorker(
         throw new UserExecException(
             ErrorMessage.builder()
                 .message("IOException while finishing worker execution:")
+                .exception(e)
                 .build()
                 .toString());
       }
diff --git a/src/main/java/com/google/devtools/build/lib/worker/WorkerTestStrategy.java b/src/main/java/com/google/devtools/build/lib/worker/WorkerTestStrategy.java
index 114f491b7f4288..040f543a303b67 100644
--- a/src/main/java/com/google/devtools/build/lib/worker/WorkerTestStrategy.java
+++ b/src/main/java/com/google/devtools/build/lib/worker/WorkerTestStrategy.java
@@ -164,6 +164,7 @@ private TestResultData execInWorker(
         ErrorMessage errorMessage =
             ErrorMessage.builder()
                 .message("Worker process returned an unparseable WorkResponse:")
+                .exception(e)
                 .logText(data)
                 .build();
         executor.getEventHandler().handle(Event.warn(errorMessage.toString()));
@@ -173,15 +174,15 @@ private TestResultData execInWorker(
       worker.finishExecution(key);
 
       if (response == null) {
-        ErrorMessage errorMessage =
+        throw new UserExecException(
             ErrorMessage.builder()
                 .message(
                     "Worker process did not return a WorkResponse. This is usually caused by a bug"
                         + " in the worker, thus dumping its log file for debugging purposes:")
                 .logFile(worker.getLogFile())
                 .logSizeLimit(4096)
-                .build();
-        throw new UserExecException(errorMessage.toString());
+                .build()
+                .toString());
       }
 
       actionExecutionContext.getFileOutErr().getErrorStream().write(
diff --git a/src/test/java/com/google/devtools/build/lib/worker/ErrorMessageTest.java b/src/test/java/com/google/devtools/build/lib/worker/ErrorMessageTest.java
index f0140f492041de..181e43881e6e9d 100644
--- a/src/test/java/com/google/devtools/build/lib/worker/ErrorMessageTest.java
+++ b/src/test/java/com/google/devtools/build/lib/worker/ErrorMessageTest.java
@@ -112,4 +112,18 @@ public void testErrorMessageWithUnreadableLogFile() {
                 + "java.io.FileNotFoundException: /nope.txt (No such file or directory)\n");
     assertThat(errorMessage.toString()).endsWith("---8<---8<--- End of log ---8<---8<---");
   }
+
+  @Test
+  public void testErrorMessageWithException() {
+    ErrorMessage errorMessage =
+        ErrorMessage.builder()
+            .message("An exception occurred.")
+            .exception(new IllegalStateException("Hello World"))
+            .build();
+    assertThat(errorMessage.toString())
+        .startsWith(
+            "An exception occurred.\n\n"
+                + "---8<---8<--- Exception details ---8<---8<---\n"
+                + "java.lang.IllegalStateException: Hello World");
+  }
 }