diff --git a/.taskcluster.yml b/.taskcluster.yml
index 34e3eb29dc0..1277a5ee0cc 100644
--- a/.taskcluster.yml
+++ b/.taskcluster.yml
@@ -27,7 +27,6 @@ tasks:
         features:
           taskclusterProxy: true
         env:
-          DECISION_TASK_ID: {$eval: as_slugid("decision_task")}
           GITHUB_EVENT_OWNER: ${event.pusher.name}@users.noreply.github.com
           GITHUB_EVENT_SOURCE: ${event.compare}
           GITHUB_EVENT_CLONE_URL: ${event.repository.clone_url}
diff --git a/decision-task/run.py b/decision-task/run.py
index 06ab5378195..69694b505fc 100644
--- a/decision-task/run.py
+++ b/decision-task/run.py
@@ -2,12 +2,13 @@
 
 import os
 import sys
+import json
 
 sys.path.insert(0, os.path.join(os.path.dirname(__file__), "vendored"))
 
-import json
-
 import taskcluster
+
+decision_task_id = os.environ["TASK_ID"]
 # https://docs.taskcluster.net/docs/reference/workers/docker-worker/docs/features#feature-taskclusterproxy
 queue = taskcluster.Queue(options={"baseUrl": "http://taskcluster/queue/v1/"})
 
@@ -19,8 +20,8 @@ def create_task(name, command, artifacts=None, dependencies=None, env=None, cach
 
     task_id = taskcluster.slugId()
     payload = {
-        "taskGroupId": os.environ["DECISION_TASK_ID"],
-        "dependencies": [os.environ["DECISION_TASK_ID"]] + (dependencies or []),
+        "taskGroupId": decision_task_id,
+        "dependencies": [decision_task_id] + (dependencies or []),
         "schedulerId": "taskcluster-github",
         "provisionerId": "aws-provisioner-v1",
         "workerType": "github-worker",