diff --git a/etc/taskcluster/decision_task.py b/etc/taskcluster/decision_task.py
index d27a7111fc9..26f19c73439 100644
--- a/etc/taskcluster/decision_task.py
+++ b/etc/taskcluster/decision_task.py
@@ -5,10 +5,15 @@
 # file, You can obtain one at https://mozilla.org/MPL/2.0/.
 
 import os.path
-from decisionlib import *
+import decisionlib
+from decisionlib import CONFIG, SHARED
 
 
 def main(task_for):
+    assert CONFIG.git_ref.startswith("refs/heads/")
+    branch = CONFIG.git_ref[len("refs/heads/"):]
+    CONFIG.treeherder_repository_names.append("servo-" + branch)
+
     if task_for == "github-push":
         # FIXME https://github.com/servo/servo/issues/22325 implement these:
         macos_wpt = magicleap_dev = linux_arm32_dev = linux_arm64_dev = \
@@ -56,9 +61,6 @@ def main(task_for):
                 android_x86_wpt
             ],
         }
-        assert CONFIG.git_ref.startswith("refs/heads/")
-        branch = CONFIG.git_ref[len("refs/heads/"):]
-        CONFIG.treeherder_repository_names.append("servo-" + branch)
         for function in by_branch_name.get(branch, []):
             function()
 
@@ -74,7 +76,7 @@ def mocked_only():
     windows_release()
     linux_wpt()
     android_x86_wpt()
-    linux_build_task("Indexed by task definition").find_or_create()
+    decisionlib.DockerWorkerTask("Indexed by task definition").find_or_create()
 
 
 ping_on_daily_task_failure = "SimonSapin, nox, emilio"
@@ -141,7 +143,7 @@ def linux_tidy_unit_docs():
 
 
 def upload_docs():
-    docs_build_task_id = Task.find("docs." + CONFIG.git_sha)
+    docs_build_task_id = decisionlib.Task.find("docs." + CONFIG.git_sha)
     return (
         linux_task("Upload docs to GitHub Pages")
         .with_treeherder("Linux x64", "DocUpload")
@@ -187,7 +189,8 @@ def with_rust_nightly():
         modified_build_env["RUSTFLAGS"] = " ".join(flags)
 
     return (
-        linux_build_task("Linux x64: with Rust Nightly", build_env=modified_build_env)
+        linux_build_task("with Rust Nightly", build_env=modified_build_env)
+        .with_treeherder("Linux x64", "RustNightly")
         .with_script("""
             echo "nightly" > rust-toolchain
             ./mach build --dev
@@ -239,7 +242,7 @@ def android_x86_release():
 def android_x86_wpt():
     build_task = android_x86_release()
     return (
-        DockerWorkerTask("WPT")
+        linux_task("WPT")
         .with_treeherder("Android x86")
         .with_provisioner_id("proj-servo")
         .with_worker_type("docker-worker-kvm")
@@ -402,18 +405,28 @@ def dockerfile_path(name):
 
 
 def linux_task(name):
-    return DockerWorkerTask(name).with_worker_type("servo-docker-worker")
+    return (
+        decisionlib.DockerWorkerTask(name)
+        .with_worker_type("servo-docker-worker")
+        .with_treeherder_required()
+    )
 
 
 def windows_task(name):
-    return WindowsGenericWorkerTask(name).with_worker_type("servo-win2016")
+    return (
+        decisionlib.WindowsGenericWorkerTask(name)
+        .with_worker_type("servo-win2016")
+        .with_treeherder_required()
+    )
+
 
 
 def macos_task(name):
     return (
-        MacOsGenericWorkerTask(name)
+        decisionlib.MacOsGenericWorkerTask(name)
         .with_provisioner_id("proj-servo")
         .with_worker_type("macos")
+        .with_treeherder_required()
     )
 
 
diff --git a/etc/taskcluster/decisionlib.py b/etc/taskcluster/decisionlib.py
index 553113db326..af9aed31ffe 100644
--- a/etc/taskcluster/decisionlib.py
+++ b/etc/taskcluster/decisionlib.py
@@ -119,6 +119,7 @@ class Task:
         self.scopes = []
         self.routes = []
         self.extra = {}
+        self.treeherder_required = False
 
     # All `with_*` methods return `self`, so multiple method calls can be chained.
     with_description = chaining(setattr, "description")
@@ -135,6 +136,10 @@ class Task:
 
     with_extra = chaining(update_attr, "extra")
 
+    def with_treeherder_required(self):
+        self.treeherder_required = True
+        return self
+
     def with_treeherder(self, category, symbol=None):
         symbol = symbol or self.name
         assert len(symbol) <= 25, symbol
@@ -164,6 +169,7 @@ class Task:
                 "tc-treeherder-staging" + suffix,
             )
 
+        self.treeherder_required = False  # Taken care of
         return self
 
     def build_worker_payload(self):  # pragma: no cover
@@ -183,6 +189,8 @@ class Task:
         <https://docs.taskcluster.net/docs/reference/platform/taskcluster-queue/references/api#createTask>
         """
         worker_payload = self.build_worker_payload()
+        assert not self.treeherder_required, \
+            "make sure to call with_treeherder() for this task: %s" % self.name
 
         assert CONFIG.decision_task_id
         assert CONFIG.task_owner