--- a/taskcluster/ci/packages/kind.yml
+++ b/taskcluster/ci/packages/kind.yml
@@ -12,16 +12,17 @@ transforms:
 job-defaults:
   treeherder:
     kind: build
     platform: packages/opt
     tier: 1
   worker-type: aws-provisioner-v1/gecko-{level}-b-linux
   worker:
     max-run-time: 1800
+  run-on-projects: []
 
 jobs:
   deb7-python:
     description: "Python backport for Debian wheezy"
     treeherder:
       symbol: Deb7(python)
     run:
       using: debian-package

--- a/taskcluster/ci/toolchain/kind.yml
+++ b/taskcluster/ci/toolchain/kind.yml
@@ -5,12 +5,15 @@
 loader: taskgraph.loader.transform:loader
 
 transforms:
    - taskgraph.transforms.try_job:transforms
    - taskgraph.transforms.use_toolchains:transforms
    - taskgraph.transforms.job:transforms
    - taskgraph.transforms.task:transforms
 
+job-defaults:
+   run-on-projects: []
+
 jobs-from:
    - linux.yml
    - macosx.yml
    - windows.yml

--- a/taskcluster/ci/toolchain/linux.yml
+++ b/taskcluster/ci/toolchain/linux.yml
@@ -108,16 +108,19 @@ linux64-clang-tidy:
         using: toolchain-script
         script: build-clang-tidy-linux.sh
         resources:
             - 'build/clang-plugin/**'
             - 'build/build-clang/build-clang.py'
             - 'build/build-clang/clang-tidy-linux64.json'
             - 'taskcluster/scripts/misc/tooltool-download.sh'
         toolchain-artifact: public/build/clang-tidy.tar.xz
+    run-on-projects:
+        - trunk
+        - try
     toolchains:
         - linux64-gcc-4.9
 
 linux64-gcc-4.9:
     description: "GCC 4.9 toolchain build"
     treeherder:
         kind: build
         platform: toolchains/opt
@@ -443,16 +446,19 @@ linux64-gn:
     run:
         using: toolchain-script
         script: build-gn-linux.sh
         tooltool-downloads: public
         resources:
             - 'taskcluster/scripts/misc/tooltool-download.sh'
             - 'taskcluster/scripts/misc/build-gn-common.sh'
         toolchain-artifact: public/build/gn.tar.xz
+    run-on-projects:
+        - trunk
+        - try
     toolchains:
         - linux64-gcc-4.9
 
 linux64-upx:
     description: "UPX build for MinGW32 Cross Compile"
     treeherder:
         kind: build
         platform: toolchains/opt

--- a/taskcluster/ci/toolchain/macosx.yml
+++ b/taskcluster/ci/toolchain/macosx.yml
@@ -1,15 +1,18 @@
 # This Source Code Form is subject to the terms of the Mozilla Public
 # License, v. 2.0. If a copy of the MPL was not distributed with this
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
 job-defaults:
     worker:
         docker-image: {in-tree: toolchain-build}
+    run-on-projects:
+        - trunk
+        - try
 
 macosx64-clang:
     description: "Clang toolchain build"
     treeherder:
         kind: build
         platform: toolchains/opt
         symbol: TM(clang)
         tier: 1

--- a/taskcluster/ci/toolchain/windows.yml
+++ b/taskcluster/ci/toolchain/windows.yml
@@ -63,16 +63,19 @@ win32-clang-tidy:
         using: toolchain-script
         script: build-clang-tidy32-windows.sh
         resources:
             - 'build/clang-plugin/**'
             - 'build/build-clang/build-clang.py'
             - 'build/build-clang/clang-tidy-win32.json'
             - 'taskcluster/scripts/misc/build-clang-windows-helper32.sh'
         toolchain-artifact: public/build/clang-tidy.tar.bz2
+    run-on-projects:
+        - trunk
+        - try
 
 win64-clang-tidy:
     description: "Clang-tidy toolchain build"
     index:
         product: static-analysis
         job-name: win64-clang-tidy
     treeherder:
         kind: build
@@ -227,8 +230,11 @@ win32-gn:
             TOOLTOOL_MANIFEST: "browser/config/tooltool-manifests/win32/gn-build.manifest"
     run:
         using: toolchain-script
         script: build-gn-win32.sh
         resources:
             - 'taskcluster/scripts/misc/tooltool-download.sh'
             - 'taskcluster/scripts/misc/build-gn-common.sh'
         toolchain-artifact: public/build/gn.tar.bz2
+    run-on-projects:
+        - trunk
+        - try

--- a/taskcluster/taskgraph/transforms/job/toolchain.py
+++ b/taskcluster/taskgraph/transforms/job/toolchain.py
@@ -111,17 +111,16 @@ toolchain_defaults = {
     'sparse-profile': 'toolchain-build',
 }
 
 
 @run_job_using("docker-worker", "toolchain-script",
                schema=toolchain_run_schema, defaults=toolchain_defaults)
 def docker_worker_toolchain(config, job, taskdesc):
     run = job['run']
-    taskdesc['run-on-projects'] = ['trunk', 'try']
 
     worker = taskdesc['worker']
     worker['chain-of-trust'] = True
 
     # Allow the job to specify where artifacts come from, but add
     # public/build if it's not there already.
     artifacts = worker.setdefault('artifacts', [])
     if not any(artifact.get('name') == 'public/build' for artifact in artifacts):
@@ -183,17 +182,16 @@ def docker_worker_toolchain(config, job,
             digest_data=get_digest_data(config, run, taskdesc),
         )
 
 
 @run_job_using("generic-worker", "toolchain-script",
                schema=toolchain_run_schema, defaults=toolchain_defaults)
 def windows_toolchain(config, job, taskdesc):
     run = job['run']
-    taskdesc['run-on-projects'] = ['trunk', 'try']
 
     worker = taskdesc['worker']
 
     worker['artifacts'] = [{
         'path': r'public\build',
         'type': 'directory',
     }]
     worker['chain-of-trust'] = True