diff --git a/.github/workflows/lint-validate-openapi.yml b/.github/workflows/lint-validate-openapi.yml
new file mode 100644
index 0000000..16a00a8
--- /dev/null
+++ b/.github/workflows/lint-validate-openapi.yml
@@ -0,0 +1,51 @@
+name: Lint and validate OpenAPI specs
+
+on:
+  - push
+  - pull_request
+
+jobs:
+
+  lint:
+    name: Lint OpenAPI definition
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check out head branch
+        uses: actions/checkout@v2
+      - name: Run OpenAPI Lint Action
+        uses: nwestfall/openapi-action@v1.0.2
+        with:
+          github_token: ${{ secrets.GITHUB_TOKEN }}
+          file: openapi/task_execution_service.openapi.yaml
+
+  diff:
+    name: Show OpenAPI differences relative to target branch
+    runs-on: ubuntu-latest
+    if: ${{ github.event_name == 'pull_request' }}
+    steps:
+      - name: Check out head branch
+        uses: actions/checkout@v2
+        with:
+          ref: ${{ github.head_ref }}
+          path: head
+      - name: Check out base branch
+        uses: actions/checkout@v2
+        with:
+          ref: ${{ github.base_ref }}
+          path: base
+      - name: Run OpenAPI Diff Action
+        uses: mvegter/openapi-diff-action@v0.23.5
+        with:
+          head-spec: head/openapi/task_execution_service.openapi.yaml
+          base-spec: base/openapi/task_execution_service.openapi.yaml
+
+  validate:
+    name: Validate OpenAPI definition
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check out head branch
+        uses: actions/checkout@v2
+      - name: Run OpenAPI Validate Action
+        uses: char0n/swagger-editor-validate@v1
+        with:
+          definition-file: openapi/task_execution_service.openapi.yaml
diff --git a/openapi/task_execution_service.openapi.yaml b/openapi/task_execution_service.openapi.yaml
index 8d57d8f..f23c723 100644
--- a/openapi/task_execution_service.openapi.yaml
+++ b/openapi/task_execution_service.openapi.yaml
@@ -622,7 +622,9 @@ components:
          - `SYSTEM_ERROR`: The task was stopped due to a system error, but not from an Executor,
         for example an upload failed due to network issues, the worker's ran out
         of disk space, etc.
-         - `CANCELED`: The task was canceled by the user.
+         - `CANCELED`: The task was canceled by the user, and downstream resources have been deleted.
+         - `CANCELING`: The task was canceled by the user,
+        but the downstream resources are still awaiting deletion.
       default: UNKNOWN
       example: COMPLETE
       enum:
@@ -635,6 +637,7 @@ components:
       - EXECUTOR_ERROR
       - SYSTEM_ERROR
       - CANCELED
+      - CANCELING
     tesTask:
       required:
       - executors