diff --git a/.github/workflows/dogfood.yml b/.github/workflows/dogfood.yml
index 6bea054..3847d4f 100644
--- a/.github/workflows/dogfood.yml
+++ b/.github/workflows/dogfood.yml
@@ -19,11 +19,15 @@ on:
   pull_request_review_comment:
     types: [created]
 
+# NOTE: `workflows: write` is not a valid permissions scope — GitHub began
+# hard-rejecting it ~2026-05-01 ("Unexpected value 'workflows'"), which made
+# every push spawn a phantom failed dogfood run and broke /dogfood comments.
+# Workflow-file write access is granted by the App's Workflows permission
+# (see CONTRIBUTING.md), not by a job permissions key.
 permissions:
   contents: write
   issues: write
   pull-requests: write
-  workflows: write
 
 jobs:
   resolve:
diff --git a/tests/test_yaml.py b/tests/test_yaml.py
index 166b632..b64dc4d 100644
--- a/tests/test_yaml.py
+++ b/tests/test_yaml.py
@@ -202,17 +202,24 @@ def find_target_checkout(job):
         )
 
 
-def test_dogfood_has_workflows_write_permission():
-    """dogfood.yml must include workflows:write so the fallback github.token
-    can push workflow file changes when no app token is configured.
-
-    Regression test for issue #463.
+def test_no_invalid_workflows_permission_key():
+    """No workflow may use `workflows:` in a permissions block — it is not a
+    valid GitHub Actions permissions scope, and since ~2026-05-01 GitHub
+    hard-rejects it ("Unexpected value 'workflows'"), invalidating the whole
+    workflow file. It was originally added for issue #463 in the belief it
+    let github.token push workflow files; GITHUB_TOKEN can never modify
+    workflow files regardless of permissions — that capability comes from
+    the GitHub App's Workflows permission (see CONTRIBUTING.md).
+
+    Regression test for the May-August 2026 phantom dogfood failures.
     """
-    dogfood = load_yaml(REPO_ROOT / ".github/workflows/dogfood.yml")
-    permissions = dogfood.get("permissions", {})
-    assert permissions.get("workflows") == "write", (
-        "dogfood.yml must have 'workflows: write' in permissions"
-    )
+    for wf in (REPO_ROOT / ".github/workflows").glob("*.yml"):
+        config = load_yaml(wf)
+        permissions = config.get("permissions", {}) or {}
+        assert "workflows" not in permissions, (
+            f"{wf.name}: 'workflows' is not a valid permissions scope and "
+            f"invalidates the workflow file"
+        )
 
 
 # --- Security checks ---