diff --git a/.circleci/config.yml b/.circleci/config.yml
index 174acc91..f3be267d 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -33,6 +33,33 @@ jobs:
           command: './venv/bin/pytest -nauto --junitxml=test-results.xml'
       - store_test_results:
           path: test-results.xml
+  # Do the API and the frontend's test fixtures still agree?
+  #
+  # `api-tests` runs these too, as part of the whole suite.  This job exists for the
+  # signal: fixture drift is silent by nature -- the frontend suite passes against a body the
+  # API stopped sending -- so it is worth a check whose name says what broke, failing in under a
+  # minute rather than somewhere inside seventeen hundred results.
+  #
+  # It needs no ffmpeg or catdoc (verified), and shares the dependency cache key with the other
+  # Python jobs, so it costs a venv restore and one test file.
+  api-contract-tests:
+    docker:
+      - image: cimg/python:3.11
+    resource_class: medium
+    steps:
+      - checkout
+      - restore_cache:
+          key: deps-3.11-{{ checksum "requirements.txt" }}-5
+      - run:
+          name: Install Requirements
+          command: |
+            python3 -m venv venv
+            . venv/bin/activate
+            pip install -r requirements.txt
+      - run:
+          name: Fixtures match the OpenAPI spec, and the spec matches the handlers
+          command: './venv/bin/pytest wrolpi/test/test_api_fixtures.py -v'
+
   api-alembic-migrations:
     docker:
       - image: cimg/python:3.13
@@ -167,6 +194,7 @@ workflows:
     jobs:
       - sanic-api-start
       - api-tests
+      - api-contract-tests
       - api-alembic-migrations
   wrolpi-app-test:
     jobs:
diff --git a/.github/workflows/jest-tests.yml b/.github/workflows/jest-tests.yml
index 68bfd7aa..8a8eadba 100644
--- a/.github/workflows/jest-tests.yml
+++ b/.github/workflows/jest-tests.yml
@@ -1,10 +1,16 @@
 name: Jest Tests
 
+# `pull_request` is deliberately unfiltered.  It was `branches: [master]`, which meant a pull
+# request into anything else ran no jest and no webpack build -- so the entire Semantic UI to
+# Mantine migration, seventy-five files of it, was reviewed and merged across nine pull requests
+# into `feature/custom-theme` without either ever running on a single one of them.  The build
+# step matters most of all here: jest and tsc both pass on a named import that does not exist,
+# and only webpack rejects it.  The suite did run on the branch afterwards, which is the wrong
+# side of the merge to find out.
 on:
   push:
     branches: [master, feature/*]
   pull_request:
-    branches: [master]
 
 jobs:
   jest-tests: