diff --git a/.ci/scripts/calc_constraints.py b/.ci/scripts/calc_constraints.py
index b9af2e73f9..a9e4910312 100755
--- a/.ci/scripts/calc_constraints.py
+++ b/.ci/scripts/calc_constraints.py
@@ -4,6 +4,15 @@
 # './plugin-template --github pulpcore' to update this file.
 #
 # For more info visit https://github.com/pulp/plugin_template
+#!/usr/bin/env python
+# /// script
+# requires-python = ">=3.9"
+# dependencies = [
+#     "packaging>=26.0,<27",
+#     "pyyaml>=6.0.3,<6.1",
+#     "tomli;python_version<'3.11'",
+# ]
+# ///
 
 import argparse
 import fileinput
diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index e6444d6727..e41fd93edf 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -44,8 +44,9 @@ jobs:
           uvx twine check dist/*
       - name: "Install built packages"
         run: |
+          uv run --script .ci/scripts/calc_constraints.py -u requirements.txt > upperbounds_constraints.txt
           # This seems to be the only way to inject the constraints file.
-          uv pip install dist/pulpcore-*-py3-none-any.whl -c .ci/assets/ci_constraints.txt
+          uv pip install dist/pulpcore-*-py3-none-any.whl -c .ci/assets/ci_constraints.txt -c upperbounds_constraints.txt
       - name: "Generate api specs"
         run: |
           pulpcore-manager openapi --file "api.json"