diff --git a/zilti/packages/python.scm b/zilti/packages/python.scm
index b751b85..719b825 100644
--- a/zilti/packages/python.scm
+++ b/zilti/packages/python.scm
@@ -13,6 +13,7 @@
   #:use-module (gnu packages base)
   #:use-module (gnu packages bash)
   #:use-module (gnu packages check)
+  #:use-module (gnu packages cmake)
   #:use-module (gnu packages compression)
   #:use-module (gnu packages curl)
   #:use-module (gnu packages databases)
@@ -63,9 +64,32 @@
      (sha256
       (base32
        "1wswxrn4givsm917mfl39rafgadimf1sldpbjdjws00g1wx36hf0"))))
-   (build-system python-build-system)
+   (build-system pyproject-build-system)
    (arguments
-    '(#:tests? #f))
+    (list #:tests? #f))
+   (home-page "https://aws.amazon.com/cli/")
+   (synopsis "Command line client for AWS")
+   (description "AWS CLI provides a unified command line interface to the
+Amazon Web Services (AWS) API.")
+   (license license:asl2.0)))
+
+(define-public python-ruamel-yaml-clib
+  (package
+   (name "python-ruamel-yaml-clib")
+   (version "0.2.7")
+   (source
+    (origin
+     (method url-fetch)
+     (uri (pypi-uri "ruamel.yaml.clib" version))
+     (sha256
+      (base32
+       "15wlbw7wys3nana0xgip8mgjlpcr1f2qwrvivf04377a5ddgs20z"))))
+   (build-system pyproject-build-system)
+   (arguments
+    (list #:tests? #f))
+   (inputs
+    (list python-ruamel-base
+          python-ruamel-yaml))
    (home-page "https://aws.amazon.com/cli/")
    (synopsis "Command line client for AWS")
    (description "AWS CLI provides a unified command line interface to the
@@ -74,25 +98,50 @@ Amazon Web Services (AWS) API.")
 
 (define-public python-ruamel-yaml
   (package
-   (name "python-ruamel-yaml")
-   (version "0.17.32")
-   (source
-    (origin
-     (method url-fetch)
-     (uri (pypi-uri "ruamel.yaml" version))
-     (sha256
-      (base32
-       "1hpg033cyw7h3kv44qxbb443phikdnx5qalp892y250rfrir14zc"))))
-   (build-system python-build-system)
-   (arguments
-    '(#:tests? #f))
-   (inputs
-    (list python-ruamel-base))
-   (home-page "https://aws.amazon.com/cli/")
-   (synopsis "Command line client for AWS")
-   (description "AWS CLI provides a unified command line interface to the
+    (name "python-ruamel-yaml")
+    (version "0.17.32")
+    (source
+     (origin
+       (method url-fetch)
+       (uri (pypi-uri "ruamel.yaml" version))
+       (sha256
+        (base32
+         "1hpg033cyw7h3kv44qxbb443phikdnx5qalp892y250rfrir14zc"))))
+    (build-system pyproject-build-system)
+    (arguments
+     (list #:tests? #f
+           #:phases
+           #~(modify-phases %standard-phases
+               (delete 'sanity-check))))
+    (inputs
+     (list python-ruamel-base))
+    (home-page "https://aws.amazon.com/cli/")
+    (synopsis "Command line client for AWS")
+    (description "AWS CLI provides a unified command line interface to the
 Amazon Web Services (AWS) API.")
-   (license license:asl2.0)))
+    (license license:asl2.0)))
+
+(define-public python-awscrt
+  (package
+    (name "python-awscrt")
+    (version "0.20.5")
+    (source
+     (origin
+       (method url-fetch)
+       (uri (pypi-uri "awscrt" version))
+       (sha256
+        (base32
+         "1li94chzfaqam3vkwaw33j2c861g5lg9vkybnnx72crq6m5yk75z"))))
+    (build-system pyproject-build-system)
+    (arguments
+     (list #:tests? #f))
+    (inputs
+     (list cmake))
+    (home-page "https://aws.amazon.com/cli/")
+    (synopsis "Command line client for AWS")
+    (description "AWS CLI provides a unified command line interface to the
+Amazon Web Services (AWS) API.")
+    (license license:asl2.0)))
 
 (define-public awscli-2
   (package
@@ -111,29 +160,41 @@ Amazon Web Services (AWS) API.")
    (build-system gnu-build-system)
    (arguments
     ;; FIXME: The 'pypi' release does not contain tests.
-    '(#:tests? #f
-      #:phases
-      (modify-phases %standard-phases
-                     (add-after 'unpack 'fix-reference-to-groff
-                                (lambda* (#:key inputs #:allow-other-keys)
-                                  (substitute* "awscli/help.py"
-                                               (("if not self._exists_on_path\\('groff'\\):") "")
-                                               (("raise ExecutableNotFoundError\\('groff'\\)") "")
-                                               (("cmdline = \\['groff'")
-                                                (string-append "cmdline = ['"
-                                                               (search-input-file inputs "bin/groff")
-                                                               "'"))))))))
+    '(#:phases
+      (modify-phases
+          %standard-phases
+        (add-after 'unpack 'relax-requirements
+          (lambda* (#:key inputs #:allow-other-keys)
+            (substitute* "pyproject.toml"
+              (("cryptography>=3.3.2,<40.0.2") "cryptography>=3.3.2")
+              (("flit_core>=3.7.1,<3.8.1") "flit_core>=3.7.1")
+              (("awscrt>=0.19.18,<=0.19.19") "awscrt>=0.16.4")
+              (("ruamel.yaml>=0.15.0,<=0.17.21") "ruamel.yaml>=0.15.0")
+              (("ruamel.yaml.clib>=0.2.0,<=0.2.7") "ruamel.yaml.clib>=0.2.0"))))
+        (add-after 'unpack 'fix-reference-to-groff
+          (lambda* (#:key inputs #:allow-other-keys)
+            (substitute* "awscli/help.py"
+              (("if not self._exists_on_path\\('groff'\\):") "")
+              (("raise ExecutableNotFoundError\\('groff'\\)") "")
+              (("cmdline = \\['groff'")
+               (string-append "cmdline = ['"
+                              (search-input-file inputs "bin/groff")
+                              "'"))))))))
    (inputs
     (list groff
+          python-awscrt
           python-wrapper
           python-colorama-for-awscli
           python-botocore
+          python-distro
           python-flit-core
           python-importlib-resources
           python-executor
           python-s3transfer
           python-docutils-0.15
-          python-pyyaml
+          python-prompt-toolkit
+          python-ruamel-yaml
+          python-ruamel-yaml-clib
           python-rsa))
    (home-page "https://aws.amazon.com/cli/")
    (synopsis "Command line client for AWS")