diff --git a/.run/commands/uvbuild.sh b/.run/commands/uvbuild.sh
index 6ed5655..8684815 100644
--- a/.run/commands/uvbuild.sh
+++ b/.run/commands/uvbuild.sh
@@ -1,18 +1,45 @@
 # vim: set ft=bash ts=3 sw=3 expandtab:
 # Build release artifacts into the dist/ directory
 
+# I want the sdist to be generated with a fixed version, so the package can be
+# built reproducibly from source even when Git version information is not
+# available.  This just worked in Poetry, but it doesn't seem to be possible
+# with hatchling.  To work around that, I'm manually adjusting pyproject.toml
+# prior to the the sdist build, and then putting it back afterwards.
+#
 # The $SOURCE_DATE_EPOCH controls the timestamp on files in the generated sdist.
 # See also: https://hatch.pypa.io/1.13/config/build/#reproducible-builds
 
 command_uvbuild() {
-   rm -f dist/*
+   local EPOCH VERSION
 
-   SOURCE_DATE_EPOCH=$(TZ=UTC date "+%s") uv build --wheel --sdist
+   EPOCH=$(TZ=UTC date "+%s")
+   VERSION=$(uvx uv-dynamic-versioning)
+
+   rm -rf dist/*
+
+   SOURCE_DATE_EPOCH=$EPOCH uv build --wheel
    if [ $? != 0 ]; then
-      echo "*** Build failed"
+      echo "*** Build failed for wheel"
       exit 1
    fi
 
+   mv pyproject.toml pyproject.toml.$$
+
+   cat pyproject.toml.$$ \
+      | sed 's/, "uv-dynamic-versioning (>=.*]$/ ]/' \
+      | sed "s/^dynamic = .*$/version = \"$VERSION\"/" \
+      > pyproject.toml
+
+   SOURCE_DATE_EPOCH=$EPOCH uv build --sdist
+   if [ $? != 0 ]; then
+      echo "*** Build failed for sdist"
+      mv pyproject.toml.$$ pyproject.toml
+      exit 1
+   fi
+
+   mv pyproject.toml.$$ pyproject.toml
+
    ls -l dist/
 
    echo "done"