diff --git a/.gitignore b/.gitignore
index 0bc83a34..591a37c6 100644
--- a/.gitignore
+++ b/.gitignore
@@ -41,3 +41,9 @@ __pycache__/
 
 # Release artifacts produced by `x release`
 /dist/
+
+# Build/release tarballs anywhere in the tree. `git -C <repo> archive -o foo.tgz`
+# resolves -o relative to the repo, not the caller's directory, so a stray
+# archive lands in the root and a blanket `git add -A` will commit it.
+*.tar.gz
+*.tgz
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 6d51cfb1..eb4d23a7 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -93,17 +93,28 @@ git push origin main --follow-tags
 **Pushing the tag is what publishes.** The `release` workflow builds the
 toolchain from the IR seed, runs `x test`, `x test-tools` and `x bootstrap-cfree`
 against the tagged tree, and only then creates the Forgejo release — with the
-source tarball, a Linux toolchain build, `SHA256SUMS`, and that version's
+source tarball, a Linux toolchain build, a `.sha256` beside each, and that version's
 `CHANGELOG.md` section as the notes. It refuses to publish if the tag and
 `VERSION` disagree or the changelog has no section for it.
 
-macOS artifacts cannot be produced on the Linux runner. To attach one, run the
-same command CI runs from a Mac — it only adds assets the release is missing:
+macOS artifacts cannot be produced on the Linux runner — a `darwin-arm64` build
+needs a macOS host, and there is no cross-compile path (it would need the Xcode
+SDK and a Mach-O linker). Attaching one therefore means either registering a
+macOS runner and giving it a job, or running the same command CI runs from a
+Mac. Either way it is `x publish`, which only adds assets the release is missing:
 
 ```bash
 FORGEJO_TOKEN=… x publish v0.4.0
 ```
 
+Checksums are one `.sha256` file per artifact rather than a single `SHA256SUMS`,
+precisely because a release can be assembled from more than one host and an
+asset that already exists is never overwritten. Verify one with:
+
+```bash
+shasum -a 256 -c ludic-0.4.0-src.tar.gz.sha256
+```
+
 The tag doubles as the reproducible bootstrap point: the source archive plus its
 checked-in seed rebuild that exact toolchain.
 
diff --git a/changes/per-artifact-checksums.md b/changes/per-artifact-checksums.md
new file mode 100644
index 00000000..a94f83e5
--- /dev/null
+++ b/changes/per-artifact-checksums.md
@@ -0,0 +1,9 @@
+bump: patch
+type: fix
+Release checksums are one `.sha256` file per artifact instead of a single
+`SHA256SUMS`. A release is assembled from more than one host — a Linux runner
+cannot build the macOS toolchain — and `x publish` never overwrites an asset that
+is already attached, so a shared `SHA256SUMS` was written by whichever host
+published first and then never covered anything added afterwards. Per-artifact
+names compose across hosts. Verify one with
+`shasum -a 256 -c ludic-X.Y.Z-src.tar.gz.sha256`.
diff --git a/tools/x/release.ludic b/tools/x/release.ludic
index 9965e5a5..295064bc 100644
--- a/tools/x/release.ludic
+++ b/tools/x/release.ludic
@@ -305,8 +305,17 @@ function sha256_cmd() -> pointer {
 }
 
 # Build the release artifacts into dist/: a reproducible source+seed tarball from
-# the tag, the toolchain built on this host, and a SHA256SUMS covering both — a
+# the tag, the toolchain built on this host, and one `.sha256` beside each — a
 # release without checksums asks everyone downstream to trust the transport.
+#
+# The checksums are per-artifact rather than a single SHA256SUMS on purpose. A
+# release is assembled from more than one host (a Linux runner cannot build the
+# macOS toolchain), and `forgejo_upload_assets` skips an asset whose name is
+# already attached — so a shared SHA256SUMS would be written by whichever host
+# published first and would then never cover anything added later. One file per
+# artifact has a unique name, so each host's contribution stands on its own.
+#
+#   shasum -a 256 -c ludic-X.Y.Z-src.tar.gz.sha256
 function build_artifacts(ver: pointer) -> bool {
   run("rm -rf dist && mkdir -p dist")
   if not shq(`git archive --format=tar.gz --prefix=ludic-{ver}/ -o dist/ludic-{ver}-src.tar.gz v{ver}`) {
@@ -321,8 +330,8 @@ function build_artifacts(ver: pointer) -> bool {
       return false
     }
   }
-  if not shq(`cd dist && {sha256_cmd()} *.tar.gz > SHA256SUMS`) {
-    err("release: writing dist/SHA256SUMS failed\n")
+  if not shq(`cd dist && for f in *.tar.gz; do {sha256_cmd()} "$f" > "$f.sha256" || exit 1; done`) {
+    err("release: writing the per-artifact .sha256 files failed\n")
     return false
   }
   run("ls -l dist")