diff --git a/.changeset/all-cars-grin.md b/.changeset/all-cars-grin.md
new file mode 100644
index 00000000..17af9a37
--- /dev/null
+++ b/.changeset/all-cars-grin.md
@@ -0,0 +1,5 @@
+---
+"@changesets/action": patch
+---
+
+Fix the computed publish plan path passed internally to `changeset pack` by the `/pack` subaction.
diff --git a/src/select-mode/index.ts b/src/select-mode/index.ts
index 3fb1bc33..00e191d4 100644
--- a/src/select-mode/index.ts
+++ b/src/select-mode/index.ts
@@ -64,7 +64,9 @@ async function getMode(): Promise<ModeResult> {
   const cwd = process.cwd();
   const publishPlanPath = path.join(
     process.env.RUNNER_TEMP ?? (await fs.realpath(os.tmpdir())),
-    `changeset-publish-plan-${Date.now()}.json`,
+    `changeset-publish-plan-${Date.now()}`,
+    // we need a stable filename here (in a unique dirname) so the artifact download can find this cleanly
+    "publish-plan.json",
   );
   await execChangesetsCli(["publish-plan", "--output", publishPlanPath], {
     cwd,