diff --git a/.gitea/workflows/release.yml b/.gitea/workflows/release.yml
index 2588f67..b399353 100644
--- a/.gitea/workflows/release.yml
+++ b/.gitea/workflows/release.yml
@@ -58,6 +58,19 @@ jobs:
         with:
           fetch-depth: 0
 
+      # This self-hosted runner accumulates Docker layers/images and caches
+      # across runs, which can fill the disk (npm ci fails with ENOSPC). Reclaim
+      # space up front by pruning unused Docker data (the image is rebuilt fresh
+      # later anyway) and the apt cache.
+      - name: Free disk space
+        shell: bash
+        run: |
+          df -h / || true
+          docker system prune -af || true
+          docker builder prune -af || true
+          sudo apt-get clean || true
+          df -h / || true
+
       # Version = the UTC date of the HEAD commit, formatted yyyy.MM.dd.HHmm
       # (the project's documented version scheme). Deriving it from the commit
       # rather than "now" makes re-runs reproducible and keeps the image tag,