diff --git a/.gitea/workflows/release.yml b/.gitea/workflows/release.yml
index 16ddb32..f92d4fc 100644
--- a/.gitea/workflows/release.yml
+++ b/.gitea/workflows/release.yml
@@ -44,6 +44,21 @@ jobs:
           # the history to do that.
           fetch-depth: 0
 
+      - name: The tools this release needs are present
+        # Checked first, because everything below takes about ten minutes and
+        # discovering that the runner image has no python3 at the publishing
+        # step means doing all of it again.
+        run: |
+          missing=
+          for t in git curl python3 tar; do
+            command -v "$t" >/dev/null 2>&1 || missing="$missing $t"
+          done
+          if [ -n "$missing" ]; then
+            echo "::error::This runner is missing:$missing"
+            exit 1
+          fi
+          echo "git, curl, python3 and tar are all present."
+
       - name: The header version is the tag
         run: |
           HEADER=$(ci/version.sh)
diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index bb82eb0..d37a73c 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -50,6 +50,21 @@ jobs:
           # the history to do that.
           fetch-depth: 0
 
+      - name: The tools this release needs are present
+        # Checked first, because everything below takes about ten minutes and
+        # discovering that the runner image has no python3 at the publishing
+        # step means doing all of it again.
+        run: |
+          missing=
+          for t in git curl python3 tar; do
+            command -v "$t" >/dev/null 2>&1 || missing="$missing $t"
+          done
+          if [ -n "$missing" ]; then
+            echo "::error::This runner is missing:$missing"
+            exit 1
+          fi
+          echo "git, curl, python3 and tar are all present."
+
       - name: The header version is the tag
         run: |
           HEADER=$(ci/version.sh)