diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index aa5d701f..060ed0dd 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -86,18 +86,26 @@ jobs:
           pip install -r scripts/requirements.txt
       - name: "📦 Asset creation"
         run: |
+          if [[ "${GITHUB_REF}" == refs/tags/* ]]; then
+            export RELEASE="${GITHUB_REF/refs\/tags\//}"
+          else
+            export RELEASE="unstable"
+          fi
           # The output path matches the final deployment path at spec.matrix.org
           scripts/dump-swagger.py \
             --base-url "https://spec.matrix.org${{ needs.calculate-baseurl.outputs.baseURL }}" \
             --api application-service \
+            -r "$RELEASE" \
             -o spec/application-service-api/api.json
           scripts/dump-swagger.py \
             --base-url "https://spec.matrix.org${{ needs.calculate-baseurl.outputs.baseURL }}" \
             --api client-server \
+            -r "$RELEASE" \
             -o spec/client-server-api/api.json
           scripts/dump-swagger.py \
             --base-url "https://spec.matrix.org${{ needs.calculate-baseurl.outputs.baseURL }}" \
             --api push-gateway \
+            -r "$RELEASE" \
             -o spec/push-gateway-api/api.json
           tar -czf openapi.tar.gz spec
       - name: "📤 Artifact upload"
diff --git a/changelogs/internal/newsfragments/1561.clarification b/changelogs/internal/newsfragments/1561.clarification
new file mode 100644
index 00000000..6381ddf3
--- /dev/null
+++ b/changelogs/internal/newsfragments/1561.clarification
@@ -0,0 +1 @@
+Use tag name as the OpenAPI definition version.