diff --git a/.crow/build-all-versions-install-deps.yaml b/.crow/build-all-versions-install-deps.yaml
index 61e3dea..ee7ec16 100644
--- a/.crow/build-all-versions-install-deps.yaml
+++ b/.crow/build-all-versions-install-deps.yaml
@@ -1,10 +1,33 @@
 # Consolidated install-deps for build-all (both arches in one file).
-# Arch is a matrix axis; the existing task selector still routes it:
-#   task == "build-all-amd64" runs the amd64 row, "build-all-arm64" the arm64 row.
-# OS / OS_VERSION / R_VERSION / K8S_INSTANCE_TYPE are still passed via --var.
+# Triggered together with build-all-versions; `target_arch` routes the matrix.
+# Variables are declared so the manual-run form exposes them (crow #1165);
+# they are merged with build-all-versions' identical declarations.
+variables:
+  target_arch:
+    description: "Architecture to build."
+    options:
+      - amd64
+      - arm64
+    default: amd64
+  OS:
+    description: "Base OS image name (e.g. alpine, redhat, ubuntu)."
+    default: alpine
+  OS_VERSION:
+    description: "OS version / image tag (e.g. 3.24, 9, jammy, noble)."
+    default: "3.24"
+  R_VERSION:
+    description: "Primary R version under /opt/R."
+    options:
+      - 4.5.3
+      - 4.4.3
+    default: 4.5.3
+  K8S_INSTANCE_TYPE:
+    description: "k8s node instance-type (amd64/kubernetes only; ignored for arm64/docker)."
+    default: AX42
+
 when:
   - event: manual
-    evaluate: 'task == "build-all-${ARCH}"'
+    evaluate: 'target_arch == "${ARCH}"'
 
 skip_clone: true
 
diff --git a/.crow/build-all-versions.yaml b/.crow/build-all-versions.yaml
index 36969b2..4912c73 100644
--- a/.crow/build-all-versions.yaml
+++ b/.crow/build-all-versions.yaml
@@ -1,12 +1,34 @@
-### Required extra vars (passed via --var at manual trigger time)
-# OS (alpine) / OS_VERSION (3.22) / R_VERSION (4.5.3) / K8S_INSTANCE_TYPE (amd64)
-# Arch is selected by the task name and routed via the matrix:
-#   crow pipeline create --var task=build-all-amd64 --var OS=alpine --var OS_VERSION=3.24 --var R_VERSION=4.5.3 --var K8S_INSTANCE_TYPE=... --branch=main 5
-#   crow pipeline create --var task=build-all-arm64 --var OS=alpine --var OS_VERSION=3.24 --var R_VERSION=4.5.3 --branch=main 5
+### Manual full rebuild of all CRAN binaries for one OS/arch.
+# Set the variables below in the manual-run form (or via --var on the CLI).
+# `target_arch` routes the matrix; OS/OS_VERSION/R_VERSION/K8S_INSTANCE_TYPE
+# select the platform image, cache volume and node.
 # Skip list lives in local/excluded-packages.json (read by local/build-all.R).
+variables:
+  target_arch:
+    description: "Architecture to build."
+    options:
+      - amd64
+      - arm64
+    default: amd64
+  OS:
+    description: "Base OS image name (e.g. alpine, redhat, ubuntu)."
+    default: alpine
+  OS_VERSION:
+    description: "OS version / image tag (e.g. 3.24, 9, jammy, noble)."
+    default: "3.24"
+  R_VERSION:
+    description: "Primary R version under /opt/R."
+    options:
+      - 4.5.3
+      - 4.4.3
+    default: 4.5.3
+  K8S_INSTANCE_TYPE:
+    description: "k8s node instance-type (amd64/kubernetes only; ignored for arm64/docker)."
+    default: AX42
+
 when:
   - event: manual
-    evaluate: 'task == "build-all-${ARCH}"'
+    evaluate: 'target_arch == "${ARCH}"'
 
 skip_clone: true