diff --git a/wrappers/crucible.sh b/wrappers/crucible.sh
new file mode 100755
index 0000000..cae4637
--- /dev/null
+++ b/wrappers/crucible.sh
@@ -0,0 +1,107 @@
+#!/usr/bin/env bash
+# crucible — bootstrap wrapper (POSIX/bash). Prefers a crucible already on PATH
+# (Nix devshell / installed); otherwise downloads the latest released binary
+# from Gitea into a per-version cache and execs it.
+#
+# CANONICAL SOURCE: sow-tools/wrappers/crucible.sh. Do not hand-edit copies in
+# consumer repos — they are kept in sync by sow-tools CI (see drift-check).
+#
+# Requires: bash, curl, and sha256sum (Linux) or shasum (macOS).
+# Env: CRUCIBLE_HOME (cache dir), CRUCIBLE_TOKEN (private releases),
+#      CRUCIBLE_GITEA (default https://git.westgate.pw),
+#      CRUCIBLE_REPO (default ShadowsOverWestgate/sow-tools).
+set -euo pipefail
+
+# 0. Prefer an existing crucible (Nix users, or already installed).
+if command -v crucible >/dev/null 2>&1; then
+  exec crucible "$@"
+fi
+
+gitea="${CRUCIBLE_GITEA:-https://git.westgate.pw}"
+repo="${CRUCIBLE_REPO:-ShadowsOverWestgate/sow-tools}"
+
+# 1. --repo-local materializes into <repo>/.crucible instead of the user cache.
+repo_local=0
+if [ "${1:-}" = "--repo-local" ]; then repo_local=1; shift; fi
+
+# 2. OS/arch -> asset name.
+os="$(uname -s)"; arch="$(uname -m)"
+case "$os" in
+  Linux)  os=linux ;;
+  Darwin) os=darwin ;;
+  *) echo "crucible: unsupported OS '$os' — install ffmpeg-free crucible manually" >&2; exit 1 ;;
+esac
+case "$arch" in
+  x86_64|amd64)  arch=amd64 ;;
+  aarch64|arm64) arch=arm64 ;;
+  *) echo "crucible: unsupported arch '$arch'" >&2; exit 1 ;;
+esac
+asset="crucible-${os}-${arch}"
+
+# 3. Auth: anonymous first, token fallback.
+token="${CRUCIBLE_TOKEN:-}"
+if [ -z "$token" ] && [ -f "$HOME/.config/crucible/token" ]; then
+  token="$(cat "$HOME/.config/crucible/token")"
+fi
+fetch() { # fetch URL DEST ; tries anon then token
+  if curl -fsSL "$1" -o "$2" 2>/dev/null; then return 0; fi
+  if [ -n "$token" ]; then curl -fsSL -H "Authorization: token $token" "$1" -o "$2"; return $?; fi
+  return 1
+}
+fetch_stdout() { # prints body; anon then token
+  if curl -fsSL "$1" 2>/dev/null; then return 0; fi
+  if [ -n "$token" ]; then curl -fsSL -H "Authorization: token $token" "$1"; return $?; fi
+  return 1
+}
+
+# 4. Resolve the latest release tag (no jq dependency).
+api="${gitea}/api/v1/repos/${repo}/releases/latest"
+tag="$(fetch_stdout "$api" 2>/dev/null | grep -o '"tag_name":"[^"]*"' | head -1 | cut -d'"' -f4 || true)"
+
+# 5. Cache dir.
+if [ "$repo_local" = 1 ]; then
+  cache_root="$(cd "$(dirname "$0")" && pwd)/.crucible"
+else
+  cache_root="${CRUCIBLE_HOME:-${XDG_CACHE_HOME:-$HOME/.cache}/crucible}"
+fi
+
+# 6. Offline fallback: if tag lookup failed, use the newest cached version.
+if [ -z "$tag" ]; then
+  if [ -d "$cache_root" ]; then
+    cached="$(ls -1 "$cache_root" 2>/dev/null | sort -V | tail -1 || true)"
+    if [ -n "$cached" ] && [ -x "$cache_root/$cached/crucible" ]; then
+      echo "crucible: offline — using cached $cached" >&2
+      exec "$cache_root/$cached/crucible" "$@"
+    fi
+  fi
+  echo "crucible: cannot reach $gitea and no cached binary found." >&2
+  echo "  set CRUCIBLE_TOKEN if releases are private, or check the network." >&2
+  exit 1
+fi
+
+dest_dir="$cache_root/$tag"
+bin="$dest_dir/crucible"
+
+# 7. Download + verify on cache miss.
+if [ ! -x "$bin" ]; then
+  mkdir -p "$dest_dir"
+  base="${gitea}/${repo}/releases/download/${tag}"
+  tmp="$(mktemp -d)"; trap 'rm -rf "$tmp"' EXIT
+  echo "crucible: fetching ${asset} ${tag}..." >&2
+  fetch "${base}/${asset}" "$tmp/crucible" || { echo "crucible: download failed for ${asset}" >&2; exit 1; }
+  if fetch "${base}/SHA256SUMS" "$tmp/SHA256SUMS"; then
+    want="$(grep " ${asset}\$" "$tmp/SHA256SUMS" | awk '{print $1}')"
+    if command -v sha256sum >/dev/null 2>&1; then
+      got="$(sha256sum "$tmp/crucible" | awk '{print $1}')"
+    else
+      got="$(shasum -a 256 "$tmp/crucible" | awk '{print $1}')"
+    fi
+    if [ -n "$want" ] && [ "$want" != "$got" ]; then
+      echo "crucible: checksum mismatch for ${asset} (want $want got $got)" >&2; exit 1
+    fi
+  fi
+  chmod +x "$tmp/crucible"
+  mv "$tmp/crucible" "$bin"
+fi
+
+exec "$bin" "$@"