diff --git a/tools/ci/chunk_dl.py b/tools/ci/chunk_dl.py
new file mode 100644
index 00000000..9b83c54c
--- /dev/null
+++ b/tools/ci/chunk_dl.py
@@ -0,0 +1,88 @@
+#!/usr/bin/env python3
+r"""chunk_dl.py — 分片并行下载器（断点续传），2026-11-03 CI 迁移批收编。
+
+背景：GitHub 直连在本项目两台机器均不可用，加速镜像站速度慢且会掐连接/回错误页。
+本件把大文件切成 N 片经镜像并行拉取（单片断了自动续传重试），全部齐后拼合。
+已实证：74MB Godot Linux 包约 15 分钟拉完（2026-11-03 mac_setup 依赖此件拉 Godot macOS 包）。
+
+用法: python3 tools/ci/chunk_dl.py <URL> <输出路径> [分片数=16]
+镜像回落顺序：直连 → gh-proxy.net → gh-proxy.com（HEAD 探测 Content-Length 决定实际用的源）。
+校验：分片按字节范围落盘、按序拼合；zip 结构校验由调用方（mac_setup.sh 的 unzip -tq）承担。
+退出码：0=成功 1=失败。
+"""
+import concurrent.futures as cf
+import os
+import subprocess
+import sys
+
+MIRRORS = ["", "https://gh-proxy.net/", "https://gh-proxy.com/"]
+
+
+def pick_mirror(url: str):
+    """HEAD 探测取 Content-Length；返回（实际可用 URL, 字节数）或 (None, 0)。"""
+    for m in MIRRORS:
+        u = m + url
+        r = subprocess.run(["curl", "-sIL", "-m", "30", u], capture_output=True, text=True)
+        size = 0
+        for line in r.stdout.splitlines():
+            if line.lower().startswith("content-length:"):
+                try:
+                    size = int(line.split(":", 1)[1].strip())
+                except ValueError:
+                    size = 0
+        if size > 0:
+            return u, size
+    return None, 0
+
+
+def fetch(job) -> bool:
+    i, s, e, url, out = job
+    p = "%s.part%02d" % (out, i)
+    want = e - s + 1
+    for _attempt in range(200):
+        have = os.path.getsize(p) if os.path.exists(p) else 0
+        if have >= want:
+            return True
+        r0 = s + have
+        subprocess.run(
+            ["curl", "-sL", "--speed-limit", "1024", "--speed-time", "30",
+             "-m", "600", "-r", "%d-%d" % (r0, e), "-o", p + ".new", url],
+            capture_output=True)
+        if os.path.exists(p + ".new"):
+            with open(p, "ab") as f, open(p + ".new", "rb") as g:
+                f.write(g.read())
+            os.remove(p + ".new")
+    return False
+
+
+def main() -> int:
+    if len(sys.argv) < 3:
+        print("用法: python3 chunk_dl.py <URL> <输出路径> [分片数=16]")
+        return 1
+    url, out = sys.argv[1], sys.argv[2]
+    n = int(sys.argv[3]) if len(sys.argv) > 3 else 16
+    real, size = pick_mirror(url)
+    if not real:
+        print("全部下载源失败")
+        return 1
+    print("size=%d url=%s" % (size, real), flush=True)
+    chunk = (size + n - 1) // n
+    jobs = [(i, i * chunk, min((i + 1) * chunk, size) - 1, real, out)
+            for i in range(n) if i * chunk < size]
+    with cf.ThreadPoolExecutor(n) as ex:
+        for ok in ex.map(fetch, jobs):
+            if not ok:
+                print("分片重试耗尽")
+                return 1
+    with open(out, "wb") as f:
+        for i, _, _, _, _ in jobs:
+            with open("%s.part%02d" % (out, i), "rb") as g:
+                f.write(g.read())
+    for i, _, _, _, _ in jobs:
+        os.remove("%s.part%02d" % (out, i))
+    print("done %d" % os.path.getsize(out))
+    return 0
+
+
+if __name__ == "__main__":
+    sys.exit(main())
diff --git a/tools/ci/mac_setup.sh b/tools/ci/mac_setup.sh
index a1b592ef..d479eaf2 100644
--- a/tools/ci/mac_setup.sh
+++ b/tools/ci/mac_setup.sh
@@ -15,8 +15,8 @@
 # 幂等：重复执行只补缺件；账户密码首次生成后存 /var/db/gplan-ci-runner.pw（root 600），重跑复用。
 set -euo pipefail
 
-GODOT_VER="4.7.2-stable"
-GODOT_URL="https://github.com/godotengine/godot/releases/download/${GODOT_VER}/Godot_${GODOT_VER}-stable_macos.universal.zip"
+GODOT_VER="4.7.2"
+GODOT_URL="https://github.com/godotengine/godot/releases/download/${GODOT_VER}-stable/Godot_v${GODOT_VER}-stable_macos.universal.zip"
 GDSTYLE_VER="0.4.0"
 GDSTYLE_URL="https://github.com/atelico/gdstyle/releases/download/v${GDSTYLE_VER}/gdstyle-x86_64-apple-darwin.tar.gz"
 MIRRORS=("" "https://gh-proxy.net/" "https://gh-proxy.com/")   # 直连优先，镜像回落
@@ -94,12 +94,16 @@ else
 		_ok=0
 		for m in "${MIRRORS[@]}"; do
 			log "下载 Godot（${m:+经 $m}）"
-			if curl -fL --retry 2 -m 1800 -o "$ZIP" "${m}${GODOT_URL}"; then _ok=1; break; fi
+			# 镜像站可能回 200 的错误页体——下载后必须验 zip 结构，假成功当失败处理
+			if curl -fL --retry 2 -m 1800 -o "$ZIP" "${m}${GODOT_URL}" && unzip -tq "$ZIP" >/dev/null 2>&1; then
+				_ok=1; break
+			fi
 			log "该源失败，换下一源"
 		done
-		[ "$_ok" = 1 ] || die "全部下载源失败——手动下载 ${GODOT_URL} 后重跑并加 --godot-zip <路径>"
+		[ "$_ok" = 1 ] || die "全部下载源失败——手动下载 ${GODOT_URL} 后重跑并加 --godot-zip <路径>；或用 tools/ci/chunk_dl.py 分片拉取"
 	fi
 	TMPD="$(mktemp -d)"
+	unzip -tq "$ZIP" >/dev/null   # 双保险：本地复用的 zip 同样验结构
 	unzip -q -o "$ZIP" -d "$TMPD"
 	install -m 0755 "${TMPD}/Godot.app/Contents/MacOS/Godot" /usr/local/bin/godot
 	xattr -dr com.apple.quarantine /usr/local/bin/godot 2>/dev/null || true