diff --git a/packages/adapter-utils/src/sandbox-managed-deletions.test.ts b/packages/adapter-utils/src/sandbox-managed-deletions.test.ts
new file mode 100644
index 00000000000..caeed78cba1
--- /dev/null
+++ b/packages/adapter-utils/src/sandbox-managed-deletions.test.ts
@@ -0,0 +1,79 @@
+import { execFile } from "node:child_process";
+import fs from "node:fs/promises";
+import os from "node:os";
+import path from "node:path";
+import { promisify } from "node:util";
+import { afterEach, expect, it } from "vitest";
+import { prepareSandboxManagedRuntime, type SandboxManagedRuntimeClient } from "./sandbox-managed-runtime.js";
+
+const exec = promisify(execFile);
+const roots: string[] = [];
+afterEach(async () => {
+  for (const root of roots.splice(0)) await fs.rm(root, { recursive: true, force: true });
+});
+
+async function deletedFixture(names: string[], beforeDelete?: (remote: string) => Promise<void>) {
+  const root = await fs.mkdtemp(path.join(os.tmpdir(), "sandbox-deletions-"));
+  roots.push(root);
+  const source = path.join(root, "source"), remote = path.join(root, "remote");
+  await fs.mkdir(source);
+  const git = (...args: string[]) => exec("git", ["-C", source, ...args]);
+  await git("init");
+  for (const name of names) {
+    await fs.mkdir(path.dirname(path.join(source, name)), { recursive: true });
+    await fs.writeFile(path.join(source, name), "tracked content");
+  }
+  await git("add", "--", ".");
+  await git("-c", "user.name=Test", "-c", "user.email=test@example.test", "commit", "-qm", "fixture");
+  for (const name of names) await fs.rm(path.join(source, name));
+  const client: SandboxManagedRuntimeClient = {
+    makeDir: async directory => { await fs.mkdir(directory, { recursive: true }); },
+    writeFile: async (file, bytes) => { await fs.writeFile(file, Buffer.from(bytes)); },
+    readFile: file => fs.readFile(file),
+    listFiles: directory => fs.readdir(directory),
+    remove: file => fs.rm(file, { recursive: true, force: true }),
+    run: async command => { await exec("sh", ["-c", command]); },
+    syncIn: async operations => {
+      for (const operation of operations) {
+        for (const mapping of operation.files) {
+          await fs.mkdir(path.dirname(mapping.targetPath), { recursive: true });
+          await fs.copyFile(mapping.sourcePath, mapping.targetPath);
+        }
+        for (const { command } of operation.postUploadCommands ?? []) {
+          if (command.includes("xargs -0")) await beforeDelete?.(remote);
+          await exec("sh", ["-c", command]);
+        }
+      }
+      return { operations: [] };
+    },
+  };
+  return { root, remote, prepare: () => prepareSandboxManagedRuntime({
+    spec: { transport: "sandbox", provider: "test", sandboxId: "test", remoteCwd: remote, timeoutMs: 30_000, apiKey: null },
+    client, adapterKey: "test", workspaceLocalDir: source,
+  }) };
+}
+
+it("deletes multiple bounded batches with newline, whitespace, Unicode and leading-dash filenames", async () => {
+  const names = [" space ", "line\nbreak", "-option", "雪-💾", "wild[?]*",
+    ...Array.from({ length: 130 }, (_, index) => `nested/file-${index}`)];
+  const fixture = await deletedFixture(names);
+  const runtime = await fixture.prepare();
+  try {
+    for (const name of names) await expect(fs.lstat(path.join(fixture.remote, name))).rejects.toMatchObject({ code: "ENOENT" });
+  } finally { await runtime.cleanupWorkspaceSnapshot(); }
+});
+
+it.each(["symlink", "non_directory"] as const)("rejects a %s ancestor before deleting any entry in its batch", async kind => {
+  let outside: string;
+  const fixture = await deletedFixture(["a-valid", "z-parent/secret"], async remote => {
+    outside = path.join(path.dirname(remote), "outside");
+    await fs.mkdir(outside);
+    await fs.writeFile(path.join(outside, "secret"), "private content");
+    await fs.rm(path.join(remote, "z-parent"), { recursive: true });
+    if (kind === "symlink") await fs.symlink(outside, path.join(remote, "z-parent"));
+    else await fs.writeFile(path.join(remote, "z-parent"), "blocker");
+  });
+  await expect(fixture.prepare()).rejects.toThrow();
+  expect(await fs.readFile(path.join(outside!, "secret"), "utf8")).toBe("private content");
+  expect(await fs.readFile(path.join(fixture.remote, "a-valid"), "utf8")).toBe("tracked content");
+});
diff --git a/packages/adapter-utils/src/sandbox-managed-runtime.ts b/packages/adapter-utils/src/sandbox-managed-runtime.ts
index 8e51464ebb0..4bc6ba4e34f 100644
--- a/packages/adapter-utils/src/sandbox-managed-runtime.ts
+++ b/packages/adapter-utils/src/sandbox-managed-runtime.ts
@@ -714,15 +714,16 @@ function buildWorkspaceTarExtractCommand(input: {
 // already-confined relative paths from the git snapshot.
 function buildRemoveDeletedPathsCommand(input: { remoteDir: string; manifestPath: string }): string {
   // NUL input plus bounded xargs batches preserve whitespace and never create
-  // one argument list for the full snapshot. Refuse symlink ancestors.
+  // one argument list for the full snapshot. Validate the whole batch before
+  // removing anything, then avoid starting a separate rm process per path.
   const remove = `for entry do
     parent=$entry
     while [ "\${parent#*/}" != "$parent" ]; do
       parent=\${parent%/*}
       if [ -L "$parent" ] || { [ -e "$parent" ] && [ ! -d "$parent" ]; }; then exit 42; fi
     done
-    rm -rf -- "$entry" || exit
-  done`;
+  done
+  rm -rf -- "$@"`;
   return `cd ${shellQuote(input.remoteDir)} && xargs -0 -r -n 64 sh -c ${shellQuote(remove)} sh < ${shellQuote(input.manifestPath)} && rm -f -- ${shellQuote(input.manifestPath)}`;
 }