$ find fixtures/repo-sandbox/.m101/cache/sandbox-kits -maxdepth 3 | sort
fixtures/repo-sandbox/.m101/cache/sandbox-kits
fixtures/repo-sandbox/.m101/cache/sandbox-kits/<hash>
fixtures/repo-sandbox/.m101/cache/sandbox-kits/<hash>/manifest.json
fixtures/repo-sandbox/.m101/cache/sandbox-kits/<hash>/prompt_files
fixtures/repo-sandbox/.m101/cache/sandbox-kits/<hash>/skills

$ cat fixtures/repo-sandbox/.m101/cache/sandbox-kits/<hash>/manifest.json
{
  "agent_ref": "$CAPTURE/fixtures/agents/files-sandbox.yaml",
  "built_at": "<ts>"
}