{
  "spec": "sak-package-signature/v1",
  "algorithm": "ed25519",
  "sha256": "a6fc518503ad7564e310a123bd3ac1124ee875b93834ae9bb305389c5d70033a",
  "signature": "29MnAw0HUmJnRbQv/YmAwkPgZwKDO69fqXZPaYSnWMG6+kGkHPXsqeII5QH29W2KyrtOK2k6rIbJHGxTY/osDw==",
  "signing_key_id": "0aff169ecb84607d",
  "signed_at": "2026-08-23T23:53:42.349Z",
  "slug": "rubric-grader",
  "version": "0.1.0",
  "filename": "rubric-grader-agent-plugin.zip",
  "bytes": 3400,
  "content_digest": "4a84bd89ed093a4ed1e68156e6f1173422c254cc09abc8af6373544805a2c229",
  "content_signature": "DpgHEOQJV6eQoRseOmPNYaShaWgYd9Inqh03UQzvadmtJYXD6R8fmOQYNrILoSYTBIebsnRiKkjn1Kx1KpccCQ==",
  "files": [
    {
      "path": "mcp.json",
      "sha256": "a4ec0149cccb566b6c4b6d8413290229819ff2adcfa9eb5387c3f91d31103a57"
    },
    {
      "path": "plugin.json",
      "sha256": "8cd70c015cc1318da3adb6b793f165a39d2a825fc73cf7bc73a1276eca893d72"
    },
    {
      "path": "skills/rubric-grader/SKILL.md",
      "sha256": "79b3f8ca5cf711a281d3c2aa536e44f65cf2e2f2f19811f84082ac95a5e1bcfc"
    }
  ],
  "verify": {
    "public_key_url": "https://superagentskill.com/api/public/signing-key.pem",
    "instructions": "sha256 the downloaded .zip, compare with `sha256`, then verify the base64 `signature` as an Ed25519 signature over the ascii sha256 hex string using the public key. An extracted or repacked copy can still be verified via `content_digest` / `content_signature`. Helper: node scripts/verify-package-signature.mjs <file.zip> <signature.json> [public-key.pem]"
  }
}