{
  "$schema": "https://themachinepress.com/schemas/story-v1.schema.json",
  "schema_version": "1.0.0",
  "document_type": "machine_press_story",
  "story": {
    "story_id": "mp-2026-09-28-003",
    "source_story_id": "tmp-story-skill-cascading-attacks",
    "edition_id": "mp-2026-09-28-morning-0081",
    "edition_url": "https://themachinepress.com/edition/2026-09-28",
    "position": 3,
    "story_type": "dispatch",
    "section": "safety-security",
    "editorial_classification": "editorial",
    "headline": "Harmless-Looking Skills Combined Into One Attack",
    "slug": "harmless-looking-skills-combined-into-one-attack",
    "dek": "SkillCascade split malicious intent across components so per-skill scanners missed the whole behavior.",
    "summary": "SkillCascade split malicious intent across components so per-skill scanners missed the whole behavior.",
    "body_text": "The researchers define a skill-cascading attack as a harmful objective distributed across multiple agent skills, each modification appearing benign on its own. Their SkillCascade-Bench contains 213 validated test cases across several agent systems and domains. In the reported experiments, cascades induced harmful behavior while evading component-level scanners and runtime monitors. The preprint's examples and rates belong to its selected agents, backbones and threat models, but the structural warning is broader: reviewing packages independently can miss risk that exists only in composition.",
    "why_it_matters": "SkillCascade split malicious intent across components so per-skill scanners missed the whole behavior.",
    "limitations": [
      "The preprint's examples and rates belong to its selected agents, backbones and threat models, but the structural warning is broader: reviewing packages independently can miss risk that exists only in composition."
    ],
    "importance": 9,
    "canonical_url": "https://themachinepress.com/story/mp-2026-09-28-003/harmless-looking-skills-combined-into-one-attack",
    "json_url": "https://themachinepress.com/story/mp-2026-09-28-003.json",
    "first_published_at": "2026-09-28T09:00:00.000-04:00",
    "modified_at": "2026-09-28T09:00:00.000-04:00",
    "content_status": "new",
    "is_carryover": false,
    "carryover_reason": null,
    "key_claims": [
      {
        "claim_id": "claim-mp-2026-09-28-003-001",
        "text": "SkillCascade split malicious intent across components so per-skill scanners missed the whole behavior.",
        "source_ids": [
          "source-2026-09-28-003"
        ],
        "qualification": "The preprint's examples and rates belong to its selected agents, backbones and threat models, but the structural warning is broader: reviewing packages independently can miss risk that exists only in composition."
      }
    ],
    "source_ids": [
      "source-2026-09-28-003"
    ],
    "tags": [
      "agent skills",
      "supply-chain security",
      "red teaming"
    ],
    "image_url": "https://themachinepress.com/issues/2026-09-28/skill-cascade-laptop.webp",
    "corrections": []
  },
  "sources": [
    {
      "source_id": "source-2026-09-28-003",
      "title": "arXiv preprint 2609.30383",
      "publisher": "arXiv",
      "url": "https://arxiv.org/abs/2609.30383",
      "canonical_url": "https://arxiv.org/abs/2609.30383",
      "source_type": "primary_research",
      "is_primary_source": true,
      "published_at": "2026-09-24T14:00:18.000-04:00",
      "accessed_at": "2026-09-28T08:26:00.000-04:00",
      "supports_claim_ids": [
        "claim-mp-2026-09-28-003-001"
      ]
    }
  ],
  "corrections": [],
  "publisher": {
    "name": "The Machine Press",
    "url": "https://themachinepress.com",
    "description": "A daily newspaper for the age of artificial intelligence."
  },
  "cite_this_report": {
    "title": "Harmless-Looking Skills Combined Into One Attack",
    "publisher": "The Machine Press",
    "published_at": "2026-09-28T09:00:00.000-04:00",
    "canonical_url": "https://themachinepress.com/story/mp-2026-09-28-003/harmless-looking-skills-combined-into-one-attack"
  }
}