{
  "schema": "vedokrok.public-item.v1",
  "release_id": "MHC-RPUB-20260920-75ad787a",
  "url": "/knowledge/layer-safeguards-so-one-miss-is-not-the-last-chance",
  "id": "MHC-D-RESEARCH-1273",
  "version": "0.1.0",
  "title": "Layer safeguards so one miss is not the last chance",
  "summary": "One safeguard is also one point of failure.",
  "kind": "principle",
  "body": "For consequential paths, consider more than one protective layer: prevent the invalid action, detect deviation, contain its spread and recover if it escapes. Prefer layers that fail differently rather than repeating the same data, assumption or operator action. A second checkbox fed by the same wrong source is not much of a second defense.",
  "limits": [
    "More controls can add delay, complexity and new failure modes. Use layered protection where consequence and residual risk justify it."
  ],
  "topics": [
    "union-error-prevention-weak-signals"
  ],
  "intents": [],
  "source_ids": [
    "RS-4C0B325E51AB7663"
  ],
  "evidence": [
    {
      "claim": "CMS describes defense-in-depth as multiple coordinated security countermeasures and layers of protection rather than reliance on one control.",
      "source_id": "RS-4C0B325E51AB7663",
      "role": "supports",
      "note": "This is security architecture guidance. Applying layered protection to general operational errors is an editorial analogy that still requires domain-specific design.",
      "locator": "Defense-in-Depth"
    }
  ],
  "use_when": [
    "A single missed check, wrong assumption or failed control can directly create a high-cost consequence."
  ],
  "avoid_when": [
    "More controls can add delay, complexity and new failure modes. Use layered protection where consequence and residual risk justify it."
  ],
  "example": "A bulk data change can use input validation, a small canary batch, post-write reconciliation and a tested rollback path instead of trusting one pre-run review.",
  "check": "A single plausible control failure does not automatically become the final harmful state, and shared failure modes are named.",
  "sources": [
    {
      "id": "RS-4C0B325E51AB7663",
      "title": "TRA Guiding Principles",
      "url": "https://www.cms.gov/tra/Foundation/FD_0020_Foundation_Principles.htm"
    }
  ],
  "relations": [
    {
      "from": "MHC-D-RESEARCH-1273",
      "to": "MHC-D-RESEARCH-1274",
      "type": "useful_with",
      "url": "/knowledge/recheck-the-safeguard-after-the-workflow-changes"
    }
  ],
  "collections": [
    {
      "id": "RC-4BAD27B85771C63B",
      "title": "Catch weak signals before they become expensive errors",
      "url": "/collections/catch-weak-signals-before-they-become-expensive-errors"
    }
  ]
}