{
  "schema": "vedokrok.public-item.v1",
  "release_id": "MHC-RPUB-20260920-75ad787a",
  "url": "/knowledge/start-with-what-changed-not-with-certainty-about-it",
  "id": "MHC-D-RESEARCH-0296",
  "version": "0.1.0",
  "title": "Start with what changed, not with certainty about it",
  "summary": "The last change deserves an interview, not an automatic conviction.",
  "kind": "heuristic",
  "body": "Build a short list of deployments, configuration changes, dependency changes, data-shape shifts and load changes near the onset of the symptom. Compare their timing with the first observable deviation. Use the list to prioritize tests, but require evidence that connects a change to the failure before calling it the cause.",
  "limits": [
    "Failures can emerge without a local deployment when dependencies, data, capacity or external conditions change."
  ],
  "topics": [
    "union-diagnostic-incident-work"
  ],
  "intents": [],
  "source_ids": [
    "RS-A4A16C807A94C9D8"
  ],
  "evidence": [
    {
      "claim": "Google SRE identifies recent deployments, configuration changes and environmental shifts as productive leads when troubleshooting sudden changes in behavior.",
      "source_id": "RS-A4A16C807A94C9D8",
      "role": "supports",
      "note": "Temporal proximity is a lead, not proof of causation; an unchanged component can still fail because its inputs or dependencies changed.",
      "locator": "What touched it last"
    }
  ],
  "use_when": [
    "A previously stable system suddenly changes behavior."
  ],
  "avoid_when": [
    "Failures can emerge without a local deployment when dependencies, data, capacity or external conditions change."
  ],
  "example": "A job starts timing out after a transport import; compare the failure window and behavior before assuming the transport is responsible.",
  "check": "At least one recent-change hypothesis becomes stronger or weaker because of a test, not because of chronology alone.",
  "sources": [
    {
      "id": "RS-A4A16C807A94C9D8",
      "title": "Effective Troubleshooting",
      "url": "https://sre.google/sre-book/effective-troubleshooting/"
    }
  ],
  "relations": [
    {
      "from": "MHC-D-RESEARCH-0296",
      "to": "MHC-D-RESEARCH-0297",
      "type": "useful_with",
      "url": "/knowledge/prefer-a-test-that-kills-hypotheses"
    }
  ],
  "collections": [
    {
      "id": "RC-6F9B0E6D320D1467",
      "title": "Find the fault without making the incident harder to understand",
      "url": "/collections/find-the-fault-without-making-the-incident-harder-to-understand"
    }
  ]
}