{
  "instruction": "Isolate error handling per dependency so one failing service does not take down the entire response",
  "relevant_when": "Agent writes code that aggregates data from multiple external services, APIs, or databases in a single endpoint or function",
  "context": "When an endpoint fetches data from multiple external sources (e.g., weather + stocks + news), each source must be wrapped in its own error handling. If all sources are fetched inside a single try/catch or with Promise.all(), one failing source crashes the entire response. Use Promise.allSettled() or individual try/catch blocks per source so that available data is still returned when some sources fail. Include a warnings or errors field in the response indicating which sources are unavailable.",
  "sources": [
    {
      "type": "file",
      "filename": "skills/graceful-degradation/SKILL.md",
      "tile": "tessl-labs/graceful-degradation@0.2.0"
    }
  ],
  "checklist": [
    {
      "name": "independent-error-handling-per-source",
      "rule": "Each external data source has its own try/catch block or uses Promise.allSettled(), so that one source failing does not prevent other sources from being returned",
      "relevant_when": "Agent writes an endpoint or function that fetches from multiple external services"
    },
    {
      "name": "no-promise-all-for-external-calls",
      "rule": "Promise.all() is not used to fetch multiple external services in parallel. Use Promise.allSettled() instead, which does not reject when one promise fails.",
      "relevant_when": "Agent writes code that fetches from multiple external APIs or services in parallel"
    },
    {
      "name": "partial-response-with-warnings",
      "rule": "When some data sources fail, the response includes available data plus a warnings or errors field listing which sources are unavailable, rather than returning a complete error",
      "relevant_when": "Agent writes aggregation endpoints that combine data from multiple external sources"
    }
  ]
}