{
  "handle": "CircuitBreaker",
  "mechanism": "{{state}} machine wrapper for fallible operations. Monitors failure rates of a target resource. States: (1) 'CLOSED': Requests pass normally. (2) 'OPEN': Requests fail immediately (Fail Fast) without invoking target. (3) 'HALF-OPEN': Limited trial requests allowed to test recovery. Transitions: 'CLOSED' -> 'OPEN' if failure count > threshold. 'OPEN' -> 'HALF-OPEN' after reset timeout. It wraps operations, switching to an open state on failure to prevent cascading overloads, while using {{backoff}} and retry logic to schedule recovery probes.",
  "gloss": "Fail-fast protection against cascading failures",
  "failure_modes": [
    "Flapping: Threshold too sensitive causes circuit to oscillate between Open/Closed.",
    "Zombie {{state}}: Circuit stuck 'OPEN' because reset logic failed to trigger or persists in failure.",
    "False Positive: Transient network blips trip circuit, blocking healthy traffic."
  ],
  "invariants": [
    "Fail Fast: If {{state}} == 'OPEN', request MUST be rejected immediately with zero backend cost.",
    "Leakage Protection: In 'HALF-OPEN' state, concurrency is capped (default: 1) to prevent flood during recovery.",
    "{{state}} Persistence: Failure counts reset only on successful transition to 'CLOSED'."
  ],
  "preconditions": [
    "Failure threshold defined",
    "Target resource identified"
  ],
  "postconditions": [
    "Internal state updated based on outcome",
    "Request processed OR Blocked"
  ],
  "parameters": [
    {
      "name": "failure_threshold",
      "type": "Integer",
      "range": "[1, 100]",
      "description": "Default: 5"
    },
    {
      "name": "half_open_limit",
      "type": "Integer",
      "range": "[1, 10]",
      "description": "Max probes allowed in half-open state"
    },
    {
      "name": "reset_timeout",
      "type": "Duration",
      "range": "unspecified",
      "description": "Default: 60s"
    }
  ],
  "_meta": {
    "tier": 1,
    "ring": 1,
    "supersedes": [
      "sema:CircuitBreaker#mh:SHA-256:41621375faf5609423cb05060fbdccf92c6d8f856607a2ae4bf35a76c90cbaec",
      "sema:CircuitBreaker#mh:SHA-256:840fee4c2a300c1e17bd44e55debdf58d250ab62f79760f59c0189ca7d485824"
    ],
    "path": [
      "Infrastructure",
      "Primitives"
    ],
    "related": [
      "StopDrill#dcfb"
    ]
  },
  "sema_id": "sema:CircuitBreaker#mh:SHA-256:3caa9c387c04bb2ac66ec35a6cfe2665e11339f0d47576b96d68229226580c76",
  "sema_ref": "CircuitBreaker#3caa",
  "sema_stub": "3caa",
  "dependencies": {
    "references": {
      "backoff": "sema:Backoff#mh:SHA-256:9e59718422f5408d7892feccb6d538a21103f9573b122b891ee3c8cf66303e72",
      "state": "sema:State#mh:SHA-256:4f25e6a16ccd37dc0bc154cccc7055cb504d49daa8b712f372a425eb6c7b8cb2"
    }
  },
  "sema_layer": "Infrastructure",
  "sema_category": "Primitives",
  "used_by": {
    "references": {
      "Exception": "sema:Exception#mh:SHA-256:ae9485039008abed9587e74c05a8c31c37d9a8f70347a11c0630fe87673fb7bb",
      "FailClosed": "sema:FailClosed#mh:SHA-256:dfbcf50c68d036ae4f18719bf59f41eddd83b5510bd60ff1326f8854240d8066",
      "Retry": "sema:Retry#mh:SHA-256:4f9fdfc5b1dafd31221e9426d62c02af80c6356ef5b446eddd3f50da961d1aa2",
      "StopDrill": "sema:StopDrill#mh:SHA-256:dcfbfbf008197ff98cd87c9750daf4a8fbff691cd733431c1d0965e0947dbfe6"
    },
    "composes_with": {
      "Rollout": "sema:Rollout#mh:SHA-256:ea8c8bdf3303e53d240d6393a776de33ff7c0980a269539d6eb22a8b35e430b4"
    }
  }
}