{
  "contract_id": "numeric-port-field-partitions-v1",
  "status": "Newly authored fictional field-validation contract; not inferred product, customer or OS behavior.",
  "tested_boundary": "Direct exported Python function call with an already supplied exact integer. No text/bytes parser, type-validation adapter or network operation is executed.",
  "incoming_domain": {
    "precondition": "type(port) is int, excluding bool. All negative, zero and positive Python integers are admitted inputs to this exercise interface.",
    "invalid_values_remain_in_domain": "The incoming domain includes integers below 1 and above 65535. They reach the callable and must be rejected; the domain is not restricted to the valid subset.",
    "other_types": "Outside the declared precondition, unspecified and unperformed. No upstream guarantee or runtime type validator is established by this kit.",
    "integer_representation": "Python int has arbitrary precision; no fixed-width overflow or text parsing is tested."
  },
  "valid_subset": "Exact integers 1 through 65535 inclusive, within the wider incoming integer domain.",
  "written_rules": [
    {
      "class_id": "below",
      "predicate": "port < 1",
      "whole_response": "accepted is bool False, reason is exact str too_low; no other keys."
    },
    {
      "class_id": "valid",
      "predicate": "1 <= port <= 65535",
      "whole_response": "accepted is bool True, port is exact int equal to incoming port; no other keys."
    },
    {
      "class_id": "above",
      "predicate": "port > 65535",
      "whole_response": "accepted is bool False, reason is exact str too_high; no other keys."
    }
  ],
  "equivalence_criterion": "The authored classes share the specified response category and invalid reason; valid members must obey the same input-preservation relation. This is not identical numeric payload, identical execution path, or measured equivalence of all members.",
  "selection_plan": {
    "initial_representatives": {
      "below": -1,
      "valid": 443,
      "above": 65536
    },
    "representative_justification": "Each is a concrete member of a different written-rule class. This samples all three identified classes but does not establish defect homogeneity or every member.",
    "boundary_complement": "For inclusive lower 1 select 0/1/2; for inclusive upper 65535 select 65534/65535/65536. Literal whole responses are in cases.json.",
    "refinement": "Retain the three rule classes. Refine test-selection strata into below/lower endpoint/interior/upper endpoint/above witnesses after the endpoint defect. Do not change the required endpoint behavior to match baseline.",
    "overlap": "65536 is both the initial above representative and upper outside neighbor. 3 + 6 - 1 = 8 distinct values; boundary selection is not six new classes.",
    "boundary_convention": "The six neighbors surround the two accepted endpoints only. This is not every neighbor of every invalid-class endpoint, exhaustive boundary testing, or a standard-wide BVA denominator."
  },
  "oracle": "Independent literal whole responses, including exact keys and exact value types. Python bool/int equality alone cannot satisfy the typed contract.",
  "state_policy": "Pure helper, one exact exported call per case; no persistent state, side effects, network or service.",
  "implementations": {
    "baseline": "Wrong inclusive-upper comparison port >= 65535 rejects the endpoint.",
    "corrected": "Actual port > 65535 upper comparison preserves the accepted endpoint.",
    "accept-all": "Deliberately wrong control accepts every integer; selected invalid classes must detect it.",
    "reject-all": "Deliberately wrong control always rejects; selected valid class must detect it. Its reason is too_low below 1 and too_high otherwise."
  },
  "interpretation": "Representative pass, selected boundary pass, and class equivalence/all-input correctness are different claims. Passing eight selected values cannot prove classes behave uniformly or close a defect class.",
  "exclusions": [
    "No historical execution authenticated: the old port table was illustrative. All captured runs are new.",
    "No product, customer or network incident or discovered production defect.",
    "The fictional rejection of 0 is not general socket-bind, OS or network-port policy.",
    "No text/byte parser, malformed string, boolean/type validator, fixed-width overflow, upstream contract, container/duration/resource/concurrency or network behavior is executed.",
    "No exhaustive input enumeration, formal proof, statistical sampling, mutation-campaign score or all-member class equivalence is demonstrated.",
    "No Proof CLI, solver, generated model witness or authored data-constraint check is executed by this standard-library kit."
  ]
}