{"abstract":"Equal gate scores route according to arrival order.","category":"Mixture of experts dispatch","checks":6,"contract":"Choose the maximum-scoring expert; ties select the lexically smallest ID.","contract_signature":"scores","evaluation_group":"moe-stable-tie","failed_approach":"Reversing the input list still reverses the selected expert.","family":"w3-mixture-of-experts-dispatch-stable-tie","id":"FA-100546","implementations":{"attempt":{"sha256":"61eb5cebe25ae8733440c404f9701d3b640e8e71ff80799d656798166b96240c","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(scores):\n    return sorted(scores,key=lambda x:-x[1])[0][0]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('reverse tie',solve([('z',N),('a',N)]),'a')\ncheck('higher score',solve([('a',N),('b',N+1)]),'b')\ncheck('three-way tie',solve([('c',0),('b',0),('a',0)]),'a')\ncheck('negative',solve([('a',-N),('b',-N-1)]),'a')\ncheck('singleton',solve([('q',N)]),'q')\ncheck('permuted tie',solve([('b',N),('a',N)]),'a')\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"},"broken":{"sha256":"2e9ad18c09efd4eb93c5e5f5e9ed6668a8f87673ab5133ce7a637b9680fd1df0","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(scores):\n    return max(scores,key=lambda x:x[1])[0]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('reverse tie',solve([('z',N),('a',N)]),'a')\ncheck('higher score',solve([('a',N),('b',N+1)]),'b')\ncheck('three-way tie',solve([('c',0),('b',0),('a',0)]),'a')\ncheck('negative',solve([('a',-N),('b',-N-1)]),'a')\ncheck('singleton',solve([('q',N)]),'q')\ncheck('permuted tie',solve([('b',N),('a',N)]),'a')\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"}},"limitations":"Inputs are finite toy scores and routes; the contract does not model a production model, accelerator, or learned routing quality. This reproducer isolates one failure mechanism. Results cover the supplied fixtures. Variants within a family share a test contract and should remain grouped when constructing evaluation splits. Related mechanisms with a shared evaluation_group must also remain together; these controlled models are not independent production incidents.","method":"Deterministic executable model with adversarial boundary fixtures.","provenance":{"created_by":"Failure Map","dependencies":"Python standard library","family":"w3-mixture-of-experts-dispatch-stable-tie","generated_at":"2026-09-30T16:48:36.730485+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"A deterministic toy router makes this dispatch decision independently inspectable.","root_cause":"A tie has no deterministic expert-level secondary key.","sha256":"54eeeea084b07cb61e8dee2bacf696093a136318cfddbd8868a43a372aeb24f9","title":"Equal gate scores route according to arrival order · case 01","variant":1,"variant_policy":"The fixture code references N, supplied as 1 through 5. Fixed boundary checks may repeat. These records share one mechanism and must remain together in evaluation splits.","verified":true,"visibility":"public","verification":{"attempt":{"elapsed_ms":29.273,"exit_code":1,"observations":[{"actual":"z","check":"reverse tie","expected":"a","passed":false},{"actual":"b","check":"higher score","expected":"b","passed":true},{"actual":"c","check":"three-way tie","expected":"a","passed":false},{"actual":"a","check":"negative","expected":"a","passed":true},{"actual":"q","check":"singleton","expected":"q","passed":true},{"actual":"b","check":"permuted tie","expected":"a","passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"reverse tie\", \"actual\": \"z\", \"expected\": \"a\", \"passed\": false}, {\"check\": \"higher score\", \"actual\": \"b\", \"expected\": \"b\", \"passed\": true}, {\"check\": \"three-way tie\", \"actual\": \"c\", \"expected\": \"a\", \"passed\": false}, {\"check\": \"negative\", \"actual\": \"a\", \"expected\": \"a\", \"passed\": true}, {\"check\": \"singleton\", \"actual\": \"q\", \"expected\": \"q\", \"passed\": true}, {\"check\": \"permuted tie\", \"actual\": \"b\", \"expected\": \"a\", \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":27.719,"exit_code":1,"observations":[{"actual":"z","check":"reverse tie","expected":"a","passed":false},{"actual":"b","check":"higher score","expected":"b","passed":true},{"actual":"c","check":"three-way tie","expected":"a","passed":false},{"actual":"a","check":"negative","expected":"a","passed":true},{"actual":"q","check":"singleton","expected":"q","passed":true},{"actual":"b","check":"permuted tie","expected":"a","passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"reverse tie\", \"actual\": \"z\", \"expected\": \"a\", \"passed\": false}, {\"check\": \"higher score\", \"actual\": \"b\", \"expected\": \"b\", \"passed\": true}, {\"check\": \"three-way tie\", \"actual\": \"c\", \"expected\": \"a\", \"passed\": false}, {\"check\": \"negative\", \"actual\": \"a\", \"expected\": \"a\", \"passed\": true}, {\"check\": \"singleton\", \"actual\": \"q\", \"expected\": \"q\", \"passed\": true}, {\"check\": \"permuted tie\", \"actual\": \"b\", \"expected\": \"a\", \"passed\": false}], \"passed\": false}\n"}},"member_only":{"stages":["fixed"],"fields":["implementations.fixed","verification.fixed","harness","repair"],"note":"The verified repair, its recorded checks, the repair description, and the scoring harness are available to members."}}