{"abstract":"Per-step acceptance record marks the rejected position as accepted.","category":"Speculative decoding bookkeeping","checks":7,"contract":"For length m and rejection index k, return m booleans true exactly at indices less than k.","contract_signature":"length, rejected_at","evaluation_group":"spec-per-step-rejection","failed_approach":"Treating rejection index zero as a special falsey value mistakenly marks the first token accepted.","family":"w3-speculative-decoding-bookkeeping-per-step-rejection","id":"FA-100736","implementations":{"attempt":{"sha256":"2d06ad3723d9697fee55fa12e7012b3f11d7b9ace9cc2b127d75d6b0ed97880c","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(length, rejected_at):\n    return [i < max(1,rejected_at) for i in range(length)]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('middle rejection', solve(4,2),[True,True,False,False])\ncheck('first rejection', solve(3,0),[False,False,False])\ncheck('tail rejection', solve(3,2),[True,True,False])\ncheck('empty sequence', solve(0,0),[])\ncheck('all accepted boundary', solve(N,N),[True]*N)\ncheck('singleton reject', solve(1,0),[False])\ncheck('one accepted', solve(3,1),[True,False,False])\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":"53a3cab6dff3f55068d6fa795faf896a11296e3674913e3b410fd84004053421","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(length, rejected_at):\n    return [i <= rejected_at for i in range(length)]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('middle rejection', solve(4,2),[True,True,False,False])\ncheck('first rejection', solve(3,0),[False,False,False])\ncheck('tail rejection', solve(3,2),[True,True,False])\ncheck('empty sequence', solve(0,0),[])\ncheck('all accepted boundary', solve(N,N),[True]*N)\ncheck('singleton reject', solve(1,0),[False])\ncheck('one accepted', solve(3,1),[True,False,False])\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":"These are finite toy sequences with explicit contracts; they make no claim about production decoder behavior or model 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-speculative-decoding-bookkeeping-per-step-rejection","generated_at":"2026-09-30T16:48:39.096512+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"A self-contained bookkeeping model makes prefix and token-count semantics observable without a model runtime.","root_cause":"The boundary comparison includes the rejected position.","sha256":"2b4f8e3970a8a0bb9f8830800535a218c60dbe7ba3f6ab8f4993f431370d4096","title":"Decoding: Per-step acceptance record marks the rejected position as accepted · 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":34.797,"exit_code":1,"observations":[{"actual":[true,true,false,false],"check":"middle rejection","expected":[true,true,false,false],"passed":true},{"actual":[true,false,false],"check":"first rejection","expected":[false,false,false],"passed":false},{"actual":[true,true,false],"check":"tail rejection","expected":[true,true,false],"passed":true},{"actual":[],"check":"empty sequence","expected":[],"passed":true},{"actual":[true],"check":"all accepted boundary","expected":[true],"passed":true},{"actual":[true],"check":"singleton reject","expected":[false],"passed":false},{"actual":[true,false,false],"check":"one accepted","expected":[true,false,false],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"middle rejection\", \"actual\": [true, true, false, false], \"expected\": [true, true, false, false], \"passed\": true}, {\"check\": \"first rejection\", \"actual\": [true, false, false], \"expected\": [false, false, false], \"passed\": false}, {\"check\": \"tail rejection\", \"actual\": [true, true, false], \"expected\": [true, true, false], \"passed\": true}, {\"check\": \"empty sequence\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"all accepted boundary\", \"actual\": [true], \"expected\": [true], \"passed\": true}, {\"check\": \"singleton reject\", \"actual\": [true], \"expected\": [false], \"passed\": false}, {\"check\": \"one accepted\", \"actual\": [true, false, false], \"expected\": [true, false, false], \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":33.688,"exit_code":1,"observations":[{"actual":[true,true,true,false],"check":"middle rejection","expected":[true,true,false,false],"passed":false},{"actual":[true,false,false],"check":"first rejection","expected":[false,false,false],"passed":false},{"actual":[true,true,true],"check":"tail rejection","expected":[true,true,false],"passed":false},{"actual":[],"check":"empty sequence","expected":[],"passed":true},{"actual":[true],"check":"all accepted boundary","expected":[true],"passed":true},{"actual":[true],"check":"singleton reject","expected":[false],"passed":false},{"actual":[true,true,false],"check":"one accepted","expected":[true,false,false],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"middle rejection\", \"actual\": [true, true, true, false], \"expected\": [true, true, false, false], \"passed\": false}, {\"check\": \"first rejection\", \"actual\": [true, false, false], \"expected\": [false, false, false], \"passed\": false}, {\"check\": \"tail rejection\", \"actual\": [true, true, true], \"expected\": [true, true, false], \"passed\": false}, {\"check\": \"empty sequence\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"all accepted boundary\", \"actual\": [true], \"expected\": [true], \"passed\": true}, {\"check\": \"singleton reject\", \"actual\": [true], \"expected\": [false], \"passed\": false}, {\"check\": \"one accepted\", \"actual\": [true, true, false], \"expected\": [true, false, false], \"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."}}