{"abstract":"Proposal contains one token beyond the verifier window.","category":"Speculative decoding bookkeeping","checks":7,"contract":"Clamp window to at least zero, then return at most that many draft tokens from the beginning.","contract_signature":"draft, window","evaluation_group":"spec-proposal-limit","failed_approach":"A fixed small cap ignores larger configured windows.","family":"w3-speculative-decoding-bookkeeping-proposal-limit","id":"FA-100681","implementations":{"attempt":{"sha256":"263eb3e27ea9600e8f67dd139461d5eea24ac2bd8a01a121644b42a50d4c5fd7","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(draft, window):\n    return draft[:min(window,2)]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('truncate', solve([0,1,2,3,4],N),list(range(N)))\ncheck('zero window', solve([1],0),[])\ncheck('window exceeds', solve([1,2],5),[1,2])\ncheck('empty proposal', solve([],N),[])\ncheck('single slot', solve([N,8],1),[N])\ncheck('preserve order', solve([4,3,2],2),[4,3])\ncheck('negative window', solve([1,2],-1),[])\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":"2dd55b81b8c6356e7b7c8b97fc5511148ef556745db57e668f4813ec98a04f58","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(draft, window):\n    return draft[:window+1]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('truncate', solve([0,1,2,3,4],N),list(range(N)))\ncheck('zero window', solve([1],0),[])\ncheck('window exceeds', solve([1,2],5),[1,2])\ncheck('empty proposal', solve([],N),[])\ncheck('single slot', solve([N,8],1),[N])\ncheck('preserve order', solve([4,3,2],2),[4,3])\ncheck('negative window', solve([1,2],-1),[])\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-proposal-limit","generated_at":"2026-09-30T16:48:38.567763+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 configured window is applied as an inclusive last index.","sha256":"9576dcc48a64c6a97187806c3848a9fa66ef8d6c07932a4e0d7651d89291a8d1","title":"Decoding: Proposal contains one token beyond the verifier window · 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":32.196,"exit_code":1,"observations":[{"actual":[0],"check":"truncate","expected":[0],"passed":true},{"actual":[],"check":"zero window","expected":[],"passed":true},{"actual":[1,2],"check":"window exceeds","expected":[1,2],"passed":true},{"actual":[],"check":"empty proposal","expected":[],"passed":true},{"actual":[1],"check":"single slot","expected":[1],"passed":true},{"actual":[4,3],"check":"preserve order","expected":[4,3],"passed":true},{"actual":[1],"check":"negative window","expected":[],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"truncate\", \"actual\": [0], \"expected\": [0], \"passed\": true}, {\"check\": \"zero window\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"window exceeds\", \"actual\": [1, 2], \"expected\": [1, 2], \"passed\": true}, {\"check\": \"empty proposal\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"single slot\", \"actual\": [1], \"expected\": [1], \"passed\": true}, {\"check\": \"preserve order\", \"actual\": [4, 3], \"expected\": [4, 3], \"passed\": true}, {\"check\": \"negative window\", \"actual\": [1], \"expected\": [], \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":32.953,"exit_code":1,"observations":[{"actual":[0,1],"check":"truncate","expected":[0],"passed":false},{"actual":[1],"check":"zero window","expected":[],"passed":false},{"actual":[1,2],"check":"window exceeds","expected":[1,2],"passed":true},{"actual":[],"check":"empty proposal","expected":[],"passed":true},{"actual":[1,8],"check":"single slot","expected":[1],"passed":false},{"actual":[4,3,2],"check":"preserve order","expected":[4,3],"passed":false},{"actual":[],"check":"negative window","expected":[],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"truncate\", \"actual\": [0, 1], \"expected\": [0], \"passed\": false}, {\"check\": \"zero window\", \"actual\": [1], \"expected\": [], \"passed\": false}, {\"check\": \"window exceeds\", \"actual\": [1, 2], \"expected\": [1, 2], \"passed\": true}, {\"check\": \"empty proposal\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"single slot\", \"actual\": [1, 8], \"expected\": [1], \"passed\": false}, {\"check\": \"preserve order\", \"actual\": [4, 3, 2], \"expected\": [4, 3], \"passed\": false}, {\"check\": \"negative window\", \"actual\": [], \"expected\": [], \"passed\": true}], \"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."}}