{"abstract":"The final input token has no next-token target.","category":"Autoregressive target shifting","checks":6,"contract":"For a token stream, return adjacent [input,target] pairs; streams shorter than two yield an empty list.","contract_signature":"tokens","evaluation_group":"model-2247df1e8d59a3a6","failed_approach":"Using a two-position offset fixes length but skips the immediate successor.","family":"w3-autoregressive-target-shifting-adjacent-pairs-drop-last","id":"FA-98241","implementations":{"attempt":{"sha256":"f3845e549ceaba498fb8d9ceda73edcef15767d3bd8c334ed99a59416aaf6194","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(tokens):\n    return [[tokens[i],tokens[i+2]] for i in range(max(0,len(tokens)-2))]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('ordinary',solve([N,N+1,N+2]),[[N,N+1],[N+1,N+2]])\ncheck('two tokens',solve([N,8]),[[N,8]])\ncheck('singleton',solve([N]),[])\ncheck('empty',solve([]),[])\ncheck('repeated',solve([4,4,5]),[[4,4],[4,5]])\ncheck('longer',solve([1,N,3,4]),[[1,N],[N,3],[3,4]])\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":"8e52c278266118fb14dd8b02a6c4c19ff4d1eb91c2be7d12015357fed13518e9","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(tokens):\n    return [[a,b] for a,b in zip(tokens,tokens)]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('ordinary',solve([N,N+1,N+2]),[[N,N+1],[N+1,N+2]])\ncheck('two tokens',solve([N,8]),[[N,8]])\ncheck('singleton',solve([N]),[])\ncheck('empty',solve([]),[])\ncheck('repeated',solve([4,4,5]),[[4,4],[4,5]])\ncheck('longer',solve([1,N,3,4]),[[1,N],[N,3],[3,4]])\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 toy integer token sequences; this contract says nothing about model quality, batching, sampling, or production training frameworks. 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-autoregressive-target-shifting-adjacent-pairs-drop-last","generated_at":"2026-09-30T16:48:11.053562+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"A small deterministic token-stream contract makes next-token alignment errors inspectable.","root_cause":"The pair builder zips the stream against itself instead of offset views.","sha256":"847ab108c550671a2a9c0d0efa66f2399c9cf09595822e565ea6c4b0572783c9","title":"The final input token has no next-token target · 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":26.558,"exit_code":1,"observations":[{"actual":[[1,3]],"check":"ordinary","expected":[[1,2],[2,3]],"passed":false},{"actual":[],"check":"two tokens","expected":[[1,8]],"passed":false},{"actual":[],"check":"singleton","expected":[],"passed":true},{"actual":[],"check":"empty","expected":[],"passed":true},{"actual":[[4,5]],"check":"repeated","expected":[[4,4],[4,5]],"passed":false},{"actual":[[1,3],[1,4]],"check":"longer","expected":[[1,1],[1,3],[3,4]],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"ordinary\", \"actual\": [[1, 3]], \"expected\": [[1, 2], [2, 3]], \"passed\": false}, {\"check\": \"two tokens\", \"actual\": [], \"expected\": [[1, 8]], \"passed\": false}, {\"check\": \"singleton\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"empty\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"repeated\", \"actual\": [[4, 5]], \"expected\": [[4, 4], [4, 5]], \"passed\": false}, {\"check\": \"longer\", \"actual\": [[1, 3], [1, 4]], \"expected\": [[1, 1], [1, 3], [3, 4]], \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":27.582,"exit_code":1,"observations":[{"actual":[[1,1],[2,2],[3,3]],"check":"ordinary","expected":[[1,2],[2,3]],"passed":false},{"actual":[[1,1],[8,8]],"check":"two tokens","expected":[[1,8]],"passed":false},{"actual":[[1,1]],"check":"singleton","expected":[],"passed":false},{"actual":[],"check":"empty","expected":[],"passed":true},{"actual":[[4,4],[4,4],[5,5]],"check":"repeated","expected":[[4,4],[4,5]],"passed":false},{"actual":[[1,1],[1,1],[3,3],[4,4]],"check":"longer","expected":[[1,1],[1,3],[3,4]],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"ordinary\", \"actual\": [[1, 1], [2, 2], [3, 3]], \"expected\": [[1, 2], [2, 3]], \"passed\": false}, {\"check\": \"two tokens\", \"actual\": [[1, 1], [8, 8]], \"expected\": [[1, 8]], \"passed\": false}, {\"check\": \"singleton\", \"actual\": [[1, 1]], \"expected\": [], \"passed\": false}, {\"check\": \"empty\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"repeated\", \"actual\": [[4, 4], [4, 4], [5, 5]], \"expected\": [[4, 4], [4, 5]], \"passed\": false}, {\"check\": \"longer\", \"actual\": [[1, 1], [1, 1], [3, 3], [4, 4]], \"expected\": [[1, 1], [1, 3], [3, 4]], \"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."}}