{"abstract":"Truncation removes a retained target at the cutoff.","category":"Autoregressive target shifting","checks":6,"contract":"Given tokens and max_inputs k, return k adjacent input/next-token pairs where available; k<=0 returns empty.","contract_signature":"tokens, max_inputs","evaluation_group":"model-2247df1e8d59a3a6","failed_approach":"A slice-based repair treats a negative cap as a Python suffix limit and emits pairs instead of honoring the nonpositive cap.","family":"w3-autoregressive-target-shifting-adjacent-pairs-truncate-targets","id":"FA-98246","implementations":{"attempt":{"sha256":"bf6f643a3aa747c8243779b43e67d23a508ee4222f55df53884ce91e7eccdf76","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(tokens, max_inputs):\n    x=tokens[:max_inputs]\n    return [[x[i],x[i+1]] for i in range(len(x)-1)] + ([[x[-1],tokens[max_inputs]] ] if x and len(tokens)>max_inputs else [])\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('retained boundary target',solve([1,2,3,4],2),[[1,2],[2,3]])\ncheck('full stream',solve([N,N+1,N+2],9),[[N,N+1],[N+1,N+2]])\ncheck('zero inputs',solve([1,2],0),[])\ncheck('negative inputs',solve([1,2],-1),[])\ncheck('empty stream',solve([],2),[])\ncheck('one retained input',solve([7,8],1),[[7,8]])\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":"213682be73efe68ab19e6d8d83c0e0abbc9809aef2b4c3752c884f79724da4ac","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(tokens, max_inputs):\n    x=tokens[:max_inputs]\n    return [[x[i],x[i+1]] for i in range(len(x)-1)]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('retained boundary target',solve([1,2,3,4],2),[[1,2],[2,3]])\ncheck('full stream',solve([N,N+1,N+2],9),[[N,N+1],[N+1,N+2]])\ncheck('zero inputs',solve([1,2],0),[])\ncheck('negative inputs',solve([1,2],-1),[])\ncheck('empty stream',solve([],2),[])\ncheck('one retained input',solve([7,8],1),[[7,8]])\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-truncate-targets","generated_at":"2026-09-30T16:48:11.054415+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 stream is clipped to the input limit before a successor is attached.","sha256":"757189f1b45d88d3a842a6b331317c9442c43ed7bf8cba8b151f782452183b08","title":"Truncation removes a retained target at the cutoff · 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":26.621,"exit_code":1,"observations":[{"actual":[[1,2],[2,3]],"check":"retained boundary target","expected":[[1,2],[2,3]],"passed":true},{"actual":[[1,2],[2,3]],"check":"full stream","expected":[[1,2],[2,3]],"passed":true},{"actual":[],"check":"zero inputs","expected":[],"passed":true},{"actual":[[1,2]],"check":"negative inputs","expected":[],"passed":false},{"actual":[],"check":"empty stream","expected":[],"passed":true},{"actual":[[7,8]],"check":"one retained input","expected":[[7,8]],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"retained boundary target\", \"actual\": [[1, 2], [2, 3]], \"expected\": [[1, 2], [2, 3]], \"passed\": true}, {\"check\": \"full stream\", \"actual\": [[1, 2], [2, 3]], \"expected\": [[1, 2], [2, 3]], \"passed\": true}, {\"check\": \"zero inputs\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"negative inputs\", \"actual\": [[1, 2]], \"expected\": [], \"passed\": false}, {\"check\": \"empty stream\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"one retained input\", \"actual\": [[7, 8]], \"expected\": [[7, 8]], \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":27.514,"exit_code":1,"observations":[{"actual":[[1,2]],"check":"retained boundary target","expected":[[1,2],[2,3]],"passed":false},{"actual":[[1,2],[2,3]],"check":"full stream","expected":[[1,2],[2,3]],"passed":true},{"actual":[],"check":"zero inputs","expected":[],"passed":true},{"actual":[],"check":"negative inputs","expected":[],"passed":true},{"actual":[],"check":"empty stream","expected":[],"passed":true},{"actual":[],"check":"one retained input","expected":[[7,8]],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"retained boundary target\", \"actual\": [[1, 2]], \"expected\": [[1, 2], [2, 3]], \"passed\": false}, {\"check\": \"full stream\", \"actual\": [[1, 2], [2, 3]], \"expected\": [[1, 2], [2, 3]], \"passed\": true}, {\"check\": \"zero inputs\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"negative inputs\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"empty stream\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"one retained input\", \"actual\": [], \"expected\": [[7, 8]], \"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."}}