{"abstract":"Sliding window stops after the initial query rows.","category":"Attention mask construction","checks":6,"contract":"For each query i in a sequence of length L, visible keys are max(0,i-W+1)..i; W<=0 means none.","contract_signature":"length, window","evaluation_group":"query_anchored_window_v1","failed_approach":"Adding a query-relative lower bound but shifting it one extra position still drops the oldest allowed key.","family":"w3-attention-mask-construction-window-left-aligned","id":"FA-98211","implementations":{"attempt":{"sha256":"53a49bd51313d9c29c04a19be4b05c2e823c96d26d8eece84b835e785ce1b669","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(length, window):\n    return [[window>0 and max(0,i-window+2)<=j<=i for j in range(length)] for i in range(length)]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('moving boundary',solve(N+3,2),[[2>0 and max(0,i-1)<=j<=i for j in range(N+3)] for i in range(N+3)])\ncheck('window one',solve(3,1),[[True,False,False],[False,True,False],[False,False,True]])\ncheck('zero window',solve(2,0),[[False,False],[False,False]])\ncheck('oversized window',solve(2,9),[[True,False],[True,True]])\ncheck('empty sequence',solve(0,1),[])\ncheck('last query',solve(4,3)[3],[False,True,True,True])\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":"4bfd6d3c9c4ec029f79e7ba69a60a5b0c5b0bdbe218fe164222c38b45bcf00a0","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(length, window):\n    return [[j<=i and i<window for j in range(length)] for i in range(length)]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('moving boundary',solve(N+3,2),[[2>0 and max(0,i-1)<=j<=i for j in range(N+3)] for i in range(N+3)])\ncheck('window one',solve(3,1),[[True,False,False],[False,True,False],[False,False,True]])\ncheck('zero window',solve(2,0),[[False,False],[False,False]])\ncheck('oversized window',solve(2,9),[[True,False],[True,True]])\ncheck('empty sequence',solve(0,1),[])\ncheck('last query',solve(4,3)[3],[False,True,True,True])\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 toy Boolean matrix contracts; they do not define a production model architecture or tensor library behavior. 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-attention-mask-construction-window-left-aligned","generated_at":"2026-09-30T16:48:10.629747+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"A small explicit visibility matrix makes sequence-attention boundary behavior reviewable.","root_cause":"Query eligibility is based on distance from sequence start, so later queries lose visibility.","sha256":"8780f666c4d975a14283260d9a0d1dc3cebdb6f39268840121b8005a7492ab0a","title":"Sliding window stops after the initial query rows · 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":27.893,"exit_code":1,"observations":[{"actual":[[true,false,false,false],[false,true,false,false],[false,false,true,false],[false,false,false,true]],"check":"moving boundary","expected":[[true,false,false,false],[true,true,false,false],[false,true,true,false],[false,false,true,true]],"passed":false},{"actual":[[false,false,false],[false,false,false],[false,false,false]],"check":"window one","expected":[[true,false,false],[false,true,false],[false,false,true]],"passed":false},{"actual":[[false,false],[false,false]],"check":"zero window","expected":[[false,false],[false,false]],"passed":true},{"actual":[[true,false],[true,true]],"check":"oversized window","expected":[[true,false],[true,true]],"passed":true},{"actual":[],"check":"empty sequence","expected":[],"passed":true},{"actual":[false,false,true,true],"check":"last query","expected":[false,true,true,true],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"moving boundary\", \"actual\": [[true, false, false, false], [false, true, false, false], [false, false, true, false], [false, false, false, true]], \"expected\": [[true, false, false, false], [true, true, false, false], [false, true, true, false], [false, false, true, true]], \"passed\": false}, {\"check\": \"window one\", \"actual\": [[false, false, false], [false, false, false], [false, false, false]], \"expected\": [[true, false, false], [false, true, false], [false, false, true]], \"passed\": false}, {\"check\": \"zero window\", \"actual\": [[false, false], [false, false]], \"expected\": [[false, false], [false, false]], \"passed\": true}, {\"check\": \"oversized window\", \"actual\": [[true, false], [true, true]], \"expected\": [[true, false], [true, true]], \"passed\": true}, {\"check\": \"empty sequence\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"last query\", \"actual\": [false, false, true, true], \"expected\": [false, true, true, true], \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":29.838,"exit_code":1,"observations":[{"actual":[[true,false,false,false],[true,true,false,false],[false,false,false,false],[false,false,false,false]],"check":"moving boundary","expected":[[true,false,false,false],[true,true,false,false],[false,true,true,false],[false,false,true,true]],"passed":false},{"actual":[[true,false,false],[false,false,false],[false,false,false]],"check":"window one","expected":[[true,false,false],[false,true,false],[false,false,true]],"passed":false},{"actual":[[false,false],[false,false]],"check":"zero window","expected":[[false,false],[false,false]],"passed":true},{"actual":[[true,false],[true,true]],"check":"oversized window","expected":[[true,false],[true,true]],"passed":true},{"actual":[],"check":"empty sequence","expected":[],"passed":true},{"actual":[false,false,false,false],"check":"last query","expected":[false,true,true,true],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"moving boundary\", \"actual\": [[true, false, false, false], [true, true, false, false], [false, false, false, false], [false, false, false, false]], \"expected\": [[true, false, false, false], [true, true, false, false], [false, true, true, false], [false, false, true, true]], \"passed\": false}, {\"check\": \"window one\", \"actual\": [[true, false, false], [false, false, false], [false, false, false]], \"expected\": [[true, false, false], [false, true, false], [false, false, true]], \"passed\": false}, {\"check\": \"zero window\", \"actual\": [[false, false], [false, false]], \"expected\": [[false, false], [false, false]], \"passed\": true}, {\"check\": \"oversized window\", \"actual\": [[true, false], [true, true]], \"expected\": [[true, false], [true, true]], \"passed\": true}, {\"check\": \"empty sequence\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"last query\", \"actual\": [false, false, false, false], \"expected\": [false, true, true, true], \"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."}}