{"abstract":"The item at rank k is dropped.","category":"Vector retrieval ranking","checks":6,"contract":"Rows [id,score] return the first k IDs after descending score and ID ordering.","contract_signature":"rows, k","evaluation_group":"vector-retrieval-rank-cutoff-inclusive","failed_approach":"Starting at one skips the highest scoring result even when page size is correct.","family":"w3-vector-retrieval-ranking-rank-cutoff-inclusive","id":"FA-99496","implementations":{"attempt":{"sha256":"b16d4a00dab7d3f79c23e28aa70ad41f6f12060cd4244d16ad3912ea710113b0","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(rows, k):\n    return [r[0] for r in sorted(rows,key=lambda r:(-r[1],r[0]))[1:k+1]]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nrows=[['a',N+3],['b',N+2],['c',N+1],['d',N]]\ncheck('top one',solve(rows,1),['a'])\ncheck('top two',solve(rows,2),['a','b'])\ncheck('all',solve(rows,4),['a','b','c','d'])\ncheck('zero',solve(rows,0),[])\ncheck('empty',solve([],N),[])\ncheck('tie cutoff',solve([['b',1],['a',1],['c',0]],2),['a','b'])\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":"99b54bb9c401600112e34966451280d7cb1b3d48750080a94a821e5b0dcb8836","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(rows, k):\n    return [r[0] for r in sorted(rows,key=lambda r:(-r[1],r[0]))[:max(0,k-1)]]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nrows=[['a',N+3],['b',N+2],['c',N+1],['d',N]]\ncheck('top one',solve(rows,1),['a'])\ncheck('top two',solve(rows,2),['a','b'])\ncheck('all',solve(rows,4),['a','b','c','d'])\ncheck('zero',solve(rows,0),[])\ncheck('empty',solve([],N),[])\ncheck('tie cutoff',solve([['b',1],['a',1],['c',0]],2),['a','b'])\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 small exact toy vectors and scores. No production index, ANN recall, embedding quality, or latency claim is implied. 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-vector-retrieval-ranking-rank-cutoff-inclusive","generated_at":"2026-09-30T16:48:24.912610+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"An offline vector retrieval toy model isolates one ranking contract from embedding generation, storage, and serving.","root_cause":"The slice omits the last requested row or starts after the leader.","sha256":"d03020ff8c031622bc5e85a0c9cf28eed26acef8c2e5f76113bd70e1b6887fe4","title":"Vector retrieval: The item at rank k is dropped · 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":28.146,"exit_code":1,"observations":[{"actual":["b"],"check":"top one","expected":["a"],"passed":false},{"actual":["b","c"],"check":"top two","expected":["a","b"],"passed":false},{"actual":["b","c","d"],"check":"all","expected":["a","b","c","d"],"passed":false},{"actual":[],"check":"zero","expected":[],"passed":true},{"actual":[],"check":"empty","expected":[],"passed":true},{"actual":["b","c"],"check":"tie cutoff","expected":["a","b"],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"top one\", \"actual\": [\"b\"], \"expected\": [\"a\"], \"passed\": false}, {\"check\": \"top two\", \"actual\": [\"b\", \"c\"], \"expected\": [\"a\", \"b\"], \"passed\": false}, {\"check\": \"all\", \"actual\": [\"b\", \"c\", \"d\"], \"expected\": [\"a\", \"b\", \"c\", \"d\"], \"passed\": false}, {\"check\": \"zero\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"empty\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"tie cutoff\", \"actual\": [\"b\", \"c\"], \"expected\": [\"a\", \"b\"], \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":27.767,"exit_code":1,"observations":[{"actual":[],"check":"top one","expected":["a"],"passed":false},{"actual":["a"],"check":"top two","expected":["a","b"],"passed":false},{"actual":["a","b","c"],"check":"all","expected":["a","b","c","d"],"passed":false},{"actual":[],"check":"zero","expected":[],"passed":true},{"actual":[],"check":"empty","expected":[],"passed":true},{"actual":["a"],"check":"tie cutoff","expected":["a","b"],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"top one\", \"actual\": [], \"expected\": [\"a\"], \"passed\": false}, {\"check\": \"top two\", \"actual\": [\"a\"], \"expected\": [\"a\", \"b\"], \"passed\": false}, {\"check\": \"all\", \"actual\": [\"a\", \"b\", \"c\"], \"expected\": [\"a\", \"b\", \"c\", \"d\"], \"passed\": false}, {\"check\": \"zero\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"empty\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"tie cutoff\", \"actual\": [\"a\"], \"expected\": [\"a\", \"b\"], \"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."}}