{"abstract":"Overflow tokens disappear despite available alternatives.","category":"Mixture of experts dispatch","checks":7,"contract":"Each token has ranked (expert,score) alternatives; in token order assign its highest ranked expert with remaining per-expert capacity, or omit it.","contract_signature":"choices,capacity","evaluation_group":"moe-overflow-alternatives","failed_approach":"Overflow is rerouted to an alternate expert without checking that the alternate has remaining capacity.","family":"w3-mixture-of-experts-dispatch-overflow-reroute","id":"FA-100556","implementations":{"attempt":{"sha256":"ea2d5027afe932a3ec60f30fe8fc7a12dfa63fa7e2253b8e490282034d0a20a6","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(choices,capacity):\n    out=[]; used={}\n    for i,row in enumerate(choices):\n     ranked=sorted(row,key=lambda x:(-x[1],x[0]))\n     if not ranked: continue\n     primary=ranked[0][0]\n     if used.get(primary,0)<capacity:\n      out.append([i,primary]); used[primary]=used.get(primary,0)+1\n     elif len(ranked)>1:\n      out.append([i,ranked[1][0]])\n    return out\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ne='e'+str(N); f='f'+str(N); rows=[[(e,9),(f,8)],[(e,7),(f,6)],[(f,5),(e,4)]]\ncheck('fallback used',solve(rows,1),[[0,e],[1,f]])\ncheck('fallback capacity respected',solve([[(e,5),(f,4)],[(e,3),(f,2)],[(e,1),(f,0)]],1),[[0,e],[1,f]])\ncheck('capacity two',solve(rows,2),[[0,e],[1,e],[2,f]])\ncheck('zero capacity',solve(rows,0),[])\ncheck('empty batch',solve([],N),[])\ncheck('single route',solve([[(e,1)]],1),[[0,e]])\ncheck('no alternatives',solve([[],[(e,1)]],1),[[1,e]])\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":"369fd8278ca1aedd1054fb4478eaba30c05d1d74d903b3be77022109a33d9873","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(choices,capacity):\n    return [[i,max(row,key=lambda x:x[1])[0]] for i,row in enumerate(choices) if row]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ne='e'+str(N); f='f'+str(N); rows=[[(e,9),(f,8)],[(e,7),(f,6)],[(f,5),(e,4)]]\ncheck('fallback used',solve(rows,1),[[0,e],[1,f]])\ncheck('fallback capacity respected',solve([[(e,5),(f,4)],[(e,3),(f,2)],[(e,1),(f,0)]],1),[[0,e],[1,f]])\ncheck('capacity two',solve(rows,2),[[0,e],[1,e],[2,f]])\ncheck('zero capacity',solve(rows,0),[])\ncheck('empty batch',solve([],N),[])\ncheck('single route',solve([[(e,1)]],1),[[0,e]])\ncheck('no alternatives',solve([[],[(e,1)]],1),[[1,e]])\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 finite toy scores and routes; the contract does not model a production model, accelerator, or learned routing 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-mixture-of-experts-dispatch-overflow-reroute","generated_at":"2026-09-30T16:48:36.731021+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"A deterministic toy router makes this dispatch decision independently inspectable.","root_cause":"Each token commits to its first choice before capacity is checked.","sha256":"a1812701cba4d313d8fa0a0aba3c445fe01b7873ef3da07d123c8801faaf49c3","title":"Overflow tokens disappear despite available alternatives · 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":28.058,"exit_code":1,"observations":[{"actual":[[0,"e1"],[1,"f1"],[2,"f1"]],"check":"fallback used","expected":[[0,"e1"],[1,"f1"]],"passed":false},{"actual":[[0,"e1"],[1,"f1"],[2,"f1"]],"check":"fallback capacity respected","expected":[[0,"e1"],[1,"f1"]],"passed":false},{"actual":[[0,"e1"],[1,"e1"],[2,"f1"]],"check":"capacity two","expected":[[0,"e1"],[1,"e1"],[2,"f1"]],"passed":true},{"actual":[[0,"f1"],[1,"f1"],[2,"e1"]],"check":"zero capacity","expected":[],"passed":false},{"actual":[],"check":"empty batch","expected":[],"passed":true},{"actual":[[0,"e1"]],"check":"single route","expected":[[0,"e1"]],"passed":true},{"actual":[[1,"e1"]],"check":"no alternatives","expected":[[1,"e1"]],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fallback used\", \"actual\": [[0, \"e1\"], [1, \"f1\"], [2, \"f1\"]], \"expected\": [[0, \"e1\"], [1, \"f1\"]], \"passed\": false}, {\"check\": \"fallback capacity respected\", \"actual\": [[0, \"e1\"], [1, \"f1\"], [2, \"f1\"]], \"expected\": [[0, \"e1\"], [1, \"f1\"]], \"passed\": false}, {\"check\": \"capacity two\", \"actual\": [[0, \"e1\"], [1, \"e1\"], [2, \"f1\"]], \"expected\": [[0, \"e1\"], [1, \"e1\"], [2, \"f1\"]], \"passed\": true}, {\"check\": \"zero capacity\", \"actual\": [[0, \"f1\"], [1, \"f1\"], [2, \"e1\"]], \"expected\": [], \"passed\": false}, {\"check\": \"empty batch\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"single route\", \"actual\": [[0, \"e1\"]], \"expected\": [[0, \"e1\"]], \"passed\": true}, {\"check\": \"no alternatives\", \"actual\": [[1, \"e1\"]], \"expected\": [[1, \"e1\"]], \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":25.701,"exit_code":1,"observations":[{"actual":[[0,"e1"],[1,"e1"],[2,"f1"]],"check":"fallback used","expected":[[0,"e1"],[1,"f1"]],"passed":false},{"actual":[[0,"e1"],[1,"e1"],[2,"e1"]],"check":"fallback capacity respected","expected":[[0,"e1"],[1,"f1"]],"passed":false},{"actual":[[0,"e1"],[1,"e1"],[2,"f1"]],"check":"capacity two","expected":[[0,"e1"],[1,"e1"],[2,"f1"]],"passed":true},{"actual":[[0,"e1"],[1,"e1"],[2,"f1"]],"check":"zero capacity","expected":[],"passed":false},{"actual":[],"check":"empty batch","expected":[],"passed":true},{"actual":[[0,"e1"]],"check":"single route","expected":[[0,"e1"]],"passed":true},{"actual":[[1,"e1"]],"check":"no alternatives","expected":[[1,"e1"]],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fallback used\", \"actual\": [[0, \"e1\"], [1, \"e1\"], [2, \"f1\"]], \"expected\": [[0, \"e1\"], [1, \"f1\"]], \"passed\": false}, {\"check\": \"fallback capacity respected\", \"actual\": [[0, \"e1\"], [1, \"e1\"], [2, \"e1\"]], \"expected\": [[0, \"e1\"], [1, \"f1\"]], \"passed\": false}, {\"check\": \"capacity two\", \"actual\": [[0, \"e1\"], [1, \"e1\"], [2, \"f1\"]], \"expected\": [[0, \"e1\"], [1, \"e1\"], [2, \"f1\"]], \"passed\": true}, {\"check\": \"zero capacity\", \"actual\": [[0, \"e1\"], [1, \"e1\"], [2, \"f1\"]], \"expected\": [], \"passed\": false}, {\"check\": \"empty batch\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"single route\", \"actual\": [[0, \"e1\"]], \"expected\": [[0, \"e1\"]], \"passed\": true}, {\"check\": \"no alternatives\", \"actual\": [[1, \"e1\"]], \"expected\": [[1, \"e1\"]], \"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."}}