{"uid":"cap_nlJI6WrxA5X_NtB53M_s2","slug":"gacha-rng-chi-square-verifier-c8dc9185","name":"Gacha RNG Chi-Square Verifier","description":"Counts supplied outcomes, computes Pearson’s chi-square statistic, and estimates an upper-tail p-value with the Wilson-Hilferty normal approximation. It tests aggregate frequencies only; it cannot prove draw independence, seed fairness, code integrity, or manipulation, especially when expected counts are small.","url":"https://gaming.halowerk.com/v1/gacha-rng-verify","method":"POST","headers":{},"bodySchema":{"type":"object","properties":{"alpha":{"type":"number","maximum":0.5,"minimum":0.000001},"draws":{"type":"array","items":{"type":"string","maxLength":128,"minLength":1},"maxItems":100000,"minItems":10},"outcomes":{"type":"array","items":{"type":"object","required":["outcome","probability"],"properties":{"outcome":{"type":"string","maxLength":128,"minLength":1},"probability":{"type":"number","maximum":1,"minimum":1e-9}},"additionalProperties":false},"maxItems":100,"minItems":2}}},"responseSchema":null,"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.004","displayCostAsset":"USDC","priceDynamic":false,"priceHint":null,"priceStatus":"priced","priceSource":"probe","requiresHandshake":false,"reviewCount":0,"rating":{"score":"0.00","successRate":"0.00","reviews":0,"stars":null,"state":"unrated"},"availabilityStatus":"unknown","priceObserved":null,"sessionDeposit":null,"pricing":{"kind":"static","summary":"$0.004/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.004","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.004","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_cmtD1NcpItfFHApDkbbPi","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.004","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Runs a Pearson chi-square goodness-of-fit test on gacha draw outcomes to estimate whether the observed frequencies deviate significantly from declared drop probabilities.","exampleAgentPrompt":"I pulled 2000 gacha draws from this banner — 1800 common, 150 rare, and 50 legendary. The declared probabilities are 90%, 7.5%, and 2.5% respectively. Can you run a chi-square test at alpha 0.05 to see if the actual drop rates are statistically consistent with what the game advertises?","exampleUseCases":[{"title":"Gacha banner fairness audit","prompt":"I have 5000 pulls from a gacha game split across 4 rarity tiers: 3800 common, 800 uncommon, 350 rare, and 50 ultra-rare. The advertised probabilities are 76%, 16%, 7%, and 1%. Run a chi-square goodness-of-fit test at a 0.05 significance level and tell me if the observed rates are statistically plausible."},{"title":"Loot box drop rate complaint investigation","prompt":"Our players are complaining that the legendary skin drop rate is way lower than the advertised 0.5%. I have a log of 10000 loot box opens with outcomes: 9700 common, 250 rare, 50 legendary. The declared probabilities are 97%, 2.5%, and 0.5%. Can you compute the chi-square statistic and p-value at alpha 0.01 to see if we have a real problem?"},{"title":"Cross-banner probability comparison","prompt":"I want to statistically verify our new seasonal gacha banner. I recorded 800 pulls: 640 grey, 120 blue, 32 purple, and 8 gold. The advertised rates are 80%, 15%, 4%, and 1%. Please run a chi-square test with alpha 0.05 and tell me whether the observed frequencies are consistent with the stated odds."}],"resultDescription":"Returns the computed Pearson chi-square statistic, degrees of freedom, the Wilson-Hilferty-approximated upper-tail p-value, and a boolean pass/fail verdict comparing the p-value against the supplied alpha threshold. Does not prove independence, seed integrity, or rule out manipulation — only tests aggregate frequency fit.","failureModes":["Fewer than 10 draws supplied — minimum input size not met","Expected counts below 5 for one or more outcomes — chi-square approximation unreliable, result flagged","Probabilities in outcomes array do not sum to 1.0 — normalization error or rejection","Outcome labels in draws array don't match declared outcome names — key mismatch error","alpha value outside allowed range (0.000001 to 0.5) — validation rejection","More than 100000 draws or more than 100 outcome categories — size limit exceeded"],"whenToPreferThis":"Use this endpoint when you need a quick, structured statistical test of whether observed gacha or loot-box outcome frequencies match developer-declared drop probabilities. It is purpose-built for gaming randomness auditing with a straightforward chi-square + Wilson-Hilferty approximation pipeline. Prefer it over general-purpose statistics APIs when working within the gaming.halowerk.com ecosystem or when you need a lightweight, pay-per-call solution without setting up a full stats library. Not suitable for proving seed fairness, code integrity, or draw independence — only aggregate frequency fit.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-09-14T12:41:54.351Z","isFirstParty":false}