{"uid":"cap_b8GWZOn7FTA6DU3LTK0up","slug":"delx-commerce-seeded-holdout-assignment-8becf375","name":"Delx Commerce — Seeded Holdout Assignment","description":"Pay-per-result APIs for agents. No signup. Exact price. Verifiable delivery. USDC on Base + Solana via x402.","url":"https://commerce.delx.ai/api/v1/x402/seeded-holdout-assignment?utm_source=zero.xyz","method":"POST","headers":{},"bodySchema":{"type":"object","properties":{"seed":{"type":"string","maxLength":8192,"description":"Seed supplied to Seeded Holdout Assignment; used only for this bounded calculation and processed in memory without retention."},"subject":{"type":"string","maxLength":8192,"description":"Subject supplied to Seeded Holdout Assignment; used only for this bounded calculation and processed in memory without retention."},"holdout_fraction":{"type":"number","description":"Holdout Fraction supplied to Seeded Holdout Assignment; used only for this bounded calculation and processed in memory without retention."}}},"responseSchema":{"type":"json","example":{"result":{"group":"treatment","bucket":0.5223946972379113},"schema":"delx/util-seeded-holdout-assignment/v1","status":"pass","evidence":{"retained":false,"input_sha256":"bd5b582a9597f6cff6a8c3ed859bd7cf28c6eac4c434b4828c22df3b23d6e4ef","external_calls":0},"operation":"seeded_decision:seeded_holdout_assignment"}},"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.001","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":"$0.001/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.001","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.001","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_CUt4MAFmLRqUkwdILhiSb","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.001","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Deterministically assigns a subject to a treatment or holdout group based on a seed and holdout fraction, returning a verifiable group assignment with no data retention.","exampleAgentPrompt":"Assign user ID 'user_abc123' to either treatment or holdout using seed 'launch_v2' and a holdout fraction of 0.1 — I need to know which group they fall into for my experiment rollout.","exampleUseCases":[{"title":"Canary rollout traffic splitting","prompt":"I'm rolling out a new feature to 10% of users as a canary — use seed 'feature_dark_mode' and a holdout fraction of 0.1 to check if user 'u_987654' should get the new experience or stay in holdout."},{"title":"Reproducible A/B test assignment","prompt":"For my pricing experiment, assign customer 'cust_29301' to treatment or control using seed 'pricing_exp_q3' with a 20% holdout fraction — I need the same answer every time I call this."},{"title":"Privacy-safe experiment audit","prompt":"Can you re-check which group 'session_xyz' was assigned to in experiment seed 'onboarding_v3' with a 15% holdout? I need the bucket value and the input hash to verify the result without any stored data."}],"resultDescription":"Returns a JSON object containing the group assignment ('treatment' or 'holdout'), a deterministic bucket float value, status, schema version, and an evidence block with the input SHA-256 hash, a flag confirming no data was retained, and a count of zero external calls — enabling verifiable, auditable group assignment.","failureModes":["Missing required fields (seed, subject, holdout_fraction) result in a validation error","holdout_fraction outside [0,1] range may cause unexpected assignment behavior","Payment failure via x402 (USDC on Base or Solana) blocks the request","Malformed JSON input returns a parsing error","Extremely long seed or subject strings (>8192 chars) are rejected"],"whenToPreferThis":"Choose this endpoint when you need deterministic, reproducible, and verifiable holdout/treatment group assignments with strong privacy guarantees (no data retention) and an on-chain payment audit trail. It is ideal for agent workflows that must assign subjects to experiment groups in a stateless, pay-per-call manner without managing experiment infrastructure or user databases. Prefer it over full-featured experimentation platforms when you need a lightweight, single-call computation with cryptographic evidence of the result.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-01T00:53:53.465Z","isFirstParty":false,"canonicalSlug":"delx-commerce-seeded-holdout-assignment-8becf375"}