{"uid":"cap_zpwyexopAEhFEls0CHFLe","slug":"delx-seeded-holdout-assignment-c1b7fe84","name":"Delx Seeded Holdout Assignment","description":"Seeded Holdout Assignment: Seeded Holdout Assignment assigns a stable subject to holdout or treatment from bounded caller-supplied values without an external provider. Call Seeded Holdout Assignment when an agent needs a reproducible decision that another run can independently replay. Returns the deterministic selection plus seed provenance, population bounds, and the operation-specific outcome for Seeded Holdout Assignment as versioned deterministic JSON. Price: $0.001 USDC via x402 on Base. F…","url":"https://api.delx.ai/api/v1/x402/seeded-holdout-assignment","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_0wWP2dKbK6lsjUxsCjkr3","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 using a seed, returning a stable group label and bucket value based on a configurable holdout fraction.","exampleAgentPrompt":"Assign user ID 'user_98234' to either the treatment or holdout group using seed 'exp_launch_v2' with a 20% holdout fraction, and tell me which group they land in.","exampleUseCases":[{"title":"Gradual feature rollout gating","prompt":"I'm rolling out a new checkout flow to 80% of users — can you assign user 'acct_77123' to treatment or holdout using seed 'checkout_rollout_q3' with a holdout fraction of 0.2?"},{"title":"Reproducible A/B test assignment","prompt":"For our email subject line experiment, assign customer 'cust_abc456' to a group using seed 'email_ab_oct' and a 50% holdout fraction so we can consistently know which variant they're in."},{"title":"Agent self-gating on new capability","prompt":"Before using the new search strategy, check if session 'sess_x9q2' falls in the holdout group — use seed 'agent_search_exp' and a holdout fraction of 0.1 so only 10% of sessions skip the new behavior."}],"resultDescription":"Returns a JSON object with a 'group' field ('treatment' or 'holdout'), a numeric 'bucket' value (0–1) reflecting the deterministic hash position, the schema version, a 'status' of 'pass', and evidence metadata including whether data was retained (always false), the SHA-256 of the input, and the number of external calls made (always 0).","failureModes":["Missing required fields (seed, subject, holdout_fraction) result in a validation error","holdout_fraction outside the 0–1 range may cause unexpected behavior or an error","Overly long seed or subject strings (beyond 8192 chars) will be rejected","Payment failure via x402 protocol will prevent the call from being processed"],"whenToPreferThis":"Use this endpoint when you need a stateless, reproducible, privacy-safe way to assign subjects to holdout vs. treatment groups without storing assignment state. Ideal for agent workflows that must make consistent branching decisions across calls using only a seed and subject identifier. Prefer this over random assignment when repeatability matters, and over stateful systems when you want zero data retention guarantees.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-09-14T19:03:40.136Z","isFirstParty":false}