# Delx Commerce — Seeded A/B Assignment

> Delx Commerce — Seeded A/B Assignment is a paid API for AI agents from commerce.delx.ai, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-01).

Deterministically assigns a subject to an A/B test variant (A or B) based on a seed and optional weight, returning a verifiable bucket value and variant label.

## Facts

- Endpoint: POST https://commerce.delx.ai/api/v1/x402/seeded-ab-assignment?utm_source=zero.xyz
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-01
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/delx-commerce-seeded-a-b-assignment-c4fa38ac
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_MqCGbylmUl0-tIM6cdqNv

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability delx-commerce-seeded-a-b-assignment-c4fa38ac -d '<json body>'
```

Example prompt: Assign user 'user_8842' to an A/B test variant using seed 'experiment-v3' with a 70% weight for variant A — give me the bucket value and which variant they land in.

## When to prefer this

Choose this endpoint when you need a stateless, reproducible, and verifiable A/B assignment with no data retention — especially in agent pipelines where auditability matters, you want a cryptographic hash of inputs as evidence, and you need to pay per-result with no upfront signup or subscription.

## Known failure modes

- Missing required fields (seed or subject) may return a validation error
- Malformed JSON body returns a 400-level error
- Payment not included or insufficient USDC results in a 402 Payment Required response
- seed or subject strings exceeding 8192 characters may be rejected
- Network timeout on the Base/Solana payment settlement layer

## How this service works

Pay-per-result APIs for agents. No signup. Exact price. Verifiable delivery. USDC on Base + Solana via x402.

## Output

Returns a JSON object with the assigned variant ('A' or 'B'), a numeric bucket value between 0 and 1, the operation schema identifier, a pass/fail status, and an evidence block confirming no data was retained, the SHA-256 hash of the input, and that zero external calls were made.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "seed": {
   "type": "string",
   "maxLength": 8192,
   "description": "Seed supplied to Seeded Ab Assignment; used only for this bounded calculation and processed in memory without retention."
  },
  "subject": {
   "type": "string",
   "maxLength": 8192,
   "description": "Subject supplied to Seeded Ab Assignment; used only for this bounded calculation and processed in memory without retention."
  },
  "weight_a": {
   "type": "number",
   "description": "Weight A supplied to Seeded Ab Assignment; used only for this bounded calculation and processed in memory without retention."
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "result": {
   "bucket": 0.207537504388443,
   "variant": "A"
  },
  "schema": "delx/util-seeded-ab-assignment/v1",
  "status": "pass",
  "evidence": {
   "retained": false,
   "input_sha256": "96739ac478c933dfd4385515e11012fab06dfd8342764dd368da174bbe750bfa",
   "external_calls": 0
  },
  "operation": "seeded_decision:seeded_ab_assignment"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/delx-commerce-seeded-a-b-assignment-c4fa38ac/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from commerce.delx.ai](https://www.zero.xyz/host/commerce.delx.ai/llms.txt)