# Delx Seeded Sample Indices

> Delx Seeded Sample Indices is a paid API for AI agents from api.delx.ai, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-14).

Generates a reproducible list of random sample indices from a population using a deterministic seed string, count, and population size.

## Facts

- Endpoint: POST https://api.delx.ai/api/v1/x402/seeded-sample-indices
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/delx-seeded-sample-indices-073860a4
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_gR3D-6Gw2xX6_xzYtVOto

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-seeded-sample-indices-073860a4 -d '<json body>'
```

Example prompt: Using seed 'alpha42', pick 5 random indices from a population of 100 — make sure the same seed always gives the same result.

## When to prefer this

Choose this endpoint when you need a deterministic, reproducible random index selection — such as for auditable draws, reproducible ML splits, or any workflow where the same seed must always yield the same indices. Prefer it over client-side random sampling when auditability (via input SHA-256 evidence) and zero data retention are required. It is not suitable for weighted sampling, sampling with replacement control beyond the default, or generating non-index random values.

## Known failure modes

- count exceeds population_size when sampling without replacement — likely returns an error or invalid result
- missing required fields (seed, count, population_size) may cause a 400 or validation error
- very large population_size or count values could hit memory or timeout limits
- malformed or excessively long seed string (beyond 8192 chars) may be rejected
- non-integer values for count or population_size will fail schema validation

## How this service works

Seeded Sample Indices: Seeded Sample Indices samples unique zero-based indices from a population size from bounded caller-supplied values without an external provider. Call Seeded Sample Indices 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 Sample Indices as versioned deterministic JSON. Price: $0.001 USDC via x402 on Base. First-par…

## Output

Returns a JSON object containing an array of sampled integer indices (without replacement), a boolean replacement flag, the operation name, a SHA-256 hash of the input for auditability, confirmation that no data was retained, and an external call count of zero. Status field indicates whether the computation passed.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "seed": {
   "type": "string",
   "maxLength": 8192,
   "description": "Seed supplied to Seeded Sample Indices; used only for this bounded calculation and processed in memory without retention."
  },
  "count": {
   "type": "integer",
   "description": "Count supplied to Seeded Sample Indices; used only for this bounded calculation and processed in memory without retention."
  },
  "population_size": {
   "type": "integer",
   "description": "Population Size supplied to Seeded Sample Indices; used only for this bounded calculation and processed in memory without retention."
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "result": {
   "indices": [
    87,
    14,
    63,
    47,
    69
   ],
   "with_replacement": false
  },
  "schema": "delx/util-seeded-sample-indices/v1",
  "status": "pass",
  "evidence": {
   "retained": false,
   "input_sha256": "cbca27dc467ea1d750fe2e73d7674806e44ebcabbb22317158d7f88f92baf4d0",
   "external_calls": 0
  },
  "operation": "seeded_decision:seeded_sample_indices"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/delx-seeded-sample-indices-073860a4/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.delx.ai](https://www.zero.xyz/host/api.delx.ai/llms.txt)