# Delx Seeded Pairing

> Delx Seeded Pairing is a paid API for AI agents from api.delx.ai, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-13).

Deterministically pairs a list of participants using a seed string, returning stable bracket-style pairings and a bye participant if the count is odd.

## Facts

- Endpoint: POST https://api.delx.ai/api/v1/x402/seeded-pairing
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/delx-seeded-pairing-5fc7aea5
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_C_ROH5-dZT8ak5ZMPhp_m

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-pairing-5fc7aea5 -d '<json body>'
```

Example prompt: Pair up these 5 players — Alice, Bob, Carol, Dave, Eve — for a tournament bracket using the seed 'round1-2024', and tell me who gets the bye.

## When to prefer this

Use this endpoint when you need deterministic, reproducible participant pairings given a fixed seed — ideal for tournament brackets, agent task assignment, peer review scheduling, or any scenario where you need stable pairings that can be regenerated identically from the same inputs. Prefer it over random shuffling when auditability or reproducibility matters, since the SHA-256 evidence hash lets you verify the exact input used. It processes entirely in-memory with no data retention, making it suitable for sensitive participant lists.

## Known failure modes

- Empty participants list returns no pairs
- Participants list exceeding 256 items is rejected
- Seed string exceeding 8192 characters is rejected
- Malformed JSON body returns a 400-level error
- Network timeout if the service is temporarily unavailable

## How this service works

Seeded Pairing: Seeded Pairing creates reproducible non-overlapping pairs and reports an optional bye from bounded caller-supplied values without an external provider. Call Seeded Pairing 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 Pairing as versioned deterministic JSON. Price: $0.001 USDC via x402 on Base. First-party, stateless,…

## Output

Returns a JSON object with a 'pairs' array of two-element arrays (each pair of matched participants), an optional 'bye' field identifying the unpaired participant if the count is odd, plus evidence metadata including whether input was retained (always false), the SHA-256 of the input, and the count of external calls made (always 0).

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "seed": {
   "type": "string",
   "maxLength": 8192,
   "description": "Seed supplied to Seeded Pairing; used only for this bounded calculation and processed in memory without retention."
  },
  "participants": {
   "type": "array",
   "items": {
    "type": "string",
    "maxLength": 8192
   },
   "maxItems": 256,
   "description": "Participants supplied to Seeded Pairing; used only for this bounded calculation and processed in memory without retention."
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "result": {
   "bye": "b",
   "pairs": [
    [
     "d",
     "a"
    ],
    [
     "c",
     "e"
    ]
   ]
  },
  "schema": "delx/util-seeded-pairing/v1",
  "status": "pass",
  "evidence": {
   "retained": false,
   "input_sha256": "0bfb1a13590bf6beabbd01835232e976edb6c53d8cd2ab2a61049c2b2b57645a",
   "external_calls": 0
  },
  "operation": "seeded_decision:seeded_pairing"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/delx-seeded-pairing-5fc7aea5/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)