# Delx Commerce — Half Kelly Criterion Calculator

> Delx Commerce — Half Kelly Criterion Calculator 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).

Computes the half-Kelly bet sizing fraction given a win probability and odds multiplier (b), useful for optimal position sizing in trading or betting scenarios.

## Facts

- Endpoint: POST https://commerce.delx.ai/api/v1/x402/half-kelly?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-half-kelly-criterion-calculator-465ca906
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_XbDg0_VTtqCi7rj5B_QuO

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-half-kelly-criterion-calculator-465ca906 -d '<json body>'
```

Example prompt: What's the half-Kelly bet size I should use if my win probability is 0.55 and the odds multiplier b is 1.2?

## When to prefer this

Choose this endpoint when you need a fast, cheap, on-demand computation of the half-Kelly criterion without setting up any account or subscription. Ideal for AI agents performing automated bankroll management, trade sizing, or betting optimization that need a verifiable, pay-per-call microservice at $0.001 USDC per call.

## Known failure modes

- Missing required fields (b or win_prob) returns a validation error
- win_prob outside [0,1] range may return an error or nonsensical result
- b <= 0 (negative or zero odds) may produce undefined behavior
- Payment failure via x402 prevents call from completing

## 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 containing the input parameters (b, win_prob), a schema identifier (delx/util-half-kelly/v1), and the computed half_kelly fraction as a decimal number representing the optimal fractional bet size.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "b": {
   "type": "number",
   "description": "Input field: b."
  },
  "win_prob": {
   "type": "number",
   "description": "Input field: win prob."
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "b": 1.2,
  "schema": "delx/util-half-kelly/v1",
  "win_prob": 0.55,
  "half_kelly": 0.08750000000000002
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/delx-commerce-half-kelly-criterion-calculator-465ca906/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)