# Delx Kelly Binary Calculator

> Delx Kelly Binary Calculator 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).

Computes the Kelly Criterion fraction for a binary bet given the true probability and market price

## Facts

- Endpoint: POST https://api.delx.ai/api/v1/x402/kelly-binary
- 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-kelly-binary-calculator-817016c5
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_BM6KPbKX0PQSxWYJla17L

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-kelly-binary-calculator-817016c5 -d '<json body>'
```

Example prompt: I think the true probability of this outcome is 60% but the market is pricing it at 45% — what fraction of my bankroll does Kelly say I should wager?

## When to prefer this

Use this endpoint when you need a fast, stateless computation of the Kelly Criterion fraction for a binary outcome and you already have both a true probability estimate and a market price. Prefer this over building your own Kelly formula when you want a reliable, versioned, schema-tagged microservice result that is easy to audit. It is ideal for agents operating in prediction markets, sports betting, or binary options where position sizing discipline matters.

## Known failure modes

- Missing required fields (true_prob or market_price) returns a validation error
- market_price of 0 or 1 may cause division errors or undefined Kelly fractions
- Negative Kelly fraction (when market price exceeds true probability) indicates no edge — agent should interpret as 'do not bet'
- Non-numeric inputs for true_prob or market_price will be rejected
- Values outside [0,1] for probabilities may produce meaningless results

## How this service works

Kelly fraction for a binary market given edge and price. Call when sizing prediction-market bets with Kelly under your true_prob. Returns Kelly fraction for binary price as deterministic JSON for $0.001 USDC via x402 on Base. First-party local math only—no RPC, live market feed, API keys, storage, or mediagen. Advisory only; the caller owns capital, risk, and production controls.

## Output

Returns a JSON object containing the Kelly fraction (a number between 0 and 1 representing the optimal proportion of bankroll to wager), along with the schema identifier, the input true_prob, and the input market_price echoed back for confirmation.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "true_prob": {
   "type": "number",
   "description": "Input field: true prob."
  },
  "market_price": {
   "type": "number",
   "description": "Input field: market price."
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "kelly": 0.2727272727272727,
  "schema": "delx/util-kelly-binary/v1",
  "true_prob": 0.6,
  "market_price": 0.45
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/delx-kelly-binary-calculator-817016c5/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)