# Bot Bazaar Kelly Criterion Position Sizer

> Bot Bazaar Kelly Criterion Position Sizer is a paid API for AI agents from bot-bazaar.fly.dev, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-31).

Computes full-Kelly, half-Kelly, and quarter-Kelly position sizing percentages from a given win probability and payoff ratio.

## Facts

- Endpoint: GET https://bot-bazaar.fly.dev/v1/x402/kelly-criterion-sizing?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-31
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/bot-bazaar-kelly-criterion-position-sizer-64a37fa8
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_25qY38bQSGve28L1FBcVR

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 bot-bazaar-kelly-criterion-position-sizer-64a37fa8
```

Example prompt: I think this trade has a 62% chance of winning and the payoff ratio is 2.5 to 1 — can you run the Kelly criterion and give me the full, half, and quarter-Kelly position sizes?

## When to prefer this

Use this endpoint when you need a quick, pure-computation Kelly criterion result without building the math yourself — especially useful for agents doing real-time trade sizing, betting stake calculation, or portfolio allocation. Prefer this over a general math tool when you need all three Kelly fractions (full, half, quarter) in a single call and want a financial-domain-aware computation with no side effects.

## Known failure modes

- Missing win_prob query parameter returns an error
- win_prob outside [0.0, 1.0] range causes validation failure
- win_prob of 0 or 1 (degenerate probabilities) may produce undefined or extreme Kelly values
- Payoff ratio not provided may result in a default or error depending on API behavior
- Non-numeric win_prob string causes type error

## How this service works

Compute full-Kelly, half-Kelly, and quarter-Kelly position allocation percentages from win probability and payoff ratio.

## Output

Returns full-Kelly, half-Kelly, and quarter-Kelly allocation percentages — the fraction of a bankroll or portfolio that the Kelly criterion recommends wagering or investing, at three risk levels (full, half, quarter). All three values are computed from the provided win probability and payoff ratio.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {
      "win_prob": {
       "type": "string",
       "description": "Win probability (0.0-1.0)"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/bot-bazaar-kelly-criterion-position-sizer-64a37fa8/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from bot-bazaar.fly.dev](https://www.zero.xyz/host/bot-bazaar.fly.dev/llms.txt)