# Presenceoperations Execution Cost Estimator

> Presenceoperations Execution Cost Estimator is a paid API for AI agents from x402.presenceoperations.com, paid per call via x402, $0.0048/call, status unknown (last checked 2026-10-10).

Returns the size-weighted fill price, slippage in basis points, and book absorbability for executing a given notional in a perpetual futures market right now.

## Facts

- Endpoint: GET https://x402.presenceoperations.com/services/execution-cost?utm_source=zero.xyz
- Price: $0.0048/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-10
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/presenceoperations-execution-cost-estimator-2a1fdcae
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_Kalgdw66LgtZDcDKYGWBN

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 presenceoperations-execution-cost-estimator-2a1fdcae
```

Example prompt: What would it cost to buy $200,000 worth of BTC-PERP right now — give me the average fill price and how many basis points of slippage I'd eat walking the book.

## When to prefer this

Use this endpoint when you need real-time, size-aware execution cost estimates for perpetual futures — specifically when you need slippage in basis points and book absorbability for a given notional, not just a mid-price or last-trade price. Prefer this over generic price feeds when doing pre-trade analysis, risk sizing, or automated execution decisions that depend on actual order book depth rather than indicative prices.

## Known failure modes

- Invalid market symbol (not matching ^[A-Z0-9]{1,16}-PERP$) returns an error rather than a default
- Misspelled or invalid side parameter is refused and not charged — the call returns an error
- Notional below 1 or above 100,000,000 is rejected with a validation error
- Market not listed or no live book data available returns an error or absorbable=false
- Payment failure via x402 protocol results in no response being served

## How this service works

Pay-per-call analytics on live perpetual-futures microstructure: what it costs to execute a size, what it costs to hold a position, and how much liquidity a market really has. USDC via x402 on Base, no account and no API key. Each response states the limit of its own instrument rather than implying none.

## Output

A JSON object containing: the side and market queried, whether the book can absorb the requested notional (absorbable), the touch (best) price, average fill price after walking the book, slippage from the touch in basis points, total filled notional, number of book levels considered, the requested notional, and the timestamp the book was observed. Null fill price and slippage indicate the book cannot absorb the full size.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "market",
      "notional"
     ],
     "properties": {
      "side": {
       "enum": [
        "BUY",
        "SELL"
       ],
       "type": "string",
       "default": "BUY",
       "description": "which side of the book to walk; omitted means BUY, and anything outside BUY or SELL is refused rather than answered as the default, so a misspelled side is never charged for"
      },
      "market": {
       "type": "string",
       "pattern": "^[A-Z0-9]{1,16}-PERP$",
       "description": "the perpetual market to price, upper-cased before matching, for example BTC-PERP"
      },
      "notional": {
       "type": "number",
       "maximum": 100000000,
       "minimum": 1,
       "description": "the size to price, in quote currency, bounded so one paid call cannot become an unbounded read of the venue"
      }
     },
     "additionalProperties": false
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "side": "",
  "detail": "",
  "market": "",
  "absorbable": true,
  "touchPrice": null,
  "bookObservedAt": "",
  "filledNotional": 0,
  "averageFillPrice": null,
  "levelsConsidered": 0,
  "requestedNotional": 0,
  "slippageBasisPoints": null
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/presenceoperations-execution-cost-estimator-2a1fdcae/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402.presenceoperations.com](https://www.zero.xyz/host/x402.presenceoperations.com/llms.txt)