# Beefy Vault callReward() Harvest Truth Checker

> Beefy Vault callReward() Harvest Truth Checker is a paid API for AI agents from yonder-spotless-stranger.ngrok-free.dev, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-14).

Returns the real caller balance delta for a Beefy vault harvest, exposing the gap between the advertised callReward() bounty and the actual ETH received via eth_simulateV1 trace simulation.

## Facts

- Endpoint: GET https://yonder-spotless-stranger.ngrok-free.dev/harvest-truth
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/beefy-vault-callreward-harvest-truth-checker-7781d8bd
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_WUoVtjw6x9ve-wk49E83E

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 beefy-vault-callreward-harvest-truth-checker-7781d8bd
```

Example prompt: Before my harvester bot sends the transaction, can you tell me the real caller balance delta for this Beefy vault harvest — I want to know if callReward() is actually telling the truth or inflating the bounty by 1000x again?

## When to prefer this

Use this endpoint when you need ground-truth harvest profitability for Beefy vaults before committing gas — specifically when callReward() values are suspected of overstating the actual bounty. Prefer this over reading callReward() directly when building or auditing harvester bots that need to avoid unprofitable harvests. This is the right choice when you need simulation-verified balance deltas rather than heuristic estimates.

## Known failure modes

- Invalid or non-existent vault address returns an error or empty result
- Vault on unsupported chain returns no simulation data
- Network timeout from the underlying RPC node causes delayed or failed response
- Vault already harvested recently may show zero reward in simulation
- eth_simulateV1 node unavailability causes service degradation

## How this service works

Beefy vault callReward() advertised-vs-actual, trace-verified. The view function overstates the caller bounty by up to ~1000x (an advertised $555 harvest paid $0.0001 in simulation), so harvester bots built on it burn gas for nothing. Values here are the real caller balance delta from an eth_simulateV1 trace.

## Output

Returns the real caller balance delta derived from an eth_simulateV1 trace of the harvest transaction, alongside the advertised callReward() value, enabling direct comparison of the inflated on-chain claim versus the actual ETH the harvester would receive.

## 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"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {}
    }
   },
   "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/beefy-vault-callreward-harvest-truth-checker-7781d8bd/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from yonder-spotless-stranger.ngrok-free.dev](https://www.zero.xyz/host/yonder-spotless-stranger.ngrok-free.dev/llms.txt)