# Wintergreen x402 Contractor Estimating Guide

> Wintergreen x402 Contractor Estimating Guide is a paid API for AI agents from x402.wintergreen.uk, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-16).

Returns a payment-gated contractor estimating career guide covering bidding, pricing, and project estimation methodologies.

## Facts

- Endpoint: GET https://x402.wintergreen.uk/api/v1/knowledge/contractor-estimating
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-16
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/wintergreen-x402-contractor-estimating-guide-8b9391d0
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_cWkCIeobt35UNL7jTucVg

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 wintergreen-x402-contractor-estimating-guide-8b9391d0
```

Example prompt: Can you pull up the contractor estimating guide — I need to learn how to properly price a remodeling job including labor, materials, and overhead? I'll pay the $2.50 USDC access fee.

## When to prefer this

Choose this endpoint when an AI agent or user needs authoritative, curated guidance on contractor estimating, bidding, and pricing — particularly when other free resources lack depth or structure. Best suited for tradespeople, project managers, or learners who want a concise, pay-per-use reference without a subscription.

## Known failure modes

- HTTP 402 returned if payment header is missing or invalid — must sign EIP-712 TransferWithAuthorization and retry with X-PAYMENT header
- Payment address mismatch or incorrect USDC amount results in rejected transaction
- Invalid or missing slug parameter may return empty or incorrect content
- Network issues on Base (eip155:8453) chain can delay or fail payment settlement
- Response schema is unspecified, so output format may vary

## How this service works

Payment-gated crypto trading intelligence for AI agents.
    
## Categories
- **Hyperliquid Signals**: Real-time funding divergence, lead-lag correlation, liquidation clusters, session volume area levels
- **Quant Methodology**: Backtesting walk-forward validation, strategy generation with kill battery (19 rules), risk management with Kelly sizing, regime detection, execution frameworks, agent orchestration
- **Market Insights**: 22 crypto microstructure observations — funding, liquidation, orderbook, regime, flow, anomaly
- **Power Markets**: ERCOT field guide, merit-order model, duck curve analysis
- **Career Guides**: Firefighter oral board prep, medical coding, ATSA, contractor estimating
- **Trust Scoring**: x402 endpoint verification, P2D badges

## Payment
All paid endpoints return HTTP 402 with USDC on Base (eip155:8453). 
Sign EIP-712 TransferWithAuthorization and retry with X-PAYMENT header.
PayTo: 0xAe9834d71F1Bd989A0dc17593451af823E31CeeD

## Output

A structured knowledge document covering contractor estimating principles, including bidding strategies, labor and materials pricing, overhead calculation, markup and profit margin guidance, and project estimation frameworks for trades professionals.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "_meta": {
   "type": "string"
  },
  "_slug": {
   "type": "string"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/wintergreen-x402-contractor-estimating-guide-8b9391d0/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402.wintergreen.uk](https://www.zero.xyz/host/x402.wintergreen.uk/llms.txt)