# HALOWERK Eastern Land – Bulgaria Drainage Tendency

> HALOWERK Eastern Land – Bulgaria Drainage Tendency is a paid API for AI agents from ostland.halowerk.com, paid per call via x402, $0.003/call, status unknown (last checked 2026-09-15).

Returns a relative runoff tendency score derived from slope and terrain ruggedness for a given coordinate within Bulgaria.

## Facts

- Endpoint: POST https://ostland.halowerk.com/v1/bg-drainage-tendency
- Price: $0.003/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/halowerk-eastern-land-bulgaria-drainage-tendency-fe49ce55
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_a51rittWIrwR8L1zeTBQf

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 halowerk-eastern-land-bulgaria-drainage-tendency-fe49ce55 -d '<json body>'
```

Example prompt: What's the relative runoff tendency for the terrain at latitude 42.15, longitude 24.75 in Bulgaria — I need to understand how prone this slope is to surface drainage.

## When to prefer this

Use this endpoint when you need a terrain-derived runoff or drainage tendency score specifically for a coordinate in Bulgaria, derived from slope and ruggedness data. Prefer this over general elevation or soil endpoints when the primary concern is hydrological surface-flow tendency rather than raw elevation statistics or soil composition.

## Known failure modes

- Coordinate outside Bulgaria boundary — request is rejected before payment with a validation error
- Latitude or longitude out of the accepted European coverage range (lat 34–72.5, lon -31.5–40.5) — schema validation error
- Invalid or missing coordinate values — input schema validation failure
- Service unavailability or upstream terrain data error — 5xx response

## How this service works

Relative runoff tendency derived from slope and ruggedness. The coordinate is validated against the Natural Earth boundary for Bulgaria; results outside it are rejected before payment.

## Output

A numeric relative runoff tendency value derived from slope gradient and terrain ruggedness at the specified coordinate. The coordinate must fall within Bulgaria's Natural Earth boundary; requests outside this area are rejected before billing.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "latitude": {
   "type": "number",
   "maximum": 72.5,
   "minimum": 34,
   "description": "WGS84 latitude inside the published European coverage."
  },
  "longitude": {
   "type": "number",
   "maximum": 40.5,
   "minimum": -31.5,
   "description": "WGS84 longitude inside the published European coverage."
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/halowerk-eastern-land-bulgaria-drainage-tendency-fe49ce55/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from ostland.halowerk.com](https://www.zero.xyz/host/ostland.halowerk.com/llms.txt)