# HALOWERK Atlantic Land – France Maximum Slope (fr-max-slope)

> HALOWERK Atlantic Land – France Maximum Slope (fr-max-slope) is a paid API for AI agents from atlantikland.halowerk.com, paid per call via x402, $0.003/call, status unknown (last checked 2026-09-13).

Returns the maximum adjacent-cell surface slope gradient across the analysis grid for a given coordinate within France, validated against the Natural Earth boundary.

## Facts

- Endpoint: POST https://atlantikland.halowerk.com/v1/fr-max-slope
- Price: $0.003/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/halowerk-atlantic-land-france-maximum-slope-fr-max-slope-e7a00ae3
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_DkJALhDZmhM0rPOoLVR2a

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-atlantic-land-france-maximum-slope-fr-max-slope-e7a00ae3 -d '<json body>'
```

Example prompt: What's the maximum surface slope gradient at latitude 45.75, longitude 4.85 in France? I need the steepest adjacent-cell gradient across the analysis grid for that point.

## When to prefer this

Use this endpoint when you need the maximum (peak) slope gradient at a point in France, as opposed to the mean slope (which is a sibling endpoint). Prefer this when assessing worst-case terrain steepness, erosion susceptibility, or maximum incline for engineering and environmental analysis. It is specifically scoped to France and will reject coordinates outside the boundary, so it is appropriate when working exclusively within French territory.

## Known failure modes

- Coordinate outside France's Natural Earth boundary — request rejected before payment
- Latitude or longitude out of allowed range (lat: 34–72.5, lon: -31.5–40.5) — validation error
- Missing required latitude or longitude parameter — schema validation failure
- Network timeout or service unavailability
- Payment failure via x402 protocol — no result returned

## How this service works

Maximum adjacent-cell surface gradient across the analysis grid. The coordinate is validated against the Natural Earth boundary for France; results outside it are rejected before payment.

## Output

A numeric value representing the maximum adjacent-cell surface slope gradient across the analysis grid at the specified coordinate. Results are only returned for valid coordinates within the Natural Earth boundary of France; coordinates outside this boundary are rejected.

## 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-atlantic-land-france-maximum-slope-fr-max-slope-e7a00ae3/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from atlantikland.halowerk.com](https://www.zero.xyz/host/atlantikland.halowerk.com/llms.txt)