# Frictionless Waterhammer Characteristic Grid Boundary Transcript

> Frictionless Waterhammer Characteristic Grid Boundary Transcript is a paid API for AI agents from detect.halowerk.com, paid per call via x402, $0.003/call, status unknown (last checked 2026-11-04).

Replays a supplied ideal (frictionless) waterhammer wave propagation over a method-of-characteristics grid with explicit boundary velocities and returns the head/velocity field at requested time steps.

## Facts

- Endpoint: POST https://detect.halowerk.com/v1/F-TD2000-GEO-INDUSTRY-B008/frictionless-waterhammer-characteristic-grid-boundary-transcript?utm_source=zero.xyz
- Price: $0.003/call
- Payment: x402
- Status: unknown
- Last checked: 2026-11-04
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/frictionless-waterhammer-characteristic-grid-boundary-transcript-6eb3d0e4
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_pUinL5JbuxKgfw_Vky88L

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 frictionless-waterhammer-characteristic-grid-boundary-transcript-6eb3d0e4 -d '<json body>'
```

Example prompt: Run a frictionless waterhammer characteristic grid simulation for a 1000-meter pipe with wave speed 1200 m/s and gravity 9.81, using initial heads [50, 50, 50] meters, initial velocities [1.0, 1.0, 1.0] m/s, reservoir head of 55 meters, outlet velocities [0.0, 0.0] m/s for two time steps, and give me the head and velocity fields at sample steps 0 and 1.

## When to prefer this

Use this endpoint when you need a deterministic, frictionless method-of-characteristics waterhammer grid replay with explicit boundary control — particularly when you have a pre-defined ideal wave scenario and need head/velocity fields at specific time steps. Prefer this over full friction-inclusive solvers when validating ideal theory or teaching MOC concepts.

## Known failure modes

- Mismatched array lengths between initial_heads and initial_velocities cause validation errors
- outlet_velocities array shorter than the required number of time steps returns an error
- wave_speed or length out of allowed bounds returns a 400 validation error
- Incompatible claim object causes rejection
- Payment not provided or insufficient USDC results in 402 Payment Required

## How this service works

Replay a supplied ideal waterhammer wave grid with explicit boundary velocities.

## Output

Returns the simulated pressure head and velocity fields across the characteristic grid at the requested sample time steps, computed using the ideal (frictionless) method-of-characteristics approach with the supplied boundary conditions.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "artifact": {
   "type": "object",
   "required": [
    "waterhammer"
   ],
   "properties": {
    "waterhammer": {
     "type": "object",
     "required": [
      "data",
      "claim"
     ],
     "properties": {
      "data": {
       "type": "object",
       "required": [
        "length",
        "wave_speed",
        "gravity",
        "initial_heads",
        "initial_velocities",
        "reservoir_head",
        "outlet_velocities",
        "sample_steps"
       ],
       "properties": {
        "length": {
         "type": "number",
         "maximum": 100000,
         "minimum": 0.01
        },
        "gravity": {
         "type": "number",
         "maximum": 100,
         "minimum": 0.1
        },
        "wave_speed": {
         "type": "number",
         "maximum": 10000,
         "minimum": 1
        },
        "sample_steps": {
         "type": "array",
         "items": {
          "type": "integer",
          "maximum": 128,
          "minimum": 0
         },
         "maxItems": 32,
         "minItems": 1
        },
        "initial_heads": {
         "type": "array",
         "items": {
          "type": "number",
          "maximum": 1000000,
          "minimum": -1000000
         },
         "maxItems": 33,
         "minItems": 3
        },
        "reservoir_head": {
         "type": "number",
         "maximum": 1000000,
         "minimum": -1000000
        },
        "outlet_velocities": {
         "type": "array",
         "items": {
          "type": "number",
          "maximum": 100,
          "minimum": -100
         },
         "maxItems": 128,
         "minItems": 1
        },
        "initial_velocities": {
         "type": "array",
         "items": {
          "type": "number",
          "maximum": 100,
          "minimum": -100
         },
         "maxItems": 33,
         "minItems": 3
        }
       },
       "additionalProperties": false
      },
      "claim": {}
     },
     "additionalProperties": false
    }
   },
   "additionalProperties": false
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/frictionless-waterhammer-characteristic-grid-boundary-transcript-6eb3d0e4/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from detect.halowerk.com](https://www.zero.xyz/host/detect.halowerk.com/llms.txt)