# API Media Representation Negotiation Validator

> API Media Representation Negotiation Validator is a paid API for AI agents from detect.halowerk.com, paid per call via x402, $0.003/call, status unknown (last checked 2026-10-20).

Validates that the selected media type representation matches the declared Accept policy and selection rules

## Facts

- Endpoint: POST https://detect.halowerk.com/v1/integration/api-media-representation-negotiation?utm_source=zero.xyz
- Price: $0.003/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-20
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/api-media-representation-negotiation-validator-b718009a
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_zBfqAMcsy7f4I4CBdMvN3

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 api-media-representation-negotiation-validator-b718009a -d '<json body>'
```

Example prompt: Check whether the media type that was selected (index 2) from my list of representations actually matches my declared Accept policy — my Accept header is 'application/json, text/html;q=0.9' and the selection policy is 'first-match'.

## When to prefer this

Use this endpoint when you need to programmatically verify that HTTP content negotiation logic is correct — specifically that the chosen media type representation matches the client's declared Accept preferences and the governing selection policy. Prefer this over manual inspection when auditing APIs for standards compliance, debugging unexpected media type delivery, or validating negotiation behavior as part of an automated test pipeline.

## Known failure modes

- Missing required fields (accept, representations, selected_index, selection_policy) returns validation error
- Malformed Accept header syntax may cause parsing failure
- selected_index out of bounds for the provided representations array
- Ambiguous or unknown selection_policy value may return an unresolvable result
- Conflicting quality values in Accept header may produce indeterminate outcomes

## How this service works

Gelieferte Antwort-Medientypauswahl mit ausdruecklich deklarierter Accept-Auswahlpolitik vergleichen.

## Output

Returns a validation result indicating whether the selected representation index is compliant with the declared Accept header preferences and selection policy, including detection of any policy violations or mismatches between what was delivered and what the policy dictates.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "artifact": {
   "type": "object",
   "required": [
    "accept",
    "representations",
    "selected_index",
    "selection_policy"
   ],
   "properties": {
    "accept": {},
    "selected_index": {},
    "representations": {},
    "selection_policy": {}
   },
   "additionalProperties": true
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/api-media-representation-negotiation-validator-b718009a/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)