# RFC 2181 DNS RRset Positive Credibility Replacement & Cache Validator

> RFC 2181 DNS RRset Positive Credibility Replacement & Cache Validator is a paid API for AI agents from detect.halowerk.com, paid per call via x402, $0.003/call, status unknown (last checked 2026-11-04).

Validates and resolves DNS RRset credibility replacement rules per RFC 2181, returning authoritative cache state, expiry, and indivisible record set contents after ranked-source processing.

## Facts

- Endpoint: POST https://detect.halowerk.com/v1/F-TD2000-DATASTRUCTURES-09/rfc2181-positive-rrset-credibility-replacement-cache?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/rfc-2181-dns-rrset-positive-credibility-replacement-cache-validator-5002a8d6
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_6Rbzijv9DumHMf55oJnHg

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 rfc-2181-dns-rrset-positive-credibility-replacement-cache-validator-5002a8d6 -d '<json body>'
```

Example prompt: Check whether this DNS RRset cache replacement is correct per RFC 2181: I have an existing cache entry for 'example.com A' at rank 3 with TTL 300, and a new event arriving from a rank-5 source with TTL 120 — using 'replace_on_equal' policy, what should the final cache state, expiry, and remaining TTL be?

## When to prefer this

Use this endpoint when you need to programmatically validate or test DNS resolver logic against RFC 2181 credibility replacement rules, especially when evaluating ranked-source conflict resolution, indivisible RRset semantics, TTL expiry computation, or equal-rank policies. It is specifically suited for DNS resolver conformance testing, protocol compliance auditing, and cache state simulation — not for live DNS resolution or general DNS lookup.

## Known failure modes

- Missing required fields (dnsCredibility, data, claim) returns a 400 validation error
- Invalid rank values or malformed cache entry objects cause schema rejection
- Contradictory equal-rank policies may produce undefined replacement behavior
- Truncated events array beyond maxItems:512 results in partial processing
- Network timeout if event processing is computationally intensive

## How this service works

Recover exact positive DNS RRset replacement, expiry and indivisible set contents under complete ranked source facts.

## Output

Returns the authoritative resolved DNS cache state after applying RFC 2181 credibility replacement rules, including the winning record set, computed expiry timestamp, remaining TTL, credibility level, rank, authenticated flag, and whether replacement occurred given the equal-rank policy and input events.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "artifact": {
   "type": "object",
   "$defs": {
    "s0": {
     "type": "array",
     "items": {
      "type": "string",
      "maxLength": 20000
     },
     "maxItems": 512
    },
    "json": {
     "anyOf": [
      {
       "type": "null"
      },
      {
       "type": "boolean"
      },
      {
       "type": "number"
      },
      {
       "type": "string",
       "maxLength": 6000
      },
      {
       "type": "array",
       "items": {
        "$ref": "#/properties/input/properties/body/properties/artifact/%24defs/json"
       },
       "maxItems": 512
      },
      {
       "type": "object",
       "maxProperties": 128,
       "additionalProperties": {
        "$ref": "#/properties/input/properties/body/properties/artifact/%24defs/json"
       }
      }
     ]
    }
   },
   "required": [
    "dnsCredibility"
   ],
   "properties": {
    "dnsCredibility": {
     "type": "object",
     "required": [
      "data",
      "claim"
     ],
     "properties": {
      "data": {
       "type": "object",
       "required": [
        "equal_rank_policy",
        "events",
        "refresh_identical"
       ],
       "properties": {
        "events": {
         "type": "array",
         "items": {
          "$ref": "#/properties/input/properties/body/properties/artifact/%24defs/json"
         },
         "maxItems": 512
        },
        "equal_rank_policy": {
         "type": "string",
         "maxLength": 20000
        },
        "refresh_identical": {
         "type": "boolean"
        }
       },
       "additionalProperties": false
      },
      "claim": {
       "anyOf": [
        {
         "type": "null"
        },
        {
         "type": "object",
         "required": [
          "cache",
          "events"
         ],
         "properties": {
          "cache": {
           "type": "array",
           "items": {
            "type": "object",
            "required": [
             "authenticated",
             "cl",
             "expiry",
             "owner",
             "rank",
             "records",
             "remaining_ttl",
             "type"
            ],
            "properties": {
             "cl": {
              "type": "number"
             },
             "rank": {
              "type": "number"
             },
             "type": {
              "type": "number"
             },
             "owner": {
              "type": "string",
              "maxLength": 20000
            
… (truncated)
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/rfc-2181-dns-rrset-positive-credibility-replacement-cache-validator-5002a8d6/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)