# AgentShelf DNS SRV MQTT Lookup

> AgentShelf DNS SRV MQTT Lookup is a paid API for AI agents from agentshelf.syntexa.ch, paid per call via x402, $0.009/call, status unknown (last checked 2026-10-02).

Resolves SRV records at _mqtt._tcp.{hostname} for a given registrable domain, returning MQTT broker connection details.

## Facts

- Endpoint: POST https://agentshelf.syntexa.ch/v1/dns-srv-mqtt?utm_source=zero.xyz
- Price: $0.009/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-02
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/agentshelf-dns-srv-mqtt-lookup-bfd30255
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_fjHEBpSXNcAXUYg8MrX17

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 agentshelf-dns-srv-mqtt-lookup-bfd30255 -d '<json body>'
```

Example prompt: What MQTT broker does example.com use? Look up the SRV record at _mqtt._tcp.example.com and give me the host and port.

## When to prefer this

Use this endpoint when an agent needs to programmatically discover the MQTT broker for a domain via standard DNS SRV records, particularly in IoT, home automation, or messaging pipeline contexts where broker endpoints are published via DNS rather than hardcoded. Prefer the free sandbox endpoint POST /v1/sandbox/dns-srv-mqtt first for testing.

## Known failure modes

- No SRV record found for the given domain (NXDOMAIN or empty answer)
- Invalid or malformed hostname input
- Domain exists but has no _mqtt._tcp SRV record configured
- DNS resolution timeout
- Payment failure or insufficient USDC balance

## How this service works

Call when an agent needs SRV records at _mqtt._tcp.{hostname} for MQTT. The caller sends the registrable domain, not the underscored name. Exact $0.009 USDC. Prefer unpaid POST /v1/sandbox/dns-srv-mqtt first.

## Output

Returns the SRV record data for _mqtt._tcp.{hostname}, typically including the target broker hostname, port number, priority, and weight values that allow an MQTT client to connect to the correct broker.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "hostname": {
   "type": "string",
   "examples": [
    "example.com"
   ],
   "maxLength": 253,
   "minLength": 1,
   "description": "Public DNS hostname such as example.com. Not a URL, not an IP literal, and not a private name."
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/agentshelf-dns-srv-mqtt-lookup-bfd30255/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from agentshelf.syntexa.ch](https://www.zero.xyz/host/agentshelf.syntexa.ch/llms.txt)