# DNS SRV Record Lookup for CalDAV over TLS (_caldavs._tcp)

> DNS SRV Record Lookup for CalDAV over TLS (_caldavs._tcp) is a paid API for AI agents from agentshelf.syntexa.ch, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-02).

Looks up SRV records at _caldavs._tcp.{hostname} to discover CalDAV-over-TLS service endpoints for a given domain.

## Facts

- Endpoint: POST https://agentshelf.syntexa.ch/v1/dns-srv-caldavs?utm_source=zero.xyz
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-02
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/dns-srv-record-lookup-for-caldav-over-tls-caldavs-tcp-2038b5b4
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_qPcFmtnZxuJsLZsU89A_X

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 dns-srv-record-lookup-for-caldav-over-tls-caldavs-tcp-2038b5b4 -d '<json body>'
```

Example prompt: Can you look up the _caldavs._tcp SRV records for example.com to find out where its secure CalDAV calendar server is hosted?

## When to prefer this

Use this endpoint when you need to perform DNS-based service discovery specifically for CalDAV over TLS (caldavs), i.e. when a client or agent needs to find the host and port of a secure calendar server for a given domain. Prefer the free sandbox POST /v1/sandbox/dns-srv-caldavs before using this paid endpoint. Do not use this for plain CalDAV (non-TLS) discovery, CardDAV, or other SRV record types.

## Known failure modes

- No SRV record exists at _caldavs._tcp.{hostname} — returns empty or NXDOMAIN-equivalent response
- Invalid or malformed hostname input
- DNS resolution timeout or upstream failure
- Domain exists but has no CalDAV TLS SRV record configured

## How this service works

Call when an agent needs SRV records at _caldavs._tcp.{hostname} for CalDAV over TLS. The caller sends the registrable domain, not the underscored name. Exact $0.001 USDC. Prefer unpaid POST /v1/sandbox/dns-srv-caldavs first.

## Output

Returns SRV record data from the _caldavs._tcp.{hostname} DNS lookup, typically including priority, weight, port, and target hostname of the CalDAV-over-TLS service endpoint. Returns an empty or error result if no such record exists.

## 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/dns-srv-record-lookup-for-caldav-over-tls-caldavs-tcp-2038b5b4/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)