# agentshelf.syntexa.ch DKIM k3 TXT Lookup

> agentshelf.syntexa.ch DKIM k3 TXT Lookup is a paid API for AI agents from agentshelf.syntexa.ch, paid per call via x402, $0.009/call, status unknown (last checked 2026-10-01).

Retrieves the DKIM TXT record at k3._domainkey.{hostname} for email authentication verification

## Facts

- Endpoint: POST https://agentshelf.syntexa.ch/v1/dns-txt-dkim-k3?utm_source=zero.xyz
- Price: $0.009/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-01
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/agentshelf-syntexa-ch-dkim-k3-txt-lookup-c4a0a77d
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_H8_ruUchDYArcAaprkp8q

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-syntexa-ch-dkim-k3-txt-lookup-c4a0a77d -d '<json body>'
```

Example prompt: Can you look up the DKIM TXT record at the k3 selector for example.com so I can verify their email signing key is properly published?

## When to prefer this

Use this endpoint when you specifically need the k3 DKIM selector TXT record. If the target domain uses a different DKIM selector (selector1, selector2, or a custom one), use the corresponding sibling endpoints. Try the free sandbox endpoint POST /v1/sandbox/dns-txt-dkim-k3 first before invoking this paid endpoint to avoid unnecessary charges.

## Known failure modes

- Record does not exist — no TXT record found at k3._domainkey.{hostname}, returns empty or not-found result
- Invalid hostname format — hostname exceeds 253 characters or is malformed, request rejected
- DNS resolution failure — upstream DNS timeout or NXDOMAIN for the apex domain
- Payment failure — x402 payment not processed, endpoint returns 402 before query executes

## How this service works

Call when an agent needs TXT at k3._domainkey.{hostname}. A different selector is a different DNS name. Exact $0.009 USDC. Prefer unpaid POST /v1/sandbox/dns-txt-dkim-k3 first.

## Output

Returns the raw DNS TXT record value published at k3._domainkey.{hostname}, which typically contains a DKIM public key entry (e.g. v=DKIM1; k=rsa; p=...) or indicates the record is absent. The agent can use this to verify email signing configuration, compare key fingerprints, or diagnose deliverability issues.

## 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-syntexa-ch-dkim-k3-txt-lookup-c4a0a77d/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)