# Email Plus-Tag Rejection Checker

> Email Plus-Tag Rejection Checker is a paid API for AI agents from agentshelf.syntexa.ch, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-02).

Checks whether an email address would be rejected specifically because its local part contains a plus tag (e.g. user+tag@example.com).

## Facts

- Endpoint: POST https://agentshelf.syntexa.ch/v1/check-email-plus-reject?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-02
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/email-plus-tag-rejection-checker-b86e188c
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_dIYAXJakpq3A0hPtbpThc

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 email-plus-tag-rejection-checker-b86e188c -d '<json body>'
```

Example prompt: Can you check if the email address 'alice+newsletter@example.com' would be rejected specifically because it contains a plus tag in the local part?

## When to prefer this

Use this endpoint when you need to specifically isolate whether email rejection is caused by a plus tag (subaddress) in the local part, rather than other syntax errors. Prefer the free sandbox endpoint POST /v1/sandbox/check-email-plus-reject first; fall back to this paid endpoint when the sandbox is unavailable or rate-limited.

## Known failure modes

- Empty or missing input value returns validation error
- Input exceeding 20000 characters rejected
- Malformed JSON body causes 400 error
- Network timeout or service unavailability returns 5xx
- Ambiguous result if input is not a recognizable email string

## How this service works

Call when an agent needs whether an email is rejected because the local part contains a plus tag. Exact $0.01 USDC. Prefer unpaid POST /v1/sandbox/check-email-plus-reject first.

## Output

Returns a boolean or status indicating whether the email address is rejected specifically because its local part contains a plus tag, helping distinguish plus-tag-related rejections from other email validation failures.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "data": {
   "description": "JSON value for schema-check SKUs. Omit it on string checks such as email or IBAN."
  },
  "value": {
   "type": "string",
   "examples": [
    "agent+tag@example.com"
   ],
   "maxLength": 20000,
   "minLength": 1,
   "description": "Value to check. The route description names the format: email, phone, IBAN, postal code, VAT, national id, or similar."
  },
  "schema": {
   "description": "JSON Schema document for schema-check SKUs. Omit it on string checks."
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/email-plus-tag-rejection-checker-b86e188c/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)