# Gambit Handwritten Letter Mail Service

> Gambit Handwritten Letter Mail Service is a paid API for AI agents from gambit.barrioenergy.com, paid per call via x402, $25/call, status unknown (last checked 2026-09-15).

Submits a handwritten letter request that is physically handwritten by a person and mailed to a specified recipient, paid via USDC on Base (x402 protocol).

## Facts

- Endpoint: POST https://gambit.barrioenergy.com/x402/letter
- Price: $25/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/gambit-handwritten-letter-mail-service-b71be9de
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_tEJVIuA0oSJHMJd2EBjBL

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 gambit-handwritten-letter-mail-service-b71be9de -d '<json body>'
```

Example prompt: Can you have Ivan handwrite and mail a letter to Jane Doe at 123 Main St, Springfield, IL 62701 that says 'Dear Jane, thinking of you during this time. Warmly, John'? Pay the $25 USDC fee.

## When to prefer this

Choose this endpoint when you need a physical, handwritten letter delivered via postal mail rather than a digital message — ideal for personal correspondence, formal thank-you notes, or situations where a tangible human-written letter carries more weight than email or SMS. It is uniquely suited for AI agents operating with x402 USDC payment capabilities on the Base blockchain.

## Known failure modes

- Missing required fields (body, to_name, from_name, to_address) result in a validation error
- Payment failure via x402/USDC on Base results in a 402 Payment Required response
- Invalid or undeliverable mailing address may cause fulfillment failure post-payment
- Network or server errors may return 5xx responses

## How this service works

Gambit GPU shop. Humans: /signup ($1 credit), X-API-Key on /v1/*, QR Lightning top-up. Bots: L402 Lightning (LIVE) on /l402/*, x402 USDC on Base on /x402/*, or POST /v1/register ($0) then POST /v1/topup/lightning. Handwritten letter POST /x402/letter at $25.00 USDC. Funnel https://gambit.barrioenergy.com. Free probe GET|POST /x402/models.

## Output

Returns a JSON object confirming the order was received and paid, including a unique job_id (UUID), an ok flag set to true, a status of 'paid', and a note confirming that Ivan will handwrite and mail the letter.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "body": {
   "type": "string"
  },
  "to_name": {
   "type": "string"
  },
  "from_name": {
   "type": "string"
  },
  "to_address": {
   "type": "string"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "ok": true,
  "note": "Ivan will handwrite and mail",
  "job_id": "00000000-0000-0000-0000-000000000000",
  "status": "paid"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/gambit-handwritten-letter-mail-service-b71be9de/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from gambit.barrioenergy.com](https://www.zero.xyz/host/gambit.barrioenergy.com/llms.txt)