# PennyRail AI Chat Mini (proven-v1)

> PennyRail AI Chat Mini (proven-v1) is a paid API for AI agents from pennyrail.vercel.app, paid per call via x402, $0.02/call, status unknown (last checked 2026-09-14).

Provides a paid AI chat completion via a micropayment-gated endpoint using the x402 protocol, returning a chat response for a given input object.

## Facts

- Endpoint: POST https://pennyrail.vercel.app/api/p/premium/ai.chat-mini--proven-v1-chat
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/pennyrail-ai-chat-mini-proven-v1-98d10831
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_LqWCnd95Z9ChILQut0VIv

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 pennyrail-ai-chat-mini-proven-v1-98d10831 -d '<json body>'
```

Example prompt: Send my message 'What are three tips for writing better Python code?' to the PennyRail proven chat mini model and give me back its response — I'm okay with the $0.02 USDC per-call charge.

## When to prefer this

Choose this endpoint when you need a low-cost, per-call AI chat completion billed in USDC via the x402 micropayment protocol, especially in agent workflows where pay-per-use metering is required. It is well-suited for pipelines that want to avoid subscription billing and instead pay $0.02 per query. Prefer it over generic LLM APIs when your infrastructure already supports x402 payments.

## Known failure modes

- Payment not included or insufficient USDC — 402 Payment Required response
- Malformed input object — missing required 'input' field returns validation error
- Service unavailable or rate-limited — 503 or 429 response
- Invalid or expired payment credential — payment rejected by x402 facilitator
- Unexpected model error — 500 Internal Server Error with no structured body

## How this service works

Machine-readable settlement service

## Output

Returns a JSON object containing the AI-generated chat response to the provided input. The response schema is open (additionalProperties: true), so the agent receives the model's reply along with any additional metadata the service includes.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "object",
 "additionalProperties": true
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/pennyrail-ai-chat-mini-proven-v1-98d10831/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from pennyrail.vercel.app](https://www.zero.xyz/host/pennyrail.vercel.app/llms.txt)