# The Stall LLM Proxy — GPT-4o-mini via x402

> The Stall LLM Proxy — GPT-4o-mini via x402 is a paid API for AI agents from the-stall.intuitek.ai, paid per call via x402, $0.021/call, status unknown (last checked 2026-09-15).

Sends a prompt to GPT-4o-mini and returns the model's text response, paid per-call with USDC on Base via x402 — no API key or account required.

## Facts

- Endpoint: GET https://the-stall.intuitek.ai/cap/llm-proxy
- Price: $0.021/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/the-stall-llm-proxy-gpt-4o-mini-via-x402-b8e770fc
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_3A_bDgpPx1N-4-npWIloc

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 the-stall-llm-proxy-gpt-4o-mini-via-x402-b8e770fc
```

Example prompt: Using the pay-per-call LLM proxy on The Stall, send GPT-4o-mini the prompt 'Write a concise product description for a noise-cancelling headphone targeted at remote workers' with the system prompt 'You are a professional copywriter' and allow up to 300 output tokens.

## When to prefer this

Choose this endpoint when an AI agent needs to invoke GPT-4o-mini for text generation or reasoning without possessing an OpenAI API key or managing a subscription — particularly when operating in a crypto-native, x402-payment context on Base mainnet. Ideal for ephemeral or anonymous agent workflows where spinning up credentials is impractical and micropayment-per-call billing is preferred over monthly plans.

## Known failure modes

- Insufficient USDC balance — payment rejected before the model is called
- Prompt exceeds context limits — request fails with an input size error
- max_tokens set above 2000 — schema validation error
- Model unavailable — only gpt-4o-mini is supported on this flat-price route
- Network or Base mainnet payment confirmation timeout — call may not complete
- Missing required 'prompt' query parameter — request rejected at schema validation

## How this service works

Domain-agnostic x402 capability chassis by IntuiTek¹. 300 AI-callable data services — pay USDC on Base mainnet. No accounts or API keys required.

## Output

A plain-text response from GPT-4o-mini containing the model's generated output, up to the requested token limit, returned directly from the endpoint after the x402 USDC micropayment is processed.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "prompt"
     ],
     "properties": {
      "model": {
       "enum": [
        "gpt-4o-mini"
       ],
       "type": "string",
       "description": "Model to use. Only gpt-4o-mini is available on this flat-price route."
      },
      "prompt": {
       "type": "string",
       "description": "The user message / task to send to the LLM."
      },
      "system": {
       "type": "string",
       "description": "Optional system prompt. Sets the persona or role for the model."
      },
      "max_tokens": {
       "type": "integer",
       "maximum": 2000,
       "minimum": 1,
       "description": "Maximum output tokens. Default: 500. Increase for longer outputs (max 2,000)."
      }
     },
     "additionalProperties": false
    }
   },
   "additionalProperties": false
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/the-stall-llm-proxy-gpt-4o-mini-via-x402-b8e770fc/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from the-stall.intuitek.ai](https://www.zero.xyz/host/the-stall.intuitek.ai/llms.txt)