# ScaleDown Metered SLM Inference Credit Top-Up

> ScaleDown Metered SLM Inference Credit Top-Up is a paid API for AI agents from agents.scaledown.ai, paid per call via x402, $5/call, status unknown (last checked 2026-09-14).

Tops up an autonomous agent's ScaleDown inference credit balance using a prepaid metered payment, crediting tokens for SLM inference without requiring an API key or signup.

## Facts

- Endpoint: POST https://agents.scaledown.ai/credits
- Price: $5/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/scaledown-metered-slm-inference-credit-top-up-65125e5a
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_KML7ojiJjkEB1jcsCmf5j

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 scaledown-metered-slm-inference-credit-top-up-65125e5a -d '<json body>'
```

Example prompt: Top up my ScaleDown inference balance by paying $5 USDC through the agent payment rails so I have tokens ready for SLM inference — no API key needed.

## When to prefer this

Choose this endpoint when your autonomous agent needs to fund ScaleDown SLM inference on a pay-as-you-go basis with no signup, KYC, or API key — especially when operating over crypto/agent payment rails like x402. It is ideal for fully autonomous pipelines that need to self-fund inference capacity programmatically.

## Known failure modes

- Insufficient USDC balance in the agent wallet — payment fails and no tokens are credited
- Payment rail not supported or misconfigured — results in payment error with no state change
- Duplicate payment attempt within a short window — may result in double charge if not idempotent
- Network or provider downtime — payment may be pending with delayed or missing credit confirmation

## How this service works

Small language models that each do one job: compress long context, summarize, pull structured data out of text, and sort text into categories you define. A fraction of a general-purpose model's cost, and faster. Prepaid credits bought over a payment rail; no account, no API key.

## Output

Returns a JSON object confirming the top-up, including the endpoint name ('topup'), the amount charged in USD, the payment status ('completed'), and the new token balance credited (e.g. 100,000,000 tokens).

## Request schema (JSON Schema)

```json
{
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "type": "object",
 "properties": {
  "input": {
   "type": "object",
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "type": "string",
     "enum": [
      "POST"
     ]
    },
    "bodyType": {
     "type": "string",
     "enum": [
      "json",
      "form-data",
      "text"
     ]
    },
    "body": {
     "additionalProperties": false,
     "description": "Whole-dollar top-up amount (1-50, default 5). Crypto rails settle flat; the card path is $5 multiples plus $0.20 per $5.",
     "properties": {
      "usd": {
       "maximum": 50,
       "minimum": 1,
       "type": "integer"
      }
     },
     "type": "object"
    }
   },
   "required": [
    "type",
    "method",
    "bodyType",
    "body"
   ],
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   },
   "required": [
    "type"
   ]
  }
 },
 "required": [
  "input"
 ]
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "endpoint": "topup",
  "charged_usd": "5.00",
  "balance_tokens": 100000000,
  "payment_status": "completed",
  "credited_tokens": 100000000
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/scaledown-metered-slm-inference-credit-top-up-65125e5a/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from agents.scaledown.ai](https://www.zero.xyz/host/agents.scaledown.ai/llms.txt)