# Vextorium Zero-Shot Text Classifier

> Vextorium Zero-Shot Text Classifier is a paid API for AI agents from api.vextorium.com, paid per call via x402, $0.005/call, status down (last checked 2026-10-02).

Classifies text into user-supplied labels using local AI, returning the best label(s) with a confidence score and reason.

## Facts

- Endpoint: POST https://api.vextorium.com/clasificar-pago?utm_source=zero.xyz
- Price: $0.005/call
- Payment: x402
- Status: down
- Last checked: 2026-10-02
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/vextorium-zero-shot-text-classifier-bf5e3983
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_-yZO8oPzKO3WcdqIdOeK_

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 vextorium-zero-shot-text-classifier-bf5e3983 -d '<json body>'
```

Example prompt: Classify this customer message — 'My order arrived broken and I want a refund' — into one of these labels: billing, shipping, product defect, general inquiry. Tell me which label fits best and how confident you are.

## When to prefer this

Choose this endpoint when you need zero-shot classification against a fully custom, user-defined label set without training a model — especially useful when labels change per request, you need a confidence score and a human-readable reason, and you want a cost-effective ($0.005/call) local-AI solution rather than a heavyweight cloud NLP API.

## Known failure modes

- Fewer than 2 or more than 30 candidate labels provided — validation error
- Empty or missing 'texto' field — required field error
- Ambiguous text with very low confidence score returned (near 0.5)
- Label list contains duplicates or very similar labels causing split confidence
- Network timeout if input text is extremely long

## How this service works

Zero-shot text classification with local AI: pick the best label (or several) from your own list, with confidence and reason.

## Output

Returns a JSON object with: selected label(s) as an array, a numerical confidence score (0-1), a human-readable reason explaining the choice, and the model name used for inference.

## 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",
    "bodyType",
    "body"
   ],
   "properties": {
    "body": {
     "required": [
      "texto",
      "etiquetas"
     ],
     "properties": {
      "texto": {
       "type": "string",
       "description": "Text to classify"
      },
      "multiple": {
       "type": "boolean",
       "description": "Allow several labels (default false)"
      },
      "etiquetas": {
       "type": "array",
       "items": {
        "type": "string"
       },
       "description": "2-30 candidate labels"
      }
     }
    },
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "POST"
     ],
     "type": "string"
    },
    "bodyType": {
     "enum": [
      "json",
      "form-data",
      "text"
     ],
     "type": "string"
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "properties": {
      "modelo": {
       "type": [
        "string",
        "null"
       ]
      },
      "motivo": {
       "type": [
        "string",
        "null"
       ]
      },
      "confianza": {
       "type": [
        "number",
        "null"
       ]
      },
      "etiquetas": {
       "type": [
        "array",
        "null"
       ],
       "items": {
        "type": [
         "string",
         "null"
        ]
       }
      }
     }
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/vextorium-zero-shot-text-classifier-bf5e3983/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.vextorium.com](https://www.zero.xyz/host/api.vextorium.com/llms.txt)