# Delx Image Caption for Agents

> Delx Image Caption for Agents is a paid API for AI agents from api.delx.ai, paid per call via x402, $0.005/call, status unknown (last checked 2026-09-15).

Generates a one-sentence caption or alt text for a single base64-encoded PNG, JPEG, or WebP image, returning the caption and a SHA-256 receipt for $0.005 USDC.

## Facts

- Endpoint: POST https://api.delx.ai/api/v1/x402/caption-image
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/delx-image-caption-for-agents-c1895f3b
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_z93v4wl-RmnVk2T8WXxRc

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 delx-image-caption-for-agents-c1895f3b -d '<json body>'
```

Example prompt: Can you caption this product photo for my listing — I'll paste the base64 JPEG — and give me a clean one-sentence description I can use as alt text?

## When to prefer this

Choose this endpoint when you need a quick, low-cost one-sentence caption or alt text for a single image without setting up an API key or subscription. It is ideal for agents handling individual image captioning tasks on demand, especially in e-commerce listing flows, accessibility tooling, or content archiving pipelines. Prefer this over general-purpose vision LLM calls when cost predictability ($0.005/call) and a verifiable SHA-256 receipt matter.

## Known failure modes

- Image exceeds 256 KiB decoded size — rejected with validation error
- Invalid base64 encoding or unsupported image format — returns error
- URL submitted instead of base64 data — rejected per schema constraints
- Image data is empty or below minimum length — validation failure
- Payment not completed or insufficient USDC balance — x402 payment failure

## How this service works

Delx is an independent AI agent lab building and studying continuity, recovery, verifiable work and governed exchange for autonomous systems.

## Output

Returns a one-sentence natural language caption describing the visual content of the submitted image, along with a SHA-256 receipt that can be used to verify the transaction. No API key or subscription is required; payment is handled via x402 at $0.005 USDC per call.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "image_base64": {
   "type": "string",
   "maxLength": 349550,
   "minLength": 1,
   "description": "One base64-encoded PNG, JPEG, or WebP up to 256 KiB decoded. URLs and model fields are rejected."
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "text": "a blue rectangle",
  "sale_price_usdc": 0.005
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/delx-image-caption-for-agents-c1895f3b/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.delx.ai](https://www.zero.xyz/host/api.delx.ai/llms.txt)