# Chat Completion (basic)

> Chat Completion (basic) is a paid API for AI agents from api.eucompliance.tools, paid per call via x402, $0.005/call, status unknown (last checked 2026-09-13).

Send a prompt or messages array and get an LLM-generated text response as JSON, with no account or API key required, at a fixed per-call price with a signed auditable receipt.

## Facts

- Endpoint: POST https://api.eucompliance.tools/x402/chat
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/chat-completion-basic-338b9f91
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_w7FFbJI3D9mC3AUY18oMW

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 chat-completion-basic-338b9f91 -d '<json body>'
```

Example prompt: Ask an LLM to summarize this paragraph for me and give me the answer as JSON — I don't want to set up an API key, just pay per call: 'The European Union has enacted sweeping digital regulations aimed at increasing platform accountability and user privacy protections across member states.'

## When to prefer this

Choose this endpoint when you need a one-off or low-volume LLM completion with no account registration, no API key management, and a fixed auditable cost per call. It is ideal for agents that need to embed LLM calls in automated pipelines without committing to a subscription, or when a signed receipt is required for compliance and auditability. If you need higher output limits (beyond 1,000 tokens out or 8,000 chars in), use the sibling /x402/chat-plus endpoint instead.

## Known failure modes

- Input exceeds 8,000 character hard cap — request rejected with cap disclosure
- Output truncated at 1,000 tokens if model response would exceed limit
- Malformed messages array structure returns a 400-level error
- Payment not confirmed or x402 handshake fails — call not executed
- Model unavailable or upstream timeout returns a 5xx error

## How this service works

LLM completion per call, no account and no API key: POST a prompt (or a messages array) and get the model answer as JSON. Hard caps disclosed in every response (6,000 UTF-8 bytes in, 750 tokens out on this tier). Fixed price per call, signed receipt included so the answer stays auditable. Larger tier at /x402/chat-plus.

## Output

A JSON object containing the model's text answer to the submitted prompt or messages array, along with usage metadata (character/token counts), hard cap disclosures (8,000 chars in, 1,000 tokens out), and a signed cryptographic receipt confirming the response for auditability. No streaming; response is returned synchronously.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "prompt": {
   "type": "string",
   "description": "the question or task"
  },
  "system": {
   "type": "string",
   "description": "optional system prompt"
  },
  "messages": {
   "type": "array",
   "description": "optional OpenAI-style messages instead of prompt"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/chat-completion-basic-338b9f91/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.eucompliance.tools](https://www.zero.xyz/host/api.eucompliance.tools/llms.txt)