# LLM API Anthropic-Style Messages Endpoint

> LLM API Anthropic-Style Messages Endpoint is a paid API for AI agents from agents.llmapi.ai, paid per call via MPP, price unknown, status unknown (last checked 2026-10-14).

Sends an Anthropic-style message request to a selected frontier LLM model and returns a non-streaming text completion.

## Facts

- Endpoint: POST https://agents.llmapi.ai/zc/v1/messages?utm_source=zero.xyz
- Price: price unknown
- Payment: MPP
- Status: unknown
- Last checked: 2026-10-14
- Activations on Zero: 0
- Provider: agents.llmapi.ai
- Website: https://agents.llmapi.ai
- Canonical page: https://www.zero.xyz/c/agents-llmapi-ai-llm-api-anthropic-style-messages-endpoint-cf16fe1a
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_btLDN2p_bn4fRdgNn2Jos

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 agents-llmapi-ai-llm-api-anthropic-style-messages-endpoint-cf16fe1a -d '<json body>'
```

Example prompt: Ask claude-sonnet-5 to summarize the following text in three bullet points, keeping the response under 200 tokens: 'Quantum computing uses quantum-mechanical phenomena such as superposition and entanglement to perform computation...'

## When to prefer this

Choose this endpoint when you need pay-per-call access to a curated set of frontier models (Claude, GPT, Gemini, DeepSeek, Grok, Kimi, GLM) using the Anthropic native messages format, without committing to a subscription. Ideal for agents that need deterministic, non-streaming completions billed by exact token usage across multiple model families through a single unified API surface.

## Known failure modes

- Invalid or unsupported model ID returns a validation error
- Omitting required fields (model, messages, max_tokens) causes a 400 bad request
- Setting stream to true is rejected by this storefront
- Exceeding token limits for the selected model causes an error
- Insufficient account credits results in a payment or authorization error
- Malformed messages array (wrong structure) returns a schema validation error

## How this service works

Sends a message to the conversation endpoint.

## Output

Returns an Anthropic-style response object containing the assistant's generated message content, the model used, stop reason, and token usage counts for input and output tokens.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "example": {
  "model": "claude-sonnet-5",
  "messages": [
   {
    "role": "user",
    "content": "Say hello in five words."
   }
  ],
  "max_tokens": 32
 },
 "required": [
  "model",
  "messages",
  "max_tokens"
 ],
 "properties": {
  "model": {
   "enum": [
    "claude-opus-5",
    "claude-sonnet-5",
    "gpt-5.2",
    "gpt-5.1",
    "gpt-5-mini",
    "gemini-3.1-pro-preview",
    "gemini-3.7-flash",
    "deepseek-v4-pro",
    "deepseek-v4-flash",
    "grok-4.6",
    "kimi-k2.6",
    "glm-5.3"
   ],
   "type": "string",
   "description": "One of the storefront model ids."
  },
  "stream": {
   "type": "boolean",
   "description": "Must be false or omitted on this storefront."
  },
  "content": {
   "type": "string"
  },
  "messages": {
   "type": "array",
   "items": {
    "type": "object"
   },
   "description": "Anthropic style message list."
  },
  "max_tokens": {
   "type": "integer",
   "description": "Required output token ceiling."
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/agents-llmapi-ai-llm-api-anthropic-style-messages-endpoint-cf16fe1a/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from agents.llmapi.ai](https://www.zero.xyz/host/agents.llmapi.ai/llms.txt)