# Anthropic Messages API (Claude)

> Anthropic Messages API (Claude) is a paid API for AI agents from Anthropic at anthropic.mpp.tempo.xyz, paid per call via MPP, $0.01025/call, status unknown (last checked 2026-10-10, last successful call 2026-05-28).

Send a prompt to Claude (Sonnet, Opus, or Haiku) and receive a generated text response via Anthropic's native Messages API

## Facts

- Endpoint: POST https://anthropic.mpp.tempo.xyz/v1/messages?utm_source=zero.xyz
- Price: $0.01025/call
- Payment: MPP
- Status: unknown
- Last checked: 2026-10-10
- Last successful call: 2026-05-28
- Success rate: 50% of calls made through Zero
- Activations on Zero: 26
- Provider: Anthropic
- Docs: https://docs.anthropic.com
- Website: https://anthropic.com
- Tags: llm, claude, sonnet, opus, haiku, chat, ai
- Canonical page: https://www.zero.xyz/c/anthropic-messages-5dc4e187
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_J84akKk5QKgCTk2QXbbhb

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 anthropic-messages-5dc4e187 -d '<json body>'
```

Example prompt: Ask Claude Sonnet to explain the pros and cons of microservices architecture in about 3 paragraphs, keeping the tone technical but accessible.

## When to prefer this

Choose this endpoint when you need to call Claude via Anthropic's native Messages API format (not OpenAI-compatible) and want access to the full range of Claude models including Opus, Sonnet, and Haiku with model-specific pricing. Prefer this over the OpenAI-compatible completions endpoint when you want direct Anthropic API semantics, system prompt support, and structured multi-turn message arrays.

## Known failure modes

- Invalid or unsupported model name returns 400 error
- Exceeding max_tokens limit for the chosen model
- Malformed messages array (missing role or content fields)
- Rate limiting or quota exceeded returns 429
- Payment failure or insufficient USDC balance blocks the request
- Prompt triggers content policy filter returning 400 or refusal

## How this service works

Create messages with Claude (Sonnet, Opus, Haiku) - price varies by model

## Output

Returns a Claude-generated text completion including the assistant's message content, the model used, stop reason (e.g. end_turn, max_tokens), input/output token counts, and a unique message ID.

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/anthropic-messages-5dc4e187/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from anthropic.mpp.tempo.xyz](https://www.zero.xyz/host/anthropic.mpp.tempo.xyz/llms.txt)