---
title: Messages
description: Anthropic Messages API-compatible endpoint for Claude Code and Anthropic SDK clients.
---

# Messages

Anthropic-compatible `POST /api/v1/messages` for Claude Code and other clients that expect the Anthropic Messages API.

## Endpoint

<div className="api-endpoint">
  <span className="method-badge method-badge-post">POST</span>
  <span className="path">/api/v1/messages</span>
</div>

## Authentication

Use your Cloud API key with either `Authorization: Bearer ...` or `X-API-Key`.

Claude Code and Anthropic SDK clients should also send:

- `anthropic-version: 2023-06-01`
- `Content-Type: application/json`

## Example

<Tabs>
  <Tab title="cURL">

```bash
curl -X POST "https://elizacloud.ai/api/v1/messages" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "anthropic-version: 2023-06-01" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "claude-sonnet-4-6",
    "max_tokens": 512,
    "messages": [
      {
        "role": "user",
        "content": [
          { "type": "text", "text": "summarize my priorities for today" }
        ]
      }
    ]
  }'
```
  </Tab>
  <Tab title="Claude Code">

```bash
export ANTHROPIC_BASE_URL="https://elizacloud.ai/api/v1"
export ANTHROPIC_API_KEY="YOUR_API_KEY"
claude
```
  </Tab>
</Tabs>

## Supported Fields

| Field            | Type            | Required | Notes                                                       |
| ---------------- | --------------- | -------- | ----------------------------------------------------------- |
| `model`          | string          | yes      | Accepts Anthropic-style model ids such as `claude-sonnet-4-6` |
| `max_tokens`     | integer         | yes      | Output token cap                                            |
| `messages`       | array           | yes      | Anthropic message array                                     |
| `system`         | string or array | no       | Anthropic system prompt format                              |
| `stream`         | boolean         | no       | Emits Anthropic SSE events                                  |
| `temperature`    | number          | no       | Passed through when supported                               |
| `top_p`          | number          | no       | Passed through when supported                               |
| `top_k`          | number          | no       | Passed through when supported                               |
| `stop_sequences` | array           | no       | Anthropic stop sequences                                    |
| `tools`          | array           | no       | Anthropic tool definitions                                  |
| `tool_choice`    | object          | no       | `auto`, `any`, `none`, or a named tool                      |

## Message Content

Supported content blocks:

- `{ "type": "text", "text": "..." }`
- `{ "type": "image", "source": { "type": "url", "url": "..." } }`
- `{ "type": "image", "source": { "type": "base64", "media_type": "image/png", "data": "..." } }`
- `{ "type": "tool_use", "id": "...", "name": "...", "input": { ... } }`
- `{ "type": "tool_result", "tool_use_id": "...", "content": "..." }`

## Streaming

When `stream: true`, the route emits Anthropic-style SSE events such as:

- `message_start`
- `content_block_start`
- `content_block_delta`
- `content_block_stop`
- `message_delta`
- `message_stop`
- `error`

Tool calls stream as Anthropic `tool_use` content blocks so Claude Code can continue multi-step workflows.

<Info>
  This route is intended as a compatibility layer. Billing, auth, moderation,
  and credit enforcement still run through elizaOS Cloud.
</Info>