Anthropic-Compatible Proxy API

WorldFlow AI provides a drop-in replacement for the Anthropic Messages API. Point Claude Code or your Anthropic SDK at the WorldFlow AI base URL for transparent semantic caching.

Messages

POST /v1/messages

Fully compatible with the Anthropic Messages API. WorldFlow AI checks the semantic cache before forwarding to Anthropic.

Request

Same schema as Anthropic. Key fields:

Field	Type	Required	Description
model	string	yes	Model name (e.g., "claude-sonnet-4-20250514")
messages	array	yes	Conversation messages
max_tokens	integer	yes	Maximum response tokens
stream	boolean	no	Enable streaming (default: false)
system	string/array	no	System prompt (supports cache_control)
temperature	number	no	Sampling temperature
tools	array	no	Tool definitions

Headers

Header	Required	Description
Authorization	yes	Bearer <synapse_token>
x-api-key	alternative	Anthropic API key (for pass-through auth)
anthropic-version	yes	API version (e.g., "2023-06-01")
Content-Type	yes	application/json

Example

curl -X POST https://api.worldflowai.com/v1/messages \
  -H "Authorization: Bearer $TOKEN" \
  -H "anthropic-version: 2023-06-01" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "claude-sonnet-4-20250514",
    "max_tokens": 200,
    "messages": [
      {"role": "user", "content": "Explain semantic caching in 2 sentences."}
    ]
  }'

Response

Same schema as Anthropic:

{
  "id": "msg_abc123",
  "type": "message",
  "role": "assistant",
  "content": [
    {
      "type": "text",
      "text": "Semantic caching stores LLM responses indexed by meaning rather than exact text. When a semantically similar query arrives, the cached response is returned instantly."
    }
  ],
  "model": "claude-sonnet-4-20250514",
  "stop_reason": "end_turn",
  "usage": {
    "input_tokens": 18,
    "output_tokens": 35
  }
}

Response Headers

Header	Values	Description
X-Cache-Status	HIT, MISS	Whether the response was served from cache
X-Request-ID	UUID	Request identifier for debugging

Streaming

Set "stream": true for Server-Sent Events. WorldFlow AI handles streaming for both cache hits and misses:

curl -X POST https://api.worldflowai.com/v1/messages \
  -H "Authorization: Bearer $TOKEN" \
  -H "anthropic-version: 2023-06-01" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "claude-sonnet-4-20250514",
    "max_tokens": 200,
    "messages": [{"role": "user", "content": "Hello"}],
    "stream": true
  }'

System Prompts with Cache Control

Anthropic's cache_control directive is supported:

{
  "model": "claude-sonnet-4-20250514",
  "max_tokens": 200,
  "system": [
    {
      "type": "text",
      "text": "You are a helpful coding assistant.",
      "cache_control": {"type": "ephemeral"}
    }
  ],
  "messages": [
    {"role": "user", "content": "Write a Python hello world"}
  ]
}

Claude Code Integration

Claude Code routes through WorldFlow AI when ANTHROPIC_BASE_URL is set:

export ANTHROPIC_BASE_URL=https://api.worldflowai.com/v1

Or for local development:

export ANTHROPIC_BASE_URL=http://localhost:8080/v1

Python SDK

import anthropic

client = anthropic.Anthropic(
    base_url="https://api.worldflowai.com/v1",
    api_key="YOUR_SYNAPSE_JWT_TOKEN",
)

message = client.messages.create(
    model="claude-sonnet-4-20250514",
    max_tokens=200,
    messages=[{"role": "user", "content": "What is a REST API?"}],
)
print(message.content[0].text)

TypeScript SDK

import Anthropic from "@anthropic-ai/sdk";

const client = new Anthropic({
  baseURL: "https://api.worldflowai.com/v1",
  apiKey: "YOUR_SYNAPSE_JWT_TOKEN",
});

const message = await client.messages.create({
  model: "claude-sonnet-4-20250514",
  max_tokens: 200,
  messages: [{ role: "user", content: "What is a REST API?" }],
});
console.log(message.content[0].text);