https://api.derestricted.ai. The SDK appends /v1/messages; including /v1 twice produces an incorrect URL.
Supported behavior
POST /v1/messagesacceptsmessages, an optional top-levelsystemprompt, and client-defined tool schemas/results.stream: truereturns Messages-style SSE events, including content-block events and keepalives.stream: falsereturns a complete message with content blocks and usage.POST /v1/messages/count_tokensreturns an approximate input estimate. It is not the deployed model’s tokenizer.
Compatibility boundaries
The request fieldsthinking, output_config, context_management, mcp_servers, container, betas, and service_tier are ignored. Tool defer_loading is also removed. These controls do not enable Anthropic-hosted features or change the model’s reasoning configuration.
Use text messages and application-executed tools. Managed MCP connections, hosted tools, computer use, media generation, files, and message batches are not provided. Sending Anthropic beta headers does not enable those features. Provider-specific prompt-cache behavior is not guaranteed.
For endpoint details, see Messages and token estimates. For a coding-agent setup, see Claude Code.