Update docs/configuration.md

Author: ericdallo

docs/configuration.md

@@ -203,16 +203,6 @@ interface Config {
 When configuring custom providers, choose the appropriate API type:
 
 - **`openai-responses`**: OpenAI's new responses API endpoint (`/v1/responses`). Best for OpenAI models with enhanced features like reasoning and web search.
-- **`openai-chat`**: Standard OpenAI Chat Completions API (`/v1/chat/completions`). Use this for most third-party providers:
-  - OpenRouter
-  - DeepSeek
-  - Together AI
-  - Groq
-  - Local LiteLLM servers
-  - Any OpenAI-compatible provider
-- **`anthropic`**: Anthropic's native API for Claude models.
-
-Most third-party providers use the `openai-chat` API for compatibility with existing tools and libraries.
 
 ### Default values