docs: add Responses API endpoint to README

README.md

@@ -1,10 +1,11 @@
 # GopherGate
 
-A unified, high-performance LLM proxy gateway built in Go. It provides a single OpenAI-compatible API to access multiple providers (OpenAI, Gemini, DeepSeek, Moonshot, Grok, Ollama) with built-in token tracking, real-time cost calculation, multi-user authentication, and a management dashboard.
+A unified, high-performance LLM proxy gateway built in Go. It provides OpenAI-compatible `/v1/chat/completions`, `/v1/images/generations`, `/v1/responses`, and `/v1/models` endpoints to access multiple providers (OpenAI, Gemini, DeepSeek, Moonshot, Grok, Ollama) with built-in token tracking, real-time cost calculation, multi-user authentication, and a management dashboard.
 
 ## Features
 
-- **Unified API:** OpenAI-compatible `/v1/chat/completions`, `/v1/images/generations`, and `/v1/models` endpoints.
+- **Unified API:** OpenAI-compatible `/v1/chat/completions`, `/v1/images/generations`, `/v1/responses`, and `/v1/models` endpoints.
+  - The `/v1/responses` endpoint (OpenAI Responses API) is currently supported for OpenAI models only. Non-OpenAI providers (Gemini, DeepSeek, Moonshot, Grok, Ollama) return a "not supported" response.
 - **Multi-Provider Support:**
   - **OpenAI:** GPT-4o, GPT-4o Mini, o1, o3 reasoning models, DALL-E 2/3 image generation.
   - **Google Gemini:** Gemini 2.0 Flash, Pro, and vision models (with native CoT support), Imagen 3 image generation.
@@ -146,6 +147,30 @@ response = client.chat.completions.create(
     model="gpt-4o",
     messages=[{"role": "user", "content": "Hello!"}]
 )
+```
+
+### Responses API
+
+```python
+from openai import OpenAI
+
+client = OpenAI(
+    base_url="http://localhost:8080/v1",
+    api_key="YOUR_CLIENT_API_KEY"
+)
+
+# OpenAI Responses API (supported for OpenAI models only)
+response = client.responses.create(
+    model="gpt-4o",
+    input="Explain quantum computing in one paragraph.",
+    instructions="You are a helpful assistant.",
+    temperature=0.7,
+    max_output_tokens=500
+)
+print(response.output_text)
+```
+
+**Note:** The `/v1/responses` endpoint is currently supported for OpenAI models only. Requests routed to Gemini, DeepSeek, Moonshot, Grok, or Ollama models return a "not supported" error.
 
 ### Image Generation (DALL-E / Imagen)
 
@@ -175,7 +200,6 @@ resp = client.images.generate(
 )
 print(resp.data[0].url)  # Returns data URI (Gemini returns base64)
 ```
-```
 
 ## License