open-responses-agent-dev

Open Responses Agent Development

Build autonomous agents with the Open Responses API - the open-source standard for multi-provider, agentic LLM interfaces via HuggingFace Inference Providers.

When to Use This Skill

Activate this skill when:

• Building autonomous agents (not chatbots)
• Need multi-step workflows in a single request
• Want multi-provider routing with a single endpoint
• Need reasoning visibility (see agent thinking)
• Building sub-agent loops with tools
• Want to use the OpenAI SDK with open-source models

Key Concept: Single Unified Endpoint

IMPORTANT: Open Responses uses ONE unified endpoint with provider routing via model suffixes.

Endpoint: https://router.huggingface.co/v1
Model format: model-id:provider (e.g., moonshotai/Kimi-K2-Instruct-0905:groq)

Providers are specified as suffixes on the model name:

• :groq - Groq inference
• :together - Together AI
• :nebius - Nebius AI
• :auto - Automatic provider selection
• (no suffix) - Default provider

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Core Concepts

1. The Responses Endpoint

POST https://router.huggingface.co/v1/responses
Authorization: Bearer $HF_TOKEN
Content-Type: application/json

Request Structure:

{
  "model": "moonshotai/Kimi-K2-Instruct-0905:groq",
  "instructions": "You are a helpful assistant.",
  "input": "User request",
  "tools": [...],
  "tool_choice": "auto",
  "reasoning": { "effort": "medium" },
  "stream": false
}

Response Structure:

{
  "id": "resp_abc123",
  "model": "moonshotai/Kimi-K2-Instruct-0905:groq",
  "output": [
    { "type": "reasoning", "content": "Let me think..." },
    { "type": "function_call", "name": "search", "arguments": "{...}" },
    { "type": "function_call_output", "output": "..." },
    { "type": "message", "content": "Final response" }
  ],
  "output_text": "Final response",
  "usage": { "input_tokens": 100, "output_tokens": 200 }
}

2. Sub-Agent Loops

The API automatically handles:

1. Model samples a response
2. Emits tool calls if needed
3. Executes tools (for server-side tools like MCP)
4. Feeds results back
5. Repeats until completion