Responses API

Responses API reference for multi-turn agentic workflows with tool calling on the new gateway.

The Responses API supports multi-turn agentic workflows with built-in tool calling and parallel tool execution. It uses the standard Parasail gateway.

Endpoint

POST https://api.parasail.io/v1/responses

Authentication

Use your existing Parasail API key—the same key as for all other Parasail endpoints. Pass it in the Authorization header:

Authorization: Bearer <PARASAIL_API_KEY>

See Authentication for how to create and store a key.

Key requirements

• store must be false on every request—server-side state storage is not supported.

• No previous_response_id—pass the full conversation history in input each turn.

• Same API key as the standard gateway.

Request

Python (OpenAI SDK)

from openai import OpenAI

client = OpenAI(
    base_url="https://api.parasail.io/v1",
    api_key="<PARASAIL_API_KEY>"
)

response = client.responses.create(
    model="parasail-kimi-k25-elicit",
    store=False,
    input="Explain the difference between TCP and UDP in two sentences."
)

print(response.output_text)

cURL

curl https://api.parasail.io/v1/responses \
  -H "Authorization: Bearer $PARASAIL_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "parasail-kimi-k25-elicit",
    "store": false,
    "input": "Explain the difference between TCP and UDP in two sentences."
  }'

Request parameters

Parameter	Type	Default	Description
model	string	required	Model ID (for example, parasail-kimi-k25-elicit)
input	string or array	required	Prompt string, or the full message/history array for multi-turn calls
store	boolean	required	Must be false—server-side state is not supported
tools	array	None	Tool/function definitions for function calling
tool_choice	string	"auto"	"auto", "required", or "none"
stream	boolean	false	Stream events as they're generated

These fields follow the OpenAI schema. For exhaustive field semantics, see the OpenAI Responses API reference.

Response

A successful request returns a response object. The convenience field output_text aggregates the generated text; the full output array contains the structured items (messages, tool calls):

{
  "id": "resp_abc123",
  "object": "response",
  "model": "parasail-kimi-k25-elicit",
  "status": "completed",
  "output": [
    {
      "type": "message",
      "role": "assistant",
      "content": [
        { "type": "output_text", "text": "TCP is connection-oriented and reliable; UDP is connectionless and faster but lossy." }
      ]
    }
  ],
  "usage": {
    "input_tokens": 18,
    "output_tokens": 22,
    "total_tokens": 40
  }
}

See the OpenAI Responses object reference for every field.

Streaming

Set stream: true to receive the response as a stream of server-sent events (for example response.output_text.delta events carrying incremental text, ending with a completion event). See the Responses API product page for streaming and agentic-loop examples.

Error responses

Errors use OpenAI-compatible status codes and a JSON body with an error object (message, type, code).

Status Code	Description
400	Malformed request—invalid JSON, missing required field, or store set to true
401	Missing or invalid API key
403	API key lacks access to the requested model or resource
404	Model or endpoint not found
429	Rate limit or quota exceeded—back off and retry
500	Internal server error—retry with exponential backoff

Compatibility summary

Feature	Supported
Single-turn completions	Yes
Multi-turn conversations	Yes (pass full history in input)
Reasoning / thinking	Yes
Function / tool calling	Yes
Parallel tool calls	Yes
store: true (server-side state)	No
previous_response_id (stateful chaining)	No
Streaming	Yes
Web search tool	No
File search tool	No
Computer use tool	No

Next steps

• Responses API product page—multi-turn, function calling, agentic loops, and the full compatibility table

• Agents and tool calling use case—building agentic workflows

• Chat completions API—endpoint compatibility matrix and base URL

• Authentication—creating and using API keys