Agents and Tool Calling

Build agentic workflows with function calling, multi-step reasoning, and tool use on Parasail.

Build AI agents that can call functions, reason across multiple steps, and interact with external tools. Parasail supports both the Chat Completions API with tool calling and the Responses API for multi-turn agentic workflows.

Two approaches

Approach	Best for	API
Chat Completions + tools	Single-model function calling	/v1/chat/completions
Responses API	Multi-turn agentic loops, parallel tool calls	/v1/responses

Function calling with Chat Completions

from openai import OpenAI
import json

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

tools = [
    {
        "type": "function",
        "function": {
            "name": "get_weather",
            "description": "Get the current weather for a city.",
            "parameters": {
                "type": "object",
                "properties": {
                    "city": {"type": "string", "description": "City name"}
                },
                "required": ["city"]
            }
        }
    }
]

response = client.chat.completions.create(
    model="parasail-deepseek-r1",
    messages=[{"role": "user", "content": "What's the weather in Tokyo?"}],
    tools=tools
)

print(response.choices[0].message.tool_calls)

Responses API (multi-turn agentic)

The Responses API supports multi-turn conversations with parallel tool calls. It uses the standard Parasail gateway:

• Base URL: https://api.parasail.io/v1

• Required: Set store: false on every request (server-side state is not supported).

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,
    tools=tools,
    input=[{"role": "user", "content": "What's the weather in Tokyo?"}]
)

Relevant guides

• Tool/Function Calling guide—detailed function calling tutorial

API reference

• Chat Completions API

• Responses API—full spec, compatibility table, and agentic loop example