Step 5 Preview - Kyma API

Overview

StepFun’s flagship for agentic work, a 600B MoE with 27B active: repeated tool calls, execution, verification and revision over long context. 1M context, image input, reasoning. Preview release.

Specs

Field	Value
Model ID	`step-5-preview`
Best for	Long-horizon agentic and software-engineering work
Context window	1.048576M
Max output tokens	64K
Input modalities	Text, Image
Output modalities	Text
Tool calling	Yes
Structured outputs	Yes
Prompt caching	Yes
Vision	Yes
Reasoning	Yes
Speed	Medium
Cost band	Premium
Release stage	Preview

Pricing

	Per 1M tokens
Input	$1.35
Output	$3.645

Example

from openai import OpenAI

client = OpenAI(base_url="https://kymaapi.com/v1", api_key="kyma-...")

response = client.chat.completions.create(
    model="step-5-preview",
    messages=[{"role": "user", "content": "..."}],
    tools=[...],  # function calling supported
)

Agent query example

Ask the API which models fit, instead of hardcoding an id:

curl "https://kymaapi.com/v1/models?recommended_for=chat&tools=true&quality_tier=frontier-open"

​Overview

​Specs

​Pricing

​Example

​Agent query example

Overview

Specs

Pricing

Example

Agent query example