stepfun/step-5-previewOpen WeightsStepFun's next-generation flagship base model for coding and professional knowledge work, with native text, image, and video input and a 1M-token context window
TECHNICAL SPECIFICATIONS
MODEL CONTEXT PROTOCOL (MCP) READINESS
✓ Step 5 Preview natively supports OpenAI / Anthropic format tool calling and is fully compatible with MCP servers and agent loops.
MCP Context Window Recommendations
With a context capacity of 1,000,000 tokens, this model can handle extremely large MCP resource manifests, complete database schemas, and multiple active server tool definitions simultaneously without degradation.
API CALL INVOCATION EXAMPLE
// Example: Calling Step 5 Preview via OpenAI SDK
import OpenAI from "openai";
const client = new OpenAI({
apiKey: process.env.STEPFUN_API_KEY,
});
const response = await client.chat.completions.create({
model: "stepfun/step-5-preview",
messages: [{ role: "user", content: "Hello! Can you inspect MCP tools?" }],
});
console.log(response.choices[0].message.content);PRICING BY PROVIDER
Rates in USD per 1M tokens. Rates synchronized from models.dev public catalog.
This model supports prompt caching at $0.10 / 1M tokens, saving up to 90% on repetitive MCP tool definitions and system instructions.
MODEL RESOURCES
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