stepfun/step-3.5-flash-2603Open WeightsStepFun flash model for efficient multimodal reasoning, coding, and tool use
TECHNICAL SPECIFICATIONS
MODEL CONTEXT PROTOCOL (MCP) READINESS
✓ Step 3.5 Flash 2603 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 256,000 tokens, this model can handle moderately large MCP tool definitions and multi-turn conversation logs comfortably.
STANDARDIZED BENCHMARKS & EVALS
API CALL INVOCATION EXAMPLE
// Example: Calling Step 3.5 Flash 2603 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-3.5-flash-2603",
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 $0.02 / 1M tokens, saving up to 80% on repetitive MCP tool definitions and system instructions.
MODEL RESOURCES
More Models by StepFun (China)
Alternative and family models from the same lab
StepFun'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
StepFun flash lane for quick multimodal reasoning and coding assistance
Newer StepFun flash model for faster agents, coding, and multimodal prompts