Seed 2.1 Pro

ByteDance SeedMCP Tool CallReasoning

bytedance-seed/seed-2.1-proClosed API

Flagship ByteDance Seed 2.1 model for complex multimodal reasoning, coding, and agents

Benchmark Pricing$1.00 / 1M in$5.00 / 1M out$0.50 cache read

Context: 256,000 tokens•Max Output: 256,000 tokens•Released: 2026-06-23

TECHNICAL SPECIFICATIONS

Context Window256,000256K tokens

Max Output256,000256K tokens

LicenseProprietaryCloud API only

Input Modalities

TextVisionVideo

Function / Tool CallingSupported (MCP Ready)

Structured OutputsGuaranteed Schema

MODEL CONTEXT PROTOCOL (MCP) READINESS

✓ Seed 2.1 Pro 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.

API CALL INVOCATION EXAMPLE

// Example: Calling Seed 2.1 Pro via OpenAI SDK
import OpenAI from "openai";

const client = new OpenAI({
  apiKey: process.env.BYTEDANCE-SEED_API_KEY,
});

const response = await client.chat.completions.create({
  model: "bytedance-seed/seed-2.1-pro",
  messages: [{ role: "user", content: "Hello! Can you inspect MCP tools?" }],
});

console.log(response.choices[0].message.content);