Grok TTS

xai/grok-ttsClosed API

Convert text into spoken audio with a single API call. The API supports a rich set of expressive voices, inline speech tags for fine-grained delivery control, and output formats from high-fidelity MP3 to telephony-optimized μ-law.

Benchmark Pricing$0.00 / 1M in$0.00 / 1M out

Context: 15,000 tokens•Max Output: 15,000 tokens•Released: 2026-03-16

TECHNICAL SPECIFICATIONS

Context Window15,00015K tokens

Max Output15,00015K tokens

LicenseProprietaryCloud API only

Input Modalities

Text

Function / Tool CallingNot Supported

Structured OutputsPrompt Based

MODEL CONTEXT PROTOCOL (MCP) READINESS

⚠ Grok TTS does not natively advertise tool-calling capabilities. When connecting to MCP servers, function calling must be handled via structured prompt injection.

MCP Context Window Recommendations

With a context capacity of 15,000 tokens, this model can handle compact tool sets. Consider keeping MCP server tool manifests minimal to preserve headroom.

API CALL INVOCATION EXAMPLE

// Example: Calling Grok TTS via OpenAI SDK
import OpenAI from "openai";

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

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

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