Frontier models are becoming menu items you pick from a cloud marketplace. On June 15, 2026, AWS added xAI's Grok 4.3 to Amazon Bedrock. Grok 4.3 is a reasoning-first model that keeps reasoning always on, priced at $1.25 per million input tokens and $2.50 per million output tokens. It supports a 1M context and tool calling, tuned for agent workloads. ASAP summarizes how this changes model competition, from the primary announcement.

It joined Bedrock as a reasoning-first model

Grok 4.3 joined Bedrock as a reasoning-first model that keeps reasoning always on. AWS added xAI Grok 4.3 to Amazon Bedrock on June 15, 2026, with configurable reasoning effort across none, low, medium, and high. Because reasoning is always active, it behaves more consistently across multi-step agent loops.

$1.25 per million input tokens

Grok 4.3 is priced on Bedrock on-demand at $1.25 per million input tokens and $2.50 per million output tokens. Cached input is $0.20 per million, making it one of the most affordable frontier reasoning models on Bedrock. Lower high-volume inference cost favors running agents at scale.

A 1M context and tool calling

Grok 4.3 is a model with a 1 million token context, native video input, and tool calling support. It is built for reliable agents with strong tool use and instruction following. It suits enterprise workloads such as customer support, web development, case-law research, and financial document Q&A.

It runs on the Mantle engine

Grok 4.3 runs on Mantle, a new inference engine in Amazon Bedrock. Mantle is built for price performance and supports tool calling, structured output, and response streaming. AWS optimized not just the model but the inference infrastructure around it.

What it means: models become cloud commodities

Grok 4.3's arrival on Bedrock shows frontier models becoming menu items you pick from a cloud marketplace. With xAI listed alongside the likes of Anthropic, customers choose a model by task and price. Where and at what price a model is served is becoming as competitive as the model itself.

Wrap-up

xAI Grok 4.3 is now available on Amazon Bedrock as of June 15, 2026. Its reasoning-first design, $1.25 per million input tokens, and 1M context are the core. As frontier models become cloud-marketplace commodities, picking a model per task matters more.

Source: ASAP summary of AWS's addition of xAI Grok 4.3 to Amazon Bedrock (June 15, 2026; reasoning-first with configurable effort, $1.25 input and $2.50 output per million tokens, 1M context, Mantle inference engine).