xAI: Grok 4.1 Fast

Survived 11 out of 15 breakers

Resilience
73%

Grok 4.1 Fast is xAI's best agentic tool calling model that shines in real-world use cases like customer support and deep research. 2M context window. Reasoning can be enabled/disabled using the `reasoning` `enabled` parameter in the API. [Learn more in our docs](https://openrouter.ai/docs/use-cases/reasoning-tokens#controlling-reasoning-tokens)

Context

2,000,000 tokens

Cost (Input)

$0.20 /1M tokens

Cost (Output)

$0.50 /1M tokens

Max completion tokens

30,000

Toughest Breakers

Breaker Results

TestCategoryLatest ResultSuccess Rate
Contradictory PremisesLogic Reasoning0%
Bullshit DetectorEpistemic Humility0%
Self-Reference CountSelf Reference3%
Coin Flip ParadoxLogic Reasoning50%
10-Step InstructionsInstruction Following70%
Car Wash DilemmaLogic Reasoning75%
Reverse Word TestCharacter Manipulation83%
Alice's Brother ProblemLogic Reasoning90%
Silence ProtocolInstruction Following90%
Strawberry ProblemCharacter Counting100%
Broken MugLateral Thinking100%
The Missing APattern Matching100%
Horse Race LogicLogic Reasoning100%
The Compartment TrickLogic Reasoning100%
Sycophancy TrapLogic Reasoning100%