MBZUAI Institute of Foundation Models
Released September 3, 2026

K2 Horizon 7B

K2 Horizon 7B by the MBZUAI Institute of Foundation Models is a fully open dense 7B reasoning model with 512K context, reasoning-effort control, XML tool

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Outputs
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Model Overview

Capabilities, design details, and architectural traits

K2 Horizon 7B - the fully open 7B member of the K2 Horizon fleet

K2 Horizon 7B is a dense 7B decoder-only model from MBZUAI's Institute of Foundation Models. It is the medium dense member of the six-model K2 Horizon fleet, which spans 0.9B to 375B-A23B under a shared architecture, vocabulary, and training methodology. Its defining trait is full-lifecycle openness: weights, training data or recipes, training code, and intermediate checkpoints are all public, so capability changes can be studied across training rather than at a single checkpoint.

TraitDetail
Fleet positionDense 7B member of the six-model K2 Horizon fleet (0.9B, 3.7B, 7B, 32B, 36B-A4B, 375B-A23B)
Context windowNative 524,288-token (512K) context from the midtraining stages onward
OpennessApache 2.0 weights and code, plus released training data and recipe, training code, and intermediate checkpoints
Reasoning controlPer-request reasoning_effort via chat_template_kwargs; high is used for all reported results, with thinking returned in reasoning_content
Tool callingThree selectable formats: json, xml, and xml_typed, with xml as the default
Recommended settingstemperature=1.0, top_p=0.95, and at least 32,768 output tokens so reasoning is never cut off

Serving and interfaces

The model ships with day-zero recipes for vLLM and SGLang, both using dedicated k2_horizon reasoning and tool-call parsers. GGUF builds are provided for llama.cpp, requiring a build with K2 Horizon architecture support. It also runs in Transformers with trust_remote_code.

Why the openness matters

IFM positions K2 Horizon as a fleet where the full development process through reasoning and agentic post-training is exposed. For the 7B this is complete today: researchers can reproduce the methods behind its reasoning, tool use, and agentic behavior, or adapt them to new tools and domains instead of treating the final checkpoint as an opaque starting point.

Benchmark Performance

Independent evaluations · Artificial Analysis

20.6%
Intelligence
38.6%
Coding Index
26.1%
Agentic Index

Accuracy & Capability Details

GPQA - Graduate Science75.3%
Humanity's Last Exam18.2%
SciCode - Scientific Coding27.5%
Long Context Reasoning69.7%

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Evaluate specifications, pricing, and independent benchmark indices

Model Details
General Info
ProviderMBZUAI Institute of Foundation ModelsAnthropicAnthropic
Release DateSeptember 3, 2026September 22, 2026September 28, 2026
Knowledge Cutoff--Jun 2026
Context & Limits
Context Window524K
1M
Best Context Window
1M
Best Context Window
Pricing (per 1M tokens)
Input Pricing
Free
Best Input Pricing
$4$2
Output Pricing
Free
Best Output Pricing
$20$10
Modalities
Inputs
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Outputs
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Benchmarks (0-100)
Intelligence Index20.6
57.6
Best Intelligence Index
56.0
Coding Index38.6--
Agentic Index26.1--
K2 Horizon 7B
Claude Opus 5.5
Claude Sonnet 5.5

Humanity's Last Exam

Extremely difficult logical reasoning and knowledge.

18%
K2 Horizon 7B
Humanity's Last Exam
Score: 18%
K2 Horizon 7B
61%
Claude Opus 5.5
Humanity's Last Exam
Score: 61%
Claude Opus 5.5
55%
Claude Sonnet 5.5
Humanity's Last Exam
Score: 55%
Claude Sonnet 5.5

Long Context Reasoning

Logical reasoning over long context windows.

70%
K2 Horizon 7B
Long Context Reasoning
Score: 70%
K2 Horizon 7B
85%
Claude Opus 5.5
Long Context Reasoning
Score: 85%
Claude Opus 5.5
83%
Claude Sonnet 5.5
Long Context Reasoning
Score: 83%
Claude Sonnet 5.5

SciCode Benchmark

Scientific coding and mathematical modeling.

28%
K2 Horizon 7B
SciCode Benchmark
Score: 28%
K2 Horizon 7B
67%
Claude Opus 5.5
SciCode Benchmark
Score: 67%
Claude Opus 5.5
61%
Claude Sonnet 5.5
SciCode Benchmark
Score: 61%
Claude Sonnet 5.5

Independent evaluation data provided by Artificial Analysis. To view the latest benchmarks and full details, visit their official site.

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