Sign up

IFM/K2-Horizon-7B

🤗 On Hugging Facetext-generationapache-2.09B params18 GBsafetensors✓ HF checksums availableupdated today
Magnet

K2-Horizon-7B

K2-Horizon-7B is the medium dense member of the K2-Horizon family: a 7B-core decoder-only model with a 512K context window.

K2-Horizon-7B Highlights

  • Strong dense baseline. A 7B-class dense model evaluated across agentic, coding, long-context, and reasoning benchmarks.
  • 512K context. Native 524,288-token context from the midtraining stages onward.
  • Intermediate checkpoints. Intermediate checkpoints are released so capability changes can be studied across training rather than at a single checkpoint.
  • Fully open. Training data and recipe, training code, and evaluation resources are public.

Benchmark Results

The chart at the top of this card shows K2-Horizon-7B against selected reference models. The table below lists every comparison model used in the figure.

Full Results

Reference models · weak to strong

BenchmarkK2-Horizon-7BReference 1Reference 2Reference 3

Math

HMMT Feb 2026

Competition mathematics

73.3Gemma 4-12B

63.1

Qwen3.5-9B

65.7

Granite 4.2-8B

66.5

Coding

SWE-bench Verified

Software engineering

70.6Gemma 4-12B

30.6

Granite 4.2-8B

47.7

Qwen3.5-9B

50.8

Scientific Reasoning

HLE

Expert-level reasoning

18.6Granite 4.2-8B

9.7

Qwen3.5-9B

14.9

Gemma 4-12B

15.7

Coding

SciCode

Scientific coding

31.6Qwen3.5-9B

27.5

Mistral Small 4

28.0

Granite 4.2-8B

30.4

General

LCR

Long-context reasoning

68.0Granite 4.2-8B

43.3

Gemma 4-12B

61.7

Qwen3.5-9B

65.3

Coding

Terminal-Bench 2.1

Agentic terminal use

39.1Granite 4.2-8B

18.4

Gemma 4-12B

27.3

Qwen3.5-9B

29.2

Agents

tau3-Banking

Agentic tool use

25.8Qwen3.5-9B

7.0

Granite 4.2-8B

7.6

Muse Glimmer-30B

24.0

BrowseComp

Web browsing

59.0DeepSeek V4 Flash-0423

53.5

GPT-5

54.9

LongCat Flash Thinking-2601

56.6

Scores in %. Bold marks the best score in each row. BrowseComp: our model uses the Discard-all@95k context-length protocol proposed in the DeepSeek-V3.2 technical report; comparison models may use different harnesses.

Quickstart

Serving

vLLM, recipe at recipes.vllm.ai/IFM:

vllm serve IFM/K2-Horizon-7B \
  --trust-remote-code \
  --dtype bfloat16 \
  --max-model-len 131072 \
  --tensor-parallel-size 1 \
  --reasoning-parser k2_horizon \
  --enable-auto-tool-choice \
  --tool-call-parser k2_horizon

SGLang, this is the recipe validated in the SGLang K2 Horizon cookbook:

sglang serve \
  --model-path IFM/K2-Horizon-7B \
  --revision 69ada542b68fe13d767479db2ab9421baff88681 \
  --tp 1 \
  --dtype bfloat16 \
  --attention-backend fa3 \
  --reasoning-parser k2_horizon \
  --host 0.0.0.0 \
  --port 30000

API Usage

[!Tip]
Recommended settings: reasoning_effort="high", temperature=1.0, top_p=0.95, and at least 32,768 output tokens.
Reasoning depth is selected per request through chat_template_kwargs. Thinking is returned in reasoning_content and the answer in content.
from openai import OpenAI

client = OpenAI(base_url="http://localhost:30000/v1", api_key="EMPTY")
response = client.chat.completions.create(
    model="IFM/K2-Horizon-7B",
    messages=[{"role": "user", "content": "Explain the result step by step."}],
    temperature=1.0,
    top_p=0.95,
    max_tokens=32768,
    extra_body={"chat_template_kwargs": {"reasoning_effort": "high"}},
)
message = response.choices[0].message
print("Reasoning:", getattr(message, "reasoning_content", None))
print("Answer:", message.content)

Transformers

Validated with Transformers 5.15.0, PyTorch 2.13.0, Safetensors 0.8.0.

from transformers import AutoModelForCausalLM, AutoTokenizer

model_id = "IFM/K2-Horizon-7B"
tokenizer = AutoTokenizer.from_pretrained(model_id, trust_remote_code=True)
model = AutoModelForCausalLM.from_pretrained(
    model_id, device_map="auto", dtype="bfloat16", low_cpu_mem_usage=True, trust_remote_code=True
)

inputs = tokenizer("Explain why long-context evaluation is difficult.", return_tensors="pt").to(model.device)
inputs.pop("token_type_ids", None)
outputs = model.generate(**inputs, max_new_tokens=32768, temperature=1.0, top_p=0.95, do_sample=True)
print(tokenizer.decode(outputs[0], skip_special_tokens=True))

Best Practices

1. Reasoning effort: always high. All reported results use high reasoning effort. Pass {"chat_template_kwargs": {"reasoning_effort": "high"}} on every request; medium and low trade accuracy for speed and are not recommended for evaluation.

2. Sampling parameters. temperature=1.0, top_p=0.95.

3. Output length. Allow at least 32,768 output tokens so reasoning is never cut off. Truncated reasoning is a failed response, not a shorter one.

4. Serving. Use the validated SGLang recipe above: BF16, TP=1, FlashAttention-3. Full recipes for every K2-Horizon size, with measured H200 latency and throughput, are in the SGLang cookbook.

5. Parsers. Enable the k2_horizon reasoning parser for chat, and add the k2_horizon tool-call parser for agent use. Leave both off for plain completion-style generation.

6. Revisions. Pin a revision tag when reproducibility matters. main is the default checkpoint; base_final and the mid_*_final tags identify training stages.

Citation

@misc{k2horizon2026,
  title  = {Introducing K2 Horizon: Frontier Performance, Radically Open},
  author = {{IFM Team}},
  year   = {2026},
  url    = {https://ifm.ai/blog/k2/},
}