README.md

---
library_name: transformers
inference: false
extra_gated_description: >-
  To learn more about how we process your personal data, please read our <a
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tags:
- laguna-s-2.1
- vllm
license: openmdw-1.1
pipeline_tag: text-generation
---

<p align="center">
  <img alt="poolside-banner" src="https://poolside.ai/assets/laguna/laguna-s-2-1-banner.svg" width="800px">
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<p align="center">
  <a href="https://openrouter.ai/poolside/laguna-s-2.1"><strong>Use on OpenRouter</strong></a> ·
  <a href="https://vercel.com/ai-gateway/models/laguna-s-2.1"><strong>Use on Vercel AI Gateway</strong></a> ·
  <a href="https://poolside.ai/blog/introducing-laguna-s-2-1"><strong>Release blog post</strong></a>
</p>

<br>

# Laguna S 2.1

Laguna S 2.1 is a 118B total parameter Mixture-of-Experts model with 8B activated
parameters per token, designed for agentic coding and long-horizon work. It sits
between [Laguna XS 2.1](https://huggingface.co/poolside/Laguna-XS-2.1) (33B-A3B) and
Laguna M.1 (225B-A23B) in the Laguna series and shares the family recipe: a
token-choice router with softplus gating over 256 routed experts plus one shared
expert, grouped-query attention, and interleaved full/sliding-window attention.

## Highlights

- **Mixed SWA and global attention layout**: 48 layers in a 1:3 global-to-SWA ratio
  (12 global attention layers, 36 sliding-window layers, window 512), with softplus
  attention gating and per-layer-type rotary scales
- **1M context**: 1,048,576-token context window
- **Native reasoning support**: interleaved thinking between tool calls, with
  per-request control via `enable_thinking`
- **Speculative decoding**: a trained
  [DFlash draft model](https://huggingface.co/poolside/Laguna-S-2.1-DFlash) is available
  for lower-latency serving
- **Quantized variants**:
  [FP8](https://huggingface.co/poolside/Laguna-S-2.1-FP8),
  [NVFP4](https://huggingface.co/poolside/Laguna-S-2.1-NVFP4),
  [INT4](https://huggingface.co/poolside/Laguna-S-2.1-INT4) and
  [GGUF](https://huggingface.co/poolside/Laguna-S-2.1-GGUF)
- **OpenMDW-1.1 license**: Use and modify the model and associated materials freely
  for commercial and non-commercial purposes
  ([learn more about OpenMDW](https://openmdw.ai/))

## Model overview

- Number of parameters: 118B total, ~8B activated per token
- Layers: 48 (12 global attention, 36 sliding-window attention)
- Experts: 256 routed (top-10) plus 1 shared expert
- Attention: grouped-query, 8 KV heads, head dim 128; per-head softplus output gating
- Sliding window: 512 tokens
- Context window: 1,048,576 tokens
- Vocabulary: 100,352 tokens (Laguna family tokenizer)
- Modality: text-to-text
- Reasoning: interleaved thinking with preserved thinking

## Benchmark results

<p align="center">
  <img alt="benchmarks" src="https://poolside.ai/assets/laguna/laguna-s-2-1-chart.svg" width="800px">
</p>

| Model | Size | Terminal-Bench 2.1 | SWE-bench Multilingual | SWE-Bench Pro (Public Dataset) | DeepSWE | SWE Atlas (Codebase QnA) | Toolathlon Verified |
|---|---|---|---|---|---|---|---|
| **Laguna S 2.1** | 118B-A8B | **70.2%** | **78.5%** | **59.4%** | **40.4%** | **46.2%** | **49.7%** |
| Tencent Hy3 | 295B-A21B | 71.7% | 75.8% | 57.9% | - | - | - |
| Inkling | 975B-A41B | 63.8% | - | 54.3% | - | - | 45.5%* |
| Nemotron 3 Ultra | 550B-A55B | 56.4% | 67.7% | - | - | - | 34.3%* |
| DeepSeek-V4-Pro Max | 1.6T-A49B | 64.0%* | 76.2% | 55.4% | 9.0%* | 27.2%* | 55.9%* |
| Kimi K3 | 2800B-A50B | 88.3% | - | - | 69% | - | - |
| Qwen 3.7 Max | - | 74.5%* | 78.3% | 60.6% | - | - | - |
| Muse Spark 1.1 | - | 80% | - | 61.5% | 53.3% | 42.2%* | 75.6% |
| Claude Fable 5 | - | 88% | - | 80.3% | 70% | - | - |

Benchmarks as of 21 July 2026. Laguna S 2.1 in **bold**; a dash (-) marks a benchmark a model was not evaluated on. Scores marked * are as reported by third parties: Terminal-Bench 2.1 and DeepSWE via Artificial Analysis, SWE Atlas via Scale AI's official leaderboard, and Toolathlon Verified via its official leaderboard. Full evaluation trajectories: [trajectories.poolside.ai](https://trajectories.poolside.ai).

## Usage

Laguna S 2.1 uses the same `laguna` architecture as Laguna XS 2.1, so the same
engine integrations apply (vLLM, SGLang, Transformers, TRT-LLM, llama.cpp). At 118B
parameters the BF16 checkpoint needs multiple GPUs (roughly 236GB of weights);
quantized variants reduce this substantially.

### vLLM

```shell
vllm serve \
    --model poolside/Laguna-S-2.1 \
    --tensor-parallel-size 4 \
    --tool-call-parser poolside_v1 \
    --reasoning-parser poolside_v1 \
    --enable-auto-tool-choice \
    --served-model-name laguna \
    --default-chat-template-kwargs '{"enable_thinking": true}'
```

> [!NOTE]
> **Optional: speculative decoding with DFlash.** Pair with the
> [Laguna S 2.1 DFlash draft model](https://huggingface.co/poolside/Laguna-S-2.1-DFlash)
> by adding
> `--speculative-config '{"model":"poolside/Laguna-S-2.1-DFlash","num_speculative_tokens":7,"method":"dflash"}'`.

### SGLang

```shell
python -m sglang.launch_server \
  --model-path poolside/Laguna-S-2.1 \
  --tp-size 4 \
  --reasoning-parser poolside_v1 \
  --tool-call-parser poolside_v1 \
  --trust-remote-code
```

### TRT-LLM

```shell
trtllm-serve poolside/Laguna-S-2.1 --trust-remote-code \
    --tool_parser poolside_v1 --reasoning_parser laguna
```

Note the flag names differ from vLLM's (`--tool_parser`, and the reasoning parser
is `laguna`, not `poolside_v1`).

### llama.cpp

GGUF conversions are available at
[poolside/Laguna-S-2.1-GGUF](https://huggingface.co/poolside/Laguna-S-2.1-GGUF).
Serve with poolside's llama.cpp fork, branch
[`laguna`](https://github.com/poolsideai/llama.cpp/tree/laguna), which carries
full Laguna support including DFlash speculative decoding. (Base Laguna support
is also in upstream review:
[ggml-org/llama.cpp#25165](https://github.com/ggml-org/llama.cpp/pull/25165).)

```shell
git clone --branch laguna https://github.com/poolsideai/llama.cpp
cd llama.cpp && cmake -B build && cmake --build build -j

./build/bin/llama-server -m laguna-s-2.1-Q4_K_M.gguf --jinja --port 8000

# with DFlash speculative decoding:
./build/bin/llama-server -m laguna-s-2.1-Q4_K_M.gguf \
  -md laguna-s-2.1-DFlash-BF16.gguf \
  --spec-type draft-dflash --spec-draft-n-max 7 -fa on --jinja --port 8000
```

### Ollama

Run directly from the [Ollama library](https://ollama.com/library/laguna-s-2.1):

```shell
ollama run laguna-s-2.1
```

Quantization variants are available as tags (`q4_K_M`, `q8_0`, `f16`, `mxfp8`,
`nvfp4`, `mlx-bf16`), for example `ollama run laguna-s-2.1:q8_0`. The Laguna chat
template is baked into the model, so tool-calling and interleaved reasoning work
automatically.

## Controlling reasoning

Laguna S 2.1 has native reasoning support and works best with *preserved thinking*:
keep `reasoning_content` from prior assistant messages in the message history.
The model will generally reason before calling tools and between tool calls, and
may stop reasoning in follow-up steps if prior thinking blocks are dropped.

Thinking is controlled per request via the chat template:

```python
extra_body={"chat_template_kwargs": {"enable_thinking": False}}
```

or at the server level with
`--default-chat-template-kwargs '{"enable_thinking": true}'`. For agentic coding
use cases we recommend enabling thinking and preserving reasoning in the message
history.

## License

This model is licensed under the [OpenMDW-1.1 License](https://huggingface.co/poolside/Laguna-S-2.1/blob/main/LICENSE.md).

## Intended and Responsible Use

Laguna S 2.1 is designed for software engineering and agentic coding use cases, and you are responsible for confirming that it is appropriate for your intended application. Laguna S 2.1 is subject to the [OpenMDW-1.1 License](https://huggingface.co/poolside/Laguna-S-2.1/blob/main/LICENSE.md), and should be used consistently with Poolside's [Acceptable Use Policy](https://poolside.ai/legal/acceptable-use-policy). We advise against circumventing Laguna S 2.1 safety guardrails without implementing substantially equivalent mitigations appropriate for your use case.

Please report security vulnerabilities or safety concerns to [security@poolside.ai](mailto:security@poolside.ai).