Inkling 2 Small

Thinking Machines

Multimodal autoregressive transformer with sparse MoE feed-forward backbone

Open Weights Commercial Use Multimodal NVFP4 (modelopt) Inkling English Multilingual (general capabilities)

Parameters

594.1B / 17.0B active

MoE total / active

Context

1,048,576 tokens

native

Modalities

text, image text

input → output

License

Apache License 2.0

Openness Index

100.0/100

About

Inkling 2 Small is a general-purpose multimodal model from Thinking Machines Lab that accepts text and image inputs and generates text outputs. It is a 48-layer decoder-only transformer with a sparse Mixture-of-Experts (MoE) feed-forward backbone – each token is routed to 8 of 384 experts – with a hybrid of local and global attention layers. The model is natively multimodal: images are encoded via a vision transformer and projected into a shared hidden space, processed jointly by the decoder.

From the model card: 594B total / 17B active parameters, context window of up to 1M tokens; pretrained, midtrained and post-trained in NVFP4 (NVFP4 is the native precision; an MXFP8 checkpoint variant exists). The NVFP4 checkpoint requires ≥500 GB aggregate VRAM (e.g. 2x NVIDIA B300 or 4x H200), the MXFP8 checkpoint ≥800 GB (e.g. 4x B300 or 8x H200). Released with open weights under Apache-2.0 to support research, fine-tuning and integration into third-party products. Intended for developers building agentic and tool-use systems, coding assistants, chatbots and retrieval-augmented generation systems, as well as general-purpose conversational use. Local inference via SGLang, vLLM, TokenSpeed or Unsloth; API access is available through NVIDIA, Fireworks, Together, Baseten, Nebius, Modal and Cloudflare; fine-tuning is available via Tinker (Tinker Cookbook).

Training Data Broad mix of content types: text, images and video, drawn from publicly available sources, third-party acquired data, internally generated and synthetic/augmented data. Curation includes deduplication and filtering (Model Card §4). Documentation: https://thinkingmachines.ai/training-data-documentation/

Benchmark Scores

Benchmark Score Date Standing
GPQA Diamond
stem_reasoning
97.54%
13.11.2026
#7/83
better than 91%
BioMysteryBench
stem_reasoning
58.75%
13.11.2026
#6/11
better than 50%
MuirBench
video_understanding
100.00%
13.11.2026
#1/2
better than 100%
SimpleVQA
vision_language
85.52%
13.11.2026
#2/17
better than 94%
Global-MMLU-Lite
multilingual
100.00%
13.11.2026
#1/5
better than 100%
TAU3-Bench
general_agent
57.90%
13.11.2026
#9/22
better than 62%
HMMT Feb 26
stem_reasoning
97.54%
13.11.2026
#7/45
better than 84%
MMMU-Pro
vision_language
95.67%
13.11.2026
#3/36
better than 94%
DeepSearch QA
general_agent
87.69%
13.11.2026
#4/10
better than 67%
ScreenSpot Pro
general_agent
100.00%
13.11.2026
#1/12
better than 100%

Hardware Requirements

Estimated VRAM per quantization at 4,096 tokens context — MoE: all experts must fit in VRAM, only 17.0B are active per token

Quantization Weights KV Cache Total VRAM On your hardware
FP16 — 16-bit 1188.1 GB 2.6 GB 1250.1 GB Which GPUs can run it? Calculate on your GPU
INT8 — 8-bit 594.1 GB 1.3 GB 625.1 GB Which GPUs can run it? Calculate on your GPU
INT4 — 4-bit 297.0 GB 0.7 GB 312.5 GB Which GPUs can run it? Calculate on your GPU
FP4 — 4-bit 297.0 GB 0.7 GB 312.5 GB Which GPUs can run it? Calculate on your GPU

Only datacenter GPUs — FP16 needs 1250.1 GB. For consumer hardware, choose the INT4 build with a multi-GPU setup.

Architecture

Decoder Block input Embedding Full Attention MoE FFN 384 experts Final RMSNorm LM Head output

Multimodal autoregressive transformer (decoder-only text decoder + ViT vision encoder)

MoE Vision
Parameters
594.1B
Active params
17B
Attention
GQA Grouped Query Attention
Experts
384
Context
1M
Nvfp4 Sparse top-8 routing of…

Source: extracted model record · model repo

Source

https://huggingface.co/thinkingmachines/Inkling-2-Small/raw/main/config.json and Model Card section 3

Text Decoder

hidden_size 4608, vocab 201024, intermediate_size 2304, GQA 48 query / 8 KV heads, head_dim 128, sliding window 1024 on local layers, 40 local / 8 global of 48 layers

Training Pipeline

  1. 1
    pretraining

    Pre-training (NVFP4)

    The model was pretrained, midtrained and post-trained in NVFP4, so this is the native precision of the model (Model Card, Required hardware).

  2. 2
    cpt

    Mid-training (NVFP4)

    Mid-training phase in native NVFP4 precision (Model Card). No hyperparameters disclosed.

  3. 3
    other

    Post-training (NVFP4)

    Post-training in native NVFP4 precision (Model Card). No details on SFT/RL phases disclosed.

Training & Evaluation Datasets

NameRoleSizeModalitiesCollection
Inkling 2 pre-/mid-/post-training corpus (per model card) pretraining Broad variety of content types: text, images, video; drawn from publicly available sources, third-party acquired data, internally generated data and synthetic/augmented data. text, image, video mixed

Comments (0)

No comments yet

Be the first to share your thoughts!

What now?

You have read the full card for Inkling 2 Small — here is where to go next.