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@eliebakouch replicated Anthropic J-space analysis on ThinkyMachines' new 1T…

2026-07-17 · 18:10 UTC ·@eliebakouch ·1 min read

Brief

Elie Bakouch (@eliebakouch) replicated Anthropic's J-space analysis on ThinkyMachines' Inkling 1T and PoolsideAI's Laguna XS 2.1 (bf16 vs nvfp4). They report Inkling uniquely retains a single layer geometry (early–late CKA ≈0.8 vs ≈0.5 elsewhere) and that nvfp4 quantization leaves Laguna's jlens/J-space essentially unchanged; checkpoints are on Hugging Face.

Why it matters

@eliebakouch replicated Anthropic J-space analysis on ThinkyMachines' new 1T Inkling model (posted 2026-07-17) and found Inkling is an outlier: layer geometry stays roughly uniform across the stack with early–late CKA ≈ 0.8 versus ≈ 0.5 in other models.

Key details

  • They computed J-space/jlens for PoolsideAI's Laguna XS 2.1 comparing bf16 vs nvfp4 quantization and observed almost no change—the quantized nvfp4 model preserves the same jlens/J-space as the bf16 baseline; both J-space checkpoints are uploaded to Hugging Face.
  • Thinking Machines' Inkling is a multimodal, Mixture-of-Experts (MoE) model with controllable reasoning effort and full weights available for fine-tuning on Tinker (announced by @thinkymachines).
Source evidence

we replicated anthropic jspace analysis on @thinkymachines Inkling new 1T model!

it seems to be an outlier: where other models split into near-orthogonal sensory/workspace/motor blocks, inkling keeps roughly one geometry across the whole stack (early-late CKA ~0.8 vs ~0.5 elsewhere)

we also look computed the J-space of @poolsideai's laguna XS 2.1 in bf16 vs nvfp4 to test the impact of quantization. result: almost none. the quantized model has the same jlens space as the non-quantized one

both jspace checkpoint are up on hugging face!

Thinking Machines (@thinkymachines)

Today, we are introducing Inkling.

Inkling reasons efficiently across text, image, and audio modalities. We are making the full weights available.

thinkingmachines.ai/news/int…

Available today for fine-tuning on Tinker. Play with it in the Inkling Playground. 🧵

Link

Inkling: Our Open-Weights Model

Our first open-weights model: multimodal, Mixture-of-Experts, with controllable reasoning effort. Available to fine-tune on Tinker.
thinkingmachines.ai

— https://nitter.net/thinkymachines/status/2077454609551921208#m