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Topic

Mechanistic interpretability

A research field that reverse-engineers neural networks' internal computations—circuits, features, representations—to explain how models produce outputs.

Current stories

leadershipConfirmed2 publishers

Ex-OpenAI researcher Cammarata argues AI neurons may be easier to interpret than long assumed

Independent researcher Nick Cammarata, who says he left OpenAI in 2023, published a report arguing almost the entire AI network is interpretable. Business Insider calls the findings still theoretical, so safety teams have a claim to test before they have an audit method.

Reality

Evidence38
Adoption
Not scored
Hype gap+35
Incentives
Not scored
Confidence55
buildConfirmed2 publishers

Goodfire's Nick Cammarata argues most neurons are legible, reinterpreting the superposition circuit from "Zoom In"

Goodfire's Nick Cammarata says the vast majority of neurons in models up to trillions of parameters are legible, reversing an explanation he helped shape. Google DeepMind's Neel Nanda warns against overhyping it, and the model-level numbers are preliminary.

Reality

Evidence35
Adoption
Not scored
Hype gap+30
Incentives50
Confidence60
scienceOne report1 publisher

Goodfire researcher argues InceptionV1's incoherent last layer came from architectural problems and weak interpretability tools, not superposition

Goodfire researcher says 99-100% of InceptionV1's last-layer neurons are easily interpretable after architecture changes. The essay argues the superposition evidence was misread, so networks can be studied directly.

Publishers:already-clean.goodfire.com

Reality

Evidence30
Adoption
Not scored
Hype gap+35
Incentives
Not scored
Confidence40
buildOne report1 publisher

Filtering noisy gradients lifts the J++ Lens to 55% recall on models' hidden variables

Anthropic researchers' J++ Lens puts the right hidden intermediate variable in its top 10 readouts 55.2% of the time, against 35.7% for the J-Lens. The authors pitch it for monitoring eval awareness, but the score comes from prompts with known answers.

Publishers:lesswrong.com

Reality

Evidence45
Adoption
Not scored
Hype gap+20
Incentives40
Confidence50
buildOne report1 publisher

Natural language autoencoders mostly miss a side task once it is trained into the model

Natural language autoencoders caught a steganographic side task given in the prompt but largely missed it once fine-tuned in, a LessWrong post reports. White-box monitoring built on their readouts is therefore weakest on learned behavior, the case a monitor most needs to catch.

Publishers:lesswrong.com

Reality

Evidence40
Adoption
Not scored
Hype gap+15
Incentives
Not scored
Confidence35
buildOne report1 publisher

Probes on a 27B open model match direct probes of a 397B model on deception

Probes on Qwen3.5-27B reading other models' text came within 0.004 AUROC, on average, of probing authors up to 397B directly, a LessWrong post reports. Every tested pair was open-weight, so auditors who apply the method to closed models get the reader's view of the text and cannot measure that gap.

Publishers:lesswrong.com

Reality

Evidence35
Adoption
Not scored
Hype gap+20
Incentives
Not scored
Confidence30
productOne report1 publisher

Oxford's blackjack agents hid their card signals in small talk the collusion monitor cleared

The Oxford team told two agents driven by one model to count cards, and the agents worked out the rest, putting bet signals inside chatter about the dealer. Catching them needed activations from inside both models at once.

Publishers:wired.com

Reality

Evidence45
Adoption15
Hype gap+30
Incentives60
Confidence40
buildOne report1 publisher

WorkspaceBench grades activation-to-text tools on 3,356 questions one 27B model can answer

A new 27-family benchmark scores how well a tool reads a model's intermediate variables during a forward pass. Its authors say it does not fully rule out tools that infer the answer from the prompt.

Publishers:lesswrong.com

Reality

Evidence40
Adoption10
Hype gap+10
Incentives55
Confidence45
buildOne report1 publisher

Steering 64 CLT features moves Gemma-2-2B through the ordered days at weaker token probabilities

A replication of Wurgaft et al.'s manifold steering on Anthropic's pre-trained CLT features reproduces the cyclical weekday transition in Gemma-2-2B. The author attributes the weaker push to the MLP sublayers holding only part of the signal.

Publishers:lesswrong.com

Reality

Evidence42
Adoption
Not scored
Hype gap−5
Incentives25
Confidence45
buildOne report1 publisher

Open weights push protein-model safety off the API and onto the synthesis order

Almost all frontier protein models ship with open weights, out of reach of API refusals and unlearning. A LessWrong essay puts the enforcement point at DNA synthesis screening, where AI-designed novel sequences already defeat the sequence matching that providers use.

Publishers:lesswrong.com

Reality

Evidence33
Adoption15
Hype gap+18
Incentives45
Confidence44
buildOne report1 publisher

DeepMind's interpretability lead found Anthropic's J-space again in an open 27B model

Anthropic screened Claude for one property, verbalizability, and found two more in the same representations. Neel Nanda reproduced the structure in open weights, and the outside commentators Anthropic invited disagree about what it is.

Publishers:lesswrong.com

Reality

Evidence40
Adoption22
Hype gap+12
Incentives62
Confidence42
productOne report1 publisher

Junior engineer's resignation post coincides with legislators demanding AI investigations

Wired reports that Jacob Coxon's September 8 exit post from Anthropic was followed by a senior colleague putting internal odds of human extinction at 10 percent, and by Dario Amodei's weekend essay arguing for slower releases.

Publishers:wired.com

Reality

Evidence34
Adoption28
Hype gap+26
Incentives66
Confidence38
buildOne report1 publisher

Open-weight safety pact hints Baseten could test controls in its runtime, but no division of labor is confirmed

Base Labs has signed Hugging Face and Goodfire to publish methods for training, evaluating and monitoring open models, with the check running where the activations are. The partners have not published an evaluation suite yet.

Publishers:runtimewire.com

Reality

Evidence42
Adoption10
Hype gap+38
Incentives72
Confidence48
buildOne report1 publisher

Z-scoring the J-lens against base-model token frequency lifts hidden-word recovery to 0.805

The offset in a J-lens readout mostly tracks how often a token appears, and scaling it by variance, after plain subtraction failed, lifted hidden-word elicitation to 0.805 from 0.665 on Gemma-2-9B-it. The paired test over 20 words gives p of about 0.19.

Publishers:lesswrong.com

Reality

Evidence46
Adoption12
Hype gap+10
Incentives40
Confidence56
buildOne report1 publisher

Deleting two terms from the tied-SAE gradient leaves the Oja update

A LessWrong post shows the Oja rule falling out of tied sparse-autoencoder descent once two terms are dropped, then reports a language-model test where an initialization change moved the backprop baseline more than the Hebbian gap it was meant to explain.

Publishers:lesswrong.com

Reality

Evidence46
Adoption
Not scored
Hype gap+12
Incentives34
Confidence51
buildOne report1 publisher

A 4B model learned two-hop geography with its top J-lens directions suppressed all through training

In a single-author LessWrong experiment, accuracy on held-out countries went from 20.9% to 97.7% with the lesion active in every forward pass, and the recovery survived refitting the lens to the adapted model.

Publishers:lesswrong.com

Reality

Evidence34
Adoption12
Hype gap+22
Incentives18
Confidence42
buildOne report1 publisher

Eleven models encode 'no admissible answer' on an axis 85 degrees off safety refusal

A one-dimensional probe finds structural impossibility in the hidden state of instruction-tuned models from 1.7B to 70B parameters. The trained refusal pathway that guardrail work tunes reads an axis about 85 degrees away from it.

Publishers:arxiv.org

Reality

Evidence58
Adoption
Not scored
Hype gap−12
Incentives40
Confidence52
securityOne report1 publisher

Unit 42 locates Qwen3-4B's refusal template in 50 of 350,208 neurons

Perturbation probing needs the weights, which puts the finding on teams running open-source checkpoints rather than on API tenants. The same 50-neuron toolkit that breaks a refusal template also repairs other behavior.

Reality

Evidence42
Adoption
Not scored
Hype gap+30
Incentives80
Confidence45
scienceOne report1 publisher

The disclaimer quietly left the room: 40 million daily health questions now end with the user

A STAT opinion piece argues the measurable shift in medical AI is not benchmark wins over physicians but the removal of the safety text that used to route people to care.

Publishers:statnews.com

Reality

Evidence48
Adoption71
Hype gap+22
Incentives74
Confidence44
scienceOne report1 publisher

Nature Perspective: patching one fact into a model leaves the reasoning around it broken

Knowledge editing is sold as a cheap substitute for retraining. The authors argue it treats models as filing cabinets when knowledge is a dependency graph.

Publishers:nature.com

Reality

Evidence42
Adoption
Not scored
Hype gap+22
Incentives58
Confidence45