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What comes next with open models

16 March 2026 at 13:00

2025 was the year where a lot of companies started to take open models seriously as a path to influence in the extremely valuable AI ecosystem โ€” the adoption of a strategy that was massively accelerated downstream of DeepSeek R1โ€™s breakout success. Most of this is being done as a mission of hope, principle, or generosity.

Very few businesses have a real monetary reason to build open models. Well-cited reasons, such as commoditizing oneโ€™s complements for Metaโ€™s Llama, are hard to follow up on when the cost of participating well is billions of dollars. Still, AI is in such an early phase of technological development, mostly defined by large-scale industrialization and massive scale-out of infrastructure, that having any sort of influence at the cutting edge of AI is seen as a path to immense potential value.

Open models are a very fast way to achieve this, you can obtain substantial usage and mindshare with no enterprise agreements or marketing campaigns โ€” just releasing one good model. Many companies in AI have raised a ton of money built on less.

The hype of open models is simultaneously amplified by the mix of cope, disruptive anticipation, and science fiction that hopes for the world where open models do truly surpass the closed labs. This goal could be an economically catastrophic success for the AI ecosystem, where profits and revenue plummet but the broader balance of power and control of AI models is long-term more stable.

Thereโ€™s a small chance open models win in absolute performance, but it would only be on the back of either a true scientific breakthrough that is somehow kept hidden from the leading labs or the models truly hitting a wall in performance. Both of them are definitely possible, but very unlikely.

It is important to remind yourself that there have been no walls in progress to date and all the top AI researchers we discuss this with constantly explain the low-hanging fruit they see on progress. It may not be recursive self-improvement to the singularity (more on that in a separate post), but large technology companies are on a direct path to building definitionally transformative tools. They are coming.

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The balance of power in open vs. closed models

The fair assessment of the open-closed gap is that open models have always been 6-18 months behind the best closed models. It is a remarkable testament to the open labs, operating on far smaller budgets, that this has stayed so stable. Many top analysts like myself are bewildered by the way the gap isnโ€™t bigger. Distillation helps a bit in quality, benchmaxing more than closed labs helps perceptions, but the progress of the leading open models is flat out remarkable.

The reality is that the open-closed model gap is more likely to grow than shrink. The top few labs are improving as fast as ever, releasing many great new models, with more on the docket. Many of the most impressive frontier model improvements relative to their open counterparts feel totally unmeasured on public benchmarks.

In a new era of coding agents, the popular method to โ€œcopyโ€ performance from closed models, distillation, requires more creativity to extract performance โ€” previously, you could use the entire completion from the model to train your student, but now the most important part is the complex RL environments and the prompts to place your agents in them. These are much easier to hide and all the while the Chinese labs leading in open models are always complaining about computational restrictions.

As the leading AI models move into longer-horizon and more specialized tasks, mediated by complex and expensive gate-keepers in the U.S. economy (e.g. legal or healthcare systems), I expect large gaps in performance to appear. Coding can largely be mostly โ€œsolvedโ€ with careful data processes, scraping GitHub, and clever environments. The economies of scale and foci of training are moving into domains that are not on the public web, so they are far harder to replicate than early language models.

Developing frontier AI models today is more defined by stacking medium to small wins, unlocked by infrastructure, across time. This rewards organizations that can expand scope while maintaining quality, which is extremely expensive.

All of these dynamics together create a business landscape for open models that is hard to parse. Through 2026, closed models are going to take leaps and bounds in performance in directions that it is unlikely for open models to follow. This sets us up for a world where we need to consider, fund, use, and discuss open models differently. This piece lays out how open models are changing. It is a future thatโ€™ll be clearly defined by three classes of models.

  1. True (closed) frontier models. These will drive the strongest knowledge work and coding agents. They will be truly remarkable tools that force us to reconsider our relationship to work.

  2. Open frontier models. These will be the best open-weight, large models that are attempting to compete on the same directions as above. There will be plenty of use-cases that they donโ€™t work for relative to the best models, but countless use-cases where they work remarkably well. For many use-cases, even ones as valuable as some subsets of coding, these will work great.

    The AI ecosystem will still take years to understand what it means to have intelligence of this magnitude served in private, at the marginal cost of electricity for individuals, as assistants, coaches, companions, and more. OpenClaw provided a glimpse behind the mirror that will expand and grow. The class of models around GPT-OSS 120B, Nvidia Nemotron 3 Super, or MiniMax M2.5 are the balance of performance to price that can work as local models.

  3. Open, small models as distributed intelligence. The most successful open models will be complementary tools to closed agents. This is a path for open models to complement and accelerate the frontier of progress.

    AI is slotting in to automate many repetitive, niche tasks across the technology economy. Thereโ€™s a huge pressure to shift these tasks off of the best closed models โ€” which frankly are still better at most of the things, across my conversations with businesses trying to build with open models โ€” to small, open models that can be 10X faster and 100X cheaper. There arenโ€™t really people building data and fine-tuning engines for economically viable tasks on the smallest models possible.

    These models need to be almost brain-numbingly boring and specific. In a world dominated by coding agents, I want to build open models that Claude Code is desperate to use as a tool, letting its sub agents unlock entirely new areas of work. This is possible, but remarkably under-explored. Small models from the likes of Qwen and co. are still marketed on general-task benchmarks. The hype of โ€œopen models catching the frontierโ€ distracts the world from this very large area of demand.

    This is the sort of model that moves open models from just a few, crucial static weights to more of an ecosystem. It requires creativity and a new approach. The goal of this piece is to illustrate why and how to build these, with added context on where open models stand today.

All three of these model classes hint at different ways to use agents. It is absolutely definitional to how AI is going to be built going forward that theyโ€™re not just model weights, but rather systems that think, search, and act. The weights only define one portion of those abilities.

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Open weights as part of an AI system

To start, consider what are the most impactful and impressive things that language models can do without a suite of tools at their side. When was the last time that you were blown away by something that was just autoregressive token outputs? Unless youโ€™re doing a substantial amount of work on mathematical proofs or competition code, it seems like that situation has changed little since GPT-4โ€™s release in 2023. The AI systems we use today are about far, far more than weights.

In this world, closed models have a clear advantage. Closed models get to vertically integrate everything from the chips they run on, the inference software, the weights, the tools, and the user interface. Open models on the other hand need to work on every inference setup, with many tools, and in many use-cases. This vertical integration is best expressed today in the joy of using Claude Code with Opus 4.6 or OpenAIโ€™s Codex with GPT 5.4. Open models havenโ€™t passed this point. Some are starting to focus on specific interfaces, e.g. OpenCode, but thereโ€™s an inherent tension in making an open model work only in your blessed product roadmap.

At the same time, this change could point to more about the latest AI systems being open! If you can do less with the weights alone, maybe more labs will release them.

The way to think about AI systems today is as a mix of weights, tools, and harnesses. The weights portion is familiar. The tools are the deeply integrated environments the models act in at deployment time โ€” best typified by search and code sandboxes โ€” and the harness is how these two fit together with a product that the user sees.

In this world, there are two things to consider: 1) Is there an equivalent, open system to the closed products that people are using today โ€” I mean truly equivalent, where every level of the stack can be modified and controlled (more on this later), and 2) How does this systemโ€™s view impact different future decisions in the open ecosystem?

Still looking for open model business strategies

To understand how the business and practicality of open models will evolve, let me take a tour back in time to foundational writing on the role of open-source in modern technology companies. The first is a Google blog post, The Meaning of Open, which originally was an internal memo by Jonathan Rosenberg, which sparked an intense internal debate that later resulted in it becoming public. To start, hereโ€™s a basic assessment of how open systems can work:

Open systems have the potential to spawn industries. They harness the intellect of the general population and spur businesses to compete, innovate, and win based on the merits of their products and not just the brilliance of their business tactics.

Iโ€™ve long believed that the company who will benefit most from the ecosystem of open models is the one who understands it best. This entails being deeply involved with open research and experimentation in how to use the models. So far, most of the open model company business models are not this. Rosenberg expands on this in his 2009 post, comparing the dynamics of open systems to closed products:

[Open systems] are competitive and far more dynamic. In an open system, a competitive advantage doesnโ€™t derive from locking in customers, but rather from understanding the fast-moving system better than anyone else and using that knowledge to generate better, more innovative products. The successful company in an open system is both a fast innovator and a thought leader; the brand value of thought leadership attracts customers and then fast innovation keeps them. This isnโ€™t easy โ€” far from it โ€” but fast companies have nothing to fear, and when they are successful they can generate great shareholder value.

Weโ€™ve known for some time that open weight models are not actually enough to constitute a product โ€” models are a product in the sense that they have tools and harnesses, so we donโ€™t actually have fully open systems, we have systems that are partially open partially closed, making moats messy. VLLM and a model like GLM 5 are pieces of a system, but it still takes more to deploy them โ€” expensive private GPUs and some tools with local business data.

It may turn out to be that AI is too complex and expensive to have any analogous open system to previous generations of technology. If there was a fully open system, it would win by default, as many historical generations of technology have shown us. This fully open analog does not yet exist, so we have constant debates on the role of open-source AI.

Bill Gurley recounts how Googleโ€™s free products have exemplified the open or free strategies across technology. Gurley wrote on the open-source operating system, Android, and the free browser, Chrome, in 2011:

So here is the kicker. Android, as well as Chrome and Chrome OS for that matter, are not โ€œproductsโ€ in the classic business sense. They have no plan to become their own โ€œeconomic castles.โ€ Rather they are very expensive and very aggressive โ€œmoats,โ€ funded by the height and magnitude of Googleโ€™s castle. Googleโ€™s aim is defensive not offensive. They are not trying to make a profit on Android or Chrome. They want to take any layer that lives between themselves and the consumer and make it free (or even less than free).

Because these layers are basically software products with no variable costs, this is a very viable defensive strategy. In essence, they are not just building a moat; Google is also scorching the earth for 250 miles around the outside of the castle to ensure no one can approach it.

In the same post, Gurley reflects on the limits of Googleโ€™s openness:

In this open manifesto, Jonathan opines over and over again that open systems unquestionably result in the very best solutions for end customers. That is with one exception. โ€œIn many cases, most notably our search and ads products, opening up the code would not contribute to these goals and would actually hurt users.โ€ As Rodney Dangerfield said in Caddyshack, โ€œIt looks good on you, though.โ€

Essentially, Google open-sourced so much, in fact paid people to use its products (e.g. paying phone makers to use android) to keep the funnel leading to the search profit center. This is the virtuous loop that the search business still funds to this day.

AI is still nothing like this, but signs of change are emerging. The default belief on the value of models to these companies is that the model is the product. This is obvious with products like hosted APIs, where releasing the model weights would be business suicide, but this is softening as interfaces like Claude Code, Codex, Cursor, etc. get vastly popular. It could be a path to more openness, at least in parts of the stack. We can see this with the coding plans offered by Moonshot and Z.ai โ€” where the demand is very high for the businesses, even though the model is open. Most people will just use the cheap interface with inference, instead of figuring out how to use the model themselves (as long as the business is mostly consumer or per-head services).

All of this doesnโ€™t leave me optimistic on the direction of companies becoming more open in the coming years. Iโ€™d expect the opposite still. Nvidia has the one great reason to be open โ€” to sell more GPUs to people building on open models and understand what they need to build next, but thereโ€™s no one else obvious on this list. Until there are more specific economic reasons to build open models, the companies building these at the frontier will have fewer resources to spend on the models and face a consolidation to the best few.

In the face of consolidation at the open frontier, the investment in the models should shift to areas where the models can have more differentiated upside relative to the best closed frontier models.

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Open models that are specific, cheap, fast, and ubiquitous

Thereโ€™s too much obsession with the best companies building open models to try and compete at the frontier. Thereโ€™s a vastly underserved market of enterprises that want cheap, reliable models for repetitive use-cases in their systems. Picture this, one small model with a series of LoRA adapters that specialize the model to internal skills. This can be deployed very cheaply as tools and a complement to the frontier closed models that are orchestrating agents.

Every task that a frontier agentic model does tens to hundreds of times can potentially be outsourced to a small model. There are ancillary benefits to this, e.g. privacy of a local model reading your files and summarizing to Claude, but almost no one is pushing hard in this direction. The leading model family of capable, customizable small models to date is Qwen, but thatโ€™s now shrouded in uncertainty with the departures of key personnel. Gemma, Phi, Olmo, etc. are all major steps down in quality, and therefore potential for modification.

There are a few obvious examples why this can be scaled up. There was a recent thread and discussion on how the new Qwen 3.5 4B model arguably bests the original ChatGPT model. On the research side, there are already recipes for finetuning open models on specific code-bases to match performance of much bigger models. Moondream.ai is a startup made by a friend of mine Vik, who builds some of the best, small multimodal models on a tiny budget โ€” they compete with Qwen and Llama on real world tasks. This is the tip of an iceberg.

Intelligence compression hasnโ€™t been explored with nearly as much depth (or resources) because it is less exciting than keeping track of the progress of the best few models. Investigating these areas is the standard technological diffusion process that is slow and why weโ€™re still early in understanding how people will build with AI. My contention is that too many people building open models are slightly deluded in their perception of their competitiveness. The best few models will win on general capabilities and there are still plenty of underserved niches elsewhere.

Taking this to the next level involves releasing open models that are scoped to be truly excellent at 1-3 tasks, as I hinted at the beginning of this piece. Too many people try to compete with Qwen and show that their small model does great on frontier AI benchmarks. The right benchmark here is savings in compute and time.

Itโ€™ll take years for this transition to slowly become reality. Part of why I am so excited about it is that it is driving innovation on open models being more about diversity, specialization, and curiosity, rather than the standard โ€œone model to rule them allโ€ that the frontier models presume.

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Models vs. ecosystems.
Consolidation vs. creativity.

So long as the open source ecosystem for AI is defined by a bunch of model providers trying to chase after the closed labs, it will largely lose. It will face pain on funding and substantive adoption. The same consolidation that will come for closed AI companies will come for open model builders โ€” likely even sooner.

Open systems at their best allow many people to participate and many approaches to flourish.

The world of open models needs to be more of an ecosystem. Iโ€™ve discussed in the past how China is closer to this type of environment by having a variety of companies, but the variety in approaches is still too low.

Ecosystems are self-reinforcing, whereas individual models are static artifacts in time. Ecosystems showcase clear, constant opportunities for whatโ€™s next that have growing value propositions.

The path forward for open models is to solve different problems than the frontier labs, to find places where open models are effectively free alternatives, to show ways of using specialized models that the closed labs cannot offer. The world of open models needs to embrace creativity, before building powerful AI systems grows too expensive and prices out many of the prized open labs of today.

How agentic AI helps heal the systems we can’t replace

16 March 2026 at 13:00
Many of the worldโ€™s most important systems โ€” the ones that move money, book flights, issue licenses, and process claims โ€” are slow, brittle, and deeply outdated. Built decades ago and extended repeatedly, they now sit at the center of workflows too vital to pause, take offline, rebuild, or replace. Inside Amazonโ€™s Artificial General Intelligence (AGI) Lab, teams train agents not on idealized interfaces but on high-fidelity simulations of such legacy systems. Learning the real behaviors of these systems โ€” the quirks, delays, error states, and invisible dependencies โ€” makes possible a different kind of innovation, one that grows from the systems we have instead of requiring their replacement. And by managing the idiosyncrasies of legacy systems behind the scenes, the agent effectively becomes a universal API โ€” a single interface that the customer can use to perform a wide range of special-purpose tasks. The legacy systems that power everyday life Step behind the scenes of any large institution โ€” a bank, an insurer, a hospital, a state agency โ€” and youโ€™ll find the same thing: an invisible layer of human labor holding software together. People know which buttons must be clicked in which order, which warnings can be ignored, which fields must be entered twice, and which screens must never be refreshed. The institutional knowledge required to navigate these eccentricities is passed down like the oral traditions of legacy systems. Much of the infrastructure beneath these workflows is older than the people managing it. The software backbone of modern finance, insurance, travel, scientific research, and public services took shape in the 1960s and โ€™70s, built on mainframe architectures and written in languages like COBOL and FORTRAN โ€” designed for stability rather than adaptability. When the web arrived, institutions didnโ€™t rebuild. They wrapped. Web forms fed mainframe jobs, middleware translated modern inputs into decades-old formats, and enterprise portals accumulated atop business rules that were never rewritten. Over time, modernization settled into layers: a mainframe instruction set at the bottom; a 1990s database above it; a 2000s portal above that; and a modern web interface masking everything beneath. A single transaction today might pass through all these layers โ€” scripts, connectors, and integrations holding them together in ways no one fully understands. Attempts to replace these systems routinely stall. Dependencies surface no one knew existed, migrations fail, budgets spiral, and public-sector modernization efforts collapse under their own complexity. These systems cannot be taken offline, which means institutions must keep operating them no matter how brittle they become. For Amazon, this is one of the most compelling applications of agentic AI โ€” navigating not the polished surfaces of web-era consumer apps but the deep, slow-moving architectures that keep institutions running. Learning the bad to heal the bad The hardest part of training an AI agent is not teaching it what a successful workflow looks like; itโ€™s teaching it why workflows fail. The logic behind legacy systems reveals itself most clearly through friction: the modal (mandatory) window that appears late because it encodes a sequencing rule; the field that refuses input until another value is saved; the form that resets because a backend job restarted midflow. These behaviors arenโ€™t glitches. They are the real semantics of the system. Researchers at Amazonโ€™s AGI Labs seek this friction out. To surface failure modes safely and repeatedly, Amazon trains agents inside reinforcement learning (RL) gyms โ€” synthetic environments designed to reproduce the quirks, delays, and ordering rules embedded in real workflows. These include synthetic web environments that simulate systems like state agencies, airline bookings, and specialized tax- and benefits-processing, among hundreds of others. Jason Laster, an AGI software engineer who works on agent training and replay systems, puts it plainly: โ€œI want to push our RL training gyms to have all of the warts, all of the issues.โ€ This is what โ€œlearning the bad to heal the badโ€ means: training an agent on the full spectrum of a systemโ€™s true behavior, including flaws, inconsistencies, delays, and all the embedded histories humans have quietly adapted to. By exposing agents to the same brokenness people navigate every day, Amazon trains them to move beyond surface correctness and understand the deeper logic beneath the interface. Agents as a new interface layer Once an agent can reliably navigate the idiosyncrasies of legacy interfaces, something more interesting begins to happen. Researchers have observed agents inferring not just what to click next but why โ€” the latent workflow the interface expresses. In one simulated benefits application environment, an agent that realized it had added only one dependent was able to navigate back, correct the omission, and resume the flow without restarting โ€” an early sign of understanding the nature of the system. For lab members, this marks an architectural turning point. Many institutional systems simply donโ€™t expose APIs that reflect how real workflows behave; the only faithful expression of the logic is the interface itself. As Laster puts it, โ€œthe UI was designed to be discoverable, learnable โ€” even if itโ€™s bad.โ€ When agents learn that layer deeply enough to predict outcomes and recover from failures, they begin to function as a kind of synthetic API โ€” a stable, programmatic surface over infrastructure that canโ€™t be changed. That shift enables new architectural possibilities: Stable semantics over unstable UIs: Agents turn inconsistent behaviors โ€” delays, re-renders, partial saves โ€” into predictable patterns. Cross-system abstraction: Because the agent reasons about the workflow rather than the application, it can bridge systems never designed to interoperate. Incremental modernization: Institutions can update components gradually without breaking workflows; the agent absorbs transitional fragility. Preservation of institutional logic: Agents retain operational knowledge otherwise stored only in human memory โ€” rules, sequences, dependencies no one has documented. This is not workflow automation. It is a new interface layer for the worldโ€™s oldest systems โ€” an upgrade path that doesnโ€™t require turning anything off. The work ahead Agentic AI will not replace the administrative tasks that structure daily life โ€” booking vacations, renewing licenses, scheduling medical appointments โ€” but it can help make them more efficient by allowing the evolution of systems once too fragile to change. That fragility is becoming more acute. The programmers who built the institutional backbone of the 1960s and โ€™70s โ€” COBOL batch jobs, FORTRAN routines, mainframe integrations โ€” are retiring. Few younger developers learn these languages, and the knowledge embedded in those systems grows harder to access each year. Critical workflows now run atop software whose inner workings fewer and fewer people understand. Agents offer a different form of continuity. By learning how these systems behave โ€” not from lost documentation but from the systems themselves โ€” they can preserve operational logic that would otherwise disappear. They can stabilize workflows sitting atop code no one can safely rewrite and carry forward institutional knowledge that would otherwise age out of the workforce. In that sense, โ€œthe work aheadโ€ is twofold. There is the technical work of building agents that can meet the reliability these environments demand. And there is the human work that becomes newly possible when people are no longer trapped inside brittle interfaces โ€” work grounded in judgment, coordination, empathy, and design rather than memorizing which field must be entered twice. Agents will not rebuild the foundations of our digital world. But they may rebuild something else: our notion that innovation comes only from replacement. By turning brittle systems into stable platforms, agents offer a new model of progress โ€” one that grows from what already works.

Identifying Interactions at Scale for LLMs

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Understanding the behavior of complex machine learning systems, particularly Large Language Models (LLMs), is a critical challenge in modern artificial intelligence. Interpretability research aims to make the decision-making process more transparent to model builders and impacted humans, a step toward safer and more trustworthy AI. To gain a comprehensive understanding, we can analyze these systems through different lenses: feature attribution, which isolates the specific input features driving a prediction (Lundberg & Lee, 2017; Ribeiro et al., 2022); data attribution, which links model behaviors to influential training examples (Koh & Liang, 2017; Ilyas et al., 2022); and mechanistic interpretability, which dissects the functions of internal components (Conmy et al., 2023; Sharkey et al., 2025).

Across these perspectives, the same fundamental hurdle persists: complexity at scale. Model behavior is rarely the result of isolated components; rather, it emerges from complex dependencies and patterns. To achieve state-of-the-art performance, models synthesize complex feature relationships, find shared patterns from diverse training examples, and process information through highly interconnected internal components.

Therefore, grounded or reality-checked interpretability methods must also be able to capture these influential interactions. As the number of features, training data points, and model components grow, the number of potential interactions grows exponentially, making exhaustive analysis computationally infeasible. In this blog post, we describe the fundamental ideas behind SPEX and ProxySPEX, algorithms capable of identifying these critical interactions at scale.

Attribution through Ablation

Central to our approach is the concept of ablation, measuring influence by observing what changes when a component is removed.

  • Feature Attribution: We mask or remove specific segments of the input prompt and measure the resulting shift in the predictions.
  • Data Attribution: We train models on different subsets of the training set, assessing how the modelโ€™s output on a test point shifts in the absence of specific training data.
  • Model Component Attribution (Mechanistic Interpretability): We intervene on the modelโ€™s forward pass by removing the influence of specific internal components, determining which internal structures are responsible for the modelโ€™s prediction.

In each case, the goal is the same: to isolate the drivers of a decision by systematically perturbing the system, in hopes of discovering influential interactions. Since each ablation incurs a significant cost, whether through expensive inference calls or retrainings, we aim to compute attributions with the fewest possible ablations.

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Masking different parts of the input, we measure the difference between the original and ablated outputs.

SPEX and ProxySPEX Framework

To discover influential interactions with a tractable number of ablations, we have developed SPEX (Spectral Explainer). This framework draws on signal processing and coding theory to advance interaction discovery to scales orders of magnitude greater than prior methods. SPEX circumvents this by exploiting a key structural observation: while the number of total interactions is prohibitively large, the number of influential interactions is actually quite small.

We formalize this through two observations: sparsity (relatively few interactions truly drive the output) and low-degreeness (influential interactions typically involve only a small subset of features). These properties allow us to reframe the difficult search problem into a solvable sparse recovery problem. Drawing on powerful tools from signal processing and coding theory, SPEX uses strategically selected ablations to combine many candidate interactions together. Then, using efficient decoding algorithms, we disentangle these combined signals to isolate the specific interactions responsible for the modelโ€™s behavior.

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In a subsequent algorithm, ProxySPEX, we identified another structural property common in complex machine learning models: hierarchy. This means that where a higher-order interaction is important, its lower-order subsets are likely to be important as well. This additional structural observation yields a dramatic improvement in computational cost: it matches the performance of SPEX with around 10x fewer ablations. Collectively, these frameworks enable efficient interaction discovery, unlocking new applications in feature, data, and model component attribution.

Feature Attribution

Feature attribution techniques assign importance scores to input features based on their influence on the modelโ€™s output. For example, if an LLM were used to make a medical diagnosis, this approach could identify exactly which symptoms led the model to its conclusion. While attributing importance to individual features can be valuable, the true power of sophisticated models lies in their ability to capture complex relationships between features. The figure below illustrates examples of these influential interactions: from a double negative changing sentiment (left) to the necessary synthesis of multiple documents in a RAG task (right).

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The figure below illustrates the feature attribution performance of SPEX on a sentiment analysis task. We evaluate performance using faithfulness: a measure of how accurately the recovered attributions can predict the modelโ€™s output on unseen test ablations. We find that SPEX matches the high faithfulness of existing interaction techniques (Faith-Shap, Faith-Banzhaf) on short inputs, but uniquely retains this performance as the context scales to thousands of features. In contrast, while marginal approaches (LIME, Banzhaf) can also operate at this scale, they exhibit significantly lower faithfulness because they fail to capture the complex interactions driving the modelโ€™s output.

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SPEX was also applied to a modified version of the trolley problem, where the moral ambiguity of the problem is removed, making โ€œTrueโ€ the clear correct answer. Given the modification below, GPT-4o mini answered correctly only 8% of the time. When we applied standard feature attribution (SHAP), it identified individual instances of the word trolley as the primary factors driving the incorrect response. However, replacing trolley with synonyms such as tram or streetcar had little impact on the prediction of the model. SPEX revealed a much richer story, identifying a dominant high-order synergy between the two instances of trolley, as well as the words pulling and lever, a finding that aligns with human intuition about the core components of the dilemma. When these four words were replaced with synonyms, the modelโ€™s failure rate dropped to near zero.

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Data Attribution

Data attribution identifies which training data points are most responsible for a modelโ€™s prediction on a new test point. Identifying influential interactions between these data points is key to explaining unexpected model behaviors. Redundant interactions, such as semantic duplicates, often reinforce specific (and possibly incorrect) concepts, while synergistic interactions are essential for defining decision boundaries that no single sample could form alone. To demonstrate this, we applied ProxySPEX to a ResNet model trained on CIFAR-10, identifying the most significant examples of both interaction types for a variety of difficult test points, as shown in the figure below.

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As illustrated, synergistic interactions (left) often involve semantically distinct classes working together to define a decision boundary. For example, grounding the synergy in human perception, the automobile (bottom left) shares visual traits with the provided training images, including the low-profile chassis of the sports car, the boxy shape of the yellow truck, and the horizontal stripe of the red delivery vehicle. On the other hand, redundant interactions (right) tend to capture visual duplicates that reinforce a specific concept. For instance, the horse prediction (middle right) is heavily influenced by a cluster of dog images with similar silhouettes. This fine-grained analysis allows for the development of new data selection techniques that preserve necessary synergies while safely removing redundancies.

Attention Head Attribution (Mechanistic Interpretability)

The goal of model component attribution is to identify which internal parts of the model, such as specific layers or attention heads, are most responsible for a particular behavior. Here too, ProxySPEX uncovers the responsible interactions between different parts of the architecture. Understanding these structural dependencies is vital for architectural interventions, such as task-specific attention head pruning. On an MMLU dataset (highschoolโ€usโ€history), we demonstrate that a ProxySPEX-informed pruning strategy not only outperforms competing methods, but can actually improve model performance on the target task.

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On this task, we also analyzed the interaction structure across the modelโ€™s depth. We observe that early layers function in a predominantly linear regime, where heads contribute largely independently to the target task. In later layers, the role of interactions between attention heads becomes more pronounced, with most of the contribution coming from interactions among heads in the same layer.

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Whatโ€™s Next?

The SPEX framework represents a significant step forward for interpretability, extending interaction discovery from dozens to thousands of components. We have demonstrated the versatility of the framework across the entire model lifecycle: exploring feature attribution on long-context inputs, identifying synergies and redundancies among training data points, and discovering interactions between internal model components. Moving forwards, many interesting research questions remain around unifying these different perspectives, providing a more holistic understanding of a machine learning system. It is also of great interest to systematically evaluate interaction discovery methods against existing scientific knowledge in fields such as genomics and materials science, serving to both ground model findings and generate new, testable hypotheses.

We invite the research community to join us in this effort: the code for both SPEX and ProxySPEX is fully integrated and available within the popular SHAP-IQ repository.

Designing AI agents that know when to step back

11 March 2026 at 16:00
Agentic AI is taking off, and for good reason. AI agents can now write code, conduct research, plan travel, handle customer service, and more. Yet amid the excitement about what AI agents can do, a key question has been neglected: how do we design the human side of the equation? That question is critical, because agentic AI isnโ€™t just another feature to bolt onto existing products. Itโ€™s a fundamentally different kind of software that demands fresh thinking. Unlike traditional software, agentic AI can be proactive and conversational, sometimes even anthropomorphic. It doesnโ€™t just respond to commands; it initiates actions and makes decisions autonomously. This capability is what makes agentic AI so useful, but itโ€™s also what makes effective interactions hard to design. A central user-experience (UX) challenge is coordination: the interplay between what users do, what they experience, and what the AI is doing, both visibly and behind the scenes. Trust, control, and transparency are essential to the agentic-AI user experience, and they all depend on getting this coordination right. Here, we introduce a framework for thinking about human-AI coordination. We also offer a vocabulary for characterizing agentic experiences, including when the AI feels too absent, too intrusive, or appropriately calibrated. A framework for human-AI coordination One of the most critical decisions in AI UX design is how visible and interactive AI capabilities should be. Should users direct the agent step by step, let it act autonomously, or work somewhere in-between? And how should this change based on the task, the userโ€™s expertise, and the current context? You can think of coordination along these three dimensions: Human involvement: how much effort and attention the user invests in directing or monitoring the AI; AI salience: how prominent the AI feels in the experience (for example, a conversational chatbot with a name and persona has high salience, autocomplete suggestions have lower salience, and AI-generated navigation menus and backend optimizations have little or none); AI activity: what the AI is doing, whether or not the user sees it. Coordination is about aligning these dimensions. When human involvement and AI salience are both low, coordination is light-touch. When they are high, coordination is more hands-on. The right balance is often somewhere in-between, with an awareness of what the AI is doing in the background. Three zones of coordination Rather than treating agent autonomy as a binary choice โ€” a fully autonomous system or one with a human in the loop โ€” it is practical to consider three โ€œzonesโ€ of coordination. Done with me (mutually collaborative): User and AI work closely together across multiple phases โ€” initiation, monitoring, updating, and completion. Imagine collaborating with an AI assistant on a complex document or research project, with frequent back-and-forth. AI salience and human involvement are both high. The user is very in the loop. Done for me (heavily automated): Tasks are handled by AI with minimal user input and oversight. The user initiates the task and reviews the output; most of the work happens out of view. An examples is an agent that researches competitors and delivers a summary report. The user is barely in the loop. Done under me (discreetly assisted): AI works in the background without announcing itself. The user may not even notice the assistance. Smart sorting, predictive text, and intelligently personalized content and navigation menus fall into this category. The AI quickly delivers outcomes users can assess and act on. The user is implicitly in the loop. These arenโ€™t rigid categories but calibration points for designing and delivering the right level of coordination to users. The goal is to match coordination intensity to the specific user, task, and context, rather than defaulting to a single mode everywhere or assuming that an autonomous agentic system eliminates the need for thoughtful coordination. The rhythm of human-AI coordination Because both agents and users can work independently, coordination cannot be static. Workflows often move through multiple zones: high involvement during initiation, perhaps defining goals and constraints; lower involvement during execution; and then a spike at review and next steps. We visualize these shifts as โ€œcoordination curvesโ€ โ€” a variation of user-journey mapping that shows how human involvement and AI salience rise and fall across a workflow. High-level curves reveal the overall shape of an experience. Looking beneath the surface exposes specific AI touchpoints, handoffs, and decision points, helping UX design teams collaborate on bringing adaptive agentic systems to life. As multiagent applications become more sophisticated, they enable longer, computationally intensive work such as research projects, complex analyses, and multistep workflows. These create valleys in the coordination curve: stretches where the AI operates independently and the user is minimally involved. These valleys require thoughtful design around notification, approval, monitoring, and auditing. More broadly, the UX layer must provide the transparency and controls needed to build trust, support adaptation and course correction, and ultimately deliver value. Case study: Adaptive coordination in practice We developed an approach called โ€œresponsive salienceโ€, whereby an AI agent automatically adjusts its visibility and interaction intensity to match the context. The core insight is simple: in traditional software, most of the interface is static or deterministic. With agentic AI, behavior is nondeterministic, so a userโ€™s needs for oversight can change moment to moment. A user who trusts an agent on a familiar task may prefer to be largely hands-off. In unfamiliar or high-stakes work, that same user may want more transparency, checkpoints, and tighter control. Rather than forcing users to toggle settings, responsive salience lets the system adapt automatically. In our prototype, a monitoring agent continuously evaluates signals including task complexity, perceived risk, and user comfort level. When trust appears low โ€” for example, when the user is a beginner, or the workflow involves sensitive data โ€” the system increases salience. It could do this by providing richer explanations, additional approval gates, and expanded transparency features. The user may then be notified of the change and, if needed, can override the agentโ€™s choice. Once confidence recovers or the task ends, the salience settings quietly revert. Over time, the system can learn from user behavior through user feedback loops, refining how quickly salience adapts and how far it goes. The result is autonomy that stays aligned with context. Early testing with users validated the idea while revealing some clear tradeoffs. Preferences diverged sharply: some found high-salience modes exhausting (โ€œI felt visually fatigued by the large amount of communicationโ€), while others appreciated the guidance (โ€œIt gave me options for what I might want to ask nextโ€). One participant expressed the desire for a middle ground: โ€œI want some oversight on what the agent is planning before execution. โ€ฆ The high setting was too annoying because I had to approve everything.โ€ These results underline that user preferences for autonomy versus control can vary substantially, even in similar tasks. Responsive salience offers a solution by dynamically adjusting whether a given task is done-with-me, done-for-me, or done-under-me. Tellingly, several participants did not notice responsive salience until we pointed it out. That suggests that when the system is well calibrated, dynamic coordination can feel seamless rather than intrusive. Coevolution with agentic AI Agentic AI represents a genuine shift in what software can do, but realizing its potential depends just as much on what humans do alongside it. The frameworks, protocols, and infrastructures for building agents are maturing fast. The UX layer needs to catch up. Coordination isnโ€™t a one-and-done problem but a moving target. As users gain expertise, tasks change, and AI capabilities evolve, the optimal balance of user involvement and AI salience will change too. So the goal isnโ€™t to find the perfect static design, as it might have been before generative AI, but to build systems and a shared vocabulary that evolve as we learn what works in practice. Agentic AI makes this both necessary and possible: its behavior can be unpredictable, so users and designers must adjust, yet the technology itself can also learn, adapt, and course-correct proactively. Teams that get this right wonโ€™t simply build more capable agents. They will build agents that people trust, adopt, and even enjoy collaborating with.
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