The demo to production Death Valley

If you’ve worked on an AI feature, you know the feeling. You start building something that you are excited about, set launch timelines. The model spits out a perfect response, the prototype works magically, and everybody in the room is mentally calculating how big this product will be when we launch. I’ve been in that room a lot many times and it’s fun.

Then you try to test before you ship.

Latency spikes to 10 seconds on mobile. The model starts hallucinating on edge cases that happen to represent 15% of actual user queries. Your A/B test shows no statistically significant engagement lift because the variance in AI outputs makes traditional hypothesis testing basically meaningless. The safety team flags 340 failure cases in the first week, and you’re now debugging nondeterministic cases that fail in creative, novel ways every single day.

Most often than not, it’s not a model problem but an engineering discipline problem. Shipping an AI product is very different from traditional software. I’ve figured this out the hard way. This playbook shares my learnings.

Latency budgets

Every AI feature comes with a latency tax. Large language model inference takes time. We’re talking 500 milliseconds to 5 or even 50 seconds depending on model size, input length, and infrastructure setup. For consumer products where people expect sub-200-millisecond interactions, this is a hard constraint you have to design around.

The mistake I see most often is teams measuring only p50 latency. A feature with 800 milliseconds p50 sounds fine until you discover the p90 is 15 seconds. That means 10 in every 100 users sit there waiting for 15+ seconds. At scale, that’s thousands of terrible experiences per day.

The way I think about it is you define your latency budget by interaction type, not globally: Synchronous interactions, where the user is staring at a spinner, need to resolve under 1 second. Progressive interactions, where output streams token by token, need first token in under 500 milliseconds and full response under 5 seconds. Asynchronous interactions, where the user keeps doing other stuff, can take up to 20 seconds with a progress indicator.

You also need to measure cold starts separately. The first request after a model loads into memory can be 10 times slower than subsequent requests, and if your traffic is bursty, cold starts will disproportionately punish your most engaged users arriving during peak hours.

Besides, you also need to budget for the full pipeline, not just inference. A typical AI feature pipeline including input preprocessing (tokenization, context assembly, and prompt construction), model inference, output postprocessing (parsing, formatting, safety filtering, etc.), and a full response delivery adds up. Optimizing inference while ignoring the rest is like tuning your engine while driving on flat tires.

Lastly, use streaming aggressively for generative features. Pushing tokens to the user as they’re generated instead of waiting for the full response changes how users perceive latency.  A four-second response that starts appearing at 300 milliseconds feels dramatically faster than one that pops in all at once. Perception is reality when it comes to user experience.

Designing fallbacks

Traditional software fails in boring, predictable ways. AI features fail in novel, unpredictable, and occasionally creative ways. I once saw a model respond to a product recommendation query with a poem about loneliness. Your fallback strategy needs to be considerably more sophisticated than a try/catch block.

I think about fallbacks as a hierarchy. First, model fallback: When your primary model fails, drop to a simpler, faster, and more reliable model. Most failure cases get handled without the user ever knowing. Second, cache fallback: For queries similar to stuff you’ve seen before, serve a cached response. Third, template fallback: When generation fails completely, fall back to prewritten templates. Degraded beats dead every time. Fourth, graceful omission: Sometimes the best fallback is to simply not show the AI feature at all rather than showing a broken version.

The design principle underneath all of this is that users should never encounter an unhandled AI failure. Every failure mode maps to a specific level, and transitions between levels should be invisible whenever you can manage it.

Quality measurement

Quality in traditional software is binary. The button works or it doesn’t. AI feature quality is continuous and subjective, and it changes depending on context. I’ve landed on a four-layer quality pyramid.

The foundation is safety, and it’s nonnegotiable. Does the output contain harmful content, PII, or made-up facts? This layer is binary, and you measure it with automated classifiers running against 100% of outputs.

The second layer is factual correctness, which is domain specific. Is the output actually right? For a coding assistant that means generated code compiles and passes tests. For a writing tool it means grammatical, stylistically appropriate output. You measure this with domain specific evaluation suites.

The third layer is usefulness, and it’s user centered. Did the person actually benefit? Track acceptance rate, edit distance, time to task completion, and repeat usage. This is where traditional product metrics meet AI specific ones.

The fourth layer is delight, which is experimental. Does the output feel good? Hardest to measure but often most important for adoption. Sometimes the numbers say the feature works but users’ guts say it doesn’t. This layer catches that gap.

A/B testing AI features

A/B testing AI features is fundamentally harder than traditional features because AI outputs are nondeterministic. The same user doing the same thing twice might get different outputs, introducing variance that traditional frameworks weren’t built to handle.

The core challenge is that intratreatment variance inflates the sample size you need for statistical significance, often by three to five times. If you’re running your AI experiment with normal sample size assumptions, you’re probably looking at noise and calling it signal.

Then there’s the metric selection problem. A chatbot generating entertaining but factually wrong responses might show amazing engagement numbers while actively misleading users. You have to measure engagement and quality together. “Engaged interactions where quality score exceeds threshold” is more meaningful than raw engagement alone.

The temporal problem matters too. AI feature value changes over time as users learn how to work with it. Short experiments will underestimate long-term value if there’s a learning curve, or overestimate it if there’s a novelty bump.

My practical guidance: budget two to three times more time and traffic for AI experiments than traditional ones. Lean on Bayesian methods as they handle high variance better. And always pair quantitative tests with qualitative research. Ten user interviews will surface failure modes that no amount of statistical analysis will catch.

Model drift monitoring

Model drift is the slow, invisible rot of AI output quality over time, and there are multiple culprits.

Data drift happens because the world changes and user behavior evolves. A model trained on 2024 data performs worse on 2026 queries referencing new concepts, slang, and cultural moments.

Provider drift happens because third-party APIs change without your consent. OpenAI acknowledged that GPT-4’s behavior shifted measurably between March and June 2023, and Stanford researchers documented significant performance swings. The fix: Pin your model versions so updates happen on your schedule, after your testing.

Evaluation drift is the subtlest form. Even your quality metrics can become inadequate and the evaluation criteria that made sense at launch might become inadequate as usage patterns shift and user expectations change. Quarterly reviews of your evaluation suites are essential.

At minimum you need daily automated quality evaluations on 1% to 5% of production traffic, weekly analysis of input distribution characteristics, and monthly human evaluation of 100 to 500 examples. Shipping an AI feature without drift monitoring is like deploying a service without alerting. You won’t know it’s broken until your users tell you, and by then they’re angry.

Evaluation frameworks

How do you know if your AI feature is good enough? You need two fundamentally different approaches, and you genuinely need both.

Automated evaluation gives you speed. Build a golden dataset of 500 to 2,000 labeled examples, train a classifier or use a capable model as judge, and validate against human judgment quarterly targeting 85% agreement. Automated evals chew through thousands of examples per hour, making them essential for velocity. The pitfall: They miss novel failure modes not in the training data.

Human evaluation catches what automation misses. Structure it with five to seven evaluators mixing domain experts and representative users. Use a consistent rubric covering accuracy, helpfulness, tone, completeness, and safety. Run weekly during development, monthly in production. The trade-offs: expensive at $15 to $30 per example, slow with 24 to 72 hour turnaround, and subject to human biases. Manage by rotating evaluators and capping sessions at two hours.

The model as judge approach is an increasingly viable middle ground. Judging quality is often easier than generating it, which means a model can reliably evaluate outputs even for tasks where it couldn’t produce them itself. Use it for high-volume evaluation but always validate against human judgment.

Graceful degradation and prompt engineering

Graceful degradation means when capabilities decrease, the experience gets worse smoothly instead of falling off a cliff. Design for capability levels, not binary states. Define four to five levels with specific behaviors at each. For example, for an AI writing assistant: Level 5 is full capability with real-time suggestions, tone adjustment, and structure recommendations. Level 4 is delayed suggestions appearing after a two- to three-second pause because latency is up. Level 3 is basic suggestions only like grammar and spelling with no style feedback. Each level is a deliberate design decision, not an accident.

Make degradation invisible when possible. Users shouldn’t see a “broken” experience. They see a less detailed one. That’s a huge difference psychologically. However,  when the degradation is significant enough that users will notice, proactive communication like “AI suggestions are temporarily limited” builds trust infinitely more than silently pushing poor-quality outputs.

Prompt engineering in production is software engineering. In production, prompts are code, and they need version control, testing, monitoring, and maintenance. Version controls every prompt. Parameterize prompts, don’t hardcode context. Production prompts should be templates with clearly defined injection points for user context, system state, and dynamic instructions. This makes them testable because you can inject known inputs and verify outputs, and it makes them maintainable because changing how you handle context shouldn’t require rewriting the entire prompt from scratch.

Test prompts against regression suites. Maintain 200 to 500 test cases covering the full distribution of expected inputs, including edge cases and adversarial inputs. Run the suite against every prompt change before deployment.

Monitor prompt performance in production. Track output quality metrics like acceptance rate, user edits, and regeneration requests, segmented by prompt version. When you deploy a new version, compare its production metrics against the previous one for at least 72 hours before calling it stable. This is basically canary deployment for prompts.

Ship it right

These systems aren’t optional add ons you can bolt on after launch. Every feature I’ve seen fail was built first with plans to “add production hardening later.” Later never comes.

AI features are probabilistic and nondeterministic, and they change over time without anyone touching them. Build these systems, staff them properly, and treat them with the same seriousness you’d give your core infrastructure. The gap between demo and production is wide, but it’s absolutely crossable if you build the right bridge.

Note: The research work pertaining to this article was done in a personal capacity. Views are of my own and do not reflect my employer’s views in any way.

On June 1, GitHub Copilot’s usage-based billing became active for all Copilot plans, and developers reacted quickly and loudly. A Pro plan still costs $10, but it now comes with a monthly pool of AI credits. Those credits are priced at a penny each, and they’re consumed according to the model used and the tokens processed, including input, output, and cached tokens. For a heavy agentic session running a frontier model, that makes spend feel very different from a flat subscription.

That’s the news, and it’s worth understanding, but it isn’t the important part. Nothing about the underlying cost of agentic work actually changed on June 1. The tokens were always being consumed, the loops were always running, and the tool calls were always expanding the context. What changed is that the meter became visible. A workload that had been quietly subsidized under a flat rate started showing up as an itemized bill.

Where the tokens go

To see why the bill landed so hard, it helps to compare two things that look similar and bill very differently. A chat completion is close to a single transaction. You send a prompt, the model sends an answer, and you pay roughly once for the input and once for the output. A tool-using agent doesn’t work that way at all. An agent doesn’t answer a question so much as work toward it, and it works by looping. It reasons about the task, calls a tool, reads the result, reasons again, calls another tool, and continues until it decides it’s finished.

Every pass through that loop carries a cost that’s easy to miss. In many agent harnesses, each turn carries forward a large share of the accumulated context: prior messages, tool descriptions, retrieved files, and tool results. Even when some of that context is cached, summarized, or pruned, the system is still doing metered work to preserve enough state for the next decision. The final answer you actually wanted is only a thin slice of what you paid for. The loop is the bill.

This is why agent cost doesn’t scale politely. It scales with the number of turns, and the number of turns scales with how much discovery the agent has to do, which in turn scales with how vague the request was and how much irrelevant context it’s dragging along. A clean, well-scoped task might finish in three turns, while the same task posed as an open-ended question might wander through 15, each carrying the cost of everything that came before it. Under a flat rate, that difference was invisible. Under usage-based billing, it’s the difference between a small interaction and an expensive one.

Tool design is now part of the cost model

I wrote recently about a hidden tax on Model Context Protocol servers: the way an overstuffed tool catalog quietly degrades a model’s ability to route to the right tool. Bloated descriptions, overlapping responsibilities, and vague parameters make the model’s job harder and its choices worse. That argument was about accuracy. The billing change adds a second invoice for the same bloat, and this one is denominated in dollars.

The tool catalog is often part of what gets carried through the agent’s loop. A tool described in three tight sentences and a tool described in three rambling paragraphs may both function, but the second one pays rent in the context window every time an agent has it loaded. Multiply that across a catalog of 40 tools and a workflow that runs a dozen turns, and the cost of verbose tool design stops being a rounding error. Tool design was already a correctness discipline. It’s now a cost discipline as well. The same audit that tightens routing accuracy tightens the bill.

Where prompt discipline runs out

There’s a layer of this that individual users can control, and it’s worth knowing because the savings are real and immediate. Two patterns matter most, and I’ve been handing both to the engineers on a pilot I run for a large healthcare organization. They aren’t magic tricks. They’re ways to keep the agent out of unnecessary discovery loops.

The first pattern is about input. Prompt the agent like a short requirement rather than a broad question. A request such as “look at the encounter data and tell me what you find” forces the agent into discovery mode, where it burns turns figuring out what you meant, and every one of those turns carries the full context forward. Compare that to a prompt that front-loads the specifics by naming the project and the table, naming the date field to filter on, stating the output shape you want, and calling out anything that should be excluded. A better prompt would be: “Using the curated clinical project and the silver-zone encounters table, show total encounters by month for calendar year 2025, use admission_date_time for inclusion, and return one row per month ordered chronologically.” The second prompt collapses the loop. The agent has what it needs on the first turn, so it does the work instead of interviewing you for it.

In practice, the difference isn’t just polish. The vague version forces the agent to discover the data model, infer the date semantics, choose an aggregation, and decide on a display format. The specific version turns the task into a bounded query. That difference shows up in accuracy, latency, and cost.

The second pattern is about output, and it’s the lever most people overlook. Ask for plain text or Markdown during the intermediate steps, and save rich HTML formatting for the final, confirmed deliverable. Formatted output is expensive to generate, and requirements shift. If you ask for a polished HTML report on the first pass and then change a filter, you pay full output-token freight to regenerate all that layout, often more than once. The cheaper habit is to validate the numbers in text and format only at the end.

These patterns work, and they also have a ceiling. Both of them put the entire burden of cost control on the user, and they hold only as long as every user exercises the discipline on every prompt. The day someone reverts to “tell me what you find,” the savings evaporate, and the only thing standing between the team and a surprise invoice is a budget cap that reports the overspend after it has already happened.

Cost is a governance problem, not a budgeting one

That fragility is the real lesson. A budget cap is a backstop rather than a control. It will stop a runaway, but it tells you that you overspent rather than why, and it does nothing to make the next run cheaper. Treating cost as a budgeting problem leaves you forever reacting to the meter, while treating it as an architecture problem lets you build the savings in once and stop relying on everyone’s good behavior.

That means the controls that matter belong on the platform rather than in individual prompts. By the platform I don’t mean the agent itself, the coding assistant or chat client a developer drives day-to-day, and I don’t mean the model or a router sitting beneath it. I mean the control plane that sits above the agents, the layer where an organization enforces policy, access, observability, and now cost across every agent and model its developers touch. An administrative console that gives IT visibility into who is doing what and which capabilities they can install is an early, narrow instance of it. A router that sends planning to a cheap model is one feature that belongs there. The platform is where the rules live, and the agent is a consumer of those rules rather than the place you set them. The platform should route models by task, using cheaper models for planning and reserving frontier models for work that earns the price. It should bound the loop, requiring the agent to check in after a fixed number of iterations. It should cap tool-result payloads so a careless query cannot dump a million rows into the context window. It should default intermediate work to plain text, making the cheap path the path of least resistance instead of something users have to remember.

Every one of those controls is something a user can approximate by hand and something the platform can simply guarantee. This is the same principle I keep returning to in the context of data access, where safe behavior cannot depend on the person at the keyboard remembering the rules. Prompts guide behavior. Guardrails make the cheaper and safer behavior the default. Cost governance is guardrails as control plane, with a dollar sign attached, enforced at the same layer where you already enforce who is allowed to see which row.

The pattern, not the vendor

It would be a mistake to read this as only a GitHub story. GitHub is the current example because its change is visible and recent, but usage-based billing for agentic work is the direction of travel for many AI tools. The economics under the hood are similar: Agentic workloads turn single answers into loops of model calls, tool calls, and context management. The flat-rate subsidy was always going to come under pressure once the workload shifted from autocomplete to autonomy.

The organizations that treat June 1 as a pricing event will optimize a few prompts, grumble, and move on until the next vendor changes its meter. The ones that treat it as an architecture signal will push the cost controls down into the platform, where they hold regardless of which provider is counting which token. That’s the more durable place to stand. The bill didn’t get bigger this month. It got honest, and an honest bill is the kind you can engineer against.

The following article originally appeared on Addy Osmani’s blog and is being reposted here with the author’s permission.

A long-running AI agent can keep making progress over hours, days, or weeks. It can do this across many context windows and sandboxes, recover from failure, leave structured artifacts behind, and resume where it left off.

For two years the dominant image of an “AI agent” has been a chat window with a clever loop in it. You type a goal; the agent calls some tools; you watch tokens stream by; you stop watching when the work runs out of patience or the context window fills up. That paradigm got us a long way, but it has a ceiling. The model forgets. It declares “task complete” when it isn’t. It reintroduces a bug it fixed nine turns ago. The whole thing is structured around a single sitting.

Long-running agents are what comes next. The idea is easy to state: an agent that keeps making forward progress on a goal across many sessions and many sandboxes, possibly many days or weeks, while leaving the workspace clean enough that the next session can pick up where the last one left off. The engineering is harder. You have to solve for persistence, recovery, and verification in a way that doesn’t just paper over the cracks. You have to build a state layer that lives outside the model’s context window, and you have to design the handoff between sessions so the agent doesn’t lose its mind when it wakes up and finds itself in a different sandbox with a different context window.

This post is my attempt to lay out what’s changed, who’s pushing on it, and how an engineer can use long-running agents today without writing the whole thing from scratch.

What “long-running” actually means

“Long-running” used to mean at least three different things in practice, and it helps to keep them separate.

Long-horizon reasoning. The agent has to plan and execute over many dependent steps. This is mostly a model-quality story: coherence, planning, the ability to recover from a wrong turn 10 steps ago. METR has been tracking this with their time horizon metric, which estimates how long a task a frontier model can complete with 50% reliability. The headline finding is that the metric has been doubling roughly every seven months since 2019, and their TH1.1 update earlier this year doubled the count of eight-hour-plus tasks in the eval set. If that curve holds, frontier agents complete tasks at the day scale by 2028 and the year scale by 2034.

Long-running execution. The agent’s process runs for hours or days. Maybe it’s a coding job, maybe it’s a research sweep, maybe it’s a 24-7 monitoring service. The model might be invoked thousands of times across the run. This is mostly a harness story, and it’s the one this post is mostly about.

Persistent agency. The agent has an identity that outlives any single task. It accumulates memory, learns user preferences, and is always available. This is the Memory Bank flavor of long-running.

In practice the three blur together. A real production agent does long-horizon reasoning inside a long-running execution backed by persistent agency. But the engineering problems are different in each, and so are the products that solve them.

Why this matters

There are two reasons I believe this work matters a lot right now.

The first is a phase change in what’s economically feasible to delegate. An agent that runs for 10 minutes can answer a question, summarize a doc, fix a small bug. An agent that runs for 10 hours can own an entire feature, finish a migration that was on the backlog for six quarters, or do the kind of overnight research sweep that used to require a junior analyst. One of Anthropic’s Claude Sonnet announcements put concrete numbers on this last fall: 30+ hours of autonomous coding in internal tests, including one run that produced an 11,000-line Slack-style app. That’s already past the threshold where the answer to “Should I delegate this?” is no longer obvious.

The second is that persistence changes what the agent is. A stateless agent answers your question and disappears. A long-running one accumulates context: which competitor moved which way last week, which test flaked twice on Tuesday, what you usually mean by “the dashboard.” Anthropic’s Project Vend was the most public early demonstration of this. They had a Claude instance run an actual office vending business for a month, managing inventory, setting prices, talking to suppliers. It failed in informative ways, and the second phase ran much better, but the point wasn’t profitability. The point was watching what kinds of weird coherence problems show up when an agent has to maintain identity across weeks instead of turns.

Those are the same problems every team building production agents now hits.

The three walls every long-running agent hits

Three walls show up in basically every write-up I’ve read this year.

Finite context. Even a 1M-token window fills. And context rot, the steady degradation of model performance as the window gets full, kicks in well before the hard limit. A 24-hour run is not going to fit in any context window the field has on its roadmap. Something has to give.

No persistent state. A new session starts blank. Anthropic’s framing in their scientific computing post is the cleanest version I’ve seen: “Imagine a software project staffed by engineers working in shifts, where each new engineer arrives with no memory of what happened on the previous shift.” Without an explicit persistence story, every shift change is a productivity disaster.

No self-verification. Models reliably skew positive when they grade their own work. Asked “Are you done?” they answer “yes” more often than they should. Without a separate signal that the work meets a bar, you get the agent that ships at 30% complete with full confidence.

Long-running agent designs are mostly answers to these three problems. The major labs have converged on similar shapes of answer, but with very different surface area.

The Ralph loop: One of the simpler practitioner versions of long-running agents

The Ralph loop (sometimes called the Ralph Wiggum technique) is one of “simpler” practitioner version of long-running agents, popularized by Geoffrey Huntley and Ryan Carson. The reference implementation is literally a bash script that loops:

1. Pick the next unfinished task from a list (prd.json or equivalent).
2. Build a prompt with the task, the relevant context, and any persistent notes.
3. Call the agent.
4. Run tests or other checks.
5. Append what happened to progress.txt.
6. Update the task list (done, failed, blocked).
7. Go back to step 1.

The reason it works is the same reason any of the harnesses below work: State lives outside the agent’s context. prd.json is the plan, progress.txt is the lab notes, and AGENTS.md is the rolling rulebook. The agent itself is amnesiac, but the filesystem isn’t. Each iteration starts fresh and reads enough state from disk to keep going. Carson’s Compound Product extends the idea by chaining multiple loops (an analysis loop that reads daily reports, a planning loop that emits a PRD, an execution loop that writes the code), which is roughly the open source version of the planner-generator-evaluator triad Anthropic landed on independently.

I went deeper on all of this in “Self-Improving Coding Agents”: task list structure, progress files, QA gates, monitoring, the failure modes you’ll actually hit. The short version is that you can build a working long-running agent in an evening with a bash script and a JSON file. Most of what Google and Anthropic have productized is the work of making this pattern recoverable, secure, and observable at scale.

The big-lab stories below are different ways of paying for that production-readiness.

Anthropic: Harnesses, then the brain/hands/session split

Anthropic has been the most public about the engineering. Two posts are worth reading end to end.

The first is “Effective Harnesses for Long-Running Agents,” which lays out a two-agent harness for autonomous full stack development. An initializer agent runs once at the start of a project to set up the environment, expand the prompt into a structured feature-list.json, and write an init.sh that future sessions will run on boot. A coding agent is then woken up over and over, each session asked to make incremental progress on one feature, run tests, leave a claude-progress.txt note, and commit. A test ratchet (“it is unacceptable to remove or edit tests because this could lead to missing or buggy functionality”) sits in the prompt to stop the very common failure of an agent deleting failing tests to “make them pass.” InfoQ’s writeup extends this into a planner, generator, and evaluator triad, on the same logic that separating generation from evaluation matters because models grade their own work too generously.

The second is “Scaling Managed Agents: Decoupling the Brain from the Hands,” the architectural post behind Claude Managed Agents (Anthropic’s hosted runtime, launched in early April). The argument is that an agent has three components that should be independently replaceable. The Brain is the model and the harness loop that calls it. The Hands are sandboxed, ephemeral execution environments where tools actually run. The Session is an append-only event log of every thought, tool call, and observation.

This sounds abstract, but it isn’t. Here’s Anthropic’s framing: “Every component in a harness encodes an assumption about what the model can’t do on its own.” When you couple them, an assumption that goes stale (e.g., the model used to need an explicit planner and now plans natively) means the whole system has to change at once. When you decouple them, the harness becomes stateless, sandboxes become cattle, not pets, and a brain crash doesn’t lose the run. A fresh container calls wake(sessionId) and reconstitutes the state from the log. They reported time-to-first-token dropped ~60% at p50 and over 90% at p95 just from being able to start inference before the sandbox is ready.

The session-as-event-log idea is the part most teams underappreciate. It is what makes a long-running agent recoverable. Without it, a container failure is a session failure and you’re debugging into a stale snapshot. With it, the agent’s memory is a queryable artifact that lives outside whatever process happens to be running at the moment.

For the scientific computing crowd, Anthropic’s “long-running Claude” post reduces all of this to a simpler stack: CLAUDE.md as a living plan the agent edits as it learns, CHANGELOG.md as portable lab notes, tmux plus SLURM plus git as the execution and coordination layer, and the Ralph loop, a for loop that kicks the agent back into context whenever it claims completion and asks if it’s really done. Their flagship case study is a Boltzmann solver Claude Opus 4.6 built over a few days that reached subpercent agreement with a reference CLASS implementation. Months to years of researcher time, compressed.

Same patterns across all three posts: an explicit plan file, an explicit progress file, structured handoffs between sessions, separate generation from evaluation, and a loop that refuses to let the agent stop early.

Cursor: Planners, workers, judges

Cursor’s “Scaling Long-Running Autonomous Coding” is the other essential read this year. They walked into walls that Anthropic mostly papered over.

Their first attempt was a flat coordination model: equal-status agents writing to shared files with locks. It became a bottleneck and made the agents risk averse, churning rather than committing. Their second attempt swapped locks for optimistic concurrency control, which removed the bottleneck but didn’t fix the coordination problem. The third design is what’s running in production now and what they describe as solving most of the problem:

• Planners continuously explore the codebase and emit tasks. They can recursively spawn subplanners.
• Workers are focused executors. They don’t coordinate with each other and they don’t worry about the big picture.
• Judges decide when an iteration is finished and when to restart.

Two things stand out from the post. One: “A surprising amount of the system’s behavior comes down to how we prompt the agents” more than the harness or the model. Two: Different models slot into different roles. Their reported finding is that a GPT model was better than Opus for extended autonomous work specifically because Opus tended to stop early and take shortcuts. Same task, different role, different model. The matching is becoming part of the design surface.

This pairs with Composer 2 (their proprietary frontier coding model that ships in Cursor 3) and their background cloud agents: long-running tasks that run on Anysphere’s cloud infrastructure rather than your laptop. Eight-hour refactors and codebase-wide migrations survive a closed lid. You can start a task locally, hit run in cloud when you realize it’ll take 30 minutes, and reattach later from your phone. Each agent runs in an isolated Git worktree and merges back via PR. The handoff between local and remote is the part most teams haven’t figured out yet, and Cursor’s bet is that it has to be its own product surface.

The shape ends up close to Anthropic’s: Roles are split, sessions are durable, judges sit beside the worker, and a long task runs in a cloud sandbox with Git as the coordination substrate.

Google: Long-running agents on the Agent Platform

Google’s announcement at Cloud Next ’26 folded Vertex AI into the Gemini Enterprise Agent Platform and turned long-running agents into a named product, with named SLAs.

The pieces that matter for this post:

• Agent Runtime supports agents that “run autonomously for days at a time” with sub-second cold starts and on-demand sandbox provisioning. The launch post’s example use case is a sales prospecting sequence that takes a week to play out, which is roughly the right shape for it.
• Agent Sessions persist conversation and event history. You can pin them to a custom session ID that maps to your own CRM or DB record, so the agent’s state lives next to the business state instead of in a separate AI silo.
• Agent Memory Bank is the persistent long-term memory layer, generally available as of Next ’26. It curates memories from sessions, scopes them to a user identity, and exposes a search API so the next agent invocation can pull what’s relevant. Payhawk reported that auto-submitting expenses through a Memory Bank-backed agent cut submission time by over 50%.
• Agent Sandbox handles hardened code execution.
• Agent-to-Agent Orchestration, Agent Registry, Agent Identity, Agent Gateway, Agent Observability, and Agent Simulation cover basically every operational concern you’d otherwise build by hand for a production fleet, including the cryptographic-identity-and-audit-log story enterprises actually need to ship.

Architecturally this is the same brain/hands/session split Anthropic described, just productized at platform scale and bundled with ADK (the code-first dev kit) and Agent Studio (the visual one). If you’re building inside Google Cloud, you don’t have to design a session log or a memory store from scratch anymore. You wire an ADK agent into Memory Bank and Sessions, deploy onto Agent Runtime, and the persistence question is answered.

Notice how much this looks like the pattern Anthropic and Cursor describe, just unbundled into named services with SLAs. Three years ago you’d have built all of this yourself. Now you pick which version of “decoupled brain, hands, and session” you want to rent.

Five patterns for long-running agents in production

Shubham Saboo and I wrote up five design patterns we’ve seen separate working long-running agents from demos. They aren’t Google-specific, but they map cleanly onto the primitives Agent Runtime now exposes, so it’s worth walking through them here in shortened form.

Checkpoint-and-resume. The most common multiday failure is context loss. An agent processes 200 documents over four hours, hits an error on document 201, and without a checkpoint you start from scratch. Treat the agent like a long-running server process: write intermediate state to disk, checkpoint every N units of work, recover from failures. The Agent Runtime sandbox gives you a persistent filesystem, but choosing the right checkpoint granularity (not every step, not only the end) is on you.

Delegated approval (human-in-the-loop). Most “human-in-the-loop” implementations are: serialize state to JSON, fire a webhook, hope someone responds. The state goes stale, the notification gets buried, the agent re-deserializes into a slightly different world. Long-running runtimes let the agent pause in place with full execution state intact: reasoning chain, working memory, tool history, pending action. Hours of human time pass, the agent consumes zero compute, and it resumes with subsecond latency. Mission Control is Google’s inbox for this. The pattern works regardless of vendor.

Memory-layered context. A seven-day agent needs more than session state. Memory Bank handles long-term curated memory, Memory Profiles add low-latency lookups, and the failure mode you’ll hit in production is memory drift: The agent learns a procedural shortcut from a few atypical interactions and starts applying it broadly. Govern memory like you govern microservices. Agent Identity controls who can read and write which banks. Agent Registry tracks which version of which agent is running. Agent Gateway enforces policy on the wire. The auditing question stops being “What are my agents doing?” and becomes “What are my agents remembering, and how is that changing their behavior?”

Ambient processing. Not every long-running agent talks to a human. Some sit on a Pub/Sub stream or a BigQuery table and act on events as they arrive: content moderation, anomaly detection, inbox triage. The architectural decision worth making early is to not hardcode policy into the agent. Define it in the Gateway and the fleet picks up policy changes without redeploys. Ambient agents run unsupervised for long stretches, and the only sane way to update a hundred of them is to update the policy layer once.

Fleet orchestration. In real systems, you rarely have one agent. A coordinator delegates subtasks to specialists (a Lead Researcher Agent, a Scoring Agent, an Outreach Agent), each running independently for different durations. Each specialist gets its own Identity (so the Outreach Agent can’t read financial data meant for Scoring), its own policy enforcement, its own Registry entry. This is the same coordinator/worker shape distributed systems have used for decades. What’s new is that ADK handles it declaratively with graph-based workflows, and a bad deployment in one specialist doesn’t cascade to the others.

The patterns compose. A compliance system might use checkpointing for document processing, delegated approval for review gates, memory layering for cross-session knowledge, and fleet orchestration to coordinate the specialists. The opening question is always the same: What’s the longest uninterrupted unit of work your agent needs to perform? Minutes, and you don’t need long-running agents. Hours or days, and these patterns are where to start. The full write-up with code samples covers each pattern in depth.

So how do you actually build one today?

This is the practical question, and it has a different answer depending on what you’re building.

You’re a developer who wants long-running coding work on your own repo. Just use Claude Code (or Antigravity, Cursor, or Codex). The harness is already there. Treat your AGENTS.md like a pilot’s checklist: short, every line earned by a real failure. Add hooks for typecheck and lint that surface failures back to the agent. Write a plan file before the agent starts. Use the Ralph loop when the agent claims it’s done and you don’t believe it. For multihour or overnight jobs, run in a worktree so a closed laptop doesn’t kill the run, and have it commit progress every meaningful unit of work. This is the path most people should take, and it’s where the most leverage is right now.

You’re building a hosted agent product. Don’t build the runtime. Pick a managed one. The three real options today: Google’s Agent Platform (Agent Engine + Memory Bank + Sessions), Claude Managed Agents, or roll something on top of ADK, the Claude Agent SDK, or Codex SDK and host it yourself. The trade-off is the usual one. Managed gets you the brain/hands/session split, observability, identity, and an audit trail out of the box. Self-hosted gets you control and the ability to use weird models for weird roles (Cursor’s pattern). For most teams, the right starting point is a managed runtime plus your own ADK or SDK code for the actual loop.

You’re doing something autonomous and operational (monitoring, research, ops). Memory Bank-style persistence is what you want, and it’s the part that doesn’t exist in Claude Code. ADK + Memory Bank + Cloud Run + Cloud Scheduler is the cleanest stack I’ve seen for “agent runs every N hours, accumulates state, alerts on a threshold.” This is also where Cursor’s planner/worker/judge split starts to matter more than it does for IDE coding, because the work is genuinely parallel and the failure modes are different.

A few things matter regardless of which path you take.

Write down the done condition before the agent starts. This is the single highest-leverage move for long runs. The Anthropic harness post calls it the feature list; Cursor calls it the planner’s task spec. Either way, it’s an external file with explicit, testable completion criteria, and it exists so the agent can’t quietly redefine done midrun.

Separate the evaluator from the generator. Self-grading is the failure mode. A planner/worker/judge pipeline, or a generator/evaluator pair, is a real architectural pattern, not a stylistic preference. Even if it’s the same model in different roles with different prompts.

Invest in the session log, not just the prompt. The append-only event log is what makes the agent recoverable, debuggable, and auditable. If you can’t reconstruct what the agent did in the last 24 hours from durable storage, what you have is a long-running shell script that happens to call an LLM, not a long-running agent.

Treat compaction and context resets as first class. Anthropic is explicit that summarization-as-compaction wasn’t enough for very long jobs; they had to do full context resets where the harness tears the session down and rebuilds it from a structured handoff file. It is essentially how humans onboard a new engineer.

There are some real limitations right now

A few things are still genuinely unsolved.

Cost. A 24-hour run with a frontier model and a few tools is not cheap. Without budgets, circuit breakers, and a hard cap on tool spend, an agent can quietly burn through a week’s API budget in an afternoon. This is solvable, but it’s an explicit step you have to take.

Security. A long-running agent with API keys, cloud access, and the ability to run shell commands has a much larger attack surface than a chat session. The brain/hands separation pattern matters here too: Credentials should be unreachable from the sandbox where model-generated code runs, which is one of the benefits Anthropic calls out for Managed Agents.

Alignment drift. Over many context windows, agents drift. The original goal gets summarized, then resummarized, then loses fidelity. This is the part hooks and judges exist to defend against. It is also the most common reason “the agent went off and did something I didn’t ask for.”

Verification. Auditing 24 hours of autonomous activity is a real human-time problem. Observability and structured artifacts (PRs, commits, briefings, test runs) are how you make this tractable. Without them, you’re scrolling logs and you’ll miss what matters.

The human role. This is the one I keep coming back to. Defining work crisply enough that an agent can run for a day on it is harder than doing the work yourself. The skill that’s appreciating in value isn’t writing code. It’s writing specs that survive contact with an autonomous executor.

Where this is going

Google, Anthropic, and Cursor have converged on roughly the same shape. Separate the model loop from the execution sandbox from the durable session log. Split planning from generation from evaluation. Bake in compaction, hooks, and context resets. Expose memory as a managed service that any agent invocation can query.

Surface area is what differs. Google’s Agent Platform is the enterprise-stack version, with the identity and audit trail story baked in. The patterns underneath are the same. Claude Managed Agents is “Anthropic’s harness, hosted.” Cursor’s background agents are “long-running coding, pulled out of the IDE and into the cloud.”

The harder problems for the next year aren’t in any of those layers individually. They’re in the coordination above them. Many long-running agents on a shared codebase. Agents that read their own traces and patch their own harnesses. Harnesses that assemble tools and context just in time for a task instead of being preconfigured at startup. That’s where the agent stops looking like a smarter chat window and starts looking like a colleague who’s been on the project longer than you have.

The model is still load-bearing. But the gap between a chat window and an agent you can leave running overnight is mostly in the state, sessions, and structured handoffs wrapped around it. That’s where I’d spend my learning time right now.

The following article originally appeared on Paolo Perrone’s The AI Engineer Substack and is being reposted here with the author’s permission.

Your team picks LangGraph for a customer support chatbot. Three weeks in, you’ve got 14 nodes in a state graph, a custom checkpointer writing to Redis, and retry logic for tool calls that fail once a week. The agent answers refund questions. It calls one API. A 50-line script on the OpenAI SDK with two MCP servers would have done the same thing. But nobody mapped which layers the problem actually needed.

In November 2024, Letta published an AI agents stack diagram that became the default reference for half the engineering teams I talk to. If you’ve seen a “layers of an agent” visual on LinkedIn or pinned in a Slack channel, it probably traces back to that article.

That diagram is 14 months old now, and a lot has changed since. MCP didn’t exist yet. Memory was still treated as a subset of your vector database. Nobody was shipping provider-native agent SDKs. Eval wasn’t even on the map. The stack has six layers in 2026, and at least three of them didn’t exist as distinct categories when Letta drew the original.

So we drew it from scratch. This is the 2026 version.

TL;DR

That’s the starting stack. Add complexity when something specific breaks, not before.

What are we even mapping?

Before the stack, there was a loop. In “What Is an AI Agent?,” we defined an agent as the think-act-observe cycle: The model reasons about a task, takes an action (calls a tool, writes to memory), observes the result, and loops until the task is done. That loop is the atomic unit. Everything in this issue is infrastructure that makes that loop work reliably, at scale, in production.

The agent stack is not the LLM stack. A chatbot needs inference and maybe RAG. An agent needs state management across multistep execution, tool access governed by protocols, memory that persists across sessions, autonomous reasoning loops, and guardrails that constrain behavior in real time. That’s a fundamentally different set of infrastructure problems.

We’re mapping the six layers between your LLM and a production agent. We’re not covering training infrastructure, data pipelines, or model fine-tuning. Those are adjacent stacks. We covered RAG in depth in Issue #5. Today we’re zooming out to show where RAG fits in the bigger picture.

Three things redrew the map between 2024 and 2026. MCP standardized tool connectivity, and the entire tools layer is new because of it. Reasoning models changed what agents can do autonomously, with single-call agents replacing some multistep chains. And memory became a first-class architectural primitive, not an afterthought bolted onto a vector database.

How to evaluate each layer

When choosing tools at each layer, ask three questions. How much state do you need to manage? A stateless tool caller and a multi-session agent that learns over time are different engineering problems, and the layers where state management is hardest (memory, frameworks) are where most teams get stuck. How much vendor lock-in can you tolerate? MCP is an open standard, provider SDKs are not, and every tool choice either increases or decreases how painful your next migration will be. And how hard is it to go from demo to production? Some layers (model serving) have almost no gap, while others (eval, guardrails) have a massive one. The layer where you feel that gap most is the one to invest in first.

We take each layer from the bottom up, starting with the most stable and ending with the least mature.

Layer 1: Models and inference

How you run the model that powers your agent: call an API, use a managed open weight provider, or self-host.

The inference layer changed more in tone than in substance. Reasoning models like o1, o3, DeepSeek R1, and Claude with extended thinking shifted what agents can plan and execute. Agents that previously needed multistep chains can now solve problems in a single reasoning call. Open weight models like Llama 3.3, DeepSeek V3, and Qwen 2.5 closed the quality gap dramatically, so “always use the biggest closed model” is no longer default advice. The emerging pattern is to prototype on closed source and deploy on open weight.

The honest take: This layer is commoditizing. Model differences matter less each quarter. The real decision is the cost and latency trade-off, not which model is “smartest.”

On the evaluation side, API calls are stateless. Send a request, get a response. Nothing to manage. Lock-in risk runs high for closed APIs because each model reasons differently, so switching providers means retuning prompts, adjusting for different failure modes, and retesting your eval suite. It’s low for open weight, where you can swap the model and keep the infra. The prototype-to-production gap is the smallest of any layer. Your demo API call is the same as your production API call.

Self-host when your agent call volume makes API pricing untenable or when you need sub-100ms latency that API round-trips can’t deliver.

Layer 2: Protocols and tools

How your agent calls external tools and APIs: through MCP servers, browser automation, or agent-to-agent protocols.

This layer didn’t exist as a distinct category in 2024. Every framework had its own JSON schema for tool definitions. Now MCP is the standard, with 97M monthly SDK downloads, adoption by OpenAI, Google, and Microsoft, and a donation to the Linux Foundation.

Browser Use exploded in parallel, hitting 78K GitHub stars in under a year. Nobody was shipping browser agents in production in 2024. And agents can now talk to other agents. IBM launched ACP, and Google launched A2A. Neither is standard yet, but the problem they solve (agents coordinating with other agents) is real and growing.

Security is the open problem. Endor Labs analyzed 2,614 MCP servers and found 82% prone to path traversal and 67% to code injection.

The honest take: The protocol debate is over. MCP won. The only question left is how you lock down your MCP servers before someone exploits them.

State management is nonexistent here. Your agent calls a tool, gets a response, done. No session, no memory between calls. Lock-in risk is low because MCP is an open standard, so if you build MCP servers, any MCP-compatible agent can use them. The prototype-to-production gap is medium. Your demo MCP server works until someone sends a malicious tool description. Security and governance are the gap.

MCP standardized how agents use tools. It says nothing about how agents talk to each other. ACP and A2A are trying to solve that, but neither has reached critical mass. If you need multi-agent coordination today, you’re building it yourself at the framework layer. We covered MCP in depth in Issue #4.

Layer 3: Memory and knowledge

How your agent stores and retrieves what it knows: in-context state, vector search, or persistent memory across sessions.

All three tiers feed into the same place: The context window your agent sees on every call.

In 2024, memory meant “pick a vector database and do RAG.” In 2026, memory is a first-class architectural primitive with three distinct tiers. Context windows got massive. Gemini hit 1M+ tokens, Claude 200K. Bigger windows didn’t kill the need for memory. They changed the trade-off: What do you stuff in-context versus what do you retrieve on demand?

“Context engineering” replaced “prompt engineering” as the core discipline. Instead of writing a better prompt, you architect what information the agent sees on every call. Memory blocks appeared as named, structured fields in the context window that the agent can read and overwrite every turn. Instead of dumping everything into the system prompt, the agent manages its own state: what to keep, what to update, what to drop.

On the infrastructure side, pgvector became the default for teams that don’t need a dedicated vector database. It’s just Postgres with an extension. GraphRAG emerged as a second retrieval option: follow relationships between entities instead of matching embeddings, with Neo4j leading this space. Sleep-time compute, where agents process information during idle time, is research stage but signals where tier 3 is heading.

The honest take: Most teams overcomplicate memory. Start with conversation history in Postgres and a structured system prompt. Add vector search when your history exceeds context limits. Add agentic memory management only when your agent needs to learn across sessions.

This IS the state layer. You’re deciding what your agent remembers, how it retrieves it, and when it forgets. Highest complexity in the stack. Lock-in risk is medium. pgvector is portable because it’s just Postgres, while specialized tools like Mem0 or Zep are harder to migrate away from. The prototype-to-production gap is large. Demo memory works because context windows are big enough. Production memory breaks when conversations get long and your agent starts forgetting the important parts.

In-context memory breaks down when agents need to share memory across instances or maintain state across model provider switches. That’s where dedicated memory infrastructure like Letta, Zep, and Mem0 earns its keep.

Layer 4: Frameworks and SDKs

How you wire together the model calls, tool use, and control flow that make your agent work: a provider’s built-in toolkit (SDK), a graph-based framework like LangGraph, or raw code.

Every major AI lab now ships its own agent SDK. OpenAI has the Agents SDK (evolved from Swarm). Google released ADK. Microsoft has Semantic Kernel and AutoGen. Hugging Face built smolagents. Two years ago, LangChain was the only game. Now you pick between three camps: provider SDKs that are fast to start but locked to one model, graph-based frameworks like LangGraph that are portable but require more setup, or no framework at all. That choice didn’t exist in 2024.

LangGraph solidified as the graph-based orchestration leader with v1.0 released October 2025 and production deployments at Uber, JPMorgan, LinkedIn, and Klarna. LangChain agents are now built on LangGraph under the hood. Meanwhile, the “build it yourself” camp grew. Teams that tried LangChain in 2024 and fought the abstraction are now writing thin wrappers over provider APIs + MCP. No framework means full control. This works until your agent needs state management or complex branching.

A quick note on naming: “LangChain” and “LangGraph” are not the same thing. LangChain is the integration layer handling model connectors, tool calling, and prompt templates. LangGraph is the orchestration engine managing state, control flow, and graphs. Most production teams use both together, but LangGraph is where the agent logic lives.

The honest take: Most teams pick too much framework. If your agent calls a model and a few tools, you don’t need LangGraph. A provider SDK and a couple of tool calls will get you to production faster than any graph.

Provider SDKs manage state for you. LangGraph makes you define every state transition explicitly. Build-it-yourself means you roll your own. Lock-in risk is the highest in the stack. Your orchestration code doesn’t port. A LangGraph agent rewritten for CrewAI is a new codebase. Provider SDKs are worse because you’re locked to one model too. The prototype-to-production gap is large. Demo works because nothing goes wrong. Production means handling tool failures, retries, timeouts, and humans who need to approve before the agent acts.

The framework you pick determines your migration cost. Provider SDKs are fastest to start but lock you to one model. LangGraph is portable but complex. Building your own gives you full control until your agent outgrows your wrapper. MCP is the one layer that transfers across all three camps.

Layer 5: Eval and observability

How you measure whether your agent is doing its job: tracing runs, scoring outputs, and catching regressions before users do.

This layer barely existed in 2024. Now it’s the gap. LangChain’s State of Agent Engineering survey found 89% of teams with production agents have implemented observability, but only 52% have evals. That 37-point gap is where production quality dies.

“Evaluation as infrastructure” is converging on three tiers: fast checks on every PR (Did the agent call the right tools?), nightly regression suites that use an LLM to judge output quality, and continuous production monitoring that alerts when agent performance drifts. New agent-specific benchmarks have emerged too, including Context-Bench for memory management, Recovery-Bench for error recovery, and Terminal-Bench for coding agents.

The honest take: Most teams skip eval until something breaks in production. By then they’re debugging blind. The teams that don’t have this problem built evals before they deployed.

State management matters here because your agent runs 12 steps, step 3 picked the wrong tool, and steps 4–12 were doomed from there. If your eval only checks the final output, you’ll never know why. Lock-in risk is moderate. Most tools export OpenTelemetry traces, so switching observability providers is doable, but switching eval frameworks means rebuilding your test suites. The prototype-to-production gap is the biggest of any layer. Most prototypes have zero eval. You don’t feel the pain until production users find the failures for you.

Current eval tools are strongest for single-turn and tool-calling evaluation. Multi-agent evaluation, long-horizon task assessment, and evaluating agents that learn over time are all unsolved problems. If your agent does any of those, you’ll need custom eval infrastructure beyond what the platforms offer today.

Layer 6: Guardrails and safety

How you stop your agent from doing things it shouldn’t: filtering inputs, authorizing tool calls, and validating outputs.

Agent guardrails became a separate discipline from LLM guardrails. In 2024, guardrails meant input/output filters on a model. In 2026, your agent calls tools, spends money, and takes actions. Guardrails now means authorizing tool calls, enforcing rate limits, and validating what the agent actually did.

The “guardrails before action” pattern emerged from teams that learned the hard way. They now enforce authorization at the tool execution layer, not the output layer. By the time you filter the response, the agent already sent the email. OWASP published the MCP Top 10 (beta), which is the first real security checklist for tool-connected agents. Deployment is still DIY. LangGraph Cloud and Bedrock Agents exist, but most production teams are still deploying with FastAPI and their own infra. This layer is where you’ll spend the most unplanned engineering time.

The honest take: This is the least mature layer in the stack. No dominant framework, no established patterns. You’re writing policy code from scratch.

Guardrails need to know what the agent is doing right now to decide what it shouldn’t do next. That means tracking agent state in real time. Lock-in risk is low because most guardrails are custom policy code you write yourself. NeMo Guardrails is the closest thing to a framework, but you’ll still write most rules from scratch. The prototype-to-production gap is effectively infinite. Your demo has no guardrails because nobody’s trying to break it. Production will.

Current guardrails tools focus on single-agent systems. If you’re running multi-agent workflows where agents delegate to each other, guardrail propagation across agent boundaries is an unsolved problem. You’ll need custom authorization logic.

What are you building?

This is the decision that cuts through the framework confusion. The agent type determines which layers you invest in and which tools to pick at each one.

A stateless tool caller answers questions from a knowledge base, looks up an order, or checks inventory. You need a provider SDK, MCP, and Postgres. No framework, no vector database. This is a weekend project.

A multistep workflow processes a refund end to end, reviews a PR across five files, or triages and routes support tickets. Steps depend on each other, things fail in the middle, and humans need to approve before the agent acts. You need LangGraph, MCP, and eval. Build evals before you deploy because these agents break silently.

An agent that learns remembers your preferences across sessions, gets better at your codebase over time, or tracks project context across weeks. You need a memory-first architecture, a vector DB, and eval. Orchestration is the easy part. The hard part is deciding what to remember, what gets dropped, and how you stop old context from polluting new answers.

A multi-agent system has agents that delegate to other agents, split a research task across specialists, or run parallel workstreams. You need the full stack. Two agents passing context to each other is already hard to debug. Five is impossible without trace-level evals on every handoff. Build eval infrastructure before you build the second agent.

Coding agents: All 6 layers in action

Coding agents like Cursor, Claude Code, Codex, and Windsurf are the most proven application of the AI agents stack. All six layers, working together.

At the inference layer, these tools serve hundreds of millions of daily requests. Cursor routes between Claude, GPT-4, and its own fine-tuned models depending on the task. At the protocols layer, MCP servers connect to editors, terminals, filesystems, and Git, which is how the agent reads your code and runs commands. The memory layer uses codebase-aware retrieval with reranking. The agent doesn’t read your whole repo. It retrieves the files that matter for this specific edit.

At the framework layer, these are custom orchestration systems with RL loops. Not LangGraph, not a provider SDK. Purpose-built control flow for code generation, review, and iteration. At the eval layer, Cursor retrains its acceptance-rate model every 90 minutes based on whether users accept or reject suggestions. That’s eval running in production, continuously. And at the guardrails layer, sandboxed execution prevents runaway agents. The agent can write code and run it, but inside a container that limits what it can touch.

The AI agent stack cheat sheet

Every layer scored on the three questions from the evaluation framework: How much state do you need to manage? How much vendor lock-in can you tolerate? And how hard is it to go from demo to production?

The bigger picture

Most teams are building like it’s still 2024. They pick LangGraph before they know if they need state. They add a vector database before they’ve outgrown Postgres. They design multi-agent architectures before they’ve shipped one agent that works. The decision flowchart above exists because a tool-calling chatbot and a multi-agent research system share almost no infrastructure. Treat them the same and you’ll overbuild the first and underbuild the second.

The teams that got past this run evals on every deploy, not once a quarter. Their guardrails sit at the tool call layer, not the output layer. Their memory architecture was designed, not inherited from whatever the framework defaulted to. Most teams ship the opposite: no evals, output-only filtering, and a system prompt that grows until the context window chokes. The gap isn’t talent or budget. It’s knowing which layers matter for your specific agent instead of half-building all six.

The stack is going to collapse. Provider SDKs are already absorbing memory, tool calling, and basic eval into a single API. By early 2027, most teams won’t build each layer separately. They’ll get an increasingly opinionated stack from their model provider and that will be fine for 80% of use cases. The other 20%, agents at scale where the defaults break, will still build custom at every layer. But even then, when something fails in production, you need to know which layer failed. That’s what this article is for.

Sources

1. “The AI Agents Stack,” Letta, November 2024.
2. “Donating the Model Context Protocol and Establishing the Agentic AI Foundation,” Anthropic, December 2025.
3. “120+ Agentic AI Tools Mapped Across 11 Categories [2026],” StackOne, February 2026.
4. Henrik Plate and Darren Meyer, Dependency Management Report, Endor Labs, January 2026.
5. Jason Liu, Context Engineering Series: Building Better Agentic RAG Systems, August 2025.
6. “LangChain and LangGraph Agent Frameworks Reach v1.0 Milestones,” LangChain, October 2025.
7. State of Agent Engineering, LangChain, December 2025.
8. Yunfei Bai, Allie Colin, Kashif Imran, and Winnie Xiong, “Evaluating AI Agents: Real-World Lessons from Building Agentic Systems at Amazon,” Amazon, February 2026.
9. OWASP MCP Top 10, OWASP.

On this week’s episode, host and the founder of AI advisory firm Intelligence Briefing Andreas Welsch brought together Maya Mikhailov, cofounder and CEO of Savvi AI, and Doug Shannon, generative AI and intelligent automation leader, to cover a handful of interconnected topics that practitioners are navigating right now: OpenAI’s push into personal finance, the role of metacognition in AI-assisted technical work, the growing backlash against token-based productivity metrics, and the new role of forward-deployed engineer. Together, these stories sketch a picture of an industry that’s good at generating output but is still figuring out what output is worth.

Why OpenAI wants your bank account data

When OpenAI announced it was analyzing users’ transaction data in partnership with financial institutions, the coverage focused on the consumer benefit: a smarter way to track spending, comparable to what Credit Karma or Mint offered but with a more conversational interface.

But that’s not all the company’s interested in, or even the main thing. Maya reframed the stakes: “What OpenAI wants to do is figure out consumer intent.” Being able to access users’ financial data is less about helping people manage their money and more about completing a profile the company can then monetize. OpenAI already builds a surprisingly accurate picture of users from their chat histories. Add transaction data and you get specifics that weren’t there before: what someone is saving for, what they’re anxious about, where their money is actually going. That’s a data asset worth a great deal to advertisers.

We’ve seen this pattern before, and as Andreas noted, companies have long held (and used) potentially invasive data to recommend products. The Target pregnancy prediction story is now more than a decade old, but it’s still being taught in business school, including by Andreas, precisely because it illustrates how behavioral data can be combined to infer things people haven’t explicitly disclosed—and spotlights the fine line between effective recommendations and those that feel too personalized, reminding consumers just how much information companies have on them. Companies’ profile-building capability hasn’t changed, but AI chat adds a new wrinkle, said Maya. A conversational interface makes disclosure feel natural, so the knowledge graph based on your chat history is very powerful. And these tools are also better positioned to share recommendations than traditional avenues. “By having this style that is agreeable, that is engaging,” Maya explained, “those recommendations are going to be a lot stickier than what a fragment of a sentence I type into a regular search engine.”

Metacognition as a professional skill

When you delegate thinking to a system that averages across a massive range of inputs to produce an answer, you need to know when that answer is good enough and when it isn’t.

“We’re essentially being averaged out,” Doug said. The model is doing many things behind the scenes to find a mean response. The human’s job is to ask questions about the questions, to push past the first answer, and to know whether their own judgment is still in the loop. That’s why Doug’s been pushing for a renewed interest in metacognition, or “thinking about thinking.” Offloading cognitive load that’s peripheral to your work is fine, Doug and Maya agreed. Offloading the reasoning that’s central to your job’s value—what Doug called cognitive surrender—is where organizations get into trouble.

The future advantage won’t come from access to AI. Everyone will have some kind of access to it. The advantage will come from knowing what to offload, what to question, and what should never leave human judgment. This is a skill-development question as much as a philosophical one. The people who’ll be most effective with AI tools aren’t the ones who use them most; they’re the ones who understand what to hand off and what to keep. That requires domain knowledge, judgment about when a model’s answer is plausible but wrong, and enough fluency with how these systems work to recognize when you’re being handed an average instead of an answer.

Tokenmaxxing and the wrong incentive

The tokenmaxxing debate seems to be coming to a head. Amazon abolished its AI productivity leaderboard after employees started gaming it by writing inefficient code to rack up token usage. And one company reportedly burned through $500M in Anthropic tokens in a single month after failing to set limits. The companies encouraging tokenmaxxing are incentivizing the wrong metrics, Maya argued. It’s like determining which bakery is best by the amount of flour it uses. The right question is “Are we making a quality product?”

Andreas shared his own vibe coding experience as an example of how token consumption and technical debt compound in practice. A developer starts with a modest plan and burns through their quota running agents in half an hour. They upgrade to a higher tier, paying five times more, but now the sunk-cost logic kicks in. As Andreas pointed out, now they feel like they “should also be getting five times more the value out of [their subscription],” so scope expands from a single tool into a unified business operating system. Three weeks later, the accumulated complexity has outpaced the ability to evaluate it: Repeated security audits keep surfacing new issues, each pass generating recommendations that require cybersecurity expertise most vibe coders don’t have. Here’s where Doug’s point about metacognition applies: The more a builder stays actively involved in understanding what the system is actually doing, the better their judgment about whether it is working. For less engaged users, the risk is accepting the output, shipping the debt, and discovering the consequences later.

Most of the misalignment originates in the gap between what executives expect from AI and what practitioners deal with day-to-day. Executives see a capability that could change the slope of productivity, Maya explained. Engineers and analysts live with the technical debt, the version control problems, and the regulatory constraints that don’t disappear because you have a better code completion tool. The leaderboard problem is a symptom of that disconnect.

GitHub’s recent shift from unlimited to usage-based pricing for Copilot is likely to realign these incentives faster than any internal policy change would. When more CFOs start seeing the actual bills, the leaderboards will all come down.

Doug identified a related problem emerging with the “cognitive surrender” to LLMs. When organizations encourage employees to pipe internal processes, proprietary logic, and institutional knowledge into foundation models without governance, they’re not just running up token bills. They’re giving away the operational knowledge that differentiates them. Process documentation, workflow logic, and institutional memory about why certain decisions were made are all forms of intellectual property, and once they’re encoded into a general-purpose model, the organization’s advantage from them diminishes.

Forward-deployed engineers aren’t enough on their own

Is the answer to these challenges to put a skilled engineer directly inside the customer environment to translate between what a model produces and what an organization actually needs? That’s the promise of the forward-deployed engineer (FDE) approach popularized by AI firms. Doug and Maya both had some criticisms of the model.

Maya’s objection was structural. Enterprise AI deployment isn’t a matter of adding capability on top of existing infrastructure. Organizations arrive with siloed data, legacy systems, and regulatory constraints that no forward-deployed engineer can resolve on technical skill alone. You can’t “just sprinkle some AI on it, and it’ll work just by a package of tokens,” she said. Engineers have to know the context behind why certain data can’t be used or why a particular model can’t be deployed in a regulated context. FDEs coming into an organization fresh don’t have this understanding and as a result may undo decisions that were made carefully and for reasons that aren’t written down anywhere obvious.

Doug’s concern was about communication. FDEs, in his experience, tend to arrive with strong technical instincts and limited organizational context. They get into the work quickly but struggle to communicate across the full stack of stakeholders involved. That’s why business analysts exist, to understand the customers’ problems and what the process actually is before engineers can address them. Skip that step and you get technically correct output that solves the wrong problem.

What both Maya and Doug were underscoring is that AI deployment at the enterprise level is fundamentally a context problem. The models are capable. What’s hard is knowing which capability to apply, where to do it, and with what constraints in place. That knowledge doesn’t live in the model; it lives in the people who’ve worked inside the organization long enough to know why things are the way they are.

The measurement problem

All the topics in this episode circle back to the same question: What are we actually measuring, and what incentives are we setting in place with those measurements? Token counts and lines of code don’t always correlate to the outcomes companies want. You need human expertise and a contextual knowledge of the business to figure out what goals you want to achieve and what to measure to ensure you get there.

On next Monday’s episode of This Week in AI, RecoMind founder Miguel Fierro joins host Christina Stathopoulos to discuss responsible AI, multimodal content creation, and more on how LLMs are changing personalization and user understanding. Miguel will also lead a live demo that offers a glimpse of the next generation of recommendation experiences—register here.

We’ll continue to publish our takeaways here on Radar each Friday and share full episodes on YouTube, Spotify, Apple, or wherever you get your podcasts.

I set up an AI agent on a rented GPU, pointed it at a training script, and went to bed. By morning it had run 40 experiments, improved validation loss by 5.9%, and cut memory usage from 44 GB to 17 GB. It also spent four hours chasing a bug that a linter introduced behind its back. The agent never flagged it. I only found out because the numbers stopped improving and I started reading logs.

The setup was based on Andrej Karpathy’s autoresearch project: Give an agent one file it can edit (train.py), one metric to optimize (validation bits per byte), a fixed five-minute training budget per experiment, and Git for checkpointing. If an experiment beats the current best, keep the commit. If not, revert. Loop forever. Karpathy’s own run produced 700 experiments and 20 genuine improvements across 48 hours, an 11% speedup on already-optimized code. Shopify’s Tobi Lütke pointed the same pattern at Liquid, their templating engine, and got 53% faster rendering from 93 automated commits. The pattern clearly works. The question is what breaks when you run it yourself.

The first failure: Agents fixing agents

Before running autoresearch, I had a separate problem. I had 15 custom skills for Claude Code (think reusable prompt templates with tool access, structured inputs, and specific behaviors). Most of them were broken when dispatched as parallel background agents. Vague descriptions meant the system couldn’t figure out when to invoke them. Missing tool permissions caused silent failures. Duplicate scopes between similar skills created routing confusion.

So I used the same pattern: dispatch background agents in parallel, one per skill, each tasked with reading the skill definition, identifying problems, and rewriting it. 13 out of 15 came back improved. Descriptions got specific. Dead references to nonexistent files were removed. Tool permissions were added. Two skills were left untouched because the agents couldn’t find anything wrong with them. The whole batch took under an hour.

But here’s what I didn’t expect. Three of the “improved” skills had subtle regressions. One agent removed an AskUserQuestion gate that was there for a reason, because the gate’s purpose wasn’t documented and the agent read it as unnecessary friction. Another agent rewrote a skill description so precisely that it stopped triggering on the fuzzy, misspelled queries real users actually type. I caught these during manual review, but if I had trusted the parallel output without checking, three skills would have silently degraded in production.

The second failure: The linter in the loop

Then I started the training loop. The agent worked through hyperparameters methodically. It halved the batch size early (experiment 4), which turned out to be the single biggest win: more gradient steps in the same five-minute window. It reduced model depth from eight to seven layers, dropped weight decay from 0.2 to 0.05, and tuned the learning rate schedule. Each change was small. The cumulative effect was a 5.9% improvement in validation loss and a 60% reduction in peak GPU memory.

Out of 40 experiments, the agent kept nine, discarded 28, and crashed three. That keep/discard ratio felt about right. Most ideas don’t work. The point of automation isn’t to have better ideas. It’s to try bad ones faster.

Then the numbers plateaued. Experiments 30 through 38 produced nothing worth keeping. I started digging through the logs and found something I hadn’t expected: A linter running on the remote machine had been silently modifying a hyperparameter in train.py. It changed SCALAR_LR from 0.5 to 0.3 every time the agent saved the file. The agent would set the value, commit, and run the experiment, but the linter would alter the file between the save and the execution. The agent had no way to detect this because it checked Git diffs, not the runtime state of the file. Every experiment after a certain point was running with a learning rate the agent never chose.

I lost roughly four hours of compute to this. The agent kept going, proposing new ideas, running experiments, logging results. From its perspective nothing was wrong. The experiments ran, produced numbers, and the numbers were plausible. There was no crash, no error, no alert.

Why this matters beyond my GPU bill

Gartner predicts over 40% of agentic AI projects will be canceled by the end of 2027, citing escalating costs and inadequate risk controls as the primary drivers. My overnight session was a toy example: a single GPU, a small model, and a low-stakes experiment. But the failure pattern scales. An agent that can’t detect when its inputs are being modified between decisions will make the same class of error whether it’s tuning hyperparameters or managing a production pipeline.

The autoresearch constraints are smart: one file, one metric, and Git for state. But they assume the environment is stable. Nobody checks whether something outside the loop is modifying the file between commits. The agent optimizes within its sandbox, and the sandbox has a hole in the wall that nobody thought to look for.

Anyone who has run distributed systems recognizes this. When the linter changed that hyperparameter, it was the equivalent of someone editing a database record between a read and a write. We solved that problem years ago with compare-and-swap, optimistic locking, checksums. We just haven’t brought any of it to autonomous AI workflows. The SkyPilot team recently scaled autoresearch to 16 GPUs and 910 experiments. At that scale, an undetected environment mutation doesn’t cost you four hours. It costs you a cluster.

Next time I run autoresearch, I’ll add a file integrity check before every experiment. It’s three lines of code, but it would have saved me four hours and produced a better final result. The agent did its job. The environment didn’t.

DJ Patil has spent the past several months on a listening tour. Wherever he travels, he finds a local university, pings faculty and students and anyone else who wants to show up, and runs an AMA. He’s heard from grad students who can’t get callbacks, hospital administrators dealing with federal policy changes that land like a change in the laws of physics, and executives who can’t forecast their AI spending past six months. He’s trying to synthesize all of it and help reframe the wider conversation.

DJ co-coined the term “data scientist,” served as America’s first chief data scientist under President Obama, and was chief scientist at LinkedIn. He’s a longtime O’Reilly author, going back to Building Data Science Teams and Ethics and Data Science, and he’s on the founding team at Devoted Health, where he’s spent the past decade building the kind of data infrastructure most organizations are still struggling to put in place. He calls it “the tidy house.” He sat down with me to talk about “the broken promise” in the job market that is driving AI sentiment, and why weak data infrastructure is a big part of the gap between what AI can do and what most institutions can actually absorb.

The broken promise

What DJ keeps hearing on his tour is anger and angst. One word that keeps coming up is “terrified.” Workers are worried about layoffs. Meanwhile, students, including those from top-tier universities like MIT, Carnegie Mellon, and UC Berkeley, have been applying to 300+ internships and getting fewer than 10 callbacks. Many had zero offers going into the summer. And the industry’s response has been to tell them to learn more AI and burn more tokens. What it comes down to, DJ explained, is “effectively a broken promise”:

We said, “Go to college, get these things, you’re going to get an internship, you’re going to get job training, you’re going to pay off your student loans, and then you’re going to have all the other things that are part of that social contract.”

What the students are feeling for the first time [is]. . .“Wait, if I can’t get this internship, . . .I’m fundamentally off trajectory from getting this job.” And it doesn’t have to be a technical person. It could be someone that is in marketing. It could be someone that’s in the liberal arts. It could be a researcher. . . .There are plenty of students that I have talked to who are supposed to be going to a doctoral PhD program or a medical school or something like that. The slots aren’t there because of the overall budget impacts. And so whether you call it AI impact or economic reframing, the thing is broken.

This is where both DJ and I have been trying to build a counter narrative. The story coming from the AI labs is destructive: “We’re going to put all of you out of work, and we’ll figure out the rest once the intelligence explosion arrives.” That’s bad PR for AI, but it’s also magical thinking. An economy is a circulatory system. You can’t put your customers out of work and at the same time expect that the economy will hum along as usual. A catastrophic recession could easily interrupt the funding that keeps AI on its growth path and the concentration of value that they assume will fund universal basic income and an expanded safety net.

That’s why I’m a fan of mechanism design: start from the outcome you want, then figure out the rules of the game that produces it. Right now, they’ve designed a game that concentrates all the value in the hands of AI first movers. They could be designing a game that generates value throughout the economy. But they aren’t building affordances for that.

YouTube ContentID is a good example of mechanism design leading to economic value creation. When unauthorized music use by online video creators triggered a backlash from rights holders, YouTube replied to the takedown notices with a way for both the people who owned the music and the people who wanted to use it to get paid. A whole creator economy came out of that design choice. The labs have the same opportunity in front of them and mostly aren’t taking it.

DJ had one concrete mechanism in mind:

Imagine OpenAI and Anthropic and Microsoft. . .get together and [say], “If you’re building something for your local community, we’ll fully subsidize the token cost for some period of time.”. . .We’re talking about marginal token usage relatively on the spectrum of things, but the potential innovation and use of AI to help local communities could be astounding. You’re not putting anybody out of a job with that. . . .You’re filling the holes that already exist in the system.

The OpenAI Foundation just announced it will put $1 billion into public-benefit projects this year, including $250 million aimed at building economic futures. It’s a start. But it mostly seems designed to ameliorate the bad effects of AI rather than to forestall them by building a more inclusive AI future. If the labs start investing in the human-plus-AI economy rather than just studying the job losses, the payoff to local communities could be real.

A makerspace to bridge the internship gap

DJ’s plan is to build a bridge. He’s launching a program, basically a makerspace, for students who don’t have an internship this summer. Over two four-week sprints, an initial cohort will get mentors, speakers, and the space to explore whatever they’re interested in. It doesn’t have to be AI. Whether they’re doing investigative journalism, screenwriting, or building civic tech, participants will get some experience with current tools and produce a tangible asset they can use to prove what they know. As I told DJ in our conversation, I think he’s really on to something, and I’d love O’Reilly to be part of what he’s building.

There’s a kind of person who has always been at the center of the O’Reilly community and never waited for a job description. High school and college dropouts who started companies, built open source software packages, or otherwise took the future into their own hands. People who looked around, found something that needed doing, and did it. DJ is one of them. He’s a community college kid who learned from a good local library, from the books with the “funny animals” on the cover, and from open source. That path is still open. The early O’Reilly business came out of exactly this instinct. We were a tech-writing consulting shop, and when we ran out of paid work, we wrote manuals that didn’t exist yet but that we thought were needed. Later, when there were big conferences for every corporate technology and none for open source, we ran the first one for Perl. Conferences became a whole new business for us. You look for the gap and you fill it.

DJ pushes the same idea down to the level of the neighborhood:

If you want to feel rewarded, go fix something in your neighborhood. Go help out the food pantry. Go help out the local foster child care system. Go help out. . .parks and rec. Use those skills to go do something, and then you’re going to see. . .people respond in a different way. . . .The target-rich area for problems is massive. You just have to look.

I’ve never bought the jobless-future story. Back when I wrote WTF? in 2016, I pointed out that there is so much around us that needs to be made better. The constraint has never been a shortage of problems. AI gives us new tools for solving them. It should be a way to put people to work, not out of work.

The organization is the AI bottleneck

DJ has also been visiting hospitals and clinics and talking to CIOs and CTOs as part of the tour, and what he’s seeing is alarming.

The federal changes to Medicaid and the Affordable Care Act are landing on systems that were already near collapse. Hospitals that depended on outpatient procedures like colonoscopies for margin are watching volumes drop 20% to 30% because people can’t afford insurance. Some are running $1 million a day behind, a $300 to $400 million shortfall for the year.

At the same time, AI companies are telling those same hospitals to move into the new world, and partly because of the “you will soon be replaced” narrative from the AI labs, labor is responding the way the Kaiser nurses did in California, where any use of AI was off the table as a bargaining condition. As DJ pointed out, we can’t afford to disregard AI when it has the potential to automate the most painful parts of healthcare workers’ jobs and let them “do the job they’re trained for” without the administrative burden. Businesses need to change not just their narrative but their strategy. They need to be saying, “We’re going to use AI to help you do more for our customers. We’re going to make your job more human and let the machines deal with the BS.”

There’s a version of this where the efficiencies AI creates get plowed back into better patient care. There’s also the version that’s actually happening in most places, where private equity captures the savings as profit. The difference is institutional design, and that’s where reform isn’t happening. I saw this directly with a Code for America project called Clear My Record. A California initiative had turned a number of petty crimes into misdemeanors, but very few people were petitioning to have their status changed. We started using software to streamline an absurdly convoluted criminal record expungement process, but then we asked ourselves why we were helping people fill out forms that shouldn’t exist. The law had already changed the record. The process should have been a database update, not something that required a petition to the court. That’s the kind of problem AI was born to solve. It can help us refactor old stuck processes and move to something way better.

Done right, DOGE could have been an opportunity to carry out that kind of real institutional change at scale. Instead it became a wrecking ball, and it’s given the whole idea of institutional reform a bad name.

The Silicon Valley default assumes that incumbents will just get disrupted by startups, the way media was by Google and Meta and retail was by Amazon. There’s some truth to that. But disruption takes much longer than people think, and in a domain as central as healthcare or government services, the delay means real harm to real people. Healthcare is a third of the economy. You can’t just let it fail and rebuild it fresh while people depend on it for survival.

Data infrastructure is the competitive advantage

DJ’s term for the alternative he’s living with at Devoted is “the tidy house.” He built the boring infrastructure years before LLMs existed, and that’s why the company could move the moment AI arrived. People don’t think about having well organized, effective data infrastructure as the deep secret behind enterprise AI adoption, but DJ is right. As we work on O’Reilly’s own transformation and talk with our customers about what’s holding them back, it’s a huge part of the problem.

One of the ways we’ve tried to make this work is fundamentally still data 101, unified data environments, data flows that are clean, that have a lot of organization. . . .Because we invested so heavily in that infrastructure, the dumb, boring, painful parts of making sure you’ve got a really great data warehouse, great data engineering pipes, all of the metadata that goes with it, when AI shows up, you get to use it right away. Now you get to focus on the orchestration, the harness, all those pieces.

While other organizations are reconstructing ETL inside context windows and paying for it in GPU costs, Devoted’s team gets to work on the actual clinical problems. As DJ put it, transforming a healthcare system is “like walking and chewing gum while balancing bowling balls on your head and on a unicycle,” with the laws of physics changing on you the whole time. The organizations that come through it will be the ones that did the unglamorous work of keeping clean, flowing data with its lineage and metadata intact. The ones that didn’t will keep paying to reconstruct context they should have had all along.

The pharmacists who built their own agents

The tidy house pays off when you put the tools in the hands of people who already know the domain. At Devoted, clinicians are building things without waiting for a product manager to learn the problem first. These frontline workers have already spent decades understanding it.

A pharmacist. . .says, “Hey, you know what? I’m really worried when I see these kinds of drugs show up together. That’s not a good thing. . . .Why don’t I have an agent that alerts me every time this happens? I should just automate it because maybe one of the patients gets prescribed something by another provider and we don’t see it.” So the pharmacist [says,]. . .”I’m just going to build that agent.” Now I’ve got an agent always looking for bad drug interactions. And another pharmacist says, “I’ve got my own version of that.” . . .So I say, “Hey, agent, I want you to go ask all the pharmacists that we have a quick survey of what might be happening. . . .What are the universe of things that we should be watching out for?” Now I’ve got a robust medical layer. . .looking out and protecting all of our members from bad drug interactions. Having the right infrastructure makes it possible to act on decades of accumulated judgment distributed throughout the organization.

The histogram is still the most powerful product

You don’t need exotic tooling to get value out of data, and DJ punctured the assumption that you do.

Oftentimes, I tell people, the most powerful data product you can build is still a histogram. Just give me a distribution of what’s going on. . . .AI gives us a tremendous opportunity to let people [access this data quickly], but we’ve got to figure out the guardrails, so people don’t ask [questions] or get answers. . .[without realizing] that there’s a flaw in how they’re asking it.

Every time a new technology empowers employees to make innovative use of corporate data, there is resistance. We’ve been in this loop since the beginning of the data movement, DJ explained. The stewards of the data warehouse stand at the gate and say, “You shall not pass!” Then democratization breaks it open, and the gatekeepers reconstitute themselves in the next era. Hadoop did it last time. LLMs are doing it now, and the temptation to insist that only experts can use the tools correctly is as strong as it’s ever been. You do need ways to catch errors. But the goal should always be access.

The real opportunity is in the layers above AI models

DJ and I also talked about the new discipline forming inside computer science, engineering the trade-offs between conventional software and LLMs, when to reach for a local or open weight model, and understanding what inference actually costs against the value it returns.

Getting that right requires an expanded view of mechanism design. While this isn’t how economists talk about it, many advances in technology are really just that: redesigning the rules of a game to get better outcomes. Pay-per-click advertising started as a crude auction that sold to the highest bidder, and then Google refined it into something that worked. Rob McCool wired a web server to a database with CGI and ushered in a decade of invention of new mechanisms for data-driven websites. Or take Apache Kafka, which DJ reminded us began as a project to help LinkedIn rein in its Splunk bill and only later became the foundation for a company and an ecosystem.

We’re at the front of an architectural innovation cycle now, and the biggest opportunities are not in the models themselves but in the layers above them. That’s also where a renaissance of open source for the AI era could happen.

DJ and I are both, as he says, “this giant human LLM, summarizing and distilling all the things we’re hearing” from a lot of people. What we’re hearing is that the technology is mostly ready, but our institutions are not. What’s lagging is the organizational and economic infrastructure that lets universities, hospitals, data teams, and the labs themselves actually deploy what’s been built.

It’s time to get busy!

On June 10, Harper Reed, cofounder of 2389 Research, will join me to talk about why the future of software depends on creativity, serendipity, and building weird stuff. And on July 9, Trail of Bits cofounder and CEO Dan Guido will stop by to share his playbook for going AI native. You can register to attend them live here. You can also follow Live with Tim O’Reilly on YouTube, Spotify, Apple, or wherever you get your podcasts.

A third of the way into a security-operations guide that Anthropic published in April 2026, wedged between a recommendation to patch CISA’s Known Exploited Vulnerabilities list and a suggestion to automate your deployment pipeline is a small recommendation: “Use EPSS to prioritize the rest.” For anyone who has worked on a vulnerability backlog in the last decade, the sentence is an acknowledgment of a widely felt but often unspoken fact about security programs: They have become machine-scale problems of signal to noise.

EPSS (Exploit Prediction Scoring System) is a statistical model that takes a known software flaw, runs it through a set of signals about what attackers are actually doing across the internet, and returns a probability that the flaw will be exploited in the next 30 days. It isn’t an LLM, and it does no reasoning or prompt engineering. It predicts. The company endorsing it is the same company whose newest model can surface thousands of novel, exploitable vulnerabilities in production software, many of them two or three decades old, most of them still unpatched.

As far as we can tell, this is the first time a frontier AI lab has publicly endorsed a purpose-built predictive model as the right tool for a defensive problem. LLM labs usually recommend LLMs. That Anthropic did not is worth noting, but the recommendation itself isn’t news to the practitioners it’s aimed at. It’s a description of what they’ve been doing.

The quiet consensus

The volume problem isn’t new. Anyone running a scanner against a large enterprise estate in 2015 was already generating hundreds of thousands of findings per month. Anyone running one against a cloud environment in 2020 was generating millions. Enterprises have spent the better part of a decade staring at dashboards where the number of open critical findings was larger than the capacity of the team supposed to fix them. In other words, cybersecurity has become machine scale.

Risk-based vulnerability management, as a product category, has existed since around 2018. EPSS, as a public resource, has been usable since 2021. More than 120 vendors embed it today into their products. The field has had access to a predictive baseline for years.

What has been missing is an external justification to change the status quo recommendations from auditors, model risk management teams, and even boards. Auditors want a clear set of expectations, making grading more objective and therefore easier to evaluate. Compliance frameworks like CVSS (Common Vulnerability Scoring System) because CVSS is easy, but implementing something more efficient has historically required that aforementioned external push. A working CISO could tell you she had stopped treating every vulnerability scored a severity 9.8/10 by CVSS as an emergency in 2019, but she would also tell you she still kept CVSS in the report.

Anthropic’s guidance is useful because it makes the private consensus public. Patch what you know to be exploited, then use EPSS above a threshold based on the team’s capacity or risk tolerance. DHS CISA’s practice of publishing known exploited vulnerabilities since November of 2021 is just additional proof that the existing methodologies were being overwhelmed by scale and lack of signal.

Why prediction, stated plainly

In 2014, at Black Hat, Dan Geer, then the chief information security officer of In-Q-Tel, asked the first principles question: Are vulnerabilities in software sparse or dense? Sparse meant finite, meaning every fix measurably shrank the attack surface. Dense meant weeds in a field. Geer could not answer the question because the data were not in.

Eight years later, Jonathan Spring at Carnegie Mellon’s Software Engineering Institute tied vulnerability enumeration to the halting problem and showed, in theory, that for any sufficiently complex piece of deployed software, there are always more undiscovered flaws.

The AI-driven discovery results of the last 18 months have made the density argument impossible to wave off even in a compliance review. A 27-year-old bug in OpenBSD. A 16-year-old bug in FFmpeg that five million fuzzing runs never caught. Disclosed findings, by the developers’ own accounting, are less than 1% of what has been found. But again, the volume was already a problem. With the coming release of its newest model, Mythos, Anthropic is telling teams to plan for an order of magnitude more findings over the next 24 months.

Static severity scoring can’t survive the volume problem, because it’s a human-scale solution for a machine scale problem. Neither can any process that treats every critical finding as an emergency. The threshold for action has to be probabilistic, measurable, and defensible. That’s what a predictive model is for, and that’s what working teams have been using in noisy large enterprise environments.

Pointing machines and knowing machines

Geer returned to his 2014 question in the summer of 2025, writing with Dave Aitel in Lawfare. The piece gives the industry a vocabulary for a distinction it has been fudging:

A vulnerability in the code isn’t automatically a threat. A buffer overflow is a hazard. It becomes a risk only if an attacker can exploit it reliably, in this environment, against these controls, through this traffic. Bugs are abundant but the ability to weaponize a particular bug against a particular target is much rarer.

The industry, they wrote, has built a pointing machine. It enumerates.

Even children learn early to point and name—but knowing the word “dog” doesn’t reveal whether the animal might bite. In cybersecurity, we’ve built systems that similarly point and name vulnerabilities without understanding whether they’re truly dangerous. By embracing AI solely for pattern recognition, we’ve created a powerful “pointing machine” that identifies possible threats but does not comprehend their actual impact. What we need instead is a “knowing machine,” capable of understanding how code functions within complex, real-world environments, recognizing not just hazards but the full context of how and whether those hazards might become genuine risks.

A knowing machine is a system that understands how code behaves in a particular environment and recognizes the context that turns a hazard into a risk. A predictive model is how you build a knowing machine. EPSS is the clearest public example: It covers every published CVE and is updated daily.

Global isn’t local

EPSS is a global model. It sees what attackers are doing across the whole of the internet. It picks up patterns in exploitation activity that severity scores never could. What it can’t see is any particular organization’s environment. It doesn’t know which assets carry the data the business actually cares about. It doesn’t know what compensating controls are in place, where remediation is risky, or how your telemetry and history change the odds.

A 9.8 with a 97% global probability of exploitation and a 9.8 with a 0.1% probability are not the same animal. Neither are two organizations applying the same EPSS threshold to the same CVE on different assets. One has the vulnerable code path exposed to the internet, behind a web application firewall that doesn’t inspect the relevant protocol. The other has the same CVE on an internal system that accepts authenticated input from a single service account. A scanner can’t tell them apart. A global model can’t tell them apart. Their actual risk profiles are orders of magnitude apart.

Local context is where most security teams have been stuck the entire time, and where the next decade of the field is going to be fought.

What a local knowing machine actually requires

Pair a better pointing machine with a faster remediation engine and all you’ve done is increase the speed at which you produce churn, breakage and wasted effort. You’ll also spend a king’s ransom in agent tokens fixing vulnerabilities that were never dangerous in your environment.

In contrast to an omniscient scanner, a local model trains on the specific environment being defended: asset inventory, application topology, reachability, deployed controls, attack telemetry observed on-site, and the history of the organization’s own remediations and their outcomes. The model produces probabilities specific to the enterprise. Most organizations already have the inputs, scattered across CMDBs, endpoint agents, firewall logs, ticketing systems and scanner output. This context is precisely what attackers (whether they’re using good old fashioned metasploit or Mythos with an infinite budget) are lacking in their models. The context becomes an asymmetrical advantage for defenders, perhaps the only one that exists.

The policy shifts that actually matter

The interventions that will decide whether a security program survives the next 24 months aren’t purely technical. A CISO can put most of them in motion without buying anything.

Rewrite the SLA. Most vulnerability-management SLAs are organized by severity. Criticals in 15 days, highs in 30, mediums in 90. That structure was built for a world where the count of open criticals was small enough to matter. It’s now actively harmful, because it forces teams to spend the same effort on a 9.8 nobody is exploiting and a 7.5 that’s under active attack. SLAs should be rewritten in terms of probability of exploitation and asset exposure, not severity. A CISO who can’t get that past her GRC team can at least add a second tier that makes the probability-based cut enforceable alongside the severity-based one.

Change what the board sees. If the monthly security report counts the numbers of vulnerabilities, exposures or findings in different buckets (“critical,” “open past 30 days,” etc.), the organization is being managed to the wrong metric. The metric should be exploitability-weighted exposure over time, with a second line for predicted versus observed exploitation. Boards will accept this once somebody explains it. This beats showing them a number that has no relationship to risk and is growing exponentially as new LLM models are released. More to the point: A great team can do amazing volumes of remediation work, and risk can still rise because they’re measuring and remediating the wrong thing. An efficient, context-rich team can do far less work and meaningfully move the probability of an event down.

Invest in telemetry. The single most valuable instrument a security program can build is a feedback loop between what was prioritized and what was exploited. If the loop shows you were wrong, the model improves. If the loop does not exist, you will keep being wrong indefinitely (or just not being aware of misses).

Fix the compliance conversation. The reason CVSS survives is regulatory inertia. PCI, HIPAA, and most state breach-notification frameworks still reference severity. The CISOs who will come out of the next two years in the best shape are the ones who engage their auditors now, in writing, about what a probabilistic prioritization framework looks like under the existing rules.

Staff for the bottleneck, which isn’t scanning. The industry has spent a decade hiring people to find bugs. The bottleneck now is deciding which bugs matter, getting the fixes deployed, and measuring whether the prioritization was correct. The job descriptions should reflect this. A security-data engineer may be able to increase efficiency to meet SLAs more than increasing capacity would.

None of this requires a new product. All of it requires a CISO willing to say, out loud, that the old dogma is broken and that the new one will be managed by data and probabilities. That is the shift Anthropic’s five-word sentence was really announcing. The technology is available and the models are here—both the LLM-based ones to find the vulnerabilities and the predictive knowing machines to prioritize efficiently.