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Stack Selection in the Agent Era

· 19 min read
Marvin Zhang
Software Engineer & Open Source Enthusiast

On March 11, 2025, Anders Hejlsberg published a post titled A 10x Faster TypeScript: Microsoft was porting the TypeScript compiler to Go.

For most readers this was performance news. For me it was three old blog posts colliding. In 2021 I wrote, within the space of a few months, a piece asking whether Go was really a panacea for backend development, a piece arguing that TypeScript was indispensable for large frontend projects, and a piece praising C#'s developer experience — where I pointed out, almost as trivia, that TypeScript and C# share the same creator. Five years later, all three protagonists converged in a single repository: the compiler of the language I called indispensable, rewritten in the language I interrogated, led by the man who fathered both TypeScript and C#. I knew those articles were connected. I did not expect the connection to close like this.

The collision is worth more than nostalgia, because it exposes what has changed underneath the argument. In 2021, we debated which language was better for humans: which syntax was cleaner, which learning curve was gentler, which type system annoyed you least. The debate never ended. But the referee changed. Since then, AI coding agents have become some of the highest-frequency authors — and the very first readers — of production code. An agent does not care that Go's error handling is tedious or that TypeScript's annotations are verbose. It cares about two things: how fast it gets feedback, and whether that feedback can be trusted.

That observation is the candidate thesis of this article, stated deliberately in its modest form: when agents join the authorship of your codebase, two criteria get promoted to first class in stack selection — agent loop latency (how long one edit-to-trusted-feedback cycle takes) and the density of machine-decidable verification signals (how much of your correctness can be checked automatically, deterministically, per cycle). These criteria do not replace the human ones. They re-rank them. And under the new ranking, some of 2021's verdicts get crowned while others get overturned.

To make that case honestly, I will first excavate what we actually argued about in 2021, then define the two new criteria precisely, then examine three bodies of evidence from 2025–2026, then give the strongest counterarguments their own section, and finally propose a small selection framework you can disagree with productively.

From Workshop to Factory: The Industrialization of Intelligence

· 24 min read
Marvin Zhang
Software Engineer & Open Source Enthusiast

The AWS Summit in Shanghai
The AWS Summit in Shanghai, 23–24 June 2026.

In June 2026, I gave what was almost certainly the least glamorous talk at the AWS Summit in Shanghai. I opened with a disclaimer: our Nova is not the Nova from Amazon. The Nova on my slides is an internal platform my team builds at HP; the Nova everyone else kept name-dropping is Amazon's frontier model. The room laughed at the collision — and then I spent the session on something no keynote would touch: how we moved a reporting stack off Power BI and onto Amazon Athena and Apache Iceberg. It was a thirty-minute, 300-level breakout, upstairs on the sixth floor, well away from the crowds.

The summit floor guide
The floor guide: breakout talks — mine among them — on the sixth floor, the keynote on the fifth, the expo downstairs.

Down on the ground floor, the expo hall was selling the opposite of unglamorous. Unitree humanoids reached for objects under hot lights. A dexterous robotic hand, priced at ¥9,999, flashed a peace sign for the cameras. On one screen, a swarm of coding agents shipped software with no human in the loop; on another, an AI turned footage of a football match into tactics and player metrics. The spotlight was on intelligence learning to perceive the world, to make things, and to act in it.

The expo floor
Down on the ground floor: the expo, where the crowds were.

That contrast is the argument of this piece. For two centuries, output scaled with headcount: more work meant more hands. AI is breaking that link — output is starting to scale with infrastructure (models, compute, and data) rather than people. This is the industrialization of intelligence, and like the first industrial revolution, it will be won not by whoever owns the flashiest machine but by whoever builds the floor those machines stand on. My boring migration is the proof in miniature: what made our reports better was not a smarter model but a new foundation underneath them — a refresh that once took four to six hours now finishes in one, and a report you could once only read became data anyone can now question in plain language.

So this article works from the floor up. First, the three frontiers the show floor was celebrating — machines that perceive, create, and act. Then the layer beneath all three, the one I went to Shanghai to talk about: the data foundation that decides how high any of them can climb.

Cybernetics and AI Agents: A Forgotten Old Language

· 23 min read
Marvin Zhang
Software Engineer & Open Source Enthusiast

A team of eight engineers has wired AI coding agents into their development pipeline. The agents take tickets off the top of the queue and ship pull requests faster than humans can review them. Six months in, the dashboards look enviable. Test coverage sits at 84%. The p99 latency on every changed endpoint stays under 100 ms. Merge throughput is up 3× since the agents went live. The Friday retrospective is short, because there is little to retrospect on.

Then a competitor ships a feature. It is not a clever feature. Their users had been asking for it on a public forum for six months, and the team's own users had been asking for it on the team's own forum for almost as long. No one on the team noticed. The competitor's launch lands in Slack on a Tuesday, and the room goes quiet, because everyone is asking the same question at once: which part of our system was supposed to catch this?

The honest answer is: no part. Not because someone forgot to build it, but because the team's architecture vocabulary has no word for it.

The Last Mile of AI Is Infrastructure, Not Intelligence

· 19 min read
Marvin Zhang
Software Engineer & Open Source Enthusiast

Every AI keynote in 2026 opens with the same three slides: a bigger model, a faster chip, a smarter agent. The fourth slide — the one about how any of that actually reaches a user in production — is usually missing. That missing slide is where the next decade of value will be created, and it will not be created by another round of model fine-tuning. It will be created by the most unglamorous layer in our stack: infrastructure.

The numbers back the hunch. MIT's 2025 "State of AI in Business" report found that 95% of generative-AI pilots fail to reach production. Gartner found that only 15% of IT application leaders are even piloting fully autonomous agents, despite the agent market projected to grow from $7.8B in 2025 to $52.6B by 2030. The bottleneck is not intelligence. Frontier models cluster around 70–75% on SWE-bench Verified. The bottleneck is everything between a model that can write code and an organization that can ship it — and that everything is infrastructure.

Here is the hot take, stated plainly: as coding gets cheap, infrastructure gets scarce. The DevOps, CI/CD, container, Kubernetes, and cloud-architecture knowledge that the AI narrative treats as "solved plumbing" is about to become the single biggest lever for turning AI capability into shipped product. The reason is simple. Agents can now write code. They cannot, by themselves, run a build, own a deploy, route a rollback, or provision a region. They need a substrate that does those things for them — and that substrate is the accumulated, low-cost, battle-tested output of two decades of DevOps work.

Mapping the 2026 AI Agent Landscape: From Protocols to Predictions

· 16 min read
Marvin Zhang
Software Engineer & Open Source Enthusiast

Six protocols. Six automation levels. Seventeen tools. Twelve predictions. One interactive map that ties them all together.

The AI Agent Interaction Landscape is an open-source, bilingual SPA I built to make sense of how AI agents interact with developers, editors, tools, and each other in 2026. This article walks through the key frameworks it introduces—and the insights that emerged from building it.

AI Agents: Engineering Over Intelligence

· 21 min read
Marvin Zhang
Software Engineer & Open Source Enthusiast

When SWE-bench scores improved 50% in just 14 months—from Claude 3.5 Sonnet's 49% in October 2024 to Claude 4.5 Opus's 74.4% in January 2026—you'd think AI agents had conquered software engineering. Yet companies deploying these agents at scale tell a different story. Triple Whale's CEO described their production journey: "GPT-5.2 unlocked a complete architecture shift for us. We collapsed a fragile, multi-agent system into a single mega-agent with 20+ tools... The mega-agent is faster, smarter, and 100x easier to maintain."

Introducing LeanSpec: A Lightweight SDD Framework Built from First Principles

· 8 min read
Marvin Zhang
Software Engineer & Open Source Enthusiast

Earlier this year, I was amazed by agentic AI coding with Claude Sonnet 3.7. The term "vibe coding" hadn't been coined yet, but that's exactly what I was doing—letting AI generate code while I steered the conversation. It felt magical. Until it didn't.

After a few weeks, I noticed patterns: code redundancy creeping in, intentions drifting from my original vision, and increasing rework as the AI forgot context between sessions. The honeymoon was over. I needed structure, but not the heavyweight processes that would kill the speed I'd gained.

Spec-Driven Development in 2025: Industrial Tools, Frameworks, and Best Practices

· 21 min read
Marvin Zhang
Software Engineer & Open Source Enthusiast

Introduction: The Industrial Revolution of AI-Assisted Development

25% of Y Combinator's 2025 cohort now ships codebases that are 95% AI-generated. The difference between those who succeed and those who drown in technical debt? Specifications. While "vibe coding"—the ad-hoc, prompt-driven approach to AI development—might produce impressive demos, it falls apart at production scale. Context loss, architectural drift, and maintainability nightmares plague teams that treat AI assistants like enhanced search engines.

2025 marks the tipping point. What started as experimental tooling has matured into production-ready frameworks backed by both open-source momentum and substantial enterprise investment. GitHub's Spec Kit has become the de facto standard for open-source SDD adoption. Amazon launched Kiro, an IDE with SDD built into its core. Tessl, founded by Snyk's creator, raised $125M at a $500M+ valuation to pioneer "spec-as-source" development. The industry signal is clear: systematic specification-driven development (SDD) isn't optional anymore—it's becoming table stakes for AI-augmented engineering.

If you're a technical lead evaluating how to harness AI development without sacrificing code quality, this comprehensive guide maps the entire SDD landscape. You'll understand the ecosystem of 6 major tools and frameworks, learn industry best practices from real production deployments, and get actionable frameworks for choosing and implementing the right approach for your team.

Related Reading

For theoretical foundations and SDD methodology fundamentals, see Spec-Driven Development: A Systematic Approach to Complex Features. This article focuses on the industrial landscape and practical implementation.

Leadership Skills in the AI Era: Beyond Traditional Management

· 15 min read
Marvin Zhang
Software Engineer & Open Source Enthusiast

The first time an AI system disagreed with my architectural decision and turned out to be right, I realized something fundamental had changed—not about AI, but about what leadership means. This wasn't a story about better technology; it was about how my role as a leader needed to evolve. The skills that made me effective in leading human teams weren't suddenly obsolete, but they required significant adaptation when AI became part of the equation.

If you're a tech leader today, you've likely felt this tension. As research shows, AI's impact on productivity is real but nuanced—it's not a silver bullet that solves all problems automatically. You know the traditional leadership skills that matter: technical depth, business domain knowledge, interpersonal skills, and political navigation. These haven't disappeared. But AI introduces a new dimension where these skills must expand and adapt. You're no longer just leading people or directing tools; you're orchestrating a hybrid environment where human judgment, traditional management wisdom, and AI capabilities need to work in harmony.

The Physics of Code: Understanding Fundamental Limits in Computing (Part 2)

· 16 min read
Marvin Zhang
Software Engineer & Open Source Enthusiast

Introduction: From Theory to Practice

In Part 1 of this series, we established the foundational concepts of computational limits: the distinction between fundamental and engineering limits, the four-tier computational hierarchy, formal complexity measures, and the intelligence-computability paradox. We explored why some problems that seem simple (like the halting problem) are mathematically impossible, while problems that seem to require sophisticated intelligence (like machine translation) are decidable.

Now, in Part 2, we move from abstract theory to practical application. This article explores how these fundamental limits manifest in daily engineering decisions, examines historical patterns showing that understanding constraints unleashes innovation, and connects computational limits to profound philosophical questions about logic, mathematics, and consciousness. We'll conclude with a practical framework you can use immediately to classify problems and make better engineering decisions.

Article Series

This is Part 2 of a two-part series. Part 1 covered the nature of limits, the computational hierarchy, complexity measures, and the intelligence-computability paradox. Part 2 explores practical applications, historical lessons, and philosophical foundations.