More from Irrational Exuberance
Imprint’s average engineer is merging 4x more PRs than 2 years ago. Yay. Aggregated behind the average is something even more interesting: we have two teams that are merging 10x their PRs over that period. One engineer is merging 25x the PRs per week of our average engineer two years ago, and a number are merging 10x. That’s pretty neat, and the slope of the line suggests our average in a year is going to look much closer to today’s p90 than today’s p50. Even more importantly, we aren’t just shipping more, our quality has improved: incidents are down 42% half-over-half, and critical incidents are down 78% half-over-half. I think we’ve always known the quality/velocity tradeoff wasn’t a particularly useful construct, but that’s undeniable today. As we’ve walked this path, we–like everyone else progressing down it–have run into the problem of pull request review. The p50 pull request review took about 33 minutes to complete 2 years ago, but now takes us about 77 minutes. The slope here correlates tightly with the number of pull requests getting merged. Tightly enough that addressing it became one of my priorities for the week. We solved it! Just kidding, we’ve absolutely not solved it, but I think our current approach is an interesting one, which we call the small-change. The work discussed here was shaped and done by many folks at Imprint including Dan, Joy, Daniel, Lenny, Taylor, Ted, and Annie, among many others. Why review pull requests? There are four reasons we review pull requests: Knowledge sharing between author and reviewer – software engineering is generally learned via apprenticeship, and reviews are a primary mechanism of experienced engineers teaching others what good software looks like. We believe the current volume means that this knowledge sharing will have to move towards operating on clusters of pull requests, rather than individual pull requests Preventing errors – review has always been an expensive time to catch errors, and we believe that effective CICD along with harness verification techniques like poteto’s pstack are more effective mechanisms for preventing errors than review Preventing malicious behavior – my experience is that even careful code review will generally miss competent malicious behavior, although fortunately most malicious behavior is incompetent. We believe both sorts of behavior are best identified using a combination of fixed rules (modifying these specific objects/classes/files requires review), anti-abuse mechanisms that we’ve refined in our LLM-based member support experiences, auditing, and audit log inspection Compliance obligations in our documented controls – these can be changed, but today they require that an independent human reviews changes in a subset of our repositories In the modern development paradigm, we think there is a better solution for each of these problems. But, we also want to make these changes very cautiously. Small steps with small-change We believe we move fast by finding narrow, contained ways to validate new practices, so to iterate our way into an effective solution, we’ve developed the concept of a small-change. Here’s how it works: When a pull request is marked ready, CICD determines whether it is eligible to be a small-change. This is represented as a passing Github check. There is also a label for visibility, but it is the check itself, managed by the build and not human modifiable, that determines eligibility. (The label is used for initial filtering, but the check is still independently verified.) Something is a small-change if it meets all of these criteria: It is less than 1,000 lines of code There are no p1 or p2 findings from our ai-code-review automated review bot The author has “experience” in the service or application, defined as 10+ prior merged pull requests into that service or application’s directories. For changes working across multiple services or applications, the author must have experience in all of them to qualify Impacts fewer than N distinct services or applications. N is 1 on our frontend monorepo, and N is 3 in our backend monorepo, where typical changes will modify both a gRPC service and a common HTTP gateway Shared libraries and utilities files are not eligible for small-change Each repository has a .small_change file which allows per-path customization while we continue to tune the behaviors. For example, a service dealing with money movement can be excluded Our Slack automation tags every reference to a pull request with reacji labeling the state of that pull request, for example if it has failing tests, if it has been approved but tests are still running, or if it is ready to merge. We added a small-change reacji that indicates which of those pull requests meet the small-change criteria In our internal skills repository, we created two skills that have been distributed across harnesses: review-small-change which takes a list of repositories and reviews all open, non-draft, small-changes, including providing approval if they meet the review’s criteria (all checks pass including small-change check, and not touching on sensitive topics such as payments and security) review-pr-cluster which reviews batches of pull requests to identify common themes that came up, and suggest opportunities for discussion and adding verifications We set the social expectation that any error caused by a small-change is a failure in our system, and has to be solved at the system level: improvements to ai-code-review, to our verification mechanisms, to our CICD, to our harness, etc. This took about two days of infrequent attention to implement and rollout, although I imagine we will be tuning the knobs here for a long time. Maybe forever. fleet: centrally orchestrated harness I’ll briefly mention our other approach to reducing code review volume, which anchors on our centrally-orchestrated harness, fleet. (Which is similar to Stripe’s Minions although not following the one-shot approach in particular). We rely on fleet to implement and verify software in a highly controlled harness running in the cloud, with independent evaluation mechanisms to identify the correct number of independent reviewers for any given change. That number can be as low as one (e.g. fleet writes, one human reviews) for changes evaluated as safe. Results / next steps / reception I’ll be honest, it’s too early to give a useful result here. From early results, about 10% of changes qualify as a small-change. Those are now eligible for very fast approval, and generally get it unless they trip a flag, generally due to touching a security or money adjacent topic. While 10% is a small percentage, the core concept here is working, and ultimately will succeed or fail based on our ability to expand that percentage over the next few months in tandem with expanding our verification mechanisms to be increasingly comprehensive. This is ultimately going to fail or succeed depending on our ability to improve our verifications, which does require more difficult sorts of techniques to accomplish in low scale-complexity, high domain-complexity software than in the high scale-complexity, low domain-complexity products where many techniques like incremental rollouts are exceptionally effective. (Don’t get me wrong, they still work, they just provide less coverage when most users have different configuration and behavior.) Folks have not been uniformly excited about this, it’s a substantial change from how we’ve learned to be good engineers, and it’s uncomfortable to reevaluate whether a long-held best practice has become merely dogma. The most energizing part of the current cycle is that we get to reevaluate these practices we grew up on every week; the most painful part of the current cycle is that we’re likely to fall behind if we ever stop reevaluating them.
One of the interesting challenges of the AI ecosystem in 2026 is that new, effective patterns emerge faster than I can adopt them. I’ll find a handful, get back to work, and realize a month later that I’d missed four or five more. The adoption cycle for Imprint this year has been something like: January: get every engineer onto Claude Code every single day March: ok, let’s also get everyone else onto Claude Code or Claude Cowork every single day April: local development is bottlenecked on checkout and worktree model, instead create ~10 local workspaces which each have an independent checkout of every repository, and operate at the workspace level, not at the repository level, so it can generate cross-repository pull requests across frontend, backend, infrastructure and data monorepos June: oh boy, agent-driven development is heavily constrained by lack of a common task management system with higher visibility and less permission complexity than Jira, so let’s migrate the entire company over to Linear and hard stop on Jira July: yikes, now we have visibility into all these tickets, many of them are trivial but managing them through local development isn’t scaling, let’s roll out an orchestrated harness which internally we call “Agent Fleet”, along the lines of Stripe’s Minions The most recent question for me has been figuring out how to adopt the software factory pattern. (After some light research, the specific AI-context origin of this term is slightly messy to attribute, but I think it might be Justin McCarthy in February 2026’s Software Factories And The Agentic Moment.) The software factory pattern is looping on a broad goal, and then relying on the harness to drive progress towards that goal. Our first pass at implementation is fairly basic: An agent skill /linear-project-loop which reads in a Linear project and starts by auditing that project’s goal definition on these dimensions: An RFC in Notion that describes the project’s goals, how those goals are measured, and the general approach A Datadog dashboard or Snowflake queries that measure progress against those goals If those are missing, or the Linear project is missing in its entirety, it iterates with you on creating those missing tools. Then it reviews the state of the metrics and issues for the project. If new work is identified, it adds those issues to the project. It updates the state of issues that have moved. It works on the non-blocked tasks based on the project’s current state. This is often writing a pull request, updating a pull request, pinging for review, asking a clarifying question, etc. When a task completes, if the project description is fresh, it takes on the next task. If the description hasn’t been updated in a while, it reruns the loop starting with the first step. Right now I am running this locally in a local harness, but it’s working well enough that I anticipate moving the behavior to be driven by the same orchestrated harness that we assign one-off tasks to. What I particularly like about the factory pattern is that it parallels very closely how I’ve been working locally, while forcing me to recognize the places where I was accidentally hording parts of the state for myself regarding the goals of the project. I was already asking agents to iterate on specific Linear projects, but they didn’t have the ability to evaluate if they were going in the right direction, or if it was missing necessary tasks. Now it does. The other place this has been extremely helpful for me is checking in on projects post release. For example, I shipped our passkeys implementation earlier this year, but some months go by without my checking in on how it’s going. If we saw adoption spike, or error rates start to turn, I might miss it, but running the factory in a less frequent post-release mode would catch it immediately. The final thought that’s been interesting to me is how much all of the pieces here compound only to the extent that you have the other pieces. For example, this factory pattern depends on having Datadog MCP and Snowflake access available to manage goal-tracking, but it also depends on Linear being the single source of state for the company’s work, and an orchestrated harness that can perform work independently from your laptop. Keeping up with this many migrations is a fascinating industry moment.
Six years ago, I wrote Tech Lead Management roles are a trap. My argument then was that TLM roles present themselves as easier than moving into a full management role, but the tension between doing the software engineering and engineering management aspects of the role made being a TLM a much harder first management role than a pure engineering management role. I still agree with that post, and I have some additional bad news to share: middle management roles are mostly a trap as well, if you goal is to become an executive. The core aspects of middle management roles are: Balancing between top-down executive, lateral stakeholder, and bottom-up team pressure, e.g. keeping morale up as an organization deprioritizes last year’s big initiative Defining and operating an organization’s process, e.g. creating career ladders and interview loops Competing for a share of fixed organizational resources (e.g. budget) and allocating acquired resources These are all extremely important skills to be an effective executive, and they make up the bulk of The Engineering Executive’s Primer, but they are insufficient to make you a great executive. If you don’t have them, you will be a deeply flawed executive, but even if you’re an expert at them, you can still be a terrible executive. That’s because the most important skills of an effective executive are the same exact skills that make an excellent line manager: developing domain expertise, driving execution (including setting pace), and translating both of those into an organizational culture that extends beyond you (in any of innumerable different ways). All of them are more easily practiced and mastered as a line manager than as a middle manager. Most middle management roles make practicing those skills difficult, and sometimes negatively select against developing them. As a middle manager, if you drive execution too closely, you might get told off as a micromanager. As a middle manager, if you go too deep on domain expertise, you might get told that you’re not focusing enough on your internal stakeholders. That’s undoubtedly valid feedback in many middle management roles, but it’s the perfectly wrong feedback to someone who is trying to become an effective executive. As a result, I’ve come to believe that the filters for good middle managers inadvertently negatively select out the “challenging” line managers who actually have the best chance to be excellent executives. That’s not even necessarily irrational: most companies are developing middle managers to take on more complex middle management roles; very rarely do they worry about growing future executives from within. If you’re willing to embrace this fact that a little bit of time in middle management roles is important preparation to become an executive, but spending a great deal of time in middle management only prepares you for further middle management roles–and makes you less effective as a potential executive–then the AI-driven shift in managerial fads might be a threat to your current role, but it’s likely to improve your chances to succeed as an executive.
I’ve recently been thinking a lot about the concept of “soil horizons”, which is the idea that there are many distinct layers of soil, from topsoil all the way down to bedrock, which all combine into a soil horizon. Translating this idea into software, the ideal codebase would have a single uniform “code layer”, but a surprisingly large percentage of production software has numerous, distinct code layers as the leading architect shifted over time. I’ve found this particularly true for software in problem-spaces with high essential complexity and low scale complexity, where the purifying challenges of scaling never create enough pressure to compact disjoint layers into a unified layer. Codebases with the most code layers tend to be created by small teams working on complex domains over a long period of time. In many companies this might be an identity, permissions or payments team: stuff that’s permanently valuable, but usually not the central concern at any given time. On such teams, there is often only one architect who understands the nuances of the domain well enough to make tradeoffs. When that architect leaves, they are replaced by someone who aspires to operate in the same code layer, but simply cannot because they lack enough context to do so. As a result, that new replacement creates a new code layer, despite not intending to. If the team runs through a handful of folks as the new team leads struggle, it’s easy to end up with a complex code horizon very quickly. The problem of messy code horizons is not a new one, and the general approach to addressing them is the same one I wrote about seven years ago in Reclaim unreasonable software, but with the proliferation of coding and non-coding harnesses, lately I’m running into the problem of messy code horizons more frequently. Even more concerning, I’m seeing this problem expand from impacting code horizons into impacting how organizations make decisions outside of software, e.g. the company’s general reasoning horizons. When individuals or teams rely on LLMs to reason to conclusions, rather than using LLMs to explore or draft options, it’s possible for even the most important decisions to be built on top of flawed reasoning layers underneath. In the next section, I’ll develop the problem statement a bit about what I’m running into, and then in the final section I’ll lay out the approaches that I am finding (moderately) effective to navigate that problem. Messy reasoning horizons If you give three enthusiastic engineers a problem, a new codebase, a coding harness, and self-approval rights, it’s very easy to end up with three new soil horizons as their harnesses gleefully commit code. However, in engineering we have a number of techniques to derisk this problem. First, we have manual and automated code review, and second we increasingly have the ability for the harnesses to operate off sufficiently clear instructions that they write new code consistently with the existing code, even if the operator is unaware of what good looks like. This is also true for code review, where coding harnesses can drive consistency across pull requests even if the person (or harness) creating the pull requests is not operating off the same shared context as the wider team. Many codebases are not well-configured for this new reality, and those codebases are getting worse at an accelerating rate as more harness and agent contributions get added. Legacy codebases that reach a certain size before introducing these better practices are easier to fix than before, but still require a lot of work to fix. That said, I’m confident that coding harnesses are going to substantially improve the quality of code horizons over the next year or two as the way we configure harnesses improves. That’s not the problem I’m worried about. What I’m worried about is the application of harnesses to problems outside of writing software, where there’s no static typing, linting, or unit tests to validate the output. Let me provide a very recent example from my own work that highlights this problem: I wanted to understand how our incidents were trending over time. So I pulled data via an MCP, and the analysis was unintuitive to me, in particular I thought we were having more Data related incidents than the results reflected. I had to look at the incidents in Slack, then the results in our incident tool, and understand why the two conflicted. After a bit, I recognized the results in our incident tool were only showing incidents that properly tagged a team when the alert was triggered, so it was omitting about half the relevant incidents. After having the agent manually tag the incidents without team assignments, the data made a lot more sense. After recognizing the issue, it was trivial to fix. However, if I had simply accepted the initial analysis, I would have made the perfectly wrong conclusion about what was happening. On top of that wrong conclusion, I could have easily pushed the team to take on a project to solve an illusionary problem. What’s so pernicious about messy reasoning horizons, is once any reasoning layer is poisoned, it’s impossible to reason effectively on top of it. If you take the incident analysis example, it’s easy to imagine prioritizing the perfectly wrong set of remediations, which have the artifacts of solid strategic reasoning, but are nonetheless just wrong. It’s easy to imagine a team wasting a quarter of time building a solution to this sort of problem that never existed. It’s true that poor reasoning has always existed, long before harnesses, but my experience is that poor reasoning wearing well-formatted clothing is proliferating more widely than I’ve previously seen, and it is increasingly difficult to combat because certain social norms are – at least temporarily – collapsing around folks actually thinking. That collapse is largely driven by unprincipled adoption of AI techniques without paying attention to whether they work. Widespread adoption is, in my opinion, the fundamental risk for most companies at the moment, and something companies need to be doing, but many approaches inadvertently mix play (experimenting with something new in ways that are likely to fail!) with production (creating load-bearing work product!) in ways that erode social norms for quality. The norms are not uniformly collapsing by any means, they are generally intact, but even a small increase in the proliferation of low quality reasoning layers has a devastating effect on your ability to reason successfully. Especially true the further up the poor reasoning occurs (sloppy reasoning from senior leaders) or when senior leaders rely on layers of reasoning without inspection (leaders who aren’t sufficiently “in the details” to spot likely reasoning errors in reasoning layers). As a result, we now live in a world where accepting any part of the reasoning context before inspecting it might lead to making a catastrophic mistake. This is an exhausting way to live. Make no assumptions Accepting that this is the world we live in, I wanted to lay out the techniques that I am finding useful to deal with it. Some of these are novel, but many of them are the same techniques I was using before the LLM-advent: Make no assumptions. When new hires join my team or my company, the first thing I tell them is that it’s essential that they “make no assumptions.” This is difficult to do, and it goes against every instinct because it forces you to inspect each aspect of how the company works and thinks, but I do think it’s the necessary approach. It’s a bit like learning “internet-skepticism” at some point in your life, where you realize that everything on the internet is self-motivated in some way, and you have to maintain a strict filter on what ideas you accept. This is a hard change to make, but I genuinely believe this is the correct mindset for accepting new information in the current era. The combination of fewer management layers and more flawed reasoning layers means that the core job of leadership is inspecting the details. The author must be the first human in the loop for their output. The biggest cultural failure with harnesses is when you can tell that you–the recipient of a piece of work–are the first human in the loop reviewing it. You must set a cultural norm that the creator of a piece of content is always the first human in the loop before asking another human to review it. If you fail to set that cultural expectation, then you will quickly crush the remaining team with a high standard for quality reasoning, which will lead to a full destruction of your reasoning horizon. Prioritize reasonable software. Run the Reclaim unreasonable software playbook, recognizing that migrations are cheap in 2026, so it’s much faster to remediate gaps. The core idea here is that relying on convention doesn’t work, and instead you have to rely on deterministic decisioning for each approach. For humans this can feel overly prescriptive, but harnesses don’t care. Learn faster by separating play and production. Many folks trying to learn how to use harnesses and LLMs leap directly into using them in their most critical work. This is a slow way to learn, and can lead to substantial errors in your most critical work. It’s much faster to work by buffering small pockets of time to learn. For example, our head of data has spent time building an iOS app fully “hands off the keyboard” to get a better feel for the tools. This sort of experiment goes much faster and gives you more repetitions in less time. The very practical version of this is setting aside a day or two periodically for folks to experiment. Structure how you think with LLMs. In Crafting Engineering Strategy, I lay out a structured approach to reasoning through creating a strategy document, which aims to prevent the reasoning errors that folks make in their thinking. This applies equally in how we use LLMs, and I think you can substantially reduce the chance of introducing flawed reasoning layers by focusing LLM work on exploration (gathering information on internet and via various MCPs), refinement (presenting gathered information effectively), and a final formatting pass. That takes much of the work out of strategy creation while constraining the areas you have to avoid making any assumptions about its output. I’m certain there are more things! What are you trying?
From early 2014 through late 2020, I was working in hypergrowth environments, which are challenging, but also educational. The most valuable feature of hypergrowth is that your mistakes reveal themselves next month rather than next year, because things go wrong very loudly when you’re moving fast. I’ve been thinking a lot about hypergrowth recently, because Imprint’s business is growing quickly and we did a large batch of hiring last year, but also because the AI-tooling shift has changed the pace at which it’s possible to work. This post documents the new rules I’ve revised my approach to engineering leadership around, and then talks through the specific projects I’ve worked on over the past year that caused me to believe in these rules. Revised rules Migrations can be done by an individual rather than a team. Even complex, large changes can be 95% owned by the driving individual or team, and done in 10% of the time. As the initial cost of migrations goes down, the reward/penalty of each migration’s quality goes up: even small sharp edges will break your colleagues’ mental models about the software you co-maintain. The impact of individual judgment on your company has never been higher. While 1st-pass code is nearly free, the cost of working code depends on your development harness, and is not free. We’re in an era when many companies say that everyone should be writing code, however our experience is that writing code that works well, while avoiding messy edgecases, remains difficult. Just how difficult remains a factor of your development harness, e.g. your tests, CI/CD, validation environments, preview-ability of changes, and so on. While I personally don’t imagine it’s valuable for most folks at a company to be contributing code, I suspect that most disagreement about that topic is actually a miscommunication: even at a company where “everyone codes”, the marketing team isn’t reducing allocations in your servers, instead it’s about whether there is a safe boundary where they can participate. (Much like a SaaS product that allows customization by writing software.) The good news is that this means the things that were most valuable to speed up engineering two years ago are still the things that are most valuable to speed them up today. Optimize the base-case of process for agents. Most steps of most processes can be fully automated in most cases. With the right harnesses, the right controls, domain context, and good judgment in their designers, you can fully automate the base-case of most processes in modern technology companies. For example, the base case of code review from a human is slower and less effective than a good harness’ code review. Of course, the harness will miss things, but so will human reviewers, and most areas are relatively safe to make changes. Of course, there are some higher risk areas, where this doesn’t hold true. By effectively capturing these distinctions properly, we can go much faster without introducing risk. By failing to capture these distinctions, we’ll create innumerable problems for ourselves. As a corollary, I think most planning processes like weekly or bi-weekly sprints are operating at too low an altitude. Humans planning together still matters, but should be operating at a higher level. Durable, high-ownership teams with domain-context are even more important. One of my biggest lessons at Uber was that persistent, durable teams work magic by accumulating domain-context, building a sense of camaraderie, and feeling an increasingly strong sense of ownership over an area as they continue to work in it. Even in an era where specifically doing something is much cheaper, you still have to do the right thing, which has gotten a bit easier but not much easier, and structural improvements help address this. (As a recent example of that, we had an issue in production where the necessary data to optimize it simply wasn’t being captured at all, so the harness’ ideas to solve it were reasonable but wrong, since the only real path forward was instrumenting the missing information.) As a specific disagreement, there’s a prevailing idea that AI-first companies will be run by a small number of genius engineers who create perfect versions of things one by one, doing such a good job that there’s nothing to maintain. This is a very compelling vision, but I don’t see it happening. High judgment individuals can wander across a company doing remarkable things, but at some point they do get hemmed in by lack of domain context, which is why durable teams are the fundamental building block, even in this era. Quick, good, and durable decision-making is a prerequisite to meaningfully benefit from AI. Being able to replace a legal review with automation only works if Legal can commit to that change, which depends on designing the automation thoughtfully, and also the teams’ willingness to collaborate. Implementing a new feature is only valuable if you can decide to launch that feature. Your team and company can only benefit from this increased pace of execution if you can make durable decisions quickly, and those decisions are good. This is the primary reason, in my opinion, why the average CTO role has necessarily become substantially more technical and less bureaucratic than a year ago. In many cases, I am the only person who can make binding decisions when teams disagree on the path forward, and that means I am making decisions constantly in this new world in order to maintain the pace. (That’s not an argument that executives are better decision makers, just that binding executive decisions are uniquely powerful to the extent that the executives themselves are aligned enough to honor those decisions.) What have we done in practice So, I genuinely believe the above rules based on my experiences over the past year, and let me try to connect them to specific projects we’ve worked on that have convinced me of them: Migrations A year ago, we deployed manually, and deployed ~6 times a week, and now we deploy 200-400 times a week. Our engineering headcount has doubled, but even if we double the prior deploys, we’re still up 20-30x year-over-year. This is due to a complete overhaul of how we deploy and run migrations, and this migration was done over two months and done 90% by two folks on our infrastructure team. The first day of January, about 25% of folks on our team used Claude Code or Cursor every day. By the end of February, 100% did. We did this without any top-down mandate, just by making the tooling good and chatting with non-adopters to remove sources of friction. Pretty much every PR is written by harnesses now, at least in the first pass. We migrated from a large number of varied configuration mechanisms to two configuration mechanisms (one for client or server constants that rarely change, a second for product-specific or frequently changing values). This was a large series of changes, which were largely done as a series of isolated projects by individual engineers. First, one engineer cleaned up the architecture to support this approach. Then another engineer did a reference architecture on the new approach. Then several more engineers followed the reference architecture in other areas of our codebase. This might have been a years long project of many people in the prior world, but took less than a quarter to complete, including a new internal tool for managing these values across engineering and non-engineer teams. We unified a multi-repo frontend application architecture into a mono-repo frontend architecture over about a month. This was 95% driven by one frontend engineer. We now have a shared frontend development harness, can maintain libraries cheaply, and entirely moved off using npm for package hosting, which was a source of ongoing friction. We fully statically typed our frontend code, going from a place where the majority of our frontend code was not typed. This was done by one engineer, and a lot of tokens, over the course of a few weeks. We migrated from npm to pnpm for better security defaults and faster deploys. This took one engineer a few hours a day for a few days. Cost of working code depends on your development harness. Where we’ve tried to throw design documents and PRs “over the wall” to engineers on other teams, they’ve never gone anywhere. Slop pull requests and design documents are cheap, but are actively harmful. They not only have to be cleaned up and repaired, their context poisons the LLM, leading to worse outcomes than starting over. We’ve seen tremendous success in managers contributing software, as long as those managers are validating the work directly, looking at dashboards after their changes go out, and resolving any issues their changes cause. We’ve found no positive impact from folks attempting to make changes where they don’t do those things. Optimize the base-case of process for agents. We triage all incoming issues from our customer operations team using a harness which knows our team, our open tickets, and has limited access to our data warehouse to size the impact of issues. This is complex, high-skill but not particularly interesting labor that we’re now doing better and faster with agents. Yes, there is still a human triage for the edgecases. Importantly, we’re also doing this without changing human workflows, it’s the same workflow, just with some steps automated. The first pass of code review is done by the same harness that implements the changes, cleared of the context used to write the change, allowing humans to focus on higher value feedback. We rolled out Claude Code and Cowork to all folks in the company last quarter, and have seen them also automate an increasingly large swath of their work as well. Our fraud team has been particularly ambitious in replacing manual workflows with a first-pass of automation–with attribution to the data itself–to do the initial investigation on potential attacks automatically. We’ve migrated to Linear, and off Jira, to better support this workflow with a more capable MCP and better Slack integration, making it possible for everyone internally to have better infrastructure for building these agent-first workflows. More on this later, but we’re almost done alpha-testing our internal harness pulling issues off Linear, and working to resolve them, automatically which is our biggest next step in this direction. Durable, high ownership teams with domain-context are even more important. When I joined, we had a number of areas supported by very talented folks who rotated through them quickly on a per-project basis. This worked, but it meant we were very reactive to issues. Now, we’ve been able to dedicate at least a small team to every important area of the company, where they are able to persistently invest. These teams are now wielding all the new techniques afforded by AI themselves. Without them, no one would be capturing these opportunities, because there is simply too much happening. We launched SierraAI, which is quite good, but since then the team has iterated on it relentlessly, getting it truly excellent. This is something we wouldn’t have been able to do without a dedicated, focused team. Quick, good and durable decision making is a prerequisite to benefit from AI. Changing how we do configuration was a controversial decision, and I’ve had to make repeated clarifications on the approach. This would have been very difficult to do bottom-up, because it impacts every team differently, and the benefit is only experienced at the ecosystem-level (allowing one person to configure all configuration across teams). Reworking our CI/CD pipeline was controversial, as it changed many folks’ mental models of how we deploy and release (e.g., it forced us to explicitly decouple deploy and release via feature flagging). This was a contentious decision, and would have been slow and difficult to make bottom-up. Unifying into a web mono-repo was also a controversial decision with varied opinions. It benefitted greatly from having a unified decision. Moving to SierraAI was a difficult discussion versus both various competitors, and also not doing it. It needed the executive stamp to finalize the cross-functional debate. These are just representative examples, we’ve done a lot more than these. The aperture of what’s possible has continued to expand every month this year, but the things holding us back haven’t changed all that much: organizational misalignment, lack of clarity, and poor technical architecture. It’s a wild time to be working in technology.
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It's time for a dev blogger's favorite topic: blogging about my new blogging setup. After migrating my blog from Hexo to Eleventy, building a photography website and creating a personal one-pager, it was time to find a new digital home for all my projects. If you notice any issue after the migration, please let me know. I redirect the RSS feed to the new domain, but you might want to update the feed URL in your reader. Motivation I've been maintaining three different websites under two different names: a mostly developer-oriented blog, a photography portfolio and a one-pager gluing everything together. When I started blogging about my sabbatical journey, I was thinking about making yet another page to create a clear separation. I've decided to do the opposite and merge all my websites into one instead. As I further reduce my dependency on social media and third-party services, it has become even more important to have my own space and practice POSSE. Every decision I've made was driven by two main goals: simplicity and personality. Setup I've stopped chasing the latest and greatest. I want to keep the setup as clean as possible, which means pulling fewer dependencies. Every package adds complexity and maintainability costs, so I've only added what was necessary — no more Gulp, Sass or Tailwind. Instead of taking one of my existing websites as a starting point, I created this project from scratch. I reused some of my previous code, but I didn't want to take over any technical debt (especially with the advancements in CSS). The foundation of this website hasn't changed: Eleventy (Build Awesome). It covers the fundamentals of a static site and offers a great level of customization. I've made my project more and less dependent on Eleventy at the same time: I replaced Gulp as my build pipeline with pure Eleventy processing. I replaced most shortcodes with Markdown alternatives (and markdown-it plugins), which are better supported by editors like Obsidian. I've also replaced the Nunjucks template engine with Liquid, which comes with a few trade-offs. The main reason was to avoid creating a new collection for every set of posts I render. With Liquid, you can apply array functions like filtering or sorting in the template itself: {% assign drafts = collections.all | where: "data.isDraft" | reverse %} {% for draft in drafts %} … {% endfor %} Another advantage is having date formatting included, so I don't need another library or custom code. You can even set a default date format, so you don't have to provide it each time. What I don't like is the verbosity of the template language, although I've gotten used to it by now. Nunjucks: {{ "/tags/" + tag + "/" }} {{ modified or created or date }} {% set perspectives = ["dev", "photography", "life"] %} Liquid: {{ "/tags/" | append: tag | append: "/" }} {{ modified | default: created | default: date }} {% assign perspectives = "dev, photography, life" | split: ", " %} After migrating my existing content, I've noticed the build taking way too long, both in the dev server and the production build. I've found out that the Eleventy template cache is turned off for Liquid by default. This was useful during development, but when updating actual content, it caused every template and partial to be constantly recalculated. After turning the cache on, this issue was resolved: eleventyConfig.setLiquidOptions({ cache: true }); Check the colophon for the full tech stack overview. Perspectives The main challenge was finding a way to separate and present my main personas. The Venn diagram intersection of people interested in software development, photography and my personal life is probably small. I could use tags, but they don't offer the level of personalization I was looking for. Most personal blogs separate the content by post type (blog post, note, photo), but this doesn't fit my use case. Instead, I've decided to structure my website around three perspectives, a term I have borrowed from the Eclipse IDE. Each perspective comes with its own avatar, tagline and bio. If someone is interested in everything I share (hi Mom!), they can still view all my posts. Design Since building my photography website, I've made many changes, but I never got around to share an update. The biggest change was the design, which I have used as a blueprint for the new website. I've decided to mimic a social timeline/feed, which most people are familiar with. At the same time, it should be clear that it's a personal website and not yet another walled garden. Typography is an important part of every design. The first step is to choose between a system font stack and a custom font, which comes with the usual performance vs. personality trade-offs. I've decided to go with a uniform look across all devices. I've settled on Source Sans 3 for copy text and Hack for code. Another big change was introducing a sidebar. I always felt like the empty horizontal space was "wasted" on a desktop device, but getting the sidebar UX right is challenging. I'm happy with the result, especially with the last two panels adding a personal touch to the design. Images I've made several changes to the handling of image files. To make them compatible with Markdown editors, I had to replace my custom picture shortcode. The official Eleventy image plugin is a popular choice, but it violates my simplicity goal and doesn't support everything I needed. I've decided to go with a plain Markdown image markup and a single image file (no format fallback or 2x version for retina displays). Additionally, I wrote a markdown-it plugin to turn the optional title parameter into a caption. As for the file format, both WebP and AVIF have excellent browser support. For each image, I select the format based on the quality and file size. For my photos, I'm using WebP for the timeline thumbnails and JPG for the full-size version. Theme picker There have been some recent discussions about dark mode toggles, and I considered going for a light/dark solution based on the user's OS preference. Driven by the personality goal, I knew I had to add at least one more theme, so a proper theme picker was necessary. Similar to navigation, people like to hide the theme selection on mobile devices behind a burger menu or a dropdown. I prefer the solution by Sarah L. Fossheim, where all available themes are displayed above the page footer. A friend was scrolling through my new website, and their first question was "Why is the theme picker in the footer?". This tells me the solution was a good idea — I don't think he would have noticed a typical theme button in the header. The implementation follows standard practices: Use the light or dark theme as default based on the user's OS or browser preference. Store a selected theme in the local storage and use it as the single source of truth. Prevent a flash of inaccurate color theme. Make the theme play nicely with bfcache. I might have slightly gone overboard with my third theme, but the nostalgia kept me adding more and more features. Enjoy going back to the 90s: Feeds As browser vendors decided to remove XSLT support, I didn't bother to style my feed. Instead, I've created a new web feeds page, listing all available feeds and a short explanation. I provide one feed for every perspective and one with all my posts combined. I once offered tag-based RSS feeds. This was useful for my sabbatical, but even there I had only a single subscriber. Now, all tag feeds redirect to their main perspective feed. I've also dropped the JSON feed, despite having at least 16 subscribers. Given that every web feed reader supports Atom feeds, I don't see the value of providing a JSON alternative. A JSON feed doesn't add much complexity, but handling different media types (post, photo) and properly escaping the content is one more thing to implement and maintain. Quality assurance I've put a lot of effort into my new digital home, and I want to make sure it stays in good shape. I've included several tools, most running automatically as part of the CI pipeline: eleventyDataSchema — lint Eleventy data values like titles or dates markdownlint — format/lint Markdown files Vale — lint content (grammar, writing style, formatting) Lychee — find broken links (internal and external) Evaluatory — check accessibility and validate HTML Oxlint — lint JavaScript files Eleventy linters are another option to analyze a template's output, but I haven't found a use case for it yet. Not everything can be automated, so I also did the following manually: Test with Chrome, Firefox and Safari Test with Polypane Test with Google Lighthouse Test with a screen reader Test with JavaScript disabled Test with CSS disabled Test at 200% zoom Test with a bigger browser font size Test with custom fonts disabled Test with delayed assets Performance It's difficult to compare the performance of two separate websites with that of a combined one. Some parts got worse, e.g. bigger font files and more CSS. At the same time, I've noticed that gzip compression was turned off for anything but HTML for a few years now (I must have missed it when upgrading nginx) 🙈. One improvement was to implement on-demand assets. For example, the lite-youtube-embed CSS and JavaScript is only loaded if a <lite-youtube> element is present on the page. As before, JavaScript is fully optional (except for interactive demos in individual posts). I've been using a mix of <noscript> and CSS to hide elements that require JS (like the theme picker). I don't like the user experience of pagination, so I avoided it for years. But now that I have almost 300 posts, I've decided to finally add it. I display 30 posts per page, with images further down still being lazy-loaded for better performance. I haven't applied pagination to tag pages, as that's more complex with Eleventy. Bits and pieces Here are some other noteworthy changes: I've removed post-specific social share images and use a single WebP Open Graph image instead. I've dropped JSON-LD. Open Graph and microformats are sufficient. "Naming is hard" is a common expression in software development, but it also applies to photograph titles. I've decided to use a counter as the title, e.g. #0100. Sometimes I do come up with a title that I love, like the Castle in the Sky, so I might mention it in the description. On a photo page, you can now open the previous/next photo using the left/right arrow keys (in addition to the existing navigation buttons). It's now possible to filter photos by date, gear, or location. Check the explore page for an overview. I've learned about and used some experimental CSS features (with progressive enhancement), like scroll-triggered animations or squircle corners. I've added an AI statement on my LLM usage. I finally have a proper about page. Cool URIs don't change, but it's inevitable when moving to a new domain. All my previous URLs are redirected, except for some assets that are no longer used. I will keep the old domain, so the redirects will continue to work for a foreseeable future. I've kept my previous Easter egg and added a few more. Have a happy hunt! 🕵️♂️ Inspiration I visited hundreds of personal websites looking for inspiration. Here are a few that I kept coming back to: Emma Goto. I love Emma's approach to presenting the variety of her interests, even though I went a different route. Brennan Kenneth Brown. This website has so much to offer. It's a great example of what the open web looks like. Rex Barrett. The sentence "Collecting hobbies is my hobby." hit home — so much that I had to steal borrow it for my short life bio. Conclusion This project was mostly about merging the content of two websites into one. I knew this would take a considerable amount of time, but I still greatly underestimated the effort. In the end, it was all about the journey, not the destination. I loved fine-tuning the design and tweaking little details that probably no one will ever notice. I still have many more ideas left in my backlog. How do you like my new digital home? If you have an opinion, let me know! Reply via email
New electronica album by Warrington-Runcorn New Town Development Plan
To protect against link rot and disappearing content, I save local copies of web pages I like into my web archive. Ideally, this archive is completely self-contained. I want a local copy of each page’s HTML and all the assets it depends on (CSS, images, scripts, and so on). I don’t want my archived pages fetching resources from the original website, which could disappear at any time. Initially, I was verifying self-containedness by hand. I’d open each saved page in a web browser, and check the browser dev tools. I’d check the Console tab for errors and failed requests, and watch the Network tab for requests going out to the internet. That approach was tedious and error-prone, and I wanted something better. I now automate the process using Playwright, a testing framework that allows you to control web browsers. I open each page using Playwright, and check if it’s making external requests. Detecting external requests in Playwright When you open a page in Playwright, you can subscribe to request events which tell you when the page issues a request. In this Python snippet, we start Playwright, start a WebKit browser, and open a new page. We tell the page to append external requests to a list, and then load example.com. We see that example.com makes two requests on page load: one for https://example.com, and one for a JavaScript file. from contextlib import closing from playwright.sync_api import sync_playwright with ( sync_playwright() as p, closing(p.webkit.launch()) as browser, closing(browser.new_page()) as page, ): requests = [] page.on("request", lambda msg: requests.append(msg)) page.goto("https://example.com") print("requests:", requests) # requests: [<Request url='https://example.com/' method='GET'>, # <Request url='https://example.com/s.js' method='GET'>] In a more complex scenario, we might use Playwright to interact with the page after loading – for example, clicking a button or filling in a form, and then we could see the requests triggered by each action. Once we have a list of requests made by the page, we can inspect the url property to check if any of them were fetching from an external website. I wrote a function is_external_request to carry out this check: from playwright.sync_api import Request import urllib.parse def is_external_request(req: Request, original_url: str) -> bool: """ Check if a request has a different origin than the original URL. A request is considered internal if: - it matches the original URL exactly - it has the same scheme, host, and port as the original URL - it uses a `blob:` scheme (for example, in-memory media representations) """ if req.url == original_url: return False # Compare the scheme/host of the request to that of the original URL. org_url = urllib.parse.urlsplit(original_url) req_url = urllib.parse.urlsplit(req.url) if org_url.scheme == req_url.scheme and org_url.netloc == req_url.netloc: return False # Ignore blob: URLs, which are in-memory representation of some data, # and not an external request. # # Playwright detects blob: URLs when loading media files; for example # using the <audio> or <video> tag. if req_url.scheme == "blob": return False # Fail open: if we can't decide if a request was internal or external, # assume it was external. return True assert_page_is_self_contained(ctx, url) I’ve wrapped these two steps in a function assert_page_is_self_contained(ctx, url), which is part of my chives utility library. The function takes a Playwright Browser (or BrowserContext) and a URL, then: Opens a new page in the browser Loads the URL in the page Checks what happened when the page completes loading It throws an exception if there are any: Uncaught page exceptions or errors Console warnings or errors Non-GET requests Requests targeting external resources The function tries to trigger important network requests that might be skipped on the initial page load. For example, it evaluates the body’s offsetHeight to force a synchronous reflow, which causes the browser to request any lazily loaded images or fonts that might otherwise be missed. Here’s an example which verifies a file example.html from the working directory: from chives.browser_fixtures import assert_page_is_self_contained, file_uri from contextlib import closing from playwright.sync_api import sync_playwright with ( sync_playwright() as p, closing(p.webkit.launch()) as browser, ): assert_page_is_self_contained(browser, url=file_uri("example.html")) I originally passed a Page as the first argument, but changing the function to take a Browser or BrowserContext lets it manage its own pages. It gets a fresh page for every verification, and closes it when it’s done. (The first time I ran this, I created a new page for every verification, and never closed them – my computer ground to a crawl as my script opened hundreds of browser tabs.) If you create a new context, you can emulate different browser settings, like location, locale, and window size. Here’s an example where we use contexts to test the same page in light/dark mode: with ( sync_playwright() as p, closing(p.webkit.launch()) as browser, ): with closing(browser.new_context(color_scheme="light")) as light_ctx: assert_page_is_self_contained(light_ctx, url=file_uri("example.html")) with closing(browser.new_context(color_scheme="dark")) as dark_ctx: assert_page_is_self_contained(dark_ctx, url=file_uri("example.html")) In my web archive, I check every page in light/dark mode, and at 1×/2× pixel densities. It takes at least a second to run each verification, so I cache the results. As I save new pages, they’re added to a verification queue, and I’m warned of any missing assets. Unsurprisingly, the first run flagged many missing fonts and images, which I added to my local archive. Every saved page now passes cleanly. Browser is best-effort, but may still miss things Even with automated testing, it’s difficult to guarantee a completely self-contained archive. Different instances of a browser might load different assets, and a single page load might miss different variations: Responsive images – web pages can offer different sizes of an image, and the browser chooses a specific size based on the current window dimensions Appearance settings – a browser might load different fonts or images depending on light/dark mode Interaction-dependent assets – a web page might have assets that are only required on hover or user action You can mitigate some of this by testing with multiple contexts or adding post-load interactions, but every step makes the process take longer. Fortunately, most of the pages I save are simple, blog-style pages where I’ve stripped out the JavaScript. For my specific use case, initial load verification is more than good enough. Other uses for this code There are other projects where it could be useful to intercept and audit the requests made by a web page: Verifying your Content Security Policy (CSP). The CSP header restricts what resources can be loaded by a web page, and you could check that your configuration has the correct effect. Auditing login screens. You could check that sensitive pages don’t load any external scripts, which mitigates the risk of credential theft via a compromised third-party. Testing analytics and tracking. You could script user flows, like a shopping cart checkout, and confirm that tracking events fire correctly. I don’t do much front-end web development, but Playwright has become a key tool in my toolbox. I read a lot about people using AI agents and MCPs to interact with websites, but I prefer Playwright. It’s more fiddly and requires explicit instructions, but it’s constrained, deterministic, and I never have to worry about it doing something unexpected. [If the formatting of this post looks odd in your feed reader, visit the original article]
It’s four years since I bought a printer. I thought I would provide an update on running costs, print sales, and profit. I’m happy to be completely transparent about all this as I know it can be difficult to figure this out if you are thinking of creating your own printing business. January 11th 2026, 11:30am All the photos here are work shot in the last twelve months. Year Four Investment? Nothing other than consumables this year. I did purchase a high-spec film scanner last year, detailed here, but don’t consider that as part of this. The scanner has paid for itself several times over, and it may become a factor in future years (see below). Income Income is made up of sales through a local gallery that I am part of, along with web sales: 5,940.- CHF - sales through the gallery 80.- CHF - sales through web shop = 6,020.- CHF total income Total income is down about 50% compared to 2025. Costs I had to purchase consumables (paper and ink), at a total of 957.- CHF. That cost is included in the total here under the “print consumables” category. January 11th 2026, 3:30pm Rental cost of space in the gallery was reduced due to having overpayments of rent and my loan to the gallery, from the previous year(s), paid back to me. -1,500.- CHF - rental cost of space in the gallery -957.- CHF - print consumables (paper, ink) -1,138.- CHF - framing/mounting/postage -1,135.- CHF - commission to the gallery -300.- CHF - web shop subscription 0.- CHF - stripe / paypal fees 0.- CHF - advertising (none this year) = -5,030.- CHF total costs Total costs are down by about 60% compared to 2025. Total Profit 6,020.- CHF total income -5,030.- CHF total costs = 990.- CHF total profit A Quiet Year? Actually an average year. The previous couple of years were outliers, due to large orders, so really I’m back to normal in terms of sales. The key factors in managing to generate a [small] profit this year were: 1) no longer having to pay back the loan used to finance the printer, and 2) reduced rental cost of space in the gallery due to a previous loan to it being repaid. Also having to spend almost 1,000.- CHF on ink this year ate into profit. This is probably a “once every three years” cost given the rate I print at. The principal cost is rental of space in the gallery - in a normal year this would be 3,000.- CHF. Essentially this means, given the material cost of printing and framing/mounting and commission to the gallery, I need to make about 5,500.- CHF of sales to break even. Solar Eclipse, August 12th 2026 That’s a grind. However I did receive two substantial orders at the end of October, which haven’t made it in to this year’s figures and should boost next year’s. Maybe even a good sign for the year to come? At least now the original investment loan is repaid, the printing costs cover themselves in most years. I may look at offering scanning services now that I have a high-spec film scanner, which could become a scan + print service. More thoughts about that next time.