Tech, teams, and the bits in between.

John Gregoriadis — Principal Engineer at Prosaic. Essays on AI agents, engineering teams, and the things I take apart to find out how they work.

Line-art portrait of John Gregoriadis, Principal Engineer based in Auckland, New Zealand
John Gregoriadis -36.85°, 174.76° · Auckland, NZ
2026 39 posts
DateTitleTagsMark
2026-08-05 scoutdigest ↗ Your agent forgot what it already didnew
A deterministic layer that tracks what a coding agent has already read and changed lifts first-try success by 8 points while cutting cost by 29%.
3 papers +8.0 pts at 28.9% less cost
2026-08-04 scoutdigest ↗ Your coding agent will not delete
Models find the right file for 92% of required deletions but cut the exact line under 52% of the time. Test for removal and pass rates fall from 63% to 42%.
5 papers 63.2% → 41.9%
2026-07-29 scoutdigest ↗ Stop reading pixels. Read the state.
An agent working on files and app state instead of screenshots scored higher at a ninth of the cost. Plus harness cost, hidden reasoning, and agent security.
5 papers 9× cheaper per task
2026-07-14 Ukraine’s Drone Advantage Is an Engineering Loop
A technical look at Ukraine’s drone stack, its battlefield engineering loop, and the evidence behind balloon-launched aircraft.
engineering ai drones
2026-07-14 Prove the Machine Wrong
A parking camera joined two visits together, then handed Keith Miller the job of proving it wrong.
ai new-zealand privacy
2026-07-05 Policy WhiplashPart 03 I Parsed Every Law New Zealand Has Ever Passed
38,064 XML files, 241,456 amendment events, the oldest from 1872. What the entire NZ statute book looks like as data, and why counting 'a change' turned out to be the hard part.
data open-data new-zealand
2026-07-01 Your Show HN dies in 7 hours
I scraped all 41,301 Show HN posts from the last year. Half the comments a launch will ever get arrive inside 7.2 hours, and success doesn't slow the clock.
data startup founders
2026-06-19 Policy WhiplashPart 02 The Fastest Repealers in the West
In 2025 Parliament sat 644 hours and spent a third of them in urgency. The churn isn't a personality flaw. We built the company this way.
data open-data new-zealand
2026-06-12 Policy WhiplashPart 01 Six Years, $228 Million, Zero Metres of Track
Auckland Light Rail: six years, $228 million, zero metres of track. A running tally of what changing our minds costs.
data open-data new-zealand
2026-05-31 What Happens When a Worm Drives Claude?
I wired a live C. elegans connectome into the control loop of a Claude coding agent, then watched what the worm did when the code broke.
ai engineering ai-tooling
2026-05-31 The holes that kill you are the ones you never tested
The Swiss cheese model trains you to count slices. The holes that actually kill you are the ones you never tested.
engineering architecture reliability
2026-05-26 The Laws of Human Nature
An interactive read-through of Robert Greene's 18 laws — 18 cards, full essays inside each.
psychology books human-nature
2026-05-14 Conscious Minimalism
How I build: small, narrow, niche, AI-native.
founders engineering reflection
2026-05-06 The dent and the crater
On hardening as a senior leader, the cost of walls that read as wisdom, and the quiet work that keeps a dent from becoming a crater.
leadership reflection founders
2026-05-05 I Built a Read-Later Chrome Extension Because Pocket Died
Pocket shut down in July 2025. I needed somewhere to dump the articles I keep telling myself I'll read later. So I built a Chrome extension that does exactly that and nothing else. Local-only, no accounts, no tracking.
engineering tooling privacy
2026-05-01 Product market fit isn't a stage, it's a gauntlet
PMF gets sold as a milestone. It's actually a gauntlet that bends founders, breaks teams, and quietly poisons technical decisions. Most of the damage isn't from missing PMF — it's from how you behave while looking for it.
founders leadership startup
2026-04-25 Change management
On the personal version of change management — the long, weird middle bit between who you were and who you're becoming.
leadership careers reflection
2026-04-23 Predicting Crime in AotearoaPart 07 Three Ways to Look at Time
ST-ResNet decomposes crime patterns into three temporal scales and models each one separately. Clever architecture, but does it actually help with only four years of NZ data?
data machine-learning open-data
2026-04-21 What an hour of your attention is worth
You pay Big Tech about $1,000 a year in attention. Here's how to read the meter — and why building your own is suddenly cheaper than opting out.
data privacy engineering
2026-04-16 Predicting Crime in AotearoaPart 06 Teaching a Neural Network to Watch Crime Like Video
ConvLSTM was built for weather radar. Turns out predicting crime on a grid is basically the same problem. Here's how it works and what it learned.
data machine-learning open-data
2026-04-15 Open-Source Agent That Teaches Claude Code Your Architecture
AI made software cheap to build but not cheap to scale. Evolutionary architecture with domain-aware AI agents is the missing piece.
ai claude-code architecture
2026-04-13 Firecracker MicroVM OrchestratorPart 03 Claude Code Can Now Spawn Copies of Itself in Isolated VMs
Wiring up an MCP server so Claude Code can spawn isolated VMs, the SSE-to-Streamable-HTTP migration that broke everything, streaming architecture, and what productionising this would actually look like.
ai go mcp
2026-04-13 OpenHealth – Chat with Apple Health Data, Anywhere
I built OpenHealth because Claude's and ChatGPT's Apple Health connectors are US-only. Drop your export.zip, get seven markdown files any LLM can read — browser, CLI, or phone-to-desktop over WebRTC.
ai engineering privacy
2026-04-11 The Future of Security Is an Open-Source Model That Detects and Acts on Threats
Anthropic's Glasswing is for enterprises with six-figure security budgets. The rest of us need open-source security agents that learn our systems and act autonomously.
ai security architecture
2026-04-10 Firecracker MicroVM OrchestratorPart 02 I Spent 29 Hours Debugging iptables to Boot VMs in 4 Seconds
Building a Firecracker MicroVM rootfs, wiring up TAP networking, debugging UFW's FORWARD chain, and writing a guest agent with raw vsock syscalls in Go.
go firecracker networking
2026-04-09 Predicting Crime in AotearoaPart 05 Can You Beat Last Month?
Before deep learning gets a chance, we need to know how well stupid-simple models perform. Turns out, they put up a real fight.
data machine-learning open-data
2026-04-08 Firecracker MicroVM OrchestratorPart 01 Claude Code Running Claude Code in 4-Second Disposable VMs
Anthropic has an internal platform for running Claude Code in full-permission isolation. I built my own version with Firecracker MicroVMs, Go, and a $400 Ryzen box.
ai go architecture
2026-04-05 NanoClaw ArchitecturePart 02 Stealing NanoClaw Patterns for Web Apps and SaaS
Four architectural patterns from NanoClaw's tiny codebase that translate directly to production web apps and SaaS — credential sidecars, infrastructure-level isolation, polling loops, and Postgres as your message queue.
architecture security engineering
2026-04-05 What if your browser built the UI for you?
We're still shipping hand-crafted frontends while AI can generate entire interfaces. What if the browser itself generated the UI from an API manifest and your preferences?
ai architecture engineering
2026-04-02 How I Built an SMS Gateway with a $20 Android Phone
Turn any Android phone into a programmable SMS gateway for your SaaS — no per-message fees, no carrier contracts, no vendor lock-in.
engineering tooling architecture
2026-04-02 Predicting Crime in AotearoaPart 04 What the Data Actually Shows
Before throwing deep learning at Auckland crime data, you need to actually look at it. Seasonal patterns, spatial hotspots, and the sparsity problem.
data machine-learning open-data
2026-03-26 Predicting Crime in AotearoaPart 02 Giving Crime a Place on the Map
Crime records come with names and codes but no coordinates. Here's how we joined 1.15 million records to Stats NZ boundary files and gave every crime a place in physical space.
data machine-learning open-data
2026-03-26 Predicting Crime in AotearoaPart 03 Crime as Video
Turn a million geo-tagged crime records into a 4D tensor by overlaying a 500m grid on Auckland. Crime prediction becomes video prediction.
data machine-learning open-data
2026-03-26 Predicting Crime in AotearoaPart 01 Wrangling a Million Crime Records
NZ Police's crime dataset is publicly available, but it's UTF-16 encoded, full of trailing periods, and 32% of records don't know what time the crime happened. Here's how we cleaned it up.
data machine-learning open-data
2026-03-24 Predicting Crime in AotearoaIntro Predicting Crime in Aotearoa
NZ Police publish over a million crime records openly. What happens when you point deep learning at them?
data machine-learning open-data
2026-03-23 NanoClaw ArchitecturePart 01 NanoClaw's Architecture is a Masterclass in Doing Less
I pulled apart NanoClaw's 8,000-line codebase and found six architectural patterns that most SaaS teams should steal — credential proxies, container isolation as authorization, two-cursor message processing, and more.
ai architecture security
2026-03-21 Careers in the Self-Driving Codebase Era
The engineering career ladder was built for when code was expensive. Code is now cheap. What's valuable has fundamentally shifted.
ai careers engineering
2026-03-18 Why LLMs waste half their brain
AI coding agents burn too many tool calls just figuring out where things are. I built codemap to fix that — cheap model indexes, cheap model selects, big model codes.
ai claude-code tooling
2026-03-18 What if a Worm Could Make AI Agents Smarter?
Introducing c302 — a research project that uses the C. elegans roundworm's neural dynamics as a behavioural control layer for an LLM coding agent.
ai neuroscience c302