Field Notes
Notes on event-driven Java, Spring Boot, Kafka, and secure systems for regulated banking.
The Model Context Protocol, hands on
Field notes from wiring Fastmail's MCP server into an AI client and pointing it at my real inbox — the search syntax worth memorising, plus the two gotchas (deferred schemas, and stage-vs-commit on calendar events) that cost me a few minutes.
Traces, Tempo and the LGTM stack
TraceQL has a tiny surface area but a few sharp edges. Here is the mental model — span scopes, the spanset, aggregates, and structural operators — that makes it click and stops the silent zero-result queries.
Traces, Tempo and the LGTM stack
Wiring OpenTelemetry into Spring Boot 4 — the annotation way and the manual Tracer way — plus the context model that ties them together and the gotchas that cost me time (a silent @WithSpan, http/protobuf vs gRPC, and Docker's 'is a directory').
Security and privacy, in practice
Five ways to hand a secret to a Docker container, ranked by who can read it back out. The source is just plumbing - environment variable vs file is what actually decides your exposure.
I love how my site looks, so I taught Claude to build with it — extracting a live React app into a real design system on claude.ai/design, verified component by component.
A Domain property covers your apex and every subdomain from a single DNS TXT record — if you place it right. Here is the split-field mistake that fails the first verify, and the one command that catches it before you click.
Three validation mechanisms wear one annotation vocabulary in Spring MVC. Only one hands you a ConstraintViolationException — the rest give you Spring's own web exceptions. Here's the map, with live proof.
AI agents are a new kind of reader, and they don't want your rendered HTML. llms.txt is a tiny Markdown convention that hands them a clean index instead. Here's what it is, why it matters now, and how I wired it into my own Spring Boot site, with one URL path serving two different files by host.
How I added a public, server-rendered blog to a login-gated CV site without a second app or container — one jar, two hostnames, and a host-dispatch filter.