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I’ve been using Claude Code a lot lately. It’s become a core part of how I work — planning changes, exploring unfamiliar codebases, writing and reviewing code. But giving an AI agent the ability to run arbitrary shell commands on your machine does make you think a bit more carefully about what’s happening on your host system.

The natural answer is to run it in a container. Not as a security boundary — Claude still needs access to your code, your git config, a GitHub token, and the internet — but as a way to keep all the side effects contained. If it installs random packages, creates temp files, or leaves build artifacts scattered around, that’s all happening inside the container rather than on your actual machine. It also makes the environment completely reproducible and disposable. Something goes wrong? Tear it down and rebuild.

So I built claude-docker to do exactly that.

The Optimism blog has published an article I wrote discussing the various types of tech debt. I’ve been finding it very useful lately to be able to “put words to things” better, whether that’s naming things better or just better ways to explain things.

Teku uses a really nice framework for separating different components - Event Channels. It’s based on similar patterns in the Sail library used at LMAX for sending network messages between services. In Teku though, it’s designed to work in-process while still decoupling the components in the system. Turns out I never wrote about it here, so I’m very belatedly catching up.

One of the downsides of moving from working on the Ethereum consensus layer is that you often need a real execution node sync’d, and they don’t have the near instantaneous checkpoint sync. So recently I bit the bullet and custom built a PC to run a whole bunch of different Ethereum chains on. I’m really quite happy with the result.

After nearly 5 years working with the ConsenSys protocols group, I’ll be finishing up at the end of January.

Mostly just so that I can find the recordings more easily later, here’s the recordings of DevCon VI talks I gave in Bogotá.

The process of producing attestations and getting them included into the chain has become more complex post-merge. Combined with a few issues with clients causing more missed attestations than normal there’s lots of people struggling to understand what’s causing those misses. So let’s dig into the process involved and how to identify where problems are occurring.

When debugging issues on the beacon chain, it can be useful to download all blocks on a particularly, potentially non-canonical fork. This script will do just that.

Obol Network are doing a bunch of work on distributed validator technology and have hit some challenges with the way the beacon REST API determines if validators are scheduled to be aggregators.

In the beacon chain spec, the chain is justified when at least 2/3rds of the active validating balance attests to the same target epoch. Simple enough, but there’s a couple of little quirks that are easy to miss.

One of the common concerns people raise about checkpoint sync is the risk that someone might hack Infura and return malicious initial states causing nodes to sync and be stuck on the wrong chain. Given users usually don’t verify the initial state and Infura is currently the only publicly available service supplying initial states, there is certainly some risk there but how concerned should we really be?

Apart from being awesomely fast, checkpoint sync also exists to ensure that you can safely sync despite the limitations of weak subjectivity. The initial state you use is considered trusted - you are telling your beacon node that this state is the canonical chain and it should ignore all others. So it’s important to ensure you get the right state.