Wednesday, 19th August 2026
Conceptual integrity and counting lines of code
Last week I recorded an episode of the Talking Postgres podcast with Claire Giordano on the subject of “How AI is changing software development”. We had a really great conversation. Here are a couple of my highlights from a lightly edited transcript (prompt to Claude: “very minor edits to remove disfluencies”).
[... 610 words]My hypothesis is that there is a new opportunity for Extensible Software on the web. LLMs radically lower the cost of authoring extensions, and modern sandbox primitives lower the deployment cost and provide good security boundaries. We can build our app as a solid, accountable core, and allow users to safely extend it in many directions by having LLMs fill in the missing pieces. We can give our users super powers.
— Jeremy Morrell, Extensible Software in the age of LLMs
I tasked Claude Fable 5 running in Claude Code for web with the following research task:
Put https://smolmachines.com through its paces as a fast secure sandbox. Explore what it would take to use this to run untrusted Python and JavaScript code in a way that is limited in what RAM and CPU time it can take up (protection against "while true") with no network access and filesystem access only to designated files
Goal is to be able to use this to execute user-provided tasks for things like data transformations
It quickly ran into a problem: the Claude Code for web environment can't run smol machines. Quoting the notes it wrote:
- This Claude Code container: Linux 6.18.5-fc-v20 (itself a Firecracker guest), 4 vCPU, 15GB RAM. No /dev/kvm, no vmx/svm CPU flags → no nested virt.
smolvm machine runfails as expected: "kvm not available".- Plan B: GitHub Actions ubuntu runners DO expose /dev/kvm → run the real test battery via a temporary workflow on this branch, collect logs, remove workflow in final commit.
And Plan B is what it did, installing smolvm and running these tests directly in a GitHub Actions runner against that branch.
That was a creative solution to the environmental limits posed by Claude Code for web. Another example of Fable being relentlessly proactive.