# How Filippo Valsorda actually uses coding agents

Go cryptography, age, mkcert

**If you take one thing:** `filippo-agent`, agent's own GitHub account. his agent commits from a separate, low-privilege GitHub account so it never holds his maintainer keys.

- **Agent:** Shelley (exe.dev) (web) ([source, 2026-09-27](https://gist.github.com/filippo-agent/4a76063873cdd5221ee0710803e6784b))
- **Agent:** Claude Code (cli) ([source, 2026-07-26](https://bsky.app/profile/filippo.abyssdomain.expert/post/3mrke6zps6c2f))
- **Model:** GPT-6 Astra ([source, 2026-09-27](https://gist.github.com/filippo-agent/4a76063873cdd5221ee0710803e6784b))
- **Model:** Claude Opus 4.8 ([source, 2026-07-25](https://github.com/omissis/go-jsonschema/commit/48ec8fa379592a5e08180d7f5089e946b7ebcf7e))
- **Review:** LLM review before any human review ([source, 2026-06-20](https://bsky.app/profile/filippo.abyssdomain.expert/post/3moq6sdq6xk2l))
- **Harness:** exe.dev VMs with the built-in agent, a separate agent GitHub account, Jujutsu ([source, 2025-12-24](https://bsky.app/profile/filippo.abyssdomain.expert/post/3maqkjb7ujg2l))
- **Rules file:** AGENTS.md with Go CLI tips (personal, shown as an image) ([source, 2026-01-26](https://bsky.app/profile/filippo.abyssdomain.expert/post/3mddfcuuo772w))

## In their words

> These were very low hanging performance wins with very low complexity/review/maintenance cost

I bet there’s more

Systematically look for more in the whole crypto/… tree

> *Of course* Claude Code with just WebSearch and WebFetch can fill them out for me from context.

> Model: gpt-6-astra

> Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

> Nuclear opinion: I don’t care if you use AI to write code,¹ but making a human review a change before an LLM is disrespectful.


Archetype (our label): Toolsmith. Newest source: 2026-09-27.
Card: https://www.prehistoriq.com/stacks/filosottile/ · Data: https://github.com/prehistoriq/stacks/blob/main/data/stacks/filosottile.json