# How Armin Ronacher actually uses coding agents

Flask, Earendil founder

**If you take one thing:** `/answer`, in place of plan mode. he skips plan mode and lets the agent ask questions in plain prose, then a self-built extension turns those questions into a form he fills in.

- **Agent:** Pi (cli) ([source, 2026-01-31](https://lucumr.pocoo.org/2026/1/31/pi/))
- **Agent:** Codex ([source, 2026-09-07](https://lucumr.pocoo.org/2026/9/7/astra-why/))
- **Model:** Sol ([source, 2026-09-05](https://lucumr.pocoo.org/2026/9/5/latent-powers/))
- **Model:** Fable ([source, 2026-09-05](https://lucumr.pocoo.org/2026/9/5/latent-powers/))
- **Review:** Steers as it goes, reviews when the agent says done ([source, 2026-06-23](https://lucumr.pocoo.org/2026/6/23/the-coming-loop/))
- **Harness:** Pi in the terminal, forks in Ghostty splits, subagents in tmux ([source, 2026-07-26](https://github.com/mitsuhiko/agent-stuff/blob/0865c849befd2021490679f96a8dee58c84ac857/README.md#L59-L60))
- **Rules file:** AGENTS.md in his agent-stuff repo (12 lines) ([source, 2026-01-30](https://github.com/mitsuhiko/agent-stuff/blob/0865c849befd2021490679f96a8dee58c84ac857/AGENTS.md#L12))
- **Skills:** anachb, apple-mail, audio-transcription, commit, ghidra, github, google-workspace, librarian, native-web-search, oebb-scotty, openscad, pi-share, sentry, summarize, tmux ([source, 2026-09-27](https://github.com/mitsuhiko/agent-stuff/tree/0865c849befd2021490679f96a8dee58c84ac857/skills))
- **Hooks:** uv.ts: blocks pip and python, pushes the agent to uv ([source, 2026-07-26](https://github.com/mitsuhiko/agent-stuff/blob/0865c849befd2021490679f96a8dee58c84ac857/README.md#L63))
- **MCP servers:** Sentry ([source, 2026-10-06](https://lucumr.pocoo.org/2026/10/6/codemode/))

## In their words

> And Pi happens to be, at this point, the coding agent that I use almost exclusively.

> In the Codex harness I found multiple cases where subagents resorted fully to manual string manipulation with Python instead of using the patch tool.

> Long story short: I had a conversation with Fable and Sol via Pi about what could be done with such a dongle or whether I should use a Raspberry Pi instead if I wanted to do my own thing there.

> Long story short: I had a conversation with Fable and Sol via Pi about what could be done with such a dongle or whether I should use a Raspberry Pi instead if I wanted to do my own thing there.

> In the agent loop, the model eventually says “done” and I review. Even before that, I usually steer along the way.


Archetype (our label): Toolsmith. Newest source: 2026-10-06.
Card: https://www.prehistoriq.com/stacks/mitsuhiko/ · Data: https://github.com/prehistoriq/stacks/blob/main/data/stacks/mitsuhiko.json