---
title: "Engineering principles should be runnable policy, not slide-deck nostalgia"
date: 2026-05-01
canonical: https://patrickaudley.com/#post-coding-ethos-runnable-policy
cross-posted-from: https://www.reddit.com/r/GeminiCLI/comments/1t146xk/keep_your_agents_in_line_codingethos_turns/
source-platform: Reddit (r/GeminiCLI)
tags: [ai-agents, policy-as-code, coding-ethos, mcp, static-analysis]
mentions: [https://patrickaudley.com/#proj-coding-ethos]
author: Patrick Colm Audley
author-url: https://patrickaudley.com/
license: Creative Commons BY-NC-SA CAv2.5
lang: en
---

# Engineering principles should be runnable policy, not slide-deck nostalgia

> If your team's standards live in a slide deck, your AI agents will violate them. coding-ethos compiles one YAML file
into linter configs, git hooks, agent prompts, and an MCP server so the rules cannot drift between human and machine
readers.

The thing I keep running into with multi-agent setups is that the engineering principles a team actually cares about —
how to handle errors, when to wrap shell calls, what counts as a critical path — live in a wiki page or a slide deck
nobody reads. That's already a problem for humans; for an LLM agent it is a guarantee of policy violation.

[coding-ethos](https://github.com/paudley/coding-ethos) is the position I've taken: those principles belong in a single
`coding_ethos.yml` file, and from that one file the build emits everything that needs to know about them — `CLAUDE.md`
/ `GEMINI.md` agent instructions, Ruff / Pyright / golangci-lint configs, compiled Go pre-commit hooks, agent tool-use
guards, and an Model Context Protocol server the agent can query at runtime.

The key invariant: the engine that writes the markdown rules is the exact same engine that evaluates Common Expression
Language expressions at the git-hook level. They *cannot* drift. If the hook denies an action, the agent gets back a
structured `skill_id` hint instead of a generic exit code — so the feedback loop closes inside the agent's own context
rather than landing on a human's screen.

Heavily opinionated, currently slanted toward Python and Go, in active development. Posted on r/GeminiCLI with worked
examples;
[read the original thread](https://www.reddit.com/r/GeminiCLI/comments/1t146xk/keep_your_agents_in_line_codingethos_turns/)
if you want the implementation walk-through, and feature requests are welcome on the
[repo](https://github.com/paudley/coding-ethos).

---

*Originally published 2026-05-01 —
[Reddit (r/GeminiCLI)](https://www.reddit.com/r/GeminiCLI/comments/1t146xk/keep_your_agents_in_line_codingethos_turns/).
Canonical version at <https://patrickaudley.com/#post-coding-ethos-runnable-policy>. Author:
[Patrick Colm Audley](https://patrickaudley.com/). *