nix-config AGENTS.md

nix-config AGENTS.md is an instructions file for Codex, OpenCode from joshsymonds/nix-config. It costs 153 tokens per session, scanned B, original, MIT.

Deployment guidance for Gnomon, a computer managed with Nix, a system for describing software and operating-system configurations as code. It explains where Gnomon's builds and system rebuilds must run.

In plain words
What is it for?
Use it when changing Gnomon's Nix configuration, committing and pushing a branch, connecting to the Gnomon host, and running its build or system rebuild there.
Why use it?
It prevents expensive or incorrect builds on the wrong computer. It also avoids accidentally running a system rebuild locally when the target machine is Gnomon.

Instructions file for CodexOpenCode

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add instructions/joshsymonds/nix-config/agents-md
Clone the repo
git clone --depth 1 https://github.com/joshsymonds/nix-config

Made for: Codex, OpenCode.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for nix-config AGENTS.md

README.md
[![agentmods](https://agentmods.dev/badge/instructions/joshsymonds/nix-config/agents-md.svg)](https://agentmods.dev/instructions/joshsymonds/nix-config/agents-md)
Your own site
<a href="https://agentmods.dev/instructions/joshsymonds/nix-config/agents-md"><img src="https://agentmods.dev/badge/instructions/joshsymonds/nix-config/agents-md.svg" alt="Measured on agentmods" height="20"></a>
Per session 153 This file is loaded in full into every session.
When invoked 153 The same file — it is already loaded in full.
Security scan B 1 finding. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00153 $0.00153
Opus 5 $0.00077 $0.00077
Sonnet 5 $0.00031 $0.00031
Haiku 4.5 $0.00015 $0.00015

Measured 5d ago against content hash fff813e5c4ae, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade B, and why

nix-config AGENTS.md scanned grade B with 1 finding against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 5d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Asks for rootmediumPrivilege escalation

A mod that escalates privileges can change anything on the machine, not only the project.

- Never invoke `sudo nixos-rebuild ... .#gnomon` directly from another
AGENTS.md · 14 lines

What it actually says

Repository operating notes

Gnomon builds and deployment

  • Never build Gnomon's Home Manager activation package or NixOS system closure on another host, especially Vermissian. Evaluating the target closure can trigger large local downloads and CUDA builds.
  • For Gnomon changes, commit and push the branch, SSH to joshsymonds@gnomon, pull the branch there, and run the build or nixos-rebuild locally on Gnomon.
  • Never invoke sudo nixos-rebuild ... .#gnomon directly from another host's shell. The rebuild command itself must be inside the SSH command sent to joshsymonds@gnomon.
Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 5d ago First seen · 14 lines · 153 tokens per session scan B fff813e5c4ae

Subscribe to this mod's changes

nix-config AGENTS.md is an instructions file published in the GitHub repository joshsymonds/nix-config (835 stars, last pushed today), licensed MIT. It adds 153 tokens to every session, about $0.0008 per session on Opus 5. A static security scan graded it B with 1 finding (asks for root). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.