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.
npx agentmods add instructions/braiins/llm-jail/agents-mdgit clone --depth 1 https://github.com/braiins/llm-jailWrote 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.
[](https://agentmods.dev/instructions/braiins/llm-jail/agents-md)<a href="https://agentmods.dev/instructions/braiins/llm-jail/agents-md"><img src="https://agentmods.dev/badge/instructions/braiins/llm-jail/agents-md.svg" alt="Measured on agentmods" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.01817 | $0.01817 |
| Opus 5 | $0.00908 | $0.00908 |
| Sonnet 5 | $0.00363 | $0.00363 |
| Haiku 4.5 | $0.00182 | $0.00182 |
Grade A, and why
llm-jail AGENTS.md scanned grade A with 0 findings 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.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 43 lines — stays where its author put it; the contents beside it link to each section on GitHub.
CLAUDE.md
This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
Build & Test
nix build .#claude # Build the runner script
nix run .#claude -- --help # Show CLI usage
nix flake check # Validate flake structure
End-to-end test (needs a terminal and a prior in-jail login - run nix run .#claude once and complete the login flow, which persists credentials in ~/.config/llm-jail/claude/default):
nix run .#claude -- --dangerous -- -p "Write hello to /workspace/hello.txt" --max-turns 3
After changes to guest NixOS config, rebuilds are fast (only systemd units regenerate). Changes to flake.nix inputs or writeShellApplication trigger full rebuilds.
Architecture
This is a Nix flake that runs coding agents inside QEMU microVMs with hardware-level isolation. No disk images - the guest boots on tmpfs with the host's /nix/store shared read-only via 9p. An overlayfs covers /nix/store and /nix/var is bind-mounted from the same backing volume so build artifacts land on disk (not root tmpfs) when --store-disk is used.
Data flow: flake.nix iterates tools.nix, builds a NixOS guest system per tool, wraps each with lib/mkRunner.nix into a QEMU launcher script.
Host side (lib/mkRunner.nix): A writeShellApplication that parses CLI args at runtime, writes env vars and tool args to a temp dir, sets up 9p virtfs mounts, optionally creates a store disk image, and launches QEMU with direct kernel boot. QEMU's stdout (the guest console stream) is not wired to the terminal directly but piped through pv -q -B 64M, which drains it eagerly into a 64MB buffer and writes to the tty as it becomes writable - QEMU's virtconsole silently drops guest output when the host fd can't absorb a burst (see Key Constraints), which corrupted TUI frames on busy terminals. On NixOS hosts, /run/current-system/sw and /etc/profiles/per-user/$USER are auto-mounted so host packages are available in the guest.
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.
- 5d ago First seen · 43 lines · 1,817 tokens per session scan A f4057f779876
llm-jail AGENTS.md is an instructions file published in the GitHub repository braiins/llm-jail (24 stars, last pushed yesterday), licensed MIT. It adds 1,817 tokens to every session, about $0.0091 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
Other instructions, from other repositories
codex AGENTS.md
AGENTS.md instructions for openai/codex, covering rust/codex-rs, the codex-core crate, code review rules, crate api surface and model visible context.
vscode buildNext.instructions.md
Working notes and architecture documentation for the new esbuild-based build system in build/next. Use when making changes to the new build pipeline (transpile/bundle commands, NLS plugin, source-map handling, resource copying, or self-hosting watch tasks).
spec-kit AGENTS.md
AGENTS.md instructions for github/spec-kit, covering agents.md, about spec kit and specify, quickstart — add a new integration in 5 steps, integration architecture and integrationmanifest — file tracking.
next.js AGENTS.md
AGENTS.md instructions for vercel/next.js, covering next.js development guide, codebase structure, monorepo overview, core package: packages/next and other important packages.
langchain AGENTS.md
AGENTS.md instructions for langchain-ai/langchain, covering global development guidelines for the langchain monorepo, corridor security analysis, project architecture and context, monorepo structure and development tools & commands.
vscode oss-third-party-notices.instructions.md
Instructions for microsoft/vscode, covering vs code oss third-party-notices pipeline, architecture, pipeline flow in ci, applying the notice (cutover) and fallback chain (never fail the build).