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/webern/mx/cppgit clone --depth 1 https://github.com/webern/mxWhat 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 | $0.00138 | $0.00138 |
| Opus 5 | $0.00069 | $0.00069 |
| Sonnet 5 | $0.00028 | $0.00028 |
| Haiku 4.5 | $0.00014 | $0.00014 |
Grade A, and why
mx cpp.instructions.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 2d 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.
What it actually says
Repo-wide C++ rules (see AGENTS.md):
- No new anonymous namespaces (
namespace { }) -- they break unity builds. File-local helpers get named functions (tokenIsNameChar); file-local constants get a per-type prefix (kYesNoWire). Existing anonymous namespaces are being retired as touched; do not demand drive-by fixes. - Formatting is enforced by clang-format (
make fmt/make fmt-check); do not comment on layout the formatter controls. - Keep source ASCII.
- Comments should state constraints and effects hard to ascertain from the code.
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.
- 2d ago First seen · 15 lines · 138 tokens per session scan A 8eed162f2791
mx cpp.instructions.md is an instructions file published in the GitHub repository webern/mx (93 stars, last pushed 3d ago), licensed MIT. It adds 138 tokens to every session, about $0.0007 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
librosa AGENTS.md
Instructions for librosa/librosa, covering agent interaction policy for librosa, 1. automated platform interactions, 2. exception for project-authorized automation and 3. machine-readable directive.
spotatui copilot-instructions.md
Instructions for LargeModGames/spotatui, covering copilot instructions for spotatui, build & run, ci checks (run before opening a pr), run a single test and example.
musicbox AGENTS.md
Instructions for darknessomi/musicbox, covering agents.md, cursor cloud specific instructions, running the app, audio backends (system deps, not in update script) and network / api note.
nuclear AGENTS.md
AGENTS.md instructions for nukeop/nuclear, covering agents.md, project overview, packages, commands and development.
nuclear copilot-instructions.md
Copilot instructions for nukeop/nuclear, covering nuclear music player - copilot instructions, project overview, key features, tech stack and packages.
pytheory CLAUDE.md
Instructions for kennethreitz/pytheory, covering claude code instructions, release process, version bumping, testing and publishing.