nyann:check-prereqs

nyann:check-prereqs is a command for coding agents from thettwe/nyann. It costs 56 tokens per session (453 once invoked), scanned A, original, MIT.

A read-only command that checks which tools nyann can use on the current machine. It separates required tools from optional tools that only enable specific features.

In plain words
What is it for?
Use it before bootstrapping a project, when diagnosing setup problems, or to produce a JSON report for scripts and issue reports.
Why use it?
It shows what is missing before setup and explains which nyann features will be skipped, without installing or changing anything.

Command

Part of the nyann plugin — 41 skills, 41 commands, 3 hooks shipped together

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 commands/thettwe/nyann/check-prereqs
Clone the repo
git clone --depth 1 https://github.com/thettwe/nyann

Or install nyann, the plugin that ships this one along with the rest of its 41 skills, 41 commands, 3 hooks.

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 nyann:check-prereqs

README.md
[![agentmods](https://agentmods.dev/badge/commands/thettwe/nyann/check-prereqs.svg)](https://agentmods.dev/commands/thettwe/nyann/check-prereqs)
Your own site
<a href="https://agentmods.dev/commands/thettwe/nyann/check-prereqs"><img src="https://agentmods.dev/badge/commands/thettwe/nyann/check-prereqs.svg" alt="Measured on agentmods" height="20"></a>
Per session 56 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 453 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. 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 $0.00056 $0.00453
Opus 5 $0.00028 $0.00227
Sonnet 5 $0.00011 $0.00091
Haiku 4.5 $0.00006 $0.00045

Measured 4d ago against content hash 75c23641d558, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

nyann:check-prereqs 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 4d 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.

commands/check-prereqs.md · 47 lines

What it actually says

Plugin root: This is a Claude Code plugin, NOT a CLI tool. Do NOT search via which, npm list, pip list, or brew list. This file is at <plugin_root>/commands/. All scripts: <plugin_root>/bin/. Read the matching skills/*/SKILL.md for the full flow.

/nyann:check-prereqs

Wraps bin/check-prereqs.sh. Useful before the first /nyann:bootstrap on a new machine — lets the user see which stacks are installable and which will skip-with-reason.

Classification

  • hard: git, jq, bash. nyann exits 1 on any mutating command without these.
  • soft: stack toolchains (node, pnpm, npm, go, cargo), integration helpers (gh, gitleaks, pre-commit, uv), and dev-only tooling (shellcheck, bats). Each is scoped to specific features; nyann degrades or skip-with-reasons when they're absent.

Output

Human-readable table by default. /nyann:check-prereqs --json emits a structured prereqs[] array ({kind, tool, status, version, hint}) for scripting.

When to use

  • First-time setup: "what do I need to install before bootstrapping?"
  • Before opening an issue: paste the output so the maintainer can see which tools are present.
  • In a team profile dry-run: confirm every teammate's machine has the tools a profile expects.
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. 4d ago First seen · 47 lines · 56 tokens per session scan A 75c23641d558

Subscribe to this mod's changes

nyann:check-prereqs is a command published in the GitHub repository thettwe/nyann (6 stars, last pushed 5d ago), licensed MIT. It adds 56 tokens to every session and 453 once invoked, about $0.0003 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 2026-08-31.