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 skills/utensils/nxv/skillnpx skills add utensils/nxv --skill skillgit clone --depth 1 https://github.com/utensils/nxvWrote 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/skills/utensils/nxv/skill)<a href="https://agentmods.dev/skills/utensils/nxv/skill"><img src="https://agentmods.dev/badge/skills/utensils/nxv/skill.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 | $0.00169 | $0.07728 |
| Opus 5 | $0.00084 | $0.03864 |
| Sonnet 5 | $0.00034 | $0.01546 |
| Haiku 4.5 | $0.00017 | $0.00773 |
Grade A, and why
nxv scanned grade A 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 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.
Makes network callslowCapability
Not a fault in itself. Listed so you know the mod talks to something, and to what.
curl -s "https://nxv.urandom.io/api/v1/search?q=python&version=3.11&limit=5" | jq This is a copy
100% identical to nxv — 0 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.
How it starts
The opening of the file, as written. The whole thing — 544 lines — stays where its author put it; the contents beside it link to each section on GitHub.
nxv — Nix Version Index
nxv is a Rust CLI + HTTP API that indexes nixpkgs channel-release history (2016+) into a local SQLite database with a bloom filter for fast lookups. It answers: "which exact nixpkgs commit shipped version X of package Y?" and produces the nix shell nixpkgs/<commit>#pkg command you need to actually use it.
Quick Reference
nxv search python # All python packages (most recent per version)
nxv search python 2.7 # Filter by version (prefix match)
nxv search python --exact # Exact attribute name only
nxv search "json parser" --desc # Full-text search package descriptions
nxv run python 2.7 # Resolve and open a pinned shell
nxv run python 3.11 --with nodejs@20 # Multi-package shell
nxv info python311 # Detailed info for current version
nxv info python311 3.11.4 # Detailed info for specific version
nxv history python311 # Version timeline (first/last seen)
nxv history python311 3.11.4 # When was 3.11.4 available?
nxv stats # Index statistics
nxv update # Update nxv itself to the latest release
nxv sync # Download or refresh the local package index
nxv sync --force # Force a full index re-download
nxv serve --host 0.0.0.0 --port 8080 # Start HTTP API + web UI
nxv completions zsh # Generate shell completions
nxv skill install codex # Install this skill for one explicit agent
nxv skill install --detected # Install for detected AI agents
nxv skill list # Agents, skill paths, install status
How to Use This Skill
Parse $ARGUMENTS to determine the action:
- If arguments look like a subcommand (
search,run,info,history,stats,update,sync,serve,completions,skill, and indexer-onlyindex,dedupe,publish,keygen), run that subcommand. - If arguments look like a package name (e.g.
python,nodejs 15,ruby 2.6), default tonxv search. - If arguments look like a question ("when was X added", "which commit has Y"), pick
searchorhistoryaccordingly. - If no arguments, run
nxv statsto give the user a quick health check of their index.
What ships with it
1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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.
- 4d ago First seen · 544 lines · 169 tokens per session scan A a5a5534e33c9
nxv is a skill published in the GitHub repository utensils/nxv (136 stars, last pushed 22d ago), licensed MIT. It adds 169 tokens to every session and 7,728 once invoked, about $0.0008 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). It is 100% identical to nxv, differing in 0 lines, and is treated as a copy.
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