skill-042

skill-042 is a skill for Claude Code, Codex from legendtkl/agentic-skill-router. It costs 54 tokens per session (1,089 once invoked), scanned A, a copy of jax-skills, MIT.

A skill for numerical computing and machine learning with JAX, a Python library for fast array calculations and automatic differentiation. It includes operations for arrays, gradients, compilation, and repeated transformations.

In plain words
What is it for?
Use it to work with JAX-compatible arrays, save or load .npy and .npz files, apply supported array operations, and build gradient-based or machine-learning calculations.
Why use it?
It provides defined ways to load, save, transform, and validate numerical data while checking shapes and numerical stability.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

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 skills/legendtkl/agentic-skill-router/skill-042
Any agent
npx skills add legendtkl/agentic-skill-router --skill skill-042
Clone the repo
git clone --depth 1 https://github.com/legendtkl/agentic-skill-router

Made for: Claude Code, Codex.

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 skill-042

README.md
[![agentmods](https://agentmods.dev/badge/skills/legendtkl/agentic-skill-router/skill-042.svg)](https://agentmods.dev/skills/legendtkl/agentic-skill-router/skill-042)
Your own site
<a href="https://agentmods.dev/skills/legendtkl/agentic-skill-router/skill-042"><img src="https://agentmods.dev/badge/skills/legendtkl/agentic-skill-router/skill-042.svg" alt="Measured on agentmods" height="20"></a>
Per session 54 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,089 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin 89% copy Near-identical to another mod 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 5.1 $0.00054 $0.01089
Opus 5 $0.00027 $0.00544
Sonnet 5 $0.00011 $0.00218
Haiku 4.5 $0.00005 $0.00109

Measured 6d ago against content hash 99e2dbca60dc, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

skill-042 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 6d 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.

Origin

This is a copy

89% identical to jax-skills — 3 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.

experiments/dci-compare/skillrouter-skills/skill-042/SKILL.md · 152 lines

How it starts

The opening of the file, as written. The whole thing — 152 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Requirements for Outputs

General Guidelines

Arrays

  • All arrays MUST be compatible with JAX (jnp.array) or convertible from Python lists.
  • Use .npy, .npz, JSON, or pickle for saving arrays.

Operations

  • Validate input types and shapes for all functions.
  • Maintain numerical stability for all operations.
  • Provide meaningful error messages for unsupported operations or invalid inputs.

JAX Skills

1. Loading and Saving Arrays

load(path)

Description: Load a JAX-compatible array from a file. Supports .npy and .npz.
Parameters:

  • path (str): Path to the input file.

Returns: JAX array or dict of arrays if .npz.

import jax_skills as jx

arr = jx.load("data.npy")
arr_dict = jx.load("data.npz")

save(data, path)

Description: Save a JAX array or Python array to .npy. Parameters:

  • data (array): Array to save.
  • path (str): File path to save.
jx.save(arr, "output.npy")

2. Map and Reduce Operations

map_op(array, op)

Description: Apply elementwise operations on an array using JAX vmap. Parameters:

  • array (array): Input array.
  • op (str): Operation name ("square" supported).
squared = jx.map_op(arr, "square")

reduce_op(array, op, axis)

Description: Reduce array along a given axis. Parameters:

  • array (array): Input array.
  • op (str): Operation name ("mean" supported).
  • axis (int): Axis along which to reduce.
mean_vals = jx.reduce_op(arr, "mean", axis=0)

3. Gradients and Optimization

logistic_grad(x, y, w)

Description: Compute the gradient of logistic loss with respect to weights. Parameters:

  • x (array): Input features.
  • y (array): Labels.
  • w (array): Weight vector.
grad_w = jx.logistic_grad(X_train, y_train, w_init)

Notes:

  • Uses jax.grad for automatic differentiation.
  • Logistic loss: mean(log(1 + exp(-y * (x @ w)))).

4. Recurrent Scan

rnn_scan(seq, Wx, Wh, b)

Description: Apply an RNN-style scan over a sequence using JAX lax.scan. Parameters:

  • seq (array): Input sequence.
  • Wx (array): Input-to-hidden weight matrix.
  • Wh (array): Hidden-to-hidden weight matrix.
  • b (array): Bias vector.

Read the full file on GitHub · 152 lines

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. 6d ago First seen · 152 lines · 54 tokens per session scan A 99e2dbca60dc

Subscribe to this mod's changes

skill-042 is a skill published in the GitHub repository legendtkl/agentic-skill-router (5 stars, last pushed 3mo ago), licensed MIT. It adds 54 tokens to every session and 1,089 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. It is 89% identical to jax-skills, differing in 3 lines, and is treated as a copy.

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