vaex

vaex is a skill for Claude Code from K-Dense-AI/scientific-agent-skills. It costs 100 tokens per session (2,164 once invoked), scanned A, original, MIT.

A guide to Vaex, a Python library for working with tabular data that is too large to fit in memory. It uses lazy, out-of-core processing so data can be explored without loading every row at once.

In plain words
What is it for?
Use it for large CSV, HDF5, or similar tables, fast aggregations, exploration, visualizations, and machine learning preparation.
Why use it?
It helps avoid running out of RAM when aggregating, visualizing, or modeling very large datasets.

Skill for Claude Code

Written for Claude Code: allowed-tools in frontmatter.

Good fit Use it for large CSV, HDF5, or similar tables, fast aggregations, exploration, visualizations, and machine learning preparation.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/k-dense-ai/scientific-agent-skills/vaex
About the project

Scientific Agent Skills is a collection of reusable procedures that give AI agents capabilities for scientific research across areas such as biology, chemistry, medicine, and drug discovery. It is used by researchers and by people building AI scientist workflows with compatible coding agents. The catalogue contains many of the project's skills and supporting instructions.

K-Dense-AI/scientific-agent-skills · 44,220 stars · on GitHub · arxiv.org

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.

Any agent
npx skills add K-Dense-AI/scientific-agent-skills --skill vaex
Clone the repo
git clone --depth 1 https://github.com/K-Dense-AI/scientific-agent-skills

Made for: Claude Code.

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 vaex

README.md
[![agentmods](https://agentmods.dev/badge/skills/k-dense-ai/scientific-agent-skills/vaex/github.svg)](https://agentmods.dev/skills/k-dense-ai/scientific-agent-skills/vaex)
Your own site
<a href="https://agentmods.dev/skills/k-dense-ai/scientific-agent-skills/vaex"><img src="https://agentmods.dev/badge/skills/k-dense-ai/scientific-agent-skills/vaex/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for vaex

Your own site · 80×15
<a href="https://agentmods.dev/skills/k-dense-ai/scientific-agent-skills/vaex"><img src="https://agentmods.dev/badge/skills/k-dense-ai/scientific-agent-skills/vaex.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 100 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,164 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • Socket pass 9 Apr 2026
  • Snyk warn 9 Apr 2026
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
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 5.1 $0.00100 $0.02164
Opus 5 $0.00050 $0.01082
Sonnet 5 $0.00020 $0.00433
Haiku 4.5 $0.00010 $0.00216

Measured 8d ago against content hash f9cb1c71dd2d, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

vaex 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 8d 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

Copies of this mod

8 near-identical copies found in the catalogue:

  • vaex — 89% identical, 20 lines differ
  • vaex — 89% identical, 18 lines differ
  • vaex — 88% identical, 54 lines differ
  • vaex — 88% identical, 54 lines differ
  • vaex — 88% identical, 54 lines differ
  • vaex — 86% identical, 55 lines differ
  • vaex — 84% identical, 54 lines differ
  • vaex — 84% identical, 57 lines differ
skills/vaex/SKILL.md · 221 lines

How it starts

The opening of the file, as written. The whole thing — 221 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Vaex

Overview

Vaex is a high-performance Python library designed for lazy, out-of-core DataFrames to process and visualize tabular datasets that are too large to fit into RAM. Vaex can process over a billion rows per second, enabling interactive data exploration and analysis on datasets with billions of rows.

Installation

Install the full meta-package (recommended):

uv pip install vaex

Minimal install (pick only what you need):

uv pip install vaex-core vaex-viz vaex-hdf5 vaex-ml

The vaex package is a meta-package that pulls in vaex-core, vaex-viz, vaex-hdf5, vaex-ml, and other sub-packages. Arrow support is built into vaex-core (the separate vaex-arrow package is deprecated). vaex-distributed is deprecated in favor of vaex-enterprise.

Version notes (vaex 4.19.0+): Python 3.12 and NumPy v2 require vaex >= 4.19.0. On Windows, you may need Python dev headers to build the annoy dependency.

When to Use This Skill

Use Vaex when:

  • Processing tabular datasets larger than available RAM (gigabytes to terabytes)
  • Performing fast statistical aggregations on massive datasets
  • Creating visualizations and heatmaps of large datasets
  • Building machine learning pipelines on big data
  • Converting between data formats (CSV, HDF5, Arrow, Parquet)
  • Needing lazy evaluation and virtual columns to avoid memory overhead
  • Working with astronomical data, financial time series, or other large-scale scientific datasets

Vaex vs alternatives: Use polars when data fits in RAM and you need maximum in-memory speed. Use dask when you need distributed pandas/NumPy across a cluster. Use vaex for single-machine, out-of-core analytics on tabular data that exceeds RAM via memory-mapped HDF5/Arrow files.

Core Capabilities

Vaex provides six primary capability areas, each documented in detail in the references directory:

1. DataFrames and Data Loading

Load and create Vaex DataFrames from various sources including files (HDF5, CSV, Arrow, Parquet), pandas DataFrames, NumPy arrays, and dictionaries. Reference references/core_dataframes.md for:

  • Opening large files efficiently
  • Converting from pandas/NumPy/Arrow
  • Working with example datasets
  • Understanding DataFrame structure

Read the full file on GitHub · 221 lines

Files

What ships with it

6 files 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.

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. 8d ago First seen · 221 lines · 100 tokens per session scan A f9cb1c71dd2d

Subscribe to this mod's changes

vaex is a skill published in the GitHub repository K-Dense-AI/scientific-agent-skills (44,220 stars, last pushed 4d ago), licensed MIT. It adds 100 tokens to every session and 2,164 once invoked, about $0.0005 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 2026-09-03.