vsql-extension-builder

vsql-extension-builder is a skill for Claude Code from villagesql/villagesql-skills. It costs 82 tokens per session (10,718 once invoked), scanned C, original, no licence file.

A guide for building a VillageSQL database extension from requirements through implementation, testing, review, and documentation. It supports extensions written in C++ or Rust.

In plain words
What is it for?
It helps define requirements, check feasibility, create the project structure, implement the extension, review it, run user acceptance testing, and document it.
Why use it?
It provides an ordered process for turning an extension idea into a tested and documented result, while checking the current extension API during the work.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the villagesql plugin — 2 skills shipped together

Good fit It helps define requirements, check feasibility, create the project structure, implement the extension, review it, run user acceptance testing, and document it.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/villagesql/villagesql-skills/vsql-extension-builder
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 villagesql/villagesql-skills --skill vsql-extension-builder
Clone the repo
git clone --depth 1 https://github.com/villagesql/villagesql-skills

Made for: Claude Code.

Or install villagesql, the plugin that ships this one along with the rest of its 2 skills.

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 vsql-extension-builder

README.md
[![agentmods](https://agentmods.dev/badge/skills/villagesql/villagesql-skills/vsql-extension-builder/github.svg)](https://agentmods.dev/skills/villagesql/villagesql-skills/vsql-extension-builder)
Your own site
<a href="https://agentmods.dev/skills/villagesql/villagesql-skills/vsql-extension-builder"><img src="https://agentmods.dev/badge/skills/villagesql/villagesql-skills/vsql-extension-builder/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 vsql-extension-builder

Your own site · 80×15
<a href="https://agentmods.dev/skills/villagesql/villagesql-skills/vsql-extension-builder"><img src="https://agentmods.dev/badge/skills/villagesql/villagesql-skills/vsql-extension-builder.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 82 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 10,718 The whole file, excluding the scripts and references it only reads on demand.
Security scan C 1 finding. A grade says what 26 rules found in the file — not that it is safe.
Origin unknown 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 $0.00082 $0.10718
Opus 5 $0.00041 $0.05359
Sonnet 5 $0.00016 $0.02144
Haiku 4.5 $0.00008 $0.01072

Measured 13d ago against content hash ca5530377b9a, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade C, and why

vsql-extension-builder scanned grade C 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 13d 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.

Recursive force deletehighDestructive command

rm -rf with a variable or a broad path is one typo away from removing the wrong tree.

3. `rm -rf <veb_dir>/_expanded/<extension_name>`
skills/vsql-extension-builder/SKILL.md · 873 lines

The source is not reproduced here

A licence we could not identify

The repository carries a LICENSE file, but it is custom or dual enough that GitHub cannot name it and neither can this catalogue. Unknown terms are not permission, so the body is not copied here. Read the licence at the source and decide for yourself.

Read it on GitHub

Files

What ships with it

9 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. 13d ago First seen · 873 lines · 82 tokens per session scan C ca5530377b9a

Subscribe to this mod's changes

vsql-extension-builder is a skill published in the GitHub repository villagesql/villagesql-skills (5 stars, last pushed 2d ago), with no licence file. It adds 82 tokens to every session and 10,718 once invoked, about $0.0004 per session on Opus 5. A static security scan graded it C with 1 finding (recursive force delete). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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