implement-is-odd

implement-is-odd is a skill for Claude Code, Codex from zernie/vigiles. It costs 12 tokens per session (112 once invoked), scanned A, original, MIT.

A task that implements an `isOdd(n)` function, which reports whether an integer is odd, using test-driven development. Test-driven development means writing a failing test first, then writing code to make it pass.

In plain words
What is it for?
Use it to add a named ESM export in `src/isodd.js` and a matching test in `test/isodd.test.js`.
Why use it?
It gives a fixed order for building the function, so the expected behavior is recorded before the implementation is written.

Skill for Claude CodeCodex

Part of the vigiles plugin — 27 skills, 1 agent, 4 hooks, 6 plugins 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 skills/zernie/vigiles/isodd
Any agent
npx skills add zernie/vigiles --skill isodd
Clone the repo
git clone --depth 1 https://github.com/zernie/vigiles

Made for: Claude Code, Codex.

Or install vigiles, the plugin that ships this one along with the rest of its 27 skills, 1 agent, 4 hooks, 6 plugins.

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 implement-is-odd

README.md
[![agentmods](https://agentmods.dev/badge/skills/zernie/vigiles/isodd.svg)](https://agentmods.dev/skills/zernie/vigiles/isodd)
Your own site
<a href="https://agentmods.dev/skills/zernie/vigiles/isodd"><img src="https://agentmods.dev/badge/skills/zernie/vigiles/isodd.svg" alt="Measured on agentmods" height="20"></a>
Per session 12 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 112 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 $0.00012 $0.00112
Opus 5 $0.00006 $0.00056
Sonnet 5 $0.00002 $0.00022
Haiku 4.5 $0.00001 $0.00011

Measured 5d ago against content hash dc2c6476b24c, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

implement-is-odd 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 5d 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.

bench/tdd/isodd/SKILL.md · 17 lines

What it actually says

Implement isOdd (test-driven)

Implement isOdd(n) in src/isodd.js as a named ESM export. It returns whether an integer is odd.

Follow test-driven development, in this order:

  1. First write a failing test in test/isodd.test.js.
  2. Then implement src/isodd.js to make the test pass.

Do not write the implementation before the test exists and fails.

Files

What ships with it

2 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. 5d ago First seen · 17 lines · 12 tokens per session scan A dc2c6476b24c

Subscribe to this mod's changes

implement-is-odd is a skill published in the GitHub repository zernie/vigiles (15 stars, last pushed yesterday), licensed MIT. It adds 12 tokens to every session and 112 once invoked, about $0.0001 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 2026-08-30.

Related

Other skills, from other repositories