Agent Tool Builder

Agent Tool Builder is a skill for Claude Code, Codex from mayurrathi/awesome-agent-skills. It costs 47 tokens per session (338 once invoked), scanned A, original, no licence file.

A guide for designing tools that AI agents use to interact with outside systems. It focuses on making those tools clear and reliable.

In plain words
What is it for?
Use it when creating or reviewing tools for an AI agent, such as tools that read data, change files, or call services.
Why use it?
Poorly designed tools can make an agent guess, fail without explanation, or use more tokens than needed.

Skill for Claude CodeCodex

Which agent this was written for is unclear — body not stored (licence); the path alone says nothing.

Good fit Use it when creating or reviewing tools for an AI agent, such as tools that read data, change files, or call services.

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

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 Agent Tool Builder

README.md
[![agentmods](https://agentmods.dev/badge/skills/mayurrathi/awesome-agent-skills/agent-tool-builder/github.svg)](https://agentmods.dev/skills/mayurrathi/awesome-agent-skills/agent-tool-builder)
Your own site
<a href="https://agentmods.dev/skills/mayurrathi/awesome-agent-skills/agent-tool-builder"><img src="https://agentmods.dev/badge/skills/mayurrathi/awesome-agent-skills/agent-tool-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 Agent Tool Builder

Your own site · 80×15
<a href="https://agentmods.dev/skills/mayurrathi/awesome-agent-skills/agent-tool-builder"><img src="https://agentmods.dev/badge/skills/mayurrathi/awesome-agent-skills/agent-tool-builder.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 47 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 338 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.
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 $0.00047 $0.00338
Opus 5.5 $0.00019 $0.00135
Sonnet 5.5 $0.00009 $0.00068
Haiku 4.5 $0.00005 $0.00034

Measured 1mo ago against content hash 38d3d405d8fc, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

Agent Tool Builder 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 1mo 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.

skills/agent-tool-builder/SKILL.md · 58 lines

The source is not reproduced here

No licence file

A repository with no LICENSE is all rights reserved by default, so the body is not copied here. The metadata, the measurements and the link are.

Read it on GitHub

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. 1mo ago First seen · 58 lines · 47 tokens per session scan A 38d3d405d8fc

Subscribe to this mod's changes

Agent Tool Builder is a skill published in the GitHub repository mayurrathi/awesome-agent-skills (8 stars, last pushed 7mo ago), with no licence file. It adds 47 tokens to every session and 338 once invoked, about $0.0002 per session on Opus 5.5. 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 2026-08-31.

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