tool-definition

Define Claude Code Tools with schema-first validation and permission gating.

5|Updated Apr 1, 2026

Search Tags:#validation #permissions #tooling #zod #claude-code #tool-definition #buildTool

Ready to run

npx skills add https://github.com/TechyMT/claude-code-superpowers --skill tool-definition

💬 Prompt for ChatGPT / Claude Chat▼

Please help me install this Agent Skill.
Skill: tool-definition
Source: https://github.com/TechyMT/claude-code-superpowers/tree/main/skills/tool-definition
Command: npx skills add https://github.com/TechyMT/claude-code-superpowers --skill tool-definition

SYSTEM DOCUMENTATION & REQUIREMENTS

What problem does it solve?

This Skill provides a repeatable pattern for defining Claude Code Tools with a schema-first approach, ensuring validation, permissions, and safe defaults are baked in from the start.

Core Features & Use Cases

Schema-first design using Zod to define inputs and ensure runtime validation and TypeScript types stay in sync.
Safe tool composition with buildTool factory, default flags, and a centralized permission check that runs before execution.
Use cases include adding new tools or updating existing tool behavior while maintaining security, reliability, and consistency across the Code environment.

Quick Start

Implement a new tool by calling buildTool with the appropriate inputSchema, permission checks, and default configurations.

Frequently Asked Questions about tool-definition

High-intent search queries and answers about installing and using this skill.

FAQPage Schema

How do I define Claude Code tools with schema-first validation?▼

You define Claude Code tools using a schema-first approach by calling the buildTool factory with a Zod inputSchema, applying permission checks, and returning { data } on success to ensure runtime validation and safe defaults.

What is the best way to add permission gating to Claude Code tools?▼

The best way to add permission gating is by using a centralized pre-call permission check within a buildTool-based workflow, ensuring the check runs before tool execution to enforce safe tool composition.

How does Zod validation work when building new Claude Code tools?▼

Zod validation works by defining an inputSchema getter that ensures runtime validation and TypeScript types stay in sync, providing schema-first design for safe and reliable tool execution.

Can I use buildTool to update existing tool behavior across projects?▼

Yes, you can use buildTool to update existing tool behavior across projects by applying its repeatable pattern with default flags, mandatory inputSchema getters, and pre-call permission checks to maintain consistency.

Why should I use a schema-first approach for Claude Code tool definition?▼

A schema-first approach for tool definition ensures validation, permissions, and safe defaults are baked in from the start, keeping runtime validation and TypeScript types synchronized while preventing unsafe tool execution.

Do I need to return a specific format on success when defining tools?▼

Yes, you need to return { data } on success when defining tools, which is a mandatory part of the buildTool-based workflow pattern to ensure consistent and safe output handling.