Strict Tool Implementer Skill

Strict Tool Implementer

Overview

This skill implements Anthropic's strict tool use mode for reliable agentic systems. With strict: true, tool input parameters are guaranteed to match your schema—no validation needed in your tool functions.

What This Skill Provides:

Production-ready tool schema design
Multi-tool workflow patterns
Agentic system architecture
Validation and error handling
Complete agent implementation examples

Prerequisites:

Decision made via structured-outputs-advisor
Model: Claude Sonnet 4.5 or Opus 4.1
Beta header: structured-outputs-2025-11-13

When to Use This Skill

Use for:

Building multi-step agentic workflows
Validating function call parameters
Ensuring type-safe tool execution
Complex tools with nested properties
Critical operations requiring guaranteed types

NOT for:

Extracting data from text/images → json-outputs-implementer
Formatting API responses → json-outputs-implementer
Classification tasks → json-outputs-implementer

Response Style

Tool-focused: Design tools with clear, validated schemas
Agent-aware: Consider multi-tool workflows and composition
Type-safe: Guarantee parameter types for downstream functions
Production-ready: Handle errors, retries, and monitoring
Example-driven: Provide complete agent implementations

Workflow

| Phase | Description | Details | |-------|-------------|---------| | 1 | Tool Schema Design | → workflow/phase-1-schema-design.md | | 2 | Multi-Tool Agent Implementation | → workflow/phase-2-implementation.md | | 3 | Error Handling & Validation | → workflow/phase-3-error-handling.md | | 4 | Testing Agent Workflows | → workflow/phase-4-testing.md | | 5 | Production Agent Patterns | → workflow/phase-5-production.md |

Quick Reference

Schema Template

{
    "name": "tool_name",
    "description": "Clear description",
    "strict": True,
    "input_schema": {
        "type": "object",
        "properties": {...},
        "required": [...],
        "additionalProperties": False
    }
}

Supported Schema Features

✅ Basic types, enums, format strings, nested objects/arrays, required fields

❌ Recursive schemas, min/max constraints, string length, complex regex

Reference Materials

Related Skills

structured-outputs-advisor - Choose the right mode
json-outputs-implementer - For data extraction use cases

Agent Skills: Strict Tool Implementer

Install this agent skill to your local

Skill Files