ai-models

AI Models Reference Skill

Last Updated: December 2025

Philosophy

Use the right model for the job. Bigger isn't always better - match model capabilities to task requirements. Consider cost, latency, and accuracy tradeoffs.

Model Selection Matrix

Anthropic (Claude)

Documentation

• API Docs: https://docs.anthropic.com
• Models Overview: https://docs.anthropic.com/en/docs/about-claude/models/overview
• Pricing: https://www.anthropic.com/pricing

Latest Models (December 2025)

const CLAUDE_MODELS = {
  // Flagship - highest capability
  opus: 'claude-opus-4-5-20251101',

  // Balanced - best for most tasks
  sonnet: 'claude-sonnet-4-5-20250929',

  // Previous generation (still excellent)
  opus4: 'claude-opus-4-6',
  sonnet4: 'claude-sonnet-5',

  // Fast & cheap - high volume tasks
  haiku: 'claude-haiku-4-5-20251001',
} as const;

Usage

import Anthropic from '@anthropic-ai/sdk';

const anthropic = new Anthropic({
  apiKey: process.env.ANTHROPIC_API_KEY,
});

const response = await anthropic.messages.create({
  model: 'claude-sonnet-4-5-20250929',
  max_tokens: 1024,
  messages: [
    { role: 'user', content: 'Hello, Claude!' }
  ],
});

Model Selection

claude-opus-4-5-20251101 (Opus 4.5)
├── Best for: Complex analysis, research, nuanced writing
├── Context: 200K tokens
├── Cost: $5/$25 per 1M tokens (input/output)
└── Use when: Accuracy matters most

claude-sonnet-4-5-20250929 (Sonnet 4.5)
├── Best for: Code, general tasks, balanced performance
├── Context: 200K tokens
├── Cost: $3/$15 per 1M tokens
└── Use when: Default choice for most applications

claude-haiku-4-5-20251001 (Haiku 4.5)
├── Best for: Classification, extraction, high-volume
├── Context: 200K tokens
├── Cost: $1/$5 per 1M tokens
└── Use when: Speed and cost matter most