Claude Family Prompting

# Claude Family Prompting Guide

Covers Claude Opus 4.6, Claude Sonnet 4.6, Claude Sonnet 4.5, and Claude Haiku 4.5. Based on official Anthropic documentation.

Sources:
- [Prompting Best Practices — Claude 4](https://docs.anthropic.com/en/docs/build-with-claude/prompt-engineering/claude-4-best-practices)
- [Prompt Engineering Overview](https://docs.anthropic.com/en/docs/build-with-claude/prompt-engineering/overview)
- [Extended Thinking](https://docs.anthropic.com/en/docs/build-with-claude/extended-thinking)
- [Adaptive Thinking](https://docs.anthropic.com/en/docs/build-with-claude/adaptive-thinking)
- [Tool Use](https://docs.anthropic.com/en/docs/build-with-claude/tool-use)
- [Structured Outputs](https://docs.anthropic.com/en/docs/build-with-claude/structured-outputs)
- [Citations](https://docs.anthropic.com/en/docs/build-with-claude/citations)
- [Prompt Caching](https://docs.anthropic.com/en/docs/build-with-claude/prompt-caching)
- [Vision](https://docs.anthropic.com/en/docs/build-with-claude/vision)
- [Context Engineering for AI Agents](https://www.anthropic.com/engineering/effective-context-engineering-for-ai-agents)
- [Claude Code Best Practices](https://www.anthropic.com/engineering/claude-code-best-practices)
- [Advanced Tool Use](https://www.anthropic.com/engineering/advanced-tool-use)
- [The "Think" Tool](https://www.anthropic.com/engineering/claude-think-tool)

## Model Comparison

| Aspect | Opus 4.6 | Sonnet 4.6 | Sonnet 4.5 | Haiku 4.5 |
|--------|----------|------------|------------|-----------|
| Context window | 1M (beta) | 200K (1M beta) | 200K | 200K |
| Default thinking | Adaptive | Adaptive | Extended (`budget_tokens`) | None |
| Effort parameter | Yes (default: high) | Yes (default: high) | No | No |
| Prefill support | **No** (deprecated) | **No** (deprecated) | Yes | Yes |
| Structured outputs | Yes (`strict: true`) | Yes | Yes | Limited |
| Cost (in/out per 1M) | $15/$75 | $3/$15 | $3/$15 | $0.80/$4 |
| Key strength | Hardest problems, deep research | Fast agentic coding, balance | Extended thinking with budget | Speed, volume |

## Thinking Modes

### Adaptive Thinking (Claude 4.6 — Recommended)

Claude dynamically decides when and how much to think based on query complexity and `effort` parameter.