Introduction
# Smart Model Switching
**Three-tier Claude routing: Haiku → Sonnet → Opus**
Start with the cheapest model. Escalate only when needed. Save 50-90% on API costs.
## The Golden Rule
> If a human would need more than 30 seconds of focused thinking, escalate from Haiku to Sonnet. > If the task involves architecture, complex tradeoffs, or deep reasoning, escalate to Opus.
## Cost Reality
| Model | Input | Output | Relative Cost | |-------|-------|--------|---------------| | Haiku | \$0.25/M | \$1.25/M | 1x (baseline) | | Sonnet | \$3.00/M | \$15.00/M | 12x | | Opus | \$15.00/M | \$75.00/M | 60x |
**Bottom line:** Wrong model selection wastes money OR time. Haiku for simple, Sonnet for standard, Opus for complex.
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## 💚 HAIKU — Default for Simple Tasks
**Stay on Haiku for:** - Factual Q&A — "what is X", "who is Y", "when did Z" - Quick lookups — definitions, unit conversions, short translations - Status checks — calendar, file reads, session monitoring - Heartbeats — periodic checks, HEARTBEAT_OK responses - Memory & reminders — "remember this", "remind me to..." - Casual conversation — greetings, small talk, acknowledgments - Simple file ops — read, list, basic writes - One-liner tasks — anything answerable in 1-2 sentences
### NEVER do these on Haiku - ❌ Write code longer than 10 lines - ❌ Create comparison tables - ❌ Write more than 3 paragraphs - ❌ Do multi-step analysis - ❌ Write reports or proposals
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## 💛 SONNET — Standard Work (The Workhorse)
**Escalate to Sonnet for:**
### Code & Technical - Code generation — write functions, build features, scripts - Code review — PR reviews, quality checks - Debugging — standard bug investigation - Documentation — README, comments, user guides
### Analysis & Planning - Analysis & evaluation — compare options, assess trade-offs - Planning — project plans, roadmaps, task breakdowns - Research synthesis — combining multiple sources - Multi-step reasoning — "first... then... finally"
### Writing & Content - Long-form writing — reports, proposals, articles (>3 paragraphs) - Creative writing — blog posts, descriptions, copy - Summarization — long documents, transcripts - Structured output — tables, outlines, formatted docs
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## ❤️ OPUS — Complex Reasoning Only
**Escalate to Opus for:**
### Architecture & Design - System architecture decisions - Major codebase refactoring - Design pattern selection with tradeoffs - Database schema design
### Deep Analysis - Complex debugging (multi-file, race conditions) - Security reviews - Performance optimization strategy - Root cause analysis of subtle bugs
### Strategic & Creative - Strategic planning — business decisions, roadmaps - Nuanced judgment — ethics, ambiguity, competing values - Deep research — comprehensive multi-source analysis
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## 🔄 Implementation
### For Subagents \`\`\`javascript // Routine monitoring sessions_spawn(task="Check backup status", model="haiku")
// Standard code work sessions_spawn(task="Build the REST API endpoint", model="sonnet")
// Architecture decisions sessions_spawn(task="Design the database schema for multi-tenancy", model="opus") \`\`\`
### For Cron Jobs \`\`\`json { "payload": { "kind": "agentTurn", "model": "haiku" } } \`\`\` Always use Haiku for cron unless the task genuinely needs reasoning.
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## 📊 Quick Decision Tree
\`\`\` Is it a greeting, lookup, status check, or 1-2 sentence answer? YES → HAIKU NO ↓
Is it code, analysis, planning, writing, or multi-step? YES → SONNET NO ↓
Is it architecture, deep reasoning, or critical decision? YES → OPUS NO → Default to SONNET, escalate if struggling \`\`\`
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## 📋 Quick Reference Card
\`\`\` ┌─────────────────────────────────────────────────────────────┐ │ SMART MODEL SWITCHING │ │ Haiku → Sonnet → Opus │ ├─────────────────────────────────────────────────────────────┤ │ 💚 HAIKU (cheapest) │ │ • Greetings, status checks, quick lookups │ │ • Factual Q&A, definitions, reminders │ │ • Simple file ops, 1-2 sentence answers │ ├─────────────────────────────────────────────────────────────┤ │ 💛 SONNET (standard) │ │ • Code > 10 lines, debugging │ │ • Analysis, comparisons, planning │ │ • Reports, proposals, long writing │ ├─────────────────────────────────────────────────────────────┤ │ ❤️ OPUS (complex) │ │ • Architecture decisions │ │ • Complex debugging, multi-file refactoring │ │ • Strategic planning, deep research │ ├─────────────────────────────────────────────────────────────┤ │ 💡 RULE: If a human needs > 30 sec thinking → escalate │ │ 💰 COST: Haiku 1x → Sonnet 12x → Opus 60x │ └─────────────────────────────────────────────────────────────┘ \`\`\`
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*Built for Claude-only setups with Haiku, Sonnet, and Opus.* *Inspired by save-money skill, extended with three-tier progression.*