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.
💚 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
💛 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
❤️ 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
🔄 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.
📊 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 ```
📋 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 │ └─────────────────────────────────────────────────────────────┘ ```
Built for Claude-only setups with Haiku, Sonnet, and Opus. Inspired by save-money skill, extended with three-tier progression.