Agent Model Selection

Agent Model Selection

Instructions

Core decision

Sonnet: Complex reasoning, architecture, security (2+ criteria) Haiku: Defined rules, repetitive tasks, simple commands (~95% cheaper)

Selection criteria

Use Sonnet if 2+ apply:

1. Logical reasoning and trade-off analysis
2. Architecture/design decisions
3. Semantic/intent analysis
4. Problem diagnosis and strategy
5. Multi-component interaction
6. Security/performance analysis

Use Haiku if dominant:

1. Following defined rules/templates
2. Repetitive mechanical tasks
3. Command execution and collection
4. Simple CRUD operations
5. Format validation

Decision flowchart

Architecture/design? → YES → Sonnet
Multiple options? → YES → Sonnet
Security/performance? → YES → Sonnet
Defined rules only? → YES → Haiku
Detailed guide? → YES → Haiku
Large delegated? → YES → Sonnet
Simple commands? → YES → Haiku
Default: Sonnet (quality first)

Example

Task: Add validation logic
→ Analysis: Complex rules + security + error handling
→ Decision: Sonnet (3 criteria met)

Task: Add tags to files
→ Analysis: Template exists, repetitive
→ Decision: Haiku (rule-following)

For detailed criteria, see reference.md For more examples, see examples.md