Model Selection Guide
Understanding SpecWeave's intelligent model routing
Overview
SpecWeave uses a two-tier model strategy:
- Opus 4.5 - Default for all complex work (planning, analysis, architecture, code review)
- Haiku - For simple/cheap operations (translations, mechanical tasks)
The Models
Opus 4.5 (Default - Planning, Analysis & Complex Work)
Use for:
- Strategic planning
- Architecture design
- Complex problem solving
- Security analysis
- Code review
- Quality assessment
Pricing: $15 per 1M input tokens, $75 per 1M output tokens
Characteristics:
- Deepest reasoning
- Highest quality analysis
- Best for complex tasks
- Default for all agents
Haiku 4.5 (Simple & Cheap Operations)
Use for:
- Translations
- Mechanical execution
- Simple data processing
- Configuration generation
- Routine tasks
Pricing: $1 per 1M input tokens, $5 per 1M output tokens
Characteristics:
- Fast execution
- Cost-effective
- Good for repetitive tasks
- Used when task has detailed spec
Sonnet 4 (Legacy)
Rarely used - Available for backwards compatibility.
Pricing: $3 per 1M input tokens, $15 per 1M output tokens
See full content at: https://github.com/anton-abyzov/specweave/blob/develop/.specweave/docs/public/guides/model-selection.md
Due to length, truncating here. File contains complete guide with agent classifications, phase detection algorithm, decision examples, troubleshooting, and FAQ.
Last updated: 2025-10-31