Model Selection Guide
Understanding SpecWeave's intelligent model routing
Overview
SpecWeave uses a three-layer intelligent system to automatically choose the best AI model for each task:
- Agent Preferences - Each agent declares its optimal model
- Phase Detection - Analyzes your prompt to detect planning vs execution
- Model Selector - Combines all signals to make the final decision
The Three Models
Sonnet 4.5 (Planning & Strategy)
Use for:
- Strategic planning
- Architecture design
- Complex problem solving
- Security analysis
- Code review
Pricing: $3 per 1M input tokens, $15 per 1M output tokens
Characteristics:
- Deep reasoning
- Complex analysis
- Strategic thinking
- High accuracy
Haiku 4.5 (Execution & Implementation)
Use for:
- Code implementation
- Refactoring
- Data processing
- Configuration generation
- Test writing
Pricing: $1 per 1M input tokens, $5 per 1M output tokens
Characteristics:
- Fast execution (2x Sonnet speed)
- Excellent code generation
- Pattern recognition
- Cost-effective
Opus 4.0 (Coming Soon)
Use for:
- Extremely complex reasoning
- Novel algorithm design
- Research-level tasks
Pricing: $15 per 1M input tokens, $75 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 | SpecWeave v0.4.0