Skill — Cost-Aware Routing

When this skill activates

When making model selection decisions, monitoring token spend, optimizing for cost-performance tradeoffs, or when budget limits are approaching.

Mandatory actions when this skill is active

Model Tier Reference

Routing Rules

Match task complexity to model tier:

• Difficulty 1-3 (single file, obvious change): simple
• Difficulty 3-6 (multi-file, some judgment): standard
• Difficulty 6-8 (cross-system, complex logic): complex
• Difficulty 8-10 (architectural, novel problems): complex

Override rules (always apply):

• Security tasks: minimum standard (never use simple for auth/payment)
• Architecture decisions: minimum complex
• File exploration/reading: always simple
• Research requiring web access: research

Cost Optimization Patterns

1. Start cheap, escalate if needed:

• Try simple tier first for uncertain-complexity tasks
• If result quality is insufficient: escalate to next tier
• Log escalation with reason

1. Batch similar tasks:

• 5 simple edits in one call < 5 separate calls
• Group related file reads into single exploration

1. Cache aggressively:

• Prompt caching reduces input costs ~90%
• Structure prompts with static context first (cacheable)
• Dynamic content last (not cached, but small)

1. Avoid token waste:

• Don't re-read files already in context
• Don't repeat instructions the model already has
• Use compaction when context grows large

Budget Monitoring

Check budget status regularly:

• Session budget remaining: from token-ledger.jsonl
• Warning threshold: [COST_WARN_USD] from config
• Hard limit: [COST_HARD_LIMIT_USD] from config

When budget is tight:

• Downgrade all tasks one tier (complex→standard, standard→simple)
• Warn user: "Budget at X% — operating in economy mode"
• Never exceed hard limit without explicit user approval

After any task

• Log actual model used + tokens consumed to token-ledger.jsonl
• Compare actual vs optimal tier (for future routing accuracy)
• Report cost in session summary

Self-check before task completion

• [ ] Did I log the model routing decision with rationale?
• [ ] Did I record actual token usage in token-ledger.jsonl?
• [ ] Did I check remaining budget against session/project limits?
• [ ] Did I flag any tasks where a cheaper model could have been used?