Cost Tracker
Monitor and optimize Claude Code session costs.
Trigger
Use when:
- Checking session costs
- Setting budget alerts
- Optimizing token spend
- Planning multi-session work
Cost Awareness
Check Current Costs
# Session cost is shown at the end of each session
# Mid-session: check the status bar or run /cost
Cost Drivers
| Operation | Relative Cost | Optimization |
|---|---|---|
| Large file reads | High | Use offset/limit params |
| Broad grep searches | Medium | Scope to specific dirs |
| Subagent spawning | High (new context) | Reuse agents via SendMessage |
| Repeated tool calls | Cumulative | Batch operations |
| MCP tool calls | Variable | Minimize round-trips |
| Model selection | 3-10x difference | Use haiku for simple tasks |
Token Budget by Task Type
| Task | Typical Cost | Budget Alert |
|---|---|---|
| Bug fix | $0.10-0.50 | $1.00 |
| Feature (small) | $0.50-2.00 | $3.00 |
| Feature (large) | $2.00-8.00 | $10.00 |
| Refactor | $1.00-5.00 | $7.00 |
| Code review | $0.20-1.00 | $2.00 |
Tool-Call Budgets
Set explicit budgets by task complexity:
| Task Type | Tool-Call Budget | Wrap-Up At |
|---|---|---|
| Quick fix / lookup | 20 calls | 15 |
| Bug fix | 30 calls | 25 |
| Feature (small) | 50 calls | 40 |
| Feature (large) | 80 calls | 65 |
| Refactor | 50 calls | 40 |
At the wrap-up threshold: commit progress, assess remaining work, decide whether to continue or start fresh.
Optimization Strategies
- Scope prompts tightly — "Fix the auth bug in src/auth/login.ts" vs "Fix the auth bug"
- Use the right model — Haiku for simple lookups, Sonnet for features, Opus for architecture
- Delegate to subagents — Search/explore operations in subagents keep main context lean
- Compact proactively — Don't wait for auto-compact; compact at task boundaries
- Read selectively — Use
offsetandlimitparams for large files - Batch operations — Multiple independent tool calls in one message
- One-pass discipline — Write complete solution, test once, stop if green
- No re-reads — Don't re-read unchanged files; trust cached knowledge
- Read before write — Never write a file without reading it first
- Kill output bloat — No sycophantic openers, no closing fluff, no prompt restatement
Budget Alerts
Set mental checkpoints:
- 50% budget — Are you on track? Should you compact?
- 80% budget — Wrap up current task, avoid new exploration
- 100% budget — Commit what you have, start fresh session
Output
COST TRACKER
Session cost: $X.XX
Token usage: [input]K in / [output]K out
Cache hit rate: ~XX%
Top cost drivers:
1. [operation] — $X.XX
2. [operation] — $X.XX
Optimization tips:
- [specific suggestion]
Rules
- Track costs as awareness, not hard limits
- Never sacrifice code quality to save tokens
- Compact at task boundaries, not mid-task
- Use subagents for exploration-heavy work