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

1. Scope prompts tightly — "Fix the auth bug in src/auth/login.ts" vs "Fix the auth bug"
2. Use the right model — Haiku for simple lookups, Sonnet for features, Opus for architecture
3. Delegate to subagents — Search/explore operations in subagents keep main context lean
4. Compact proactively — Don't wait for auto-compact; compact at task boundaries
5. Read selectively — Use offset and limit params for large files
6. Batch operations — Multiple independent tool calls in one message
7. One-pass discipline — Write complete solution, test once, stop if green
8. No re-reads — Don't re-read unchanged files; trust cached knowledge
9. Read before write — Never write a file without reading it first
10. 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