Numbers only, measured from my own local Claude Code session logs (2026-10-12 to 2026-10-18, 7-day daily average).
- Calls per day: 2,772
- Cache-read tokens per day: 315M
- Output tokens per day: 2.4M
Share of cost by slice:
| Slice | Share of cost |
|---|---|
| Base (system prompt + tool list) | 43.3% |
| Model replies | 25.5% |
| User input + attachments | 21.6% |
| Shell command output | 6.1% |
| Subagents | 2.1% |
| File reads | 1.2% |
| Search (grep/glob) | 0.1% |
| MCP + other tools | 0.1% |
| Web fetch | 0.0% |
Cost weights: input 1, cache write 1.25, cache read 0.1, output 5 (input token = 1).
Takeaway: the biggest slice is the fixed context that gets re-read on every call, so shorter sessions help more than trimming tool output.
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