Cost Tracking

Cost Tracking — Model Pricing & Calculation

> Provides pricing data and calculation methods for API cost estimation.

Model Pricing (per 1M tokens, USD)

| Model | Input | Output | Cache Write (5m) | Cache Read | |-------|-------|--------|------------------|------------| | claude-opus-4-6 | $5.00 | $25.00 | $6.25 | $0.50 | | claude-sonnet-4-5 | $3.00 | $15.00 | $3.75 | $0.30 | | claude-haiku-4-5 | $1.00 | $5.00 | $1.25 | $0.10 |

Prices as of 2026-02. Source: platform.claude.com/docs/en/about-claude/pricing. Update when pricing changes.

Cost Calculation

Per-Request Cost

cost = (input_tokens × input_price / 1_000_000) +
       (output_tokens × output_price / 1_000_000) +
       (cache_write_tokens × cache_write_price / 1_000_000) +
       (cache_read_tokens × cache_read_price / 1_000_000)

Session Cost Estimation

When actual API token counts are unavailable, use estimates:

estimated_input_tokens = sum(tool_input_chars) / 4
estimated_output_tokens = sum(tool_result_chars) / 4
estimated_cost = estimated_input_tokens × input_price / 1_000_000 +
                 estimated_output_tokens × output_price / 1_000_000

Accuracy note: chars/4 estimation has ±20% error. Actual API usage data (from api_traces.jsonl) provides exact costs when available.

Budget Thresholds

| Level | Threshold | Action | |-------|-----------|--------| | INFO | >$0.50/session | Log to stats | | WARNING | >$2.00/session | Alert (MEDIUM severity) | | CRITICAL | >$10.00/session | Alert (HIGH severity) |

Cost Efficiency Metrics

| Metric | Formula | Target | |--------|---------|--------| | Cost per tool call | sessioncost / toolcalls | = 8 corroborationbonus = (confirmingagents - 1) × 0.1 Confidence = min(base + corroboration_bonus, 1.0)

### Effort (1-5)

| Level | Description |
|-------|-------------|
| 1 | Single line addition/change |
| 2 | Multi-line section modification |
| 3 | New section or procedure step |
| 4 | Structural change across multiple sections |
| 5 | Component rewrite or new component |

### Risk (1-5)

| Level | Description |
|-------|-------------|
| 1 | Additive only (no existing behavior changed) |
| 2 | Minor behavior modification in non-critical path |
| 3 | Critical path modification with clear rollback |
| 4 | Cross-component change with interaction risk |
| 5 | Core algorithm/flow change |

### Priority Mapping

ROI >= 2.0 → CRITICAL ROI >= 1.0 → HIGH ROI >= 0.5 → MEDIUM ROI < 0.5 → LOW

## Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

- **Author:** [brody-0125](https://github.com/brody-0125)
- **Source:** [brody-0125/my-claude-skills](https://github.com/brody-0125/my-claude-skills)
- **License:** MIT

Install and usage instructions live in the source repository linked above.