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crypto-gains skill

/skills/crypto-gains

This skill calculates capital gains with FIFO, wash-sale detection, term classification, and Form 8949 outputs for IRS compliance.

npx playbooks add skill phrazzld/claude-config --skill crypto-gains

Review the files below or copy the command above to add this skill to your agents.

Files (1)
SKILL.md
1.2 KB
---
name: crypto-gains
description: |
  Calculate capital gains with FIFO, wash sale detection, term classification, and Form 8949 outputs.
user-invocable: true
effort: high
---

# /crypto-gains

Calculate capital gains with IRS-compliant rules.

## Steps

1. Load lots from `normalized/cost-basis.json` and transactions from `normalized/transactions.json`.
2. Build sell list and allocate FIFO lots per asset.
3. Classify each gain as short-term or long-term by holding period.
4. Detect wash sales within 30 days for securities. Mark crypto as not applicable per current policy.
5. Write gains to `normalized/capital-gains.json` and updated lots to `normalized/cost-basis-updated.json`.
6. Generate Form 8949 outputs and summaries.

## Examples

```bash
# Build FIFO gains and updated lots
pnpm gains
```

```bash
# Generate Form 8949 and tax summaries
pnpm report
```

## References

- `normalized/transactions.json`
- `normalized/cost-basis.json`
- `normalized/capital-gains.json`
- `normalized/cost-basis-updated.json`
- `reports/tax-ready/form-8949-c.csv`
- `reports/tax-ready/turbotax-import.csv`
- `reports/tax-ready/schedule-d-summary.md`
- `scripts/calculate-gains.ts`
- `scripts/generate-report.ts`

Overview

This skill calculates IRS-compliant capital gains for cryptocurrency and other assets using FIFO lot allocation, holding-period classification, and wash sale detection rules. It produces machine-readable outputs and tax-ready CSVs for Form 8949 and Schedule D summaries. The workflow updates cost-basis lots and creates a detailed capital gains ledger for downstream reporting.

How this skill works

The tool ingests normalized cost-basis lots and transaction history, then builds a sell list and allocates fills to lots using first-in, first-out rules. Each disposition is classified as short-term or long-term by computing the holding period, and wash sales are detected within the 30-day window for securities (crypto currently marked as not applicable). Results are written to updated cost-basis and capital gains files and exported as Form 8949 and other tax-ready reports.

When to use it

  • Preparing year-end capital gains calculations for tax filing
  • Reconciling trade history against cost-basis lots after many buys and sells
  • Generating Form 8949 and Schedule D summaries for import into tax software
  • Detecting potential wash sale adjustments for securities
  • Updating cost-basis lots after partial lot sales or complex allocation events

Best practices

  • Maintain clean, normalized transaction and cost-basis inputs before running calculations
  • Verify timezones and timestamps to ensure correct holding-period classification
  • Run a dry pass on a subset of assets to validate allocation logic before processing full history
  • Keep a backup of original cost-basis files; review updated lots for unexpected adjustments
  • Use the generated CSVs to cross-check totals with brokerage and exchange statements

Example use cases

  • Compute FIFO gains for a year of crypto trades and export Form 8949 CSV for tax software
  • Identify short-term vs long-term gains for high-frequency trading accounts
  • Detect wash sale candidates in a mixed portfolio of stocks and ETFs
  • Update cost-basis lots after a large partial sell to maintain accurate future basis
  • Produce a Schedule D summary and a Turbotax-import CSV to speed up tax preparation

FAQ

Does the skill apply wash sale rules to crypto?

By current policy it marks wash sale detection as not applicable to crypto; wash sale detection is performed for securities within the 30-day window.

What outputs are produced for tax filing?

It writes updated cost-basis and capital gains JSON files and generates Form 8949 CSVs, Turbotax-import CSV, and a Schedule D summary.

Which allocation method is used?

FIFO (first-in, first-out) allocation is used to match sells to prior lots.