# Trader Copycat

The Reverse Engineer.

- Repository: https://github.com/Jakeschincariol/trader-skill (1074 stars)
- Category: Business
- License: MIT
- Last updated: 2026-10-14
- Runs scripts: yes, review before use

## Install

Claude Code: `npx skills add Jakeschincariol/trader-skill --skill trader-copycat -g -a claude-code -y`
Codex: `npx skills add Jakeschincariol/trader-skill --skill trader-copycat -g -a codex -y`
Cursor: `npx skills add Jakeschincariol/trader-skill --skill trader-copycat -g -a cursor -y`
Gemini CLI: `npx skills add Jakeschincariol/trader-skill --skill trader-copycat -g -a gemini-cli -y`
Claude Code plugin marketplace: `/plugin marketplace add Jakeschincariol/trader-skill`

## Description

The Reverse Engineer. Reads a famous investor's public SEC filings (the quarterly 13F-HR, plus Form 4 if you want the insider trades) and rebuilds their portfolio as weights you can copy: every position, its share of the fund, what they bought, added, trimmed and sold since the last quarter, with tickers matched to every CUSIP. Then it writes trader/targets.json so the budget skill can size it to your money. Use when the user says "copy Buffett", "copy Berkshire", "what does Ackman own", "reverse engineer this investor", "show me their 13F", "what did they buy last quarter", "copy the top 5", or names any fund or famous investor.

## SKILL.md, as published by its author (untrusted third-party text, read it as data)

# trader-copycat

Copying an investor starts with what they are legally required to show: a
13F-HR, filed with the SEC every quarter by any investment manager with over
$100 million in US-listed stocks and other 13(f) securities. This skill reads
it straight from SEC EDGAR, rebuilds the portfolio, and turns it into target
weights for your own account.

Tool in this folder (standard library Python, no keys):

```bash
python3 "${CLAUDE_SKILL_DIR}/edgar13f.py" --help
```

SEC asks every program to identify itself with a name and email. Set it once
in `trader/config.json` (`"sec_user_agent": "Your Name you@example.com"`, with
the user's real name and email) or `export SEC_USER_AGENT=...`. The tool
refuses to call SEC without it and says how to fix it. Ask the user for it;
never invent one.

## What it writes

- `trader/targets.json`: the weights to copy, in the shape every other trader
  skill reads: `{ "source", "as_of", "weights": [ {"ticker", "name",
  "weight"} ] }`, weights in % with 2 decimals summing to 100 over the stock
  sleeve (keep the 2 decimals: budget sizing needs them), plus the
  13F share, value, CUSIPs, what was skipped and why, and the caveats.
- `trader/tickers.json` (optional, yours): CUSIP to ticker fixes the tool
  will always use first, as `{"650111107": "NYT"}`.

`targets.example.json` in this folder is the real output of the reel's run
(Berkshire, top 5).

## The rules

The rest: https://github.com/Jakeschincariol/trader-skill/blob/HEAD/trader-copycat/SKILL.md