position-sizer

position-sizer is a skill for Claude Code, Codex from BaggaT236/AI-Trading-Skills. It costs 58 tokens per session (1,543 once invoked), scanned A, original, MIT.

A stock-trading calculator that works out how many shares to buy based on account size, risk, price movement, and portfolio limits.

In plain words
What is it for?
Use it for fixed-percentage sizing, ATR-based sizing using a stock's typical price range, Kelly sizing from past results, stop-loss calculations, and concentration checks.
Why use it?
It turns a chosen risk per trade and stop-loss distance into a share count, helping prevent a single trade or sector from taking too much of a portfolio.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it for fixed-percentage sizing, ATR-based sizing using a stock's typical price range, Kelly sizing from past results, stop-loss calculations, and concentration checks.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/baggat236/ai-trading-skills/position-sizer
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add BaggaT236/AI-Trading-Skills --skill position-sizer
Clone the repo
git clone --depth 1 https://github.com/BaggaT236/AI-Trading-Skills

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for position-sizer

README.md
[![agentmods](https://agentmods.dev/badge/skills/baggat236/ai-trading-skills/position-sizer/github.svg)](https://agentmods.dev/skills/baggat236/ai-trading-skills/position-sizer)
Your own site
<a href="https://agentmods.dev/skills/baggat236/ai-trading-skills/position-sizer"><img src="https://agentmods.dev/badge/skills/baggat236/ai-trading-skills/position-sizer/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for position-sizer

Your own site · 80×15
<a href="https://agentmods.dev/skills/baggat236/ai-trading-skills/position-sizer"><img src="https://agentmods.dev/badge/skills/baggat236/ai-trading-skills/position-sizer.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 58 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,543 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00058 $0.01543
Opus 5 $0.00029 $0.00772
Sonnet 5 $0.00012 $0.00309
Haiku 4.5 $0.00006 $0.00154

Measured 10d ago against content hash 1fe79c0d268c, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

position-sizer scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 10d ago.

The scan reads SKILL.md. This mod also ships 3 executable files (scripts/position_sizer.py, scripts/tests/conftest.py, scripts/tests/test_position_sizer.py), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

skills/position-sizer/SKILL.md · 182 lines

How it starts

The opening of the file, as written. The whole thing — 182 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Position Sizer

Overview

Calculate the optimal number of shares to buy for a long stock trade based on risk management principles. Supports three sizing methods:

  • Fixed Fractional: Risk a fixed percentage of account equity per trade (default: 1%)
  • ATR-Based: Use Average True Range to set volatility-adjusted stop distances
  • Kelly Criterion: Calculate mathematically optimal risk allocation from historical win/loss statistics

All methods apply portfolio constraints (max position %, max sector %) and output a final recommended share count with full risk breakdown.

When to Use

  • User asks "how many shares should I buy?"
  • User wants to calculate position size for a specific trade setup
  • User mentions risk per trade, stop-loss sizing, or portfolio allocation
  • User asks about Kelly Criterion or ATR-based position sizing
  • User wants to check if a position fits within portfolio concentration limits

Prerequisites

  • No API keys required
  • Python 3.9+ with standard library only

Workflow

Step 1: Gather Trade Parameters

Collect from the user:

  • Required: Account size (total equity)
  • Mode A (Fixed Fractional): Entry price, stop price, risk percentage (default 1%)
  • Mode B (ATR-Based): Entry price, ATR value, ATR multiplier (default 2.0x), risk percentage
  • Mode C (Kelly Criterion): Win rate, average win, average loss; optionally entry and stop for share calculation
  • Optional constraints: Max position % of account, max sector %, current sector exposure

If the user provides a stock ticker but not specific prices, use available tools to look up the current price and suggest entry/stop levels based on technical analysis.

Step 2: Execute Position Sizer Script

Run the position sizing calculation:

# Fixed Fractional (most common)
python3 skills/position-sizer/scripts/position_sizer.py \
  --account-size 100000 \
  --entry 155 \
  --stop 148.50 \
  --risk-pct 1.0 \
  --output-dir reports/

# ATR-Based
python3 skills/position-sizer/scripts/position_sizer.py \
  --account-size 100000 \
  --entry 155 \
  --atr 3.20 \
  --atr-multiplier 2.0 \
  --risk-pct 1.0 \
  --output-dir reports/

# Kelly Criterion (budget mode - no entry)
python3 skills/position-sizer/scripts/position_sizer.py \
  --account-size 100000 \
  --win-rate 0.55 \
  --avg-win 2.5 \
  --avg-loss 1.0 \
  --output-dir reports/

# Kelly Criterion (shares mode - with entry/stop)
python3 skills/position-sizer/scripts/position_sizer.py \
  --account-size 100000 \
  --entry 155 \
  --stop 148.50 \
  --win-rate 0.55 \
  --avg-win 2.5 \
  --avg-loss 1.0 \
  --output-dir reports/

Read the full file on GitHub · 182 lines

Files

What ships with it

4 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 10d ago First seen · 182 lines · 58 tokens per session scan A 1fe79c0d268c

Subscribe to this mod's changes

position-sizer is a skill published in the GitHub repository BaggaT236/AI-Trading-Skills (121 stars, last pushed 7d ago), licensed MIT. It adds 58 tokens to every session and 1,543 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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