backtest-expert

backtest-expert is a skill for Claude Code, Codex from BaggaT236/AI-Trading-Skills. It costs 81 tokens per session (1,922 once invoked), scanned A, a copy of backtest-expert, MIT.

A guide for testing trading strategies against historical data before considering live use. Backtesting means replaying past market data to see how a rule-based strategy would have behaved.

In plain words
What is it for?
Use it to define a trading hypothesis, test parameter sensitivity, model slippage and execution costs, stress-test assumptions, and interpret backtest results.
Why use it?
It helps identify misleading results caused by overfitting, using future information, ignoring failed companies, trading costs, or changing market conditions. It emphasizes whether a strategy remains credible under less favorable assumptions.

Skill for Claude CodeCodex

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

Good fit Use it to define a trading hypothesis, test parameter sensitivity, model slippage and execution costs, stress-test assumptions, and interpret backtest results.

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

README.md
[![agentmods](https://agentmods.dev/badge/skills/baggat236/ai-trading-skills/backtest-expert/github.svg)](https://agentmods.dev/skills/baggat236/ai-trading-skills/backtest-expert)
Your own site
<a href="https://agentmods.dev/skills/baggat236/ai-trading-skills/backtest-expert"><img src="https://agentmods.dev/badge/skills/baggat236/ai-trading-skills/backtest-expert/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 backtest-expert

Your own site · 80×15
<a href="https://agentmods.dev/skills/baggat236/ai-trading-skills/backtest-expert"><img src="https://agentmods.dev/badge/skills/baggat236/ai-trading-skills/backtest-expert.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 81 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,922 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.
Origin 100% copy Near-identical to another mod 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 $0.00081 $0.01922
Opus 5 $0.00041 $0.00961
Sonnet 5 $0.00016 $0.00384
Haiku 4.5 $0.00008 $0.00192

Measured 11d ago against content hash 316c87c2d2b8, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

backtest-expert 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 11d ago.

The scan reads SKILL.md. This mod also ships 3 executable files (scripts/evaluate_backtest.py, scripts/tests/conftest.py, scripts/tests/test_evaluate_backtest.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.

Origin

This is a copy

100% identical to backtest-expert — 0 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

skills/backtest-expert/SKILL.md · 235 lines

How it starts

The opening of the file, as written. The whole thing — 235 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Backtest Expert

Systematic approach to backtesting trading strategies based on professional methodology that prioritizes robustness over optimistic results.

Core Philosophy

Goal: Find strategies that "break the least", not strategies that "profit the most" on paper.

Principle: Add friction, stress test assumptions, and see what survives. If a strategy holds up under pessimistic conditions, it's more likely to work in live trading.

When to Use This Skill

Use this skill when:

  • Developing or validating systematic trading strategies
  • Evaluating whether a trading idea is robust enough for live implementation
  • Troubleshooting why a backtest might be misleading
  • Learning proper backtesting methodology
  • Avoiding common pitfalls (curve-fitting, look-ahead bias, survivorship bias)
  • Assessing parameter sensitivity and regime dependence
  • Setting realistic expectations for slippage and execution costs

Prerequisites

  • Python 3.9+ (for evaluation script)
  • No API keys required
  • No external data dependencies — metrics are user-provided

Workflow

1. State the Hypothesis

Define the edge in one sentence.

Example: "Stocks that gap up >3% on earnings and pull back to previous day's close within first hour provide mean-reversion opportunity."

If you can't articulate the edge clearly, don't proceed to testing.

2. Codify Rules with Zero Discretion

Define with complete specificity:

  • Entry: Exact conditions, timing, price type
  • Exit: Stop loss, profit target, time-based exit
  • Position sizing: Fixed $$, % of portfolio, volatility-adjusted
  • Filters: Market cap, volume, sector, volatility conditions
  • Universe: What instruments are eligible

Critical: No subjective judgment allowed. Every decision must be rule-based and unambiguous.

3. Run Initial Backtest

Test over:

  • Minimum 5 years (preferably 10+)
  • Multiple market regimes (bull, bear, high/low volatility)
  • Realistic costs: Commissions + conservative slippage

Read the full file on GitHub · 235 lines

Files

What ships with it

5 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. 11d ago First seen · 235 lines · 81 tokens per session scan A 316c87c2d2b8

Subscribe to this mod's changes

backtest-expert is a skill published in the GitHub repository BaggaT236/AI-Trading-Skills (121 stars, last pushed 8d ago), licensed MIT. It adds 81 tokens to every session and 1,922 once invoked, about $0.0004 per session on Opus 5. A static security scan graded it A with 0 findings. It is 100% identical to backtest-expert, differing in 0 lines, and is treated as a copy.

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