prediction-market-strategy

prediction-market-strategy is a skill for Claude Code from agiprolabs/claude-trading-skills. It costs 57 tokens per session (3,182 once invoked), scanned A, original, MIT.

A strategy and testing guide for binary prediction markets, where contracts pay according to whether an event happens or not. It covers probability-based pricing, fees, position sizing, and backtesting across venues such as Kalshi and Polymarket.

In plain words
What is it for?
Use it to evaluate market opportunities, select contracts, size positions with fractional Kelly, and test strategies without leaking future information into the past.
Why use it?
It helps separate the strategy itself from the APIs and settlement rules of a particular market. Its validation approach is designed to reduce misleading backtest results and account for trading costs.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin. Also seen: positional $N argument.

Part of the trading-skills plugin — 68 skills shipped together

Good fit Use it to evaluate market opportunities, select contracts, size positions with fractional Kelly, and test strategies without leaking future information into the past.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/agiprolabs/claude-trading-skills/prediction-market-strategy
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 agiprolabs/claude-trading-skills --skill prediction-market-strategy
Clone the repo
git clone --depth 1 https://github.com/agiprolabs/claude-trading-skills

Made for: Claude Code.

Or install trading-skills, the plugin that ships this one along with the rest of its 68 skills.

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 prediction-market-strategy

README.md
[![agentmods](https://agentmods.dev/badge/skills/agiprolabs/claude-trading-skills/prediction-market-strategy/github.svg)](https://agentmods.dev/skills/agiprolabs/claude-trading-skills/prediction-market-strategy)
Your own site
<a href="https://agentmods.dev/skills/agiprolabs/claude-trading-skills/prediction-market-strategy"><img src="https://agentmods.dev/badge/skills/agiprolabs/claude-trading-skills/prediction-market-strategy/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 prediction-market-strategy

Your own site · 80×15
<a href="https://agentmods.dev/skills/agiprolabs/claude-trading-skills/prediction-market-strategy"><img src="https://agentmods.dev/badge/skills/agiprolabs/claude-trading-skills/prediction-market-strategy.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 57 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,182 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 $0.00057 $0.03182
Opus 5 $0.00028 $0.01591
Sonnet 5 $0.00011 $0.00636
Haiku 4.5 $0.00006 $0.00318

Measured 12d ago against content hash 03cc9b80ac4a, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

prediction-market-strategy 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 12d ago.

The scan reads SKILL.md. This mod also ships 1 executable file (scripts/sizing.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/prediction-market-strategy/SKILL.md · 200 lines

How it starts

The opening of the file, as written. The whole thing — 200 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Prediction Market Strategy

Binary prediction markets price contracts as probabilities. This skill covers the strategy, sizing, and validation layer that applies across all venues and market types. API mechanics live in kalshi-api / polymarket-api; contract semantics and settlement live in kalshi-weather-markets / kalshi-crypto-index-markets. This is the strategy/sizing/validation layer that applies across all of them.

Core Thesis

Price = implied probability. A contract priced at $0.18 claims an 18% chance of resolving YES. Brackets in a series sum to just above $1.00 — the overround is the house margin (roughly 5–8% for weather markets on Kalshi).

Takers systematically lose; makers systematically win. Across 300k+ Kalshi contracts, the average pre-fee return is ≈ −20%, concentrated in takers (market-order users) and in longshot buyers. Makers (resting limit orders) earn positive returns. On Polymarket (588M+ trades), the top ~1% of accounts capture ~76.5% of profit, predominantly by resting limit orders. This is the foundational result.

Favorite–longshot bias is the durable mechanism. Cheap longshots are systematically overpriced: a $0.05 contract historically wins ~2%; sub-$0.10 contracts lose ~60% of stake to buyers. Favorites are fairly- to slightly-underpriced. The repeatable expression is selling the overpriced longshot tail, maker-side — resting NO bids on brackets priced ~$0.05–$0.20, diversified across many events to survive the rare hit. This is structural/behavioral, not a forecasting edge.

Forecast skill ≠ trading edge. A good weather or event forecast is largely redundant with the market price at decision time. Markets aggregate information efficiently enough that even a measurably better model produces near-zero net edge after fees unless it finds systematic mispricings (which are behavioral, not informational). The exception is official-label ML in lightly-traded markets — but that is bounded by fill-rate and capacity, not forecast accuracy.

Read the full file on GitHub · 200 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. 12d ago First seen · 200 lines · 57 tokens per session scan A 03cc9b80ac4a

Subscribe to this mod's changes

prediction-market-strategy is a skill published in the GitHub repository agiprolabs/claude-trading-skills (356 stars, last pushed 9d ago), licensed MIT. It adds 57 tokens to every session and 3,182 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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