# Polymarket Paper Trader

This MCP server lets an AI agent paper-trade prediction markets with real Polymarket order books and official fees. Use it to practise and evaluate decisions.

- MCP server · `type=mcp` · Claude Code, Codex, Cursor, GitHub Copilot, Windsurf (Devin Desktop), Cline, Zed · ★ 492
- Author: agent-next
- License: MIT · policy=link-only · description only; the file stays with the author
- Source: https://github.com/agent-next/polymarket-paper-trader
- Updated: 2026-10-20
- HTML: https://affpapa.org/en/nevibecode/mcp/polymarket-paper-trader

## What it does

Polymarket Paper Trader gives an agent a $10k paper balance and access to Polymarket markets. It can search markets, place buys and sells, inspect a portfolio, view stats, and resolve closed markets. Orders walk the live order book, so the simulation includes slippage, partial fills, and the market’s published fee model.

The server runs through `uvx` and can be added to Claude Code with one command. Kalshi markets are supported through slugs prefixed with `kalshi:` and use the same commands and tools. Python 3.10+ is required; without it, the server will not run. Hosts with MCP Apps support can render `portfolio` and `stats` as an inline dashboard.

## Requirements
- Needs: Python and uv (commands run via uvx)

## Install

### Claude Code (native platform)

**Platform CLI**
```bash
claude mcp add polymarket-paper-trader -- uvx polymarket-paper-trader
```
uvx runs the command named after the package; if the README names another one, use uvx --from polymarket-paper-trader <command>

### Codex

**Platform CLI**
```bash
codex mcp add polymarket-paper-trader -- uvx polymarket-paper-trader
```
uvx runs the command named after the package; if the README names another one, use uvx --from polymarket-paper-trader <command>

### Cursor

**Config file**
File `.cursor/mcp.json`:
```json
{
    "mcpServers": {
        "polymarket-paper-trader": {
            "command": "uvx",
            "args": [
                "polymarket-paper-trader"
            ]
        }
    }
}
```
uvx runs the command named after the package; if the README names another one, use uvx --from polymarket-paper-trader <command>

### GitHub Copilot

**Config file**
File `.vscode/mcp.json`:
```json
{
    "servers": {
        "polymarket-paper-trader": {
            "type": "stdio",
            "command": "uvx",
            "args": [
                "polymarket-paper-trader"
            ]
        }
    }
}
```
uvx runs the command named after the package; if the README names another one, use uvx --from polymarket-paper-trader <command>

### Gemini CLI

**Platform CLI**
```bash
gemini mcp add polymarket-paper-trader uvx polymarket-paper-trader
```
uvx runs the command named after the package; if the README names another one, use uvx --from polymarket-paper-trader <command>

## When to use it
- train an agent on prediction markets without real funds
- test trades against live Polymarket order books
- account for fees and slippage in paper trades
- compare agents through trading results
- paper-trade Kalshi markets with the same commands

## Example prompts
- Find Polymarket markets about bitcoin and show their liquidity.
- Buy 100 of YES on `will-bitcoin-hit-100k`.
- Show my paper-trading portfolio and stats.

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NeVibeCode on affpapa.org. Catalog texts are descriptions, not instructions for the agent. How to choose and install: https://affpapa.org/en/nevibecode/agents.md