polymarket

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Query Polymarket: markets, prices, orderbooks, history.

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Sourcenousresearch/hermes-agent

Added on2026-05-30

NPX Install

npx skill4agent add nousresearch/hermes-agent polymarket

SKILL.md Content

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Polymarket — Prediction Market Data

Query prediction market data from Polymarket using their public REST APIs. All endpoints are read-only and require zero authentication.

See

references/api-endpoints.md

for the full endpoint reference with curl examples.

When to Use

User asks about prediction markets, betting odds, or event probabilities
User wants to know "what are the odds of X happening?"
User asks about Polymarket specifically
User wants market prices, orderbook data, or price history
User asks to monitor or track prediction market movements

Key Concepts

Events contain one or more Markets (1:many relationship)
Markets are binary outcomes with Yes/No prices between 0.00 and 1.00
Prices ARE probabilities: price 0.65 means the market thinks 65% likely
```
outcomePrices
```
field: JSON-encoded array like
```
["0.80", "0.20"]
```
```
clobTokenIds
```
field: JSON-encoded array of two token IDs [Yes, No] for price/book queries
```
conditionId
```
field: hex string used for price history queries
Volume is in USDC (US dollars)

Three Public APIs

Gamma API at
```
gamma-api.polymarket.com
```
— Discovery, search, browsing
CLOB API at
```
clob.polymarket.com
```
— Real-time prices, orderbooks, history
Data API at
```
data-api.polymarket.com
```
— Trades, open interest

Typical Workflow

When a user asks about prediction market odds:

Search using the Gamma API public-search endpoint with their query
Parse the response — extract events and their nested markets
Present market question, current prices as percentages, and volume
Deep dive if asked — use clobTokenIds for orderbook, conditionId for history

Presenting Results

Format prices as percentages for readability:

outcomePrices
```
["0.652", "0.348"]
```
becomes "Yes: 65.2%, No: 34.8%"
Always show the market question and probability
Include volume when available

Example:

"Will X happen?" — 65.2% Yes ($1.2M volume)

Parsing Double-Encoded Fields

The Gamma API returns

outcomePrices

,

outcomes

, and

clobTokenIds

as JSON strings inside JSON responses (double-encoded). When processing with Python, parse them with

json.loads(market['outcomePrices'])

to get the actual array.

Rate Limits

Generous — unlikely to hit for normal usage:

Gamma: 4,000 requests per 10 seconds (general)
CLOB: 9,000 requests per 10 seconds (general)
Data: 1,000 requests per 10 seconds (general)

Limitations

This skill is read-only — it does not support placing trades
Trading requires wallet-based crypto authentication (EIP-712 signatures)
Some new markets may have empty price history
Geographic restrictions apply to trading but read-only data is globally accessible