The options chain is what separates this from a quote lookup: strikes, implied volatility, volume, open interest and the Greeks come back together, which is enough for an assistant to reason about a spread instead of just reporting a price. It rides on Yahoo Finance, which is why it costs nothing and asks for nothing — and why the data can be delayed and rate-limited.
A Python server over Yahoo Finance. Three tools cover a quote with its key metrics, price history at whatever period and interval you want, and the options chain with Greeks and open interest.
- Current price and volume, market cap, P/E, and the 52-week high and low
- OHLC price history over periods from 1d through max, at intervals from 1m to 3mo, optionally including pre- and post-market
- Company fundamentals, analysis and calendar returned alongside the quote when you ask for them
- The options chain for the nearest expiry or one you name: calls, puts, strikes, implied volatility, volume and open interest
- Greeks — delta, gamma, theta and vega — on that chain on request
- Resources beside the tools: a company profile by symbol, and its income statement, balance sheet and cash flow
- An analyze-options prompt for working through a strategy's risk and reward
Python 3.12 or newer with the mcp and yfinance packages installed. Run it as python stockflow.py over stdio and point your client's config at that path. No account and no key — it reads Yahoo Finance, so Yahoo's rate limits apply, quotes can lag, and options data depends on market hours.
Build from source — clone the repository and build it, then point your client at the binary