You don't have to build an MCP server to give Claude access to real market data — Quantustik already runs one. This is the shortest path from "no key" to "Claude is reading live S&P 500 data": get a key, add one server entry to your MCP client config, and ask a first question.
Get a free key at /developers — no card required.
Light, anonymous use of the server also works with a soft hourly cap, but a free key raises that limit substantially, and you will need one for anything beyond a quick test. Once you have a key, every request authenticates with a standard bearer header: Authorization: Bearer <your-api-key>.
Quantustik publishes a standard MCP discovery manifest at /.well-known/mcp.json describing the transport (streamable-HTTP) and the auth scheme (bearer). Most MCP-aware clients, including Claude, accept a server entry built from those same three facts: server URL https://quantustik.com/mcp, transport streamable-http, and an Authorization header carrying your bearer key — for example, a JSON server-config block with an "mcpServers" entry named "quantustik" whose "url" is https://quantustik.com/mcp, "transport" is "streamable-http", and whose "headers" object sets "Authorization" to "Bearer <your-api-key>".
Exact config file location and syntax vary by client — check your client's MCP server documentation for where this entry goes. The manifest at /.well-known/mcp.json is the source of truth for the URL and transport if a client asks you to point at it directly instead of hand-writing the entry above.
Once the server is connected, the fastest way to see it work is to ask a plain-English question that needs live data: "What are the current market conditions?", "What did insiders buy at this company in the last 30 days?", or "What changed in the risk factors of the latest 10-K?". The agent picks the right tool, calls it, and answers from the response, which carries a generated-at timestamp so you can see how fresh the data is.
From here, an agent can go further: sweep the earnings calendar, compare insider and institutional activity across several tickers, or read filing digests. All of it is read-only, all of it carries the same disclaimer as the rest of the product, and none of it places or manages an order on your behalf.
This walks through connecting to real, live data — it does not walk through what to do with the output. Connecting an agent to the data does not make the data any better, and every tool is read-only (no order is ever placed through it). The free tier is rate-capped; see the developers page for current limits rather than a number that will drift here.
Educational research only — not investment advice.