Claude Code Setup

Connect Massive to Claude Code with the remote MCP server

Massive's remote MCP server connects Claude Code to live U.S. market data: dividends, trades, quotes, options chains, and the rest of our catalog. It queries our REST API under the hood, giving Claude Code the context to pull that data directly and write correct code against it.

This guide walks through connecting the remote MCP server, authenticating over OAuth, and verifying the integration. Setup takes about two minutes and requires Claude Code installed plus a Massive account. There is nothing else to download, and authentication happens in your browser.

What You Can Do

Once connected, the MCP server gives Claude Code a small set of composable tools for endpoint search and live API calls, so you can ask it to:

Pull every dividend declared this month across U.S. equities and rank them by yield.
Inspect the live response shape of an endpoint before writing code against it.
Build a Python project that screens options chains, then verify it against real API responses.
Figure out which Massive endpoint returns the data shape you need.

Because the server runs the calls itself, Claude Code can check real responses while it works, which is useful for confirming response shapes or chasing down a hallucinated field name.

Setup

Two steps. Allow about two minutes start to finish.

1. Install Claude Code

If you don't have it, install Claude Code and confirm it works:

claude --version

2. Add the Massive Remote MCP Server

claude mcp add --transport http massive https://mcp.massive.com/

Then launch Claude Code and authenticate:

Run claude
Type /mcp
Select massive
Select 1. Authenticate and complete the sign-in in your browser

Authentication uses OAuth against your Massive account, so there is no API key to copy or store. A free Basic account is enough to start.

Your MCP access mirrors your Massive entitlements. You can query any asset class your plan includes. If you have Stocks access, stocks data is available through MCP. Requesting data you are not entitled to (for example, Options without an Options plan) returns an access-denied error.

Test the Integration

Now that the connection is live, put it through its paces. A few prompts to start with:

"Show me the latest trade for AAPL." (Trades)
"Is the U.S. market open right now?" (Market Status)
"When is the next market holiday?" (Market Holidays)
"What dividends has AAPL paid this year?" (Dividends)
"Give me a snapshot of today's biggest gainers." (Snapshots)

When you're ready to go deeper, hand Claude Code a full brief and let it chain several calls together:

Pull all dividends declared in the last 30 days, filter to U.S. equities with a market cap over $50 billion, rank them by yield, and summarize the top five with their pay dates.

Claude Code will search for the right endpoints, make the live calls, and stitch the results into a single answer.

Troubleshooting

massive doesn't appear under /mcp. Confirm the server was added with claude mcp list. If it's missing, run the add command from Step 2 again.

Authentication didn't complete. Run /mcp, select massive, and choose Authenticate again. Make sure you finished the browser sign-in and granted access.

Claude responds with numbers but doesn't cite an MCP call. It's answering from training data. Ask it explicitly to use the Massive tools, e.g. "use the Massive MCP server to check."

Numbers look wrong or made up. The server likely isn't connected. Confirm with claude mcp list and that /mcp shows massive as connected and authenticated.