Connect your AI

Connect to Claude Code

Ask about any US public company and get the real numbers back — revenue, margins, segments, a decade of history. Your assistant stops hallucinating figures and answers from live, verified data, grounded in what each company actually reported. So you can dig into a business, size it up against peers, and chase any question as far as the filings go — with every number traceable to where it came from.

Claude Code, Anthropic's agentic CLI, speaks the Model Context Protocol (MCP), so it can pull live fundamentals from OpenCapitalwhile it works. Add the server once and it's available in your terminal from then on.

How to connect

Add the OpenCapital MCP server

Run this once in your terminal. It registers OpenCapital as an HTTP connector in Claude Code. Works on macOS, Windows, and Linux.

$ claude mcp add --transport http opencapital https://api.opencapital.sh/mcp

By default the server is added for the current project only. To make OpenCapital available in every project, add --scope user: claude mcp add --transport http --scope user opencapital https://api.opencapital.sh/mcp.

Authenticate with OpenCapital

Start Claude Code with claude, then run the /mcp slash command, select opencapital, and choose Authenticate. Claude Code opens your browser to sign in (Google) and approve read-only access, then stores the token and refreshes it automatically.

Verify the connection

Confirm OpenCapital is connected. It should appear in the list with a healthy status and its tools available.

$ claude mcp list

You can also run /mcp inside a session to see the tool count and authentication status for OpenCapital.

Now just ask.

You're all set. Open Claude Code in any project and ask about fundamentals, segments, or peer comparisons — it'll call OpenCapital as needed, right alongside your code.

Claude Code calls OpenCapital automatically — no special prefix needed.

Try asking

Lives in your terminal

Works with any recent Claude Code install. Data is read live while you work.

Read-only by design

Exposes read-only research data from public SEC filings. Claude Code cannot place trades or change any account.

Troubleshooting

My AI doesn't see OpenCapital's tools

Make sure the connector is added, enabled, and signed in. Still nothing? Ask it to “use the OpenCapitalMCP server” — in ChatGPT, start the message with @OpenCapital.

The sign-in window didn't open

Authorization opens in your browser — allow pop-ups and retry. In Claude Code run /mcp → Authenticate; in the Codex CLI, run codex mcp login opencapital.

It says “needs login” or stopped working

Tokens can expire — re-authorize from your client's connector settings, or remove and re-add the OpenCapital server.

Connection failed or the server is unreachable

Confirm the URL is exactly https://api.opencapital.sh/mcp, the transport is Streamable HTTP (not stdio), and your client is up to date.

Still stuck?

Email support@opencapital.sh and we'll help you get connected.

Disclosures

Informational only — not investment advice

OpenCapital provides financial data and research, not recommendations. Nothing here is an offer or personalized investment, legal, or tax advice — do your own research.

Data sources and accuracy

Derived automatically from public SEC filings and other sources; it may contain errors or delays and is provided “as is.” Verify against primary sources — see our methodology.

Read-only access

The OpenCapital MCP server is read-only — it cannot place trades, move money, or modify any account.

Third-party AI clients

Your prompts and the data returned are processed by your AI client (Claude, ChatGPT, Codex, Cursor) under its own terms. AI can be wrong — verify before acting.

Authorization

Connecting grants read access via OAuth; revoke it anytime from your client's settings. Use is governed by our Terms and Privacy Policy.