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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 move fast on what you find — with every number traceable to where it came from.

ChatGPT by OpenAI supports the Model Context Protocol (MCP), which lets it connect directly to OpenCapital's stock research index. Here's how to set it up in under 5 minutes.

How to connect

Add the OpenCapital connector

Follow the steps below to add OpenCapital in ChatGPT. It works the same on ChatGPT web and desktop.

Open Advanced Settings

Go to chatgpt.com, open Settings, then navigate to "Apps" in the sidebar. Click "Advanced settings" at the bottom.

Open settings

Enable Developer Mode

Toggle on "Developer mode". This allows you to add custom MCP server connections. You only need to do this once.

Create a new App

Go back to the Apps page. You'll now see a "Create app" button. Click it to set up the OpenCapital connection.

Configure the MCP connection and authorize

Name the app "OpenCapital", paste the MCP Server URL below, select "OAuth" for authentication, then click "Create". When prompted, sign in to OpenCapital and authorize read-only access.

https://api.opencapital.sh/mcp

Now just ask.

Start your message with @OpenCapital and ask about any company — ChatGPT answers with real numbers, not guesses.

Start a chat

Try asking

Works with ChatGPT Plus and Team

Works on ChatGPT Plus, Team, and Enterprise with MCP enabled. Data is read live, always current.

Read-only by design

Exposes read-only research data from public SEC filings. ChatGPT 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.