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Connect to ChatGPT

Explore company revenue, margins, business segments, and financial history with your AI assistant. Compare businesses, build charts, and search SEC filings for supporting disclosures, with sources and derivations you can check.

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.

Using Codex? Its app and terminal instructions are included below under this ChatGPT guide. Follow the setup for the application you use.

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 uses live OpenCapital data to answer with reported numbers and source links.

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.

Codex setup

Codex app and IDE

Codex, OpenAI's coding agent, speaks the Model Context Protocol (MCP), so the IDE extension and app can pull live fundamentals from OpenCapital as you work. Prefer the terminal? Use the Codex CLI guide instead.

Fastest way: just ask Codex

Already working in Codex? Skip the steps below. Tell it to connect and it sets everything up for you.

let's connect to opencapital.sh mcp

Codex adds the OpenCapital server and opens your browser to approve read-only access. Prefer to wire it up by hand? The full walkthrough is below.

How to connect

Add the server in Codex

Two interchangeable ways to register OpenCapital — use whichever you prefer.

In the Codex IDE extension (VS Code, Cursor, JetBrains), open the gear menu, choose MCP settings → Add server, select Streamable HTTP, name it opencapital (the lowercase id the config key and codex mcp login command both use), and paste the connector URL below.

https://api.opencapital.sh/mcp

Exact menu labels vary by extension version.

Authenticate with OpenCapital

Click Authenticate in Codex, or run the command below. Codex opens your browser to sign in (Google) and approve read-only access, then stores the token for you.

$ codex mcp login opencapital

Now just ask.

You're all set. Ask Codex about fundamentals, segments, or peer comparisons in any session — it'll call OpenCapital as needed, right alongside your code.

Codex calls OpenCapital automatically — no special prefix needed.

Try asking

Works across every Codex surface

One MCP config across the IDE extension, app, and CLI — add it once. Data is read live everywhere.

Read-only by design

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

Codex CLI

Codex CLI, OpenAI's terminal coding agent, speaks the Model Context Protocol (MCP), connecting to remote servers so it can pull live fundamentals from OpenCapitalwhile it works. Add the server once and it's available in your terminal from then on.

Fastest way: just ask Codex CLI

Already working in Codex CLI? Skip the steps below. Tell it to connect and it sets everything up for you.

let's connect to opencapital.sh mcp

Codex CLI adds the OpenCapital server and opens your browser to approve read-only access. Prefer to wire it up by hand? The full walkthrough is below.

How to connect

Add the OpenCapital MCP server

Two interchangeable ways to register OpenCapital — use whichever you prefer.

Run this once in your terminal. It registers OpenCapital as a remote (streamable-HTTP) MCP server in Codex.

$ codex mcp add opencapital --url https://api.opencapital.sh/mcp

Either way you need a recent Codex — check with codex --version and update via npm i -g @openai/codex or brew upgrade codex if remote servers aren't picked up. Older builds also require experimental_use_rmcp_client = true under [features].

Authenticate with OpenCapital

Codex opens your browser to sign in (Google) and approve read-only access, then stores the token for you.

$ codex mcp login opencapital

The OAuth callback uses localhost, so run this on a machine with a browser. On a headless or SSH session the login can't complete.

Verify the connection

Confirm OpenCapital is registered and authenticated.

$ codex mcp list

Inside the Codex TUI you can also run /mcp to see active servers and their tools.

Now just ask.

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

Codex CLI calls OpenCapital automatically — no special prefix needed.

Try asking

Lives in your terminal

Works with recent Codex builds that support remote MCP servers. Data is read live while you work.

Read-only by design

Exposes read-only research data from public SEC filings. Codex 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, Hermes, OpenClaw, ChatGPT, 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.