Opencapital MCP server

OpenCapital MCP Server

Every US public company, sourced from SEC filings — now available to your AI assistant.

OpenCapital is a hosted Model Context Protocol (MCP) server that gives Claude, ChatGPT, Cursor, Codex, and any other MCP-capable client read-only access to what every US public company actually reports — fundamentals, segment breakdowns, peer comparisons, and earnings for thousands of US-listed equities (common shares and ADRs), all derived directly from SEC filings.

You don't run anything. The server is hosted on OpenCapital's infrastructure. You add one URL to your client, sign in once, and start asking.

https://api.opencapital.sh/mcp

• Transport: Streamable HTTP (remote MCP server)
• Auth: OAuth 2.0 — sign in with Google, grant read-only access
• Free tier: 100 queries/day, no credit card. Paid plans remove the cap.
• Data: Fundamentals, segments, and earnings derived from US SEC filings (10-K, 10-Q, 8-K), read live

The data is free, the workflow is paid. Every metric, segment, quarter, and filing reference is free to query. OpenCapital is an independent project — not affiliated with the SEC.

Quick connect

Pick your client below, or see the full step-by-step guides at opencapital.sh/connect-ai.

Claude (claude.ai / Claude Desktop)

1. Customize → Connectors → Add custom connector
2. Name it OpenCapital, paste https://api.opencapital.sh/mcp
3. Click Connect and authorize read-only access

Full guide: opencapital.sh/connect-ai/claude

Claude Code

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

Add --scope user to make it available in every project. Then run /mcp inside a session, select opencapital, and choose Authenticate.

Full guide: opencapital.sh/connect-ai/claude-code

ChatGPT (Plus / Team / Enterprise)

1. Settings → Apps → Advanced settings → enable Developer mode
2. Create app, name it OpenCapital, paste the URL, select OAuth
3. Authorize read-only access

Full guide: opencapital.sh/connect-ai/chatgpt

Cursor

Add to ~/.cursor/mcp.json (global) or .cursor/mcp.json (project):

{
  "mcpServers": {
    "opencapital": {
      "url": "https://api.opencapital.sh/mcp"
    }
  }
}

Then enable the server under Cursor Settings → Tools & MCP → Connect.

Full guide: opencapital.sh/connect-ai/cursor

Codex / Codex CLI

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

Or add to ~/.codex/config.toml:

[mcp_servers.opencapital]
url = "https://api.opencapital.sh/mcp"

Full guides: codex · codex-cli

Any other MCP client

Add a remote / custom MCP server over the Streamable HTTP transport, pointing at https://api.opencapital.sh/mcp. Most clients also accept the mcpServers JSON shape shown in the Cursor section above. The first call opens your browser to sign in and approve read-only access.

Full guide: opencapital.sh/connect-ai/other

What you can ask

The server ships with 14 read-only tools. You rarely call them by name — just ask in natural language and your client picks the right one.

Shortened. The full README is on GitHub.