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Connect Hermes to SEC filing data

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.

Hermes Agent supports the Model Context Protocol (MCP), which lets it connect directly to OpenCapital. When you ask about a company's filings, fundamentals, segments, or peers, Hermes can use live, sourced data from OpenCapitalin its answer. Install the OpenCapital skill so Hermes chooses the right research tools and includes source links. Here's how to set it up in a few minutes.

Let Hermes set it up

Copy this prompt into Hermes. It will run the commands, pause when it needs browser approval, and continue after you return.

Set up OpenCapital for this Hermes installation. Follow this execution contract exactly.

Use the terminal tool to start this exact command with background=true, pty=true, and notify_on_complete=true:
hermes mcp add opencapital --url="https://api.opencapital.sh/mcp" --auth oauth

Treat the --url="..." argument as one literal shell token. Before running it, verify the value inside the quotes starts with http:// or https:// and ends with /mcp. Never remove the scheme, change --url to @url:, or execute the URL as a shell command. If that validation fails, stop and show me the command instead of running it. Save the returned process session_id and poll that same session for output. If it asks whether to overwrite an existing opencapital entry, write y followed by Enter to that process.

When the process prints an authorization URL, send me the complete authorization URL. Keep the same background process and PTY alive, and continue polling that process while I approve access in the browser. Treat the process's success output as confirmation that approval completed, and do not wait for a separate message from me. Do not ask me for the localhost callback URL or authorization code, do not exchange a code yourself, and do not start a second OAuth command. The callback code is single-use and belongs to the PKCE verifier held by that exact process.

If the process asks whether to enable all tools after browser authorization completes, send Enter to accept the default. Continue polling until the command exits and its output confirms that opencapital was saved. Then run hermes skills install https://api.opencapital.sh/.well-known/skills/opencapital-research/SKILL.md --now and hermes mcp test opencapital as exact commands. If the test succeeds, tell me OpenCapital is connected and ask which public company I want to research.

If the background process exits before confirming that opencapital was saved, stop and show me its exact output. Explain that any authorization code from that attempt cannot be reused. Do not install the skill or run the test. If the terminal or process tools are unavailable, tell me to use the manual steps instead.

The full walkthrough below lets you run each command yourself.

How to connect

Add the OpenCapital MCP server

Run this command to add OpenCapital. Follow the authorization link Hermes prints, then sign in and approve access.

$ hermes mcp add opencapital --url="https://api.opencapital.sh/mcp" --auth oauth

Leave this command running while you approve access. Hermes captures the localhost callback itself, so do not paste the callback URL or code into a second command.

Install the OpenCapital research skill

Install the research skill so Hermes chooses the right tools and includes source links in its answers.

$ hermes skills install https://api.opencapital.sh/.well-known/skills/opencapital-research/SKILL.md --now

Verify the connection

Run a connection test and confirm Hermes can see the OpenCapital tools.

$ hermes mcp test opencapital

Now just ask.

Ask about fundamentals, filings, segments, or peer comparisons and Hermes will call OpenCapital when it needs sourced data.

Hermes calls OpenCapital automatically — no special prefix needed.

Try asking

Works across Hermes sessions

You can keep using the same connection in later Hermes sessions. The hosted skill helps Hermes choose the right tools and include source links.

Read-only by design

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