How do you connect Claude or ChatGPT to company and filing data?
Add a data provider's MCP server as a custom connector, sign in and allow access. In Claude that sits under Settings, then Connectors, where you paste the server's address (Claude docs). Before you connect, check that the tools are read only, that answers cite their sources and that sign-in uses OAuth.
What is an MCP server for financial data?
An MCP server is a service that exposes tools an AI assistant can call, such as "search companies" or "get filings", through the Model Context Protocol. When you ask a question, the assistant calls the tool, reads the result and answers from it instead of from memory. Data vendors including PitchBook and Crunchbase now offer MCP servers for their subscribers (Morningstar; Crunchbase docs).
What should you check before connecting a data server?
Check 4 things. Anthropic warns that custom connectors can reach unverified services and that Claude can take actions within them (Claude docs), so the server's design matters.
| Check | Why it matters | What good looks like |
|---|---|---|
| Read-only tools | A tool that can write or delete can be misused if the assistant is misled by text it reads | Every tool only reads data |
| Sources on every answer | You need to verify figures before you use them | Each result carries a link to the filing or register entry |
| Sign-in | A static key pasted into a chat app can leak | OAuth sign-in with a consent screen you can revoke |
| What the provider receives | Your conversation may hold client names | The server receives only tool calls, never the conversation |
Security guides also flag prompt injection: text returned by a tool enters the model's context and can carry hidden instructions (Descope). Read-only tools limit what such text can make the assistant do.
Step 1. Pick a server and copy its address
Find the server address in the provider's documentation. It must be a remote HTTPS address; a server you run on your own laptop with a command does not work as a web connector. For Tamarly the address is https://app.tamarly.ai/api/mcp.
Step 2. Add it to Claude
In Claude, open Settings, then Connectors, choose Add custom connector, paste the address and click Add (Claude docs). On Team and Enterprise plans an admin adds the connector first, then members connect from their own settings. In Claude Code, run `claude mcp add --transport http tamarly https://app.tamarly.ai/api/mcp`.
Step 3. Or add it to ChatGPT
ChatGPT adds custom MCP servers through developer mode, under its Apps settings. OpenAI is rolling out full MCP support in beta, and which plans get it, and whether admins must turn it on, has changed during 2026, so check OpenAI's help article for your plan before you start.
Step 4. Sign in and choose Allow
The assistant opens the provider's sign-in page. Sign in, read the consent screen and choose Allow. You can revoke access later from the provider's account page or remove the connector in the assistant's settings.
Step 5. Test with a company you know
Ask for a record you can check, for example "Search for Acme Robotics and list its Form D filings with the amount sold." Open 1 or 2 of the source links. If the answer has no links, or the figures do not match the filing, do not rely on the connector for client work. Our guide on fact-checking AI answers about companies gives a fuller method.
Which data can an assistant read through MCP?
Whatever the server exposes and your plan allows. Filing-based servers can return SEC filings, Form D raises, 13F holdings and register entries. Vendor servers return their own databases, such as funding rounds and investors, within your license. No connector makes an assistant's reasoning reliable on its own, so keep checking sources. For step-by-step research examples, see how to research private companies with Claude and how to use ChatGPT for due diligence.
Where does Tamarly Intelligence fit?
Tamarly Intelligence is Tamarly's research platform on companies, funds, countries and markets, built from official filings and open data. Its MCP server at https://app.tamarly.ai/api/mcp offers 9 read-only tools: search, company profile with Form D notices and merger filings, financials, Form D venture radar, deals, fund holdings, fund managers, country risk and FRED series. Each answer comes with source links, and Tamarly receives the tool calls, never the conversation.
The connector is included in every plan. Free covers search and economic series, Level 2 at $145 a month adds companies, funds, deals and country risk, and Level 3 at $399 a month adds the venture radar. Tamarly has no market prices, no investor names on private rounds and no valuations.
Connect your assistant to sourced company data, free for 7 days
Frequently asked questions
Can ChatGPT access SEC filings?
Yes, through an MCP connector that reads EDGAR data, added in developer mode where your plan allows it (OpenAI). Without a connector it may answer from training data, which can be out of date.
Is it safe to connect Claude to a financial data server?
It is safer when the tools are read only, sign-in uses OAuth and the provider receives tool calls rather than your conversation. Anthropic advises connecting only to services you trust (Claude docs).
Do I need a paid plan to use a data connector?
It depends on the provider. Tamarly's connector works on the free plan for search and economic series. PitchBook's Premium connector needs a PitchBook license, and Crunchbase sells MCP seats per workspace.
About the author. Melvine Manchau is the founder of Tamarly and author of the Tamarly Newsletter. He previously worked at PwC, Salesforce, BlackRock/eFront and Lazard.
About Tamarly Research. Tamarly Research is part of Tamarly Media, which holds no investment positions. Tamarly is a New York research house that studies how AI is changing regulated institutions.