---
title: "How do I give Claude access to fund and ETF data by ISIN?"
description: "Add the FundFacts MCP server to claude.ai, Claude Desktop or Cowork as a custom connector and ask about any ISIN: TER, holdings, exposures, returns, overlap and portfolio look-through, shown as interactive cards."
canonical: https://fundfactsapi.com/answers/fund-data-for-claude
published: 2026-09-12
updated: 2026-10-13
publisher: FundFacts API
---

# How do I give Claude access to fund and ETF data by ISIN?

**Short answer:** Add the FundFacts MCP server as a connector: in claude.ai (Customize → Connectors → Add custom connector; Team and Enterprise: an Owner adds it under Organization settings → Connectors) or Claude Desktop, enter a name and the remote MCP server URL https://fundfactsapi.com/api/mcp, leave the advanced OAuth client fields empty and sign in with your FundFacts account when the consent screen opens. Claude then has get_fund, search_funds, compare_funds, analyze_portfolio, fund_overlap, get_scpi and search_scpi tools, answers questions about any ISIN with the current published figures and their as-of date, and shows the results as interactive cards.

**The FundFacts MCP server puts fund data inside Claude.** Connect it once as a custom connector (about a minute, on every FundFacts plan including Free) and Claude can look up, compare and look through funds, with fund, comparison, look-through, overlap and SCPI cards next to the answer. The [MCP server guide](https://fundfactsapi.com/docs/mcp) has the full tool reference and troubleshooting.

## claude.ai and Claude Desktop

Both accept remote MCP servers over Streamable HTTP as custom connectors. In **Customize → Connectors → Add custom connector** (Team and Enterprise: an Owner adds it under **Organization settings → Connectors**; the Free plan allows one custom connector), enter:

| Setting | Value |
|---|---|
| Name | FundFacts |
| Remote MCP server URL | `https://fundfactsapi.com/api/mcp` |
| OAuth client ID / secret (Advanced) | leave empty (the client registers itself) |

Click Connect and sign in with your FundFacts account when the consent screen opens. The connector signs in with your FundFacts account (OAuth 2.1, PKCE): a consent screen opens in the browser, the connection then counts against the same plan and quota as an API key, and it appears in the [dashboard](https://fundfactsapi.com/dashboard), where you can disconnect it at any time. In ChatGPT and in Claude on the web and desktop, tool results also render as cards (fund, comparison, portfolio look-through, overlap, SCPI) next to the answer. No API key goes into the URL; for code and CLIs the `Authorization` header stays the recommended form.

Claude Desktop's configuration file (`claude_desktop_config.json`) only starts local stdio servers (`command` and `args`), so a remote server goes through the Connectors screen above, or through the `mcp-remote` bridge if you prefer a config file with an API key in a header:

```json
{
  "mcpServers": {
    "fundfacts": {
      "command": "npx",
      "args": ["-y", "mcp-remote", "https://fundfactsapi.com/api/mcp", "--header", "Authorization: Bearer ffk_..."]
    }
  }
}
```

## What Claude can do with it

The MCP server exposes seven tools, each counted like the REST endpoint it wraps: `get_fund` (ISIN → the full factsheet payload), `search_funds` (name → ISINs, free), `compare_funds` (side-by-side table for several ISINs), `analyze_portfolio` (weighted look-through of a list of positions, Starter and above), `fund_overlap` (shared holdings between funds, Starter and above), `get_scpi` (French SCPI data by name or ISIN) and `search_scpi` (SCPI name → matches, free), plus a `tour` prompt that explains the service on the example fund IE00B4L5Y983, which is not counted. Every tool only reads data. Authentication is either your FundFacts account (OAuth 2.1 with PKCE, the sign-in the claude.ai, Claude Desktop and ChatGPT connectors run) or the same bearer API key as the REST API, sent as an `Authorization` header by editors, CLIs and frameworks. The [MCP server guide](https://fundfactsapi.com/docs/mcp) has the full tool reference, setup for every client and troubleshooting.

Typical prompts: "What does IE00B4L5Y983 hold and how risky is it?", "Compare the fees and 5-year returns of IE00B4L5Y983 and IE00B3RBWM25", "I hold 60% of A and 40% of B; what is my real US exposure?", "Do these three ETFs overlap?". Claude calls the right tool, and because every payload carries `dataAsOf` it can say how old the figures are.

## Claude Code and the API (for building, not chatting)

If you want Claude to *write software* against the API rather than answer questions, see [Claude Code](https://fundfactsapi.com/answers/fund-data-for-claude-code): the companion kit includes a Claude Code skill, and `claude mcp add` registers the same server for the coding agent.

Paid plans include an AI companion kit generated from the live field reference: an `AGENTS.md` with every endpoint, field, rule and a reference client; a Cursor rule; a Claude Code skill; the OpenAPI spec and TypeScript types, with your key baked in or read from an environment variable. Download it from the dashboard; the public edition without a key is at [/llms-full.txt](https://fundfactsapi.com/llms-full.txt).

## FAQ

### Is the API key exposed to Anthropic?

No. The claude.ai and Claude Desktop connectors sign in with your FundFacts account (OAuth 2.1 with PKCE), so no API key leaves your dashboard. Claude holds an access token that only works on the MCP server, never on the REST API, and you can disconnect it in the dashboard at any time. Only a bridge such as mcp-remote sends an ffk_ key as a header; create a dedicated key for it and revoke it there if needed.

### How are tool calls billed?

One request per fund found, exactly like the REST endpoints. search_funds is free. The Free plan's 5 lookups a month cover a first test; a daily-use assistant fits Starter or Pro.

### Do I need a credit card to try it?

No. The Free plan is 5 lookups per month with no card; sign up with an e-mail address or Google and the key is shown in the dashboard.

### Which ISINs work?

Any share class of a UCITS fund, ETF, money-market fund or open-end fund whose management company publishes a product page, factsheet and KID. Each share class has its own ISIN and is looked up on its own. Stocks, bonds and indices are not funds and return 404 fund_not_found.

## About FundFacts API

FundFacts turns any fund or ETF ISIN into one dated factsheet (fees and KID costs, the 1–7 risk indicator, holdings, sector and country exposure, returns) read from the fund house's own documents: as a client-ready PDF under your firm's name for advisers and wealth managers, as JSON through its API for developers, or inside ChatGPT and Claude through its MCP server.

FundFacts works inside ChatGPT and Claude as a connector (a remote MCP server): ask about any fund or ETF by ISIN, ticker or name and the assistant answers from FundFacts' dated figures, fees, risk, holdings, exposure and returns, with fund cards, side-by-side comparisons, holdings overlap and portfolio look-through.

- Free API key, no card: https://fundfactsapi.com/signup
- Documentation: https://fundfactsapi.com/docs (OpenAPI: https://fundfactsapi.com/openapi.json)
- MCP server: https://fundfactsapi.com/api/mcp (set-up for every client: https://fundfactsapi.com/mcp-server)
- Pricing: https://fundfactsapi.com/pricing
- Site index for AI assistants: https://fundfactsapi.com/llms.txt
- Informational data, not investment advice.