What is MCP, and is it safe? A plain-English guide

MCP in one sentence

MCP (Model Context Protocol) is a standard way to plug an AI assistant into your other apps and data. Anthropic, the company behind Claude, released it as an open standard so that “connectors” work the same way everywhere. Security writers often call it a “USB-C port for AI”: one kind of plug, many devices.

Why people are excited

On its own, a chatbot only knows what you paste into it. With MCP connectors, an assistant like Claude can look things up in the apps where your information already lives: your calendar, your files, a business tool, even (through specialized providers) your bank transactions. Then it can answer questions like “where did our money go last quarter?” or build a chart for you.

Why it feels scary (and what the real risks are)

The worry is reasonable: you’re giving an AI a window into your data. The real risks, according to security groups like OWASP and Microsoft’s developer security team:

1. Prompt injection. Content the AI reads (an email, a web page, a document) can contain hidden instructions that try to hijack it. The AI might be tricked into revealing data or taking an action you didn’t ask for.
2. Too much access. A connector that can send, pay or delete is riskier than one that can only read.
3. Untrustworthy connectors. A connector can be badly built, or changed after you approved it.

The five safety rules we use

1. Read-only first. Choose connectors that can only read. For money, never connect anything that can move funds.
2. Official or well-known only. Prefer connectors made by the company that owns the data, or established providers with clear terms.
3. Least access. Connect one account or one folder, not everything.
4. Human approves actions. Keep “ask before acting” on. Don’t let the AI send, pay or delete on its own.
5. Review and disconnect. Check your connected apps monthly; remove what you don’t use.

A real example: finance data

This is where MCP gets interesting for small business owners and households, and where you need to be careful:

• Plaid, the company behind many bank connections, has an official Claude connector, but it’s for Plaid’s business customers (monitoring their Plaid integration). It does not give Claude your personal bank data.
• BankBridge is a third-party service that offers a Claude connector for your own bank data. It says it’s read-only and can’t move money, and it costs $5/month for your first bank. That’s a vendor claim we haven’t tested.
• Open-source options exist for technical users (for example, community “bank MCP” servers that use your own Plaid or Teller keys), but they involve storing sensitive credentials yourself.

Bottom line: MCP is genuinely useful and the standard itself is free and open. Safety depends on which connectors you add and what they’re allowed to do. Start small, read-only, and with providers you trust.