The four kinds of bank MCP server
A year ago, the only way to get bank data into an AI agent was to paste it or upload a statement. Now there are MCP servers for it, and they come from four different places. The source decides most of the trade-offs: which banks you can connect, where your data sits, and whether the agent can change anything.
We run one of these (BankBridge), so read this with that in mind. We have tried to describe each kind by what it is built to do.
Bank-run MCP servers
A few banks now publish their own MCP server. Grasshopper Bank built one with its digital banking partner Narmi and was the first bank listed in Anthropic's connector directory; it is for business banking clients. First Internet Bank offers a beta MCP connection for Claude and ChatGPT that personal customers can use with their checking, savings, and money market accounts, with a business version too. Both are read-only.
- Good: data comes straight from the bank, no third party in between.
- Limit: one bank only. If you also have a personal checking account elsewhere, a credit card, and a brokerage, the agent sees only the one.
- Fit: someone who banks there and wants Claude or ChatGPT to answer questions about that account.
Finance apps with an MCP add-on
Some personal finance apps have added an MCP endpoint on top of the data they already sync and store. Era is an example: you connect accounts to Era, then add Era to Claude or another host. Era's entry tier is read-only and its paid tiers add write access, so the agent can recategorize transactions, add tags, and create rules. Tiller has an official Claude connector that can write categories and notes back to your spreadsheet. Monarch built one as well, but has paused it since June 29, 2026. Hosted services built around MCP from the start, such as Truthifi, OpenFinance, and Driggsby, work the same way on storage: they sync your data and keep a copy.
- Good: if you already use the app, the agent sees the same categories and rules you set up there.
- Limit: the app keeps a synced copy of your transactions, since its own interface depends on it. Write access is useful but widens what an agent can change.
- Fit: people who want an app and an agent working on the same stored ledger.
Self-hosted open source
GitHub has several open-source bank MCP servers. You clone one, sign up for a developer account with a bank-data aggregator (at least one now offers a self-serve trial with real bank data for a small number of connections), deploy the server, and point your agent at it.
- Good: full control of the code and where it runs.
- Limit: connection limits or per-connection fees, token encryption, re-authentication handling, and uptime are all on you. Remote hosts like Claude.ai also need the server reachable over HTTPS with proper auth.
- Fit: developers who want to own every layer and are fine maintaining it.
We wrote up the full list of what building it yourself involves in BankBridge vs building your own bank MCP server.
Hosted pass-through
A hosted pass-through server connects to your banks through an aggregator but does not keep a copy of the data. Each tool call fetches live and returns the result to the agent. BankBridge works this way.
- Coverage: most US banks, credit unions, credit cards, and brokerages. Connect several and the agent sees them together.
- Tools: 11 read-only data tools (accounts, transactions, search, spending summaries, recurring charges, monthly cashflow, merchant history, categories, holdings, investment transactions) plus a helper that sends you a link to connect another bank.
- Storage: account record, subscription, an encrypted bank access token, and API key hashes. No balances or transactions. Details in why we don't cache your data.
- Hosts: Claude (all surfaces, including Claude Code), ChatGPT, Cursor, Codex, Gemini CLI, Copilot, Windsurf, Zed and more, each with its own setup page.
- Price: $5 per month per connected bank.
Comparison table
| Bank-run | App add-on | Self-hosted | BankBridge | |
|---|---|---|---|---|
| Banks covered | That bank | What the app supports | What your aggregator account supports | Most US institutions, several at once |
| Copy of transactions kept | At the bank | Yes, in the app | Your choice | No |
| Write access | Read-only | On some tiers | Your choice | Read-only |
| Setup | Add connector | App account, then connector | Developer account, deploy, maintain | Link bank, add connector |
| Investments | Usually no | Varies | If you build it | Holdings and investment transactions |
Five questions to ask any bank MCP server
- Can it write? Look at the tool list. A tool that edits, transfers, or trades changes your risk.
- Does it keep a copy? If yes, ask for how long and what happens on cancel.
- Does it tell the agent when a bank is disconnected? Otherwise the agent may answer from partial data. BankBridge returns a plain-language warning with a reconnect link alongside the data.
- How do you revoke it? You want one place to cut access for every agent at once.
- Which hosts work? A server that only runs in one app ties your data to that app.
If a hosted, read-only, no-copy server fits, connect a bank and follow the setup page for your agent. For the wider list of finance MCP servers (budgets, payments, brokerage, crypto), see MCP servers for personal finance.