[Glossary](https://blnkfinance.com/glossary) MCP # What is MCP? MCP MCP is the Model Context Protocol. It gives an AI agent a typed list of tools instead of a pile of undocumented HTTP. The agent calls those tools the way your app calls an SDK. In a ledger, the useful tools are “get this balance,” “find this reference,” and “record this transfer.” MCP is the pipe. It is not a payment rail. ## How does MCP work? A server exposes tools with names, arguments, and results. The model picks a tool, fills the arguments, and waits for the result. It can chain calls: look up a wallet, then post. It does not invent a new posting rule. It uses the ones you published. ## MCP vs an API key in chat Pasting curl into a chat window is not a protocol. There is no schema, no auth boundary, and no log of which tool ran. MCP is a contract: this agent may list balances and may not refund. Treat a tool call like any other client. Give it a reference. Expect retries. ## Docs MCP vs ledger MCP A docs server answers “how do inflight holds work.” A ledger server reads and writes your book. Mixing them in one agent is fine. Mixing them in one permission is not. An agent that can search docs should not, by default, be able to move money. ## How it works with Blnk Blnk has two MCP surfaces. The [docs MCP](https://docs.blnkfinance.com/home/llms) is lookup for coding agents. [Cloud MCP](https://docs.blnkfinance.com/cloud/integrations/mcp) talks to your instance: ledgers, balances, and `record_transaction`. A Cloud MCP post is an ordinary transaction. It still queues, locks, and needs a unique reference. The agent is just another client. Related terms - [Agentic payments](https://blnkfinance.com/glossary/agentic-payments) - [Transaction](https://blnkfinance.com/glossary/transaction) - [Identity](https://blnkfinance.com/glossary/identity) - [Webhook](https://blnkfinance.com/glossary/webhook) - [Ledger](https://blnkfinance.com/glossary/ledger)