Rails MCP server

Rails MCP is a small helper you run on your own computer. It gives your AI a way to check whether an action should be treated as risky, keep a list of spending intentions, and record when a human has approved something. It is handy for people who let an AI assistant do real work and want a paper trail, not just a chat.

What this MCP server does

You ask your AI a question, like whether a certain action is safe or how much has been spent this month. The AI uses this helper to check its registry or its ledgers. The helper reads your config file and your record files, and returns a verdict, a number, or a short summary. Nothing here blocks anything by itself. It gives you the information and the record, and you decide what to do with it.

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What you can do with it

• Check whether an action type is treated as risky (it always says GATED)
• See whether an action type is listed in your registry
• Get a short fingerprint of your current registry
• See who last signed off on your registry, and when
• Write down a spending intention with amount, vendor, and purpose
• Check total spending in the last 30 days against a limit

Try asking your AI

• “Is deploy_prod a gated action?”
• “Is deploy_prod registered in my rails config?”
• “Record a spend intention of 40 dollars for OpenAI, purpose: embeddings batch”
• “Have we spent more than 200 dollars in the last 30 days?”

What it gives back to you

You get short answers in the chat. A verdict like GATED, a yes or no about whether something is registered, a 12-character fingerprint, a sign-off record or null, or a spending total compared to your limit. When you record a spend intention, you get a confirmation that the line was appended.

Before you start

Who it's for

Teams and individuals who let AI agents take real actions and want a simple, self-hosted record of what is risky, what was spent, and who approved what.