MCP Guardian

MCP Guardian is a small program that sits between your AI assistant and the tools it uses, like file readers, databases, or Slack. It checks every request against rules you write and blocks anything that breaks them. It is handy for anyone who lets an AI use tools and wants to keep an eye on what it does.

What this MCP server does

You install MCP Guardian and point it at the tools your AI already uses. From then on, when your AI asks to use a tool, the request goes to Guardian first. Guardian compares the request to your rules file, which you write in plain text. If the request is allowed, Guardian passes it to the real tool and returns the result. If it breaks a rule, Guardian blocks it and tells your AI the request was denied, so the real tool never runs.

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What you can do with it

• Block tool calls that match words or patterns you list
• Set limits on how often a tool can be used
• Set a budget on how many tokens can be spent
• See a log of every request that was allowed or blocked
• Open a dashboard to review charts and history
• Give different people or agents different levels of access

Try asking your AI

• “Show me the tool calls that were blocked in the last hour”
• “Add a rule that blocks any tool call mentioning the word password”
• “How many tokens did my AI use today?”
• “Which tool has been called the most this week?”

What it gives back to you

You get a clear answer in your chat: lists of blocked or allowed calls, counts, and summaries. The dashboard shows charts and a history of everything that happened. When a call is blocked, your AI is told it was denied and the real tool is never touched.

Before you start

Who it's for

People who let an AI use tools and want to keep it from reading the wrong files, running dangerous commands, or spending too much.