# Per-tool rules

A per-server rule is sometimes too blunt: you want `github` available, but not
`delete_repository`. Per-tool rules let you allow a server while blocking individual
tools inside it.

Open a server's row on **MCP Inventory** to set rules for the individual tools that
server exposes. The most specific rule wins: a tool rule beats its server's rule, which
beats the MCP default action.

## Why this matters more than it sounds

An MCP server's tool list is not fixed. A server you approved can add a tool later, or
change what an existing tool's description tells the model to do — the "rug pull" pattern.
Sentilai fingerprints tool definitions and flags changes, so an approved server that
starts behaving differently re-enters review instead of silently inheriting your trust.

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![Per-tool MCP rules — refine a single tool of a server, for example block only the tool that writes.](https://docs.sentilai.com/uploads/images/gallery/2026-08/utJpolicy-per-tool.png)
*Per-tool MCP rules — refine a single tool of a server, for example block only the tool that writes.*