Least-Privilege MCP Tool Design
Give every server and tool only the access required for its real use case.
Examples
- Use read-only database roles for analytics tools.
- Limit GitHub tokens to selected repositories.
- Separate
read_filefromdelete_file. - Return only necessary customer fields.
- Expose staging deployment separately from production deployment.
Why tool granularity helps
Smaller tools let clients filter capabilities and apply different approval policies. One giant admin tool makes least privilege difficult.
Least privilege limits blast radius when the model, user, server, or credential is compromised.