Model Context Protocol - Security Best Practices

Type: official-doc Tier: 1 (Official Doc) Author(s): Model Context Protocol Date: 2025-06-18 URL: https://modelcontextprotocol.io/specification/2025-06-18/basic/security_best_practices Accessed: 2026-06-02

Why This Source Matters

This is the primary source for MCP-specific security risks. It extends the Project 06 path-containment lesson into a distributed trust boundary: a host may launch or connect to external servers that can expose tools, read resources, and touch local or remote systems.

Key Claims

• Local MCP servers can introduce arbitrary code execution, data exfiltration, data loss, and command-obfuscation risks if launched without consent and sandboxing.
• Clients should show the exact command before launching a local server and require explicit approval.
• Clients should warn about dangerous command patterns, sensitive filesystem access, broad privileges, and network operations.
• Servers should run with minimal filesystem, network, and system privileges.
• Remote servers need authorization, secure session identifiers, request verification, token audience binding, and least-privilege scopes.
• Broad or wildcard scopes increase blast radius and reduce audit clarity.

Relevant To

• concepts: [mcp-security, trust-boundary, least-privilege, local-server-risk, tool-sandboxing, consent]
• projects: [06-ai-coding-copilot, 08-ai-agent, 09-personal-learning-os, elective-mcp-interface-layer]

Notes

This source should anchor the failure analysis for an MCP elective: unsafe server launch commands, over-broad filesystem access, missing input validation, and tool-result poisoning are not edge cases.