Author(s): Rizwanhoda

Originally published on Towards AI.

Your MCP server is about to give Claude access to your company’s most sensitive data. Here’s how to make sure only the right people get that access.

It was a Tuesday afternoon when the security team asked the question everyone dreads.

The article argues that MCP authentication is essential because Claude Desktop can access any configured MCP server without per-request login, creating real risks like unauthorized contractors, stolen laptops, and lingering access for departed employees. It explains three MCP OAuth flows—Authorization Code for standard user sign-in with an existing provider, Client Credentials for service-to-service/automation, and Device Code for browserless environments—then walks through implementing Authorization Code in an example MCP server (including token exchange, token validation, permission checks, and audit logging). It highlights common implementation mistakes (storing tokens insecurely, not validating tokens on every request, missing expiration, forgetting audit trails, and not using HTTPS) and compares OAuth with API keys and JWT, concluding that OAuth provides revocation, strong auditing, and fine-grained permissions when integrated with real auth systems. The piece ends with practical next steps: start with Authorization Code, validate tokens every request, log everything, enforce reasonable expiration, and test revocation behavior.

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Published via Towards AI