Giving an AI assistant read-only access to Microsoft Loop — without breaking permissions

Short summary

An open-source MCP server (loop-reader-mcp) gives AI assistants read-only access to Microsoft Loop by splitting discovery from retrieval: Graph Search runs as the user via OBO flow (security-trimmed), while content retrieval uses an app-only identity gated by the user's cached discovery results. This prevents anyone who can talk to the service from reading arbitrary Loop pages. Key lessons include avoiding platform auth gateways for remote MCP servers and binding retrieval gates to (driveId, itemId) pairs.

• •Split discovery (delegated/user identity, security-trimmed by Microsoft) from retrieval (app-only identity, gated by user's discovery cache)
• •Avoid platform auth gateways in front of remote MCP servers — they break the OAuth handshake
• •Open-sourced as loop-reader-mcp under MIT; bind retrieval to (driveId, itemId) pairs to prevent replay attacks

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