Lessons from Designing Agents for MCP at Usertour

Usertour is an open-source user onboarding tool that recently launched an MCP (Model Context Protocol) server. This enables Claude to install SDKs in real apps and directly build product tours, checklists, and surveys aligned with design systems.

Key technical insights gained from the agent design process include:

• Strict APIs and validation: Since agents cannot see real-time previews, APIs must strictly reject invalid configurations. Machine-readable errors and dry-run validation tools that immediately block unrenderable settings are essential.
• Importance of diagnostic tools: For agents, diagnostic tools like diagnose_content that explain why specific conditions do not match are far more useful than direct authoring tools.
• Security and permissions: Survey responses and similar inputs must be treated as untrusted text, requiring permission model designs that guard against prompt injection.

The feature provides an OAuth-based endpoint compatible with Claude.ai, Cursor, Codex, and others.