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Discussion on: How to Build an MCP Server with Claude: Complete Tutorial (2026)

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אחיה כהן

Great walkthrough. One lesson I'd add for first-time MCP server builders: be ruthless about state tracking if your tools mutate something the user owns (their browser tabs, files, terminal sessions).

I shipped a "safe" fallback in my Safari MCP server that defaulted to use the user's current tab when MCP loses track of its own — and an autonomous agent overwrote two of my real tabs with unsaved work mid-session. Three releases to get the guard right (v2.10.0 → v2.10.1 → v2.10.3). The permanent fix was a sticky session-scoped flag (_hasOwnedTab) that never resets, paired with thrown errors instead of silent fallback.

If you're building tools that act on user-owned state, this pattern is worth designing in up front rather than discovering it the hard way. Postmortem with the diff: dev.to/achiya-automation/an-ai-age...