Building a calculator MCP for Claude/Cursor: what 100+ downloads taught us

Building a calculator MCP for Claude/Cursor: what 100+ downloads taught us Let's look at this from first principles rather than from the marketing page. Model Context Protocol (MCP) is not a magic distribution channel. It's a structured way for AI assistants to call external tools — nothing more, nothing less. The interesting question isn't whether to build an MCP package; it's which tools deserve to be MCP-accessible and what the usage pattern reveals about how developers are actually using AI assistants in their workflows. We shipped @thicket-team/mcp-calculators three weeks ago. It's now at 107 downloads/week. Here's what the data taught us — and what it didn't. What the package actually does @thicket-team/mcp-calculators exposes a suite of scientific and financial calculators as MCP tools: BMI & body composition — Harris-Benedict and Mifflin-St Jeor TDEE, body fat estimation Mortgage & amortization — monthly payment breakdowns with full amortization tables Compound interest