Home & IoT

Add missing tools to your Home Assistant voice assistant with MCP

A developer built an MCP server for his Home Assistant voice assistant with jokes, math, unit conversion, stocks and Kagi search.

By jamesponddotco on Hacker News · Posted · Added Oct 15, 2026

Difficulty
IntermediateOur rating
Time to build
Not reportedOur estimate
Monthly cost
Not reported
Revenue
Not reportedWe only show revenue the source states
Engagement
2 replies to HN commentComment in “Ask HN: Who is using MCP in production?” (198 points, 201 comments) · fetched Oct 15, 2026

What they did

jamesponddotco felt Home Assistant’s default tools were missing things, so he built an MCP server adding jokes, math, unit conversion, stock info and Kagi web search.

How it went

He says it was approved by his wife. At work he also uses MCP to debug traces.

Worth knowing

Voice assistants need small, reliable tools more than big models.

Builder recipe

Our own starting point, written from the source. Adapt it to your setup.

Stack

  • Home Assistant
  • Custom MCP server
  • LLM conversation agent

Steps

  1. List the devices and data sources.
  2. Have the agent write the integration code.
  3. Test on one device first.
  4. Automate and monitor.

Starter prompt

Add tools to my MCP server: convert_units, calculate, stock_quote and web_search. Each returns one short sentence suitable for speaking aloud.

Tags

Industry Home

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