MDQuerySetMaxCount can lose most of your Spotlight results

Fri, 06 Nov 2026 01:30:00 +0100

oxus 0.3.0 added truncated, a flag that tells an MCP client when limit has cut a result short. The plan was cheap: ask Spotlight for limit + 1 results with MDQuerySetMaxCount, and if the extra result arrives, more matches exist.

All 125 tests passed, and the feature didn’t work.

The symptom Link to heading

Against the real binary, a search for .app with a limit of 100 returned 3 paths and no truncated. More than a thousand items matched. A search for photo returned 2 paths.

oxus: Spotlight search for MCP clients, built test-first with Claude

Tue, 03 Nov 2026 16:40:00 +0100

Why? Link to heading

I wanted to find out what test-driven development feels like when the other half of the pair is an AI. I didn’t want a code generator: I wanted a pair in the XP sense, someone to shape the design with, keep the test list honest and question each step.

An experiment like that needs a problem small enough to finish and real enough to be worth finishing. I chose an MCP server for Spotlight. I had been meaning to learn the Model Context Protocol, and the problem was right there: every Mac already keeps an index of its files, yet an agent looking for a document usually crawls the disk with find.

Macos on Calogero Sanfilippo

MDQuerySetMaxCount can lose most of your Spotlight results

The symptom Link to heading

oxus: Spotlight search for MCP clients, built test-first with Claude

Why? Link to heading