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Building Lacy Shell

Technical posts about natural language detection in the terminal, shell plugin development, and making AI work at the command line.

May 12, 2026

Why I didn't use AI to classify AI input

Everyone assumes a shell that routes to AI must use AI for detection. Lacy uses pure string matching instead. Here's why the obvious approach is wrong.

May 19, 2026

Shell reserved words are trickier than they look

Words like do, then, and in pass command -v in your shell. But they're never valid standalone commands. Catching this edge case required rethinking how we validate input.

May 26, 2026

The post-execution reroute pattern

When someone types 'make sure the tests pass', the shell runs make. It fails. Lacy catches the failure, detects natural language in the error, and silently reroutes to the AI agent.