DON'T MERGE WHAT YOU DIDN'T RUN: A TEST GATE FOR AGENT-WRITTEN CODE

Summary from the TLDR Dev newsletter

A practical test gate checks agent-written changes on a clean machine before review by reinstalling from scratch, running the full suite three times, rejecting removed or skipped tests, and restoring the base branch's tests against the new code. Running the same gate inside the agent loop turns failures into immediate repair instructions while an independent CI run keeps the verdict outside the agent's control.