Prompt · Debug
Find the root cause before you fix it
Reproduce the defect, establish why it happens, then apply a bounded fix.
/investigate sign-in links expire after 30 seconds instead of 15 minutes. Reproduce it first, then fix it with a test.$investigate sign-in links expire after 30 seconds instead of 15 minutes. Reproduce it first, then fix it with a test.@planr-investigate sign-in links expire after 30 seconds instead of 15 minutes. Reproduce it first, then fix it with a test.If /investigate runs another command, use /planr:investigate.
With the OpenPlanr plugin for Codex, use $planr:investigate.
Cursor applies the planr-investigate rule when you mention it in chat.
Why this works
Investigate starts from the smallest reproducible case and tests competing causes before it names one. It changes code only when you ask for a fix, and then runs focused regression checks.
Related prompts
Diagnose a failure without changing code
Get the root cause and the evidence for it, with no edits until you decide on a fix.
Track down a flaky test
Find out why a test fails some of the time before anyone changes the test.
Find out why a skill is missing
Diagnose the OpenPlanr installation and preview any repair before it touches a file.