Diagnosing experiment health

This skill answers: My PostHog experiment results look wrong, biased, or empty — what's going on? It is the diagnostics and health check for one experiment: its setup, its exposures, its results and what changed during the run.

Match the user's complaint in the dispatch table, then read the matching reference file for the diagnostic.

Each diagnostic in the reference files is tagged [HIGH], [MEDIUM], or [LOW] based on how strongly it's verified — [HIGH] is verified directly in PostHog code, [MEDIUM] is partially or team-source verified, [LOW] describes SDK/external behavior that wasn't verified here. Treat [LOW] items as hypotheses to test, not facts to assert.

Step 1 — Resolve the experiment

If the user refers to an experiment by name or description, load the finding-experiments skill first to resolve it to a concrete ID.

Call experiment-get and pull these fields. They are inputs for almost every diagnostic: