Prompt Engineering beginner

Run a Pre-Mortem on Any Plan

Before you commit to something, ask Claude to imagine it already failed and explain why. Catches risks you'd miss.

March 4, 2026

A pre-mortem is the opposite of a post-mortem. Instead of figuring out what went wrong after the fact, you figure it out before you start.

The Prompt

Imagine this plan failed badly. What went wrong?
Give me the 5 most likely reasons for failure, ranked
by probability. For each one, tell me how to prevent it.

Examples

Before a launch:

We're launching this feature next week. Assume the launch
goes poorly. What happened? What did we miss?

Before a migration:

We're migrating from MySQL to Postgres. Fast forward 3 months
and it's been a disaster. What went wrong? What should we
have done differently?

Before a hire:

I'm about to hire a junior developer for this role.
6 months from now it's not working out. What are the
most likely reasons?

Pair it with

Works well after getting Claude’s recommendation on something. Ask for the plan, then immediately run the pre-mortem on it. Two prompts, much better outcome.

Paste into Claude Code

Imagine this plan failed badly. What went wrong? Give me the 5 most likely reasons for failure, ranked by probability. For each one, tell me how to prevent it.