premortemlisted

# Premortem A premortem is the opposite of a postmortem: imagine the plan has **already failed**, then work backwards to find out why — before you've spent anything. It surfaces failure modes and hidden assumptions that optimism hides. This is destructive stress-testing; use [[brainstorming]] when you instead need to *generate* options. ## Procedure 1. **State the plan and a horizon.** One or two sentences, plus a date ("in 6 months"). 2. **Assert the failure.** "It is now 6 months later and this was a clear, costly failure." Write from that future as fact, not possibility — this licenses honesty that "what could go wrong?" suppresses. 3. **Brainstorm causes across categories.** Force coverage, don't just list the obvious: - **Technical** — it didn't scale, broke under load, the approach didn't fit the problem - **Scope/effort** — far bigger than estimated, never finished, gold-plated the wrong part - **Dependencies** — an external API/library/team/data source failed or changed - **Ops/people** — nobody maintained it, the one person who understood it left, no one adopted it - **Data** — wrong/missing/dirty data, migration corrupted state - **Security/safety** — a hole, a permission, a destructive action with no guard 4. **Rank by likelihood × impact.** Sort so the few that matter rise to the top. 5. **Surface hidden assumptions.** For each top risk, name the belief it depends on ("assumes the API stays stable", "assumes one repo per agent"). These are the