Not a full one, but a short review is worth doing. A harmless alert still tested how fast you could answer "are we affected?". Spend thirty minutes recording how long it took, what slowed you down and one thing to fix. The cheap rehearsal is the value.
Why bother when nothing happened
Google's SRE guidance says to define postmortem criteria before an incident, and notes that any stakeholder can request one. A false alarm rarely meets a trigger such as data loss. It does show your response time at no cost. Teams that only review real damage learn only from their worst days.
What counts as a false alarm here
- An advisory named a package you do not use.
- A version in an alert was one you never installed.
- A scanner flagged a match that proved to be a name collision.
- A rumour in a chat channel turned out to be wrong.
In each case, someone spent time proving a negative. That time is the measure.
A thirty minute review
Keep it to four questions.
- How long did "are we affected?" take to answer? From first alert to a confident no.
- How did we answer it? Inventory search, lockfile grep, asking around.
- What slowed us down? Missing inventory for a project, unclear ownership, noisy alerts.
- What is one fix? One, not five.
Write the answers in four lines in your incident log. Tag it as a false alarm so it can be found later.
What a good "no" looks like
A confident no needs evidence, not memory. For example: "Searched the inventory for the package across all repositories on this date. No match. Checked lockfile history for the last ninety days. No match." Anyone reading it later can see what was checked.
If your answer was "I think we are fine", the review should find out why you could not be sure.
Look for patterns
Once you have several of these, patterns appear. The same repository is always missing from the inventory. The same alert source is always wrong. One team always takes longest to reply. Those patterns suggest actions that a single real incident might never reveal.
When to upgrade to a full postmortem
Move to the full process if any of these happen: the package was in fact present but thought unused, someone took a risky action in a hurry, you found a gap in logging, or the false alarm repeated and wasted significant effort. At that point you have a real finding.
Quick check
How long should a false alarm review take?
About thirty minutes and four questions. If it needs more, that is a sign it was not a false alarm.
Should we share false alarm reviews outside the team?
A one paragraph note to the wider engineering group is often enough, and shows that the answer process works.
Sources
Last reviewed: 19 October 2026.
