Blueberry: Force Multiplier For The On-Call Engineer

How we built a Slack-native on-call reasoning harness at Instacart that shortens time to first insight, speeds up theory testing, and turns tribal knowledge into reusable infrastructure.

Key Contributors: Karthik Halukurike, Gabe de Oliveira, Hassan Jallad, Alan Wong

On-call work is a race to turn noisy signals into shared judgment. The hardest minutes of that race aren’t the ones spent fixing the bug — they’re the ones spent figuring out what the bug even is, while everyone in the thread is asking the same question from a slightly different angle.