Auto-Diagnose

In-workflow root cause assistance: Auto-Diagnose is integrated into Critique, Google's internal code review system, so diagnoses appear where developers are already looking at the failure. Log streams from test drivers and systems under test, spread across data centers and threads, are joined and sorted by timestamp before being passed to the LLM.

High diagnosis accuracy: In a manual evaluation of 71 real-world failures, Auto-Diagnose reached 90.14% root-cause diagnosis accuracy. This level of reliability is what justifies surfacing suggestions directly in a tool developers cannot ignore, rather than hiding them behind an opt-in query interface.

Massive-scale deployment evidence: After Google-wide rollout, the tool was used across 52,635 distinct failing tests. User feedback marked it "Not helpful" in only 5.8% of cases, and it ranked #14 in helpfulness among 370 Critique tools. This is one of the clearest data points on production LLM tooling at scale inside a major company.

A template for developer-facing LLM tools: The paper reads as a practical blueprint for embedding LLM-based diagnosis into existing engineering workflows. Rather than building a standalone product, the team integrated into the tool where the problem is already being reviewed, which likely explains the low "Not helpful" rate and high adoption.