The credential that was deleted in the very next commit
A developer committed a file containing a live AWS access key pair to a repository, noticed within four minutes, deleted the file, and committed the deletion. Both commits were pushed to a private GitHub repository with eight collaborators.
They add the path to `.gitignore` and report it resolved. GitHub's secret scanning has not alerted. The key belongs to an IAM user with S3 read access to a production bucket.
Rank what has to happen, in order, and justify the ordering. Then tell me what is wrong with the developer's mental model of what deleting a file in Git accomplishes.
Choose how you want to be interrogated
The same case under two modes is two different exercises. If you are unsure, RCA drill is the one that trains root-cause analysis most directly.
RCA drill
A symptom, and nothing else. Find the cause and prove it.
Trains: Hypothesis generation, ranking by prior, and naming the test that discriminates.
Red team
You propose. It attacks. It is trying to make you wrong.
Trains: Defending a position under pressure, and noticing when you should concede.
Socratic
Questions only. It will never tell you the answer.
Trains: Deriving from first principles instead of retrieving from memory.
Design review
Present an architecture. Justify every trade-off you made.
Trains: Stating what you optimised and what you gave up, on purpose.
Viva
Rapid escalating questions. Ends in a graded verdict.
Trains: Answering under time pressure without hedging.
Integration
Problems that span several domains at once. The hardest mode.
Trains: Reasoning across boundaries, where the cause is in a different system to the symptom.
Before you start: you begin locked. The Mentor will give you nothing — not a nudge, not a category — until you state a specific position and the mechanism you think produces it. Four genuine attempts unlock the resolution. There is no shortcut.