How would you integrate SAST into CI without alert fatigue?

WHAT THIS TESTS: This question evaluates whether you understand that security tooling succeeds only when developers actually use it. The interviewer wants to see a workflow-aware deployment strategy, not just a list of tools. You need to show how to shift security left without shifting friction left, balancing automated enforcement with developer experience.

A GOOD ANSWER COVERS: First, pipeline placement: run SAST on every commit or merge request so feedback is immediate, but keep initial execution fast by scanning only changed files or incremental deltas where possible. Second, severity-based rollout: start by reporting only high and critical findings to avoid noise, then expand coverage as the codebase improves. Third, ruleset tuning and suppression: maintain a documented exceptions list or custom rulesets to suppress false positives, and review these regularly rather than ignoring them permanently. Fourth, calibration before enforcement: run in audit-only mode for a baseline period to measure true positive rates, then introduce merge-blocking gates only after the team trusts the results. Fifth, actionable output: integrate findings into the merge request diff or IDE so developers see context and remediation steps, not just a CSV of warnings.

COMMON WRONG ANSWERS: A major red flag is proposing to block all builds on any scanner warning from day one; this creates toil and causes developers to bypass the gate. Another mistake is scanning only nightly or on main, which delays feedback until after code is merged. Suggesting manual review of every finding without automation also signals a lack of scale thinking. Finally, ignoring the false positive problem entirely or claiming the scanner is always right shows inexperience with real-world tooling.

LIKELY FOLLOW-UPS: The interviewer may ask how you would handle a legacy codebase with thousands of existing findings, how you prioritize which vulnerability classes to gate first, or how you measure whether the security program is actually reducing risk versus just creating tickets. They might also probe how you integrate SAST with DAST or dependency scanning to form a layered defense.

ONE CONCRETE EXAMPLE: In a GitLab-based workflow, you would enable SAST in the CI template and run it in merge request pipelines. You would configure the job to use custom rulesets to suppress known false positives, start by surfacing only critical and high severity issues in the merge request changes view, and set the initial pipeline to allow failure. After two sprints of calibration, you would promote the job to a non-blocking quality gate that requires approval for new critical findings, and after a month of clean metrics you would make it a hard gate for high and critical severities only. You would leverage GitLab Duo false positive detection if available to reduce manual triage, and use agentic resolution for critical auto-fixable bugs.