What The Diff solves a specific communication problem rather than trying to catch bugs: translating a pull request's code diff into plain English that a product manager, founder, or other non-technical stakeholder can actually follow. Shortcodes like wtd:summary trigger a standard summary, while others produce changelog entries or even lighter, more playful outputs for internal updates.
It integrates directly with GitHub and GitLab, posting its output as a comment on the relevant pull request, and can roll individual PR summaries up into weekly progress reports that give a team or stakeholder a sense of what shipped without reading every diff themselves.
It's free to use, which fits its scope: a narrow, genuinely useful translation layer between code changes and the people who need to understand what happened without reading code, rather than a full code review or quality tool.