Senior backend engineer, joining a new fintech startup with a 5-year-old codebase
The Challenge
New hire faced a 280-file Python codebase + 14 microservices + 8 third-party libraries the previous team had picked. Onboarding plan said 'be productive in 6 weeks'. Codebase had minimal docs, key contributors had left, and Slack history was the only oral tradition. Reading the codebase top-down would take months.
The Approach
Used Prompt Anything Pro on GitHub pages with a custom template: 'Explain this file like I have 5 years of Python experience but zero context on this library/service. What's its responsibility, who calls it, what's the most surprising thing about it?' Ran the template on key files identified by `git log --pretty=format:%H -- [filename] | wc -l` (most-changed files = most-load-bearing). Saved insights to ReadMonkey Pro tagged by service.
The Outcome
Time-to-first-meaningful-PR: 6 weeks → 11 days. Senior engineer's first PR (a critical race-condition fix) was praised as 'showing impressive familiarity with the system'. By week 6, engineer was running design reviews for 2 of the 14 microservices.