CodeBuddy: a guide for first-year developers

Problem: Beginners opening a real codebase face hundreds of files and confusing error messages, and many give up before contributing anything. I'm a first-year CSE student, and this happened to me. Solution: CodeBuddy turns IBM Bob 2.0 into a patient senior student. It's a custom Bob mode plus two skills, stored in the project's .bob folder, so it's portable to any repository. 1. Explain-repo skill: Bob runs parallel subagents (one reads the code, one reads the docs) and produces START_HERE.md, a one-page, story-first introduction, plus ONBOARDING_GUIDE.md, a detailed reference with a file map, real-life analogies and a 24-term glossary. My first version overwhelmed me as a beginner, so I redesigned it to be beginner-first. 2. Fix-error skill: On a fresh setup of the Galaxium Travels sample project, 35 tests errored. CodeBuddy traced the cause to an unpinned dependency (mcp 2.x was incompatible with fastapi-mcp), explained it with a simple analogy, fixed it with a one-line pin (mcp<2.0), added a regression test, and got all 73 tests passing. It writes a report for every fix. Impact: a beginner goes from "I don't know where to start" to understanding the project and fixing a real setup error, with every fix explained and protected by a test. The whole build used about 5 of 40 Bobcoins. Bob features used: custom modes, skills, parallel subagents, agent mode with approvals, document understanding. Session evidence is in bob_sessions/.