Analyze unfamiliar source codebases to build a reliable mental model: find entrypoints, map module boundaries and data flow, identify invariants and extension points, and produce a structured briefing. Use when onboarding to a repo, reading third-party library source, mapping architecture, or when the user mentions codebase analysis / source analysis / read the code / 源码分析 / 读代码 / 摸清项目 / 模块关系. Bug investigation defers to debugging; PR critique defers to code-review; restructuring defers to refactoring.
