code-explain

Explain code logic, triage incoming changes, or map the project architecture.

Process

1. Identify context:

   • If code changes are involved: run jj diff -s first to see changed files
   • If the user specified specific files or paths, focus on those

2. Determine goal:

   • Explain: User wants to understand existing code
   • Triage: User wants to understand/assess a diff
   • Map: User wants a high-level overview of the project structure

3. Execute based on goal:

   Explain:

   • Read the relevant files to understand the code
   • Lookup documentation for libraries/frameworks used (use WebSearch/WebFetch)
   • Identify patterns and data flow
   • Synthesize: Purpose, How it works, Patterns, Dependencies, Gotchas

   Triage:

   • Skim relevant diffs
   • Identify: Areas touched, Risk hotspots, Review order

   Map:

   • Analyze the directory structure and imports
   • Create a high-level dependency graph and module breakdown
   • Identify: Key Entry Points, Core Domain Logic, Infrastructure/Adapters

Output

For Explanation:

1. Purpose & Mechanics
2. Patterns & Dependencies
3. Gotchas

For Triage:

1. Change Summary
2. Risk Hotspots
3. Suggested Review Order

For Map:

1. High-Level Diagram (Mermaid or Text tree)
2. Key Modules & Responsibilities
3. Data Flow Overview