Systematic codebase exploration. Trigger this skill when you need to understand how a specific subsystem works, trace the downstream impact of a feature, find where a function is defined, or onboard to an entirely new area of the codebase.
Systematic codebase exploration. Trigger this skill when you need to understand how a specific subsystem works, trace the downstream impact of a feature, find where a function is defined, or onboard to an entirely new area of the codebase.
Systematic Codebase Exploration
Start with the big picture
codemap . — project tree, file counts, top extensions
codemap --deps . — how packages and files connect
Hub files (from HUBS: section) — understand these first, they define shared types/interfaces
Trace a feature
Find the entry point (CLI command, API route, event handler)
codemap --importers <entry-file> — what calls this?
codemap --deps . — follow the import chain downstream
Read hub files in the chain first
Find what you're looking for
Question
Command
Where is X defined?
codemap --deps . → scan the output
Who uses X?
codemap --importers <file>
What's the architecture?
codemap --deps . → look at hubs
What changed recently?
codemap --diff
What was I working on?
Check working set in prompt-submit hook output
Subsystems (if .codemap/config.json has routing)
Check codemap config show — routing subsystems define logical boundaries with associated docs and keywords. Read subsystem docs before tracing code.