Learn · Context management & reliability · CCAR-F task 5.4

Context in large codebases

Exploring a big repository can flood the main context. Scope the task, search before reading, delegate exploration and keep a map.

Key ideas

Reading many files into the main conversation floods its context and crowds out the task.
Delegate broad exploration to a subagent such as Claude Code's built-in Explore: it reads in its own context and returns a condensed summary.
Search before reading: use Grep and Glob to find the few relevant files, then Read only those.
Keep a map in CLAUDE.md (architecture, key directories) so Claude doesn't rediscover it every session.
Scope the task: a named directory and a concrete question beat "understand the codebase".

The second prompt names where to look, delegates the broad reading, and asks for a short result before any edits.

Reading whole directories into the main conversation "to be thorough".
Assuming a large context window removes the need to manage what goes into it.
Asking a subagent to return raw file contents instead of a condensed summary, which defeats the point of delegating.
Vague goals like "understand the codebase", which give Claude no clear place to look or stop.