Context in a Minute: Relevant file selection

In one sentence

Relevant file selection is the practice of choosing a small, sufficient set of files for the agent’s working set.

Why it matters

Reading everything feels thorough. It usually makes the model worse: diluted attention, slower loops, and accidental edits in unrelated areas.

How it works

Start from the task:

1. name the entrypoint file;
2. follow direct imports/callers one hop;
3. include the test that encodes the behavior;
4. exclude generated dirs, build output, and unrelated packages;
5. expand only when verification proves something is missing.

Ask the agent to propose the file list in the plan phase before deep reading.

Example

For a form validation bug: the form component, the validation helper, and the existing test file—not the entire app/ tree.

Agentic coding use

File selection is context engineering in practice. Good selectors outperform bigger context windows filled with junk.

Watch out

Under-selection misses shared utilities and causes repeated broken fixes. If two attempts fail for “cannot find X,” widen by one dependency hop—not by dumping the repo.