# Process Lessons

## Start reporting/read-only scripts without `set -e`

Debugging `set -e` failures in scripts that aggregate data from multiple sources (git repos, file stats, etc.) consumed significant time — the script worked in isolated tests but failed silently on real data. Begin without `-e` and add it only for scripts that perform destructive actions where fail-fast is critical.

## Spec-driven testing catches real bugs early

The spec → implement → test workflow caught real bugs during development (grep flag parsing, `local` keyword misuse, binary detection false positives). Writing tests that exercise dryrun against spec expectations is an effective pattern for this project.

## Use `git diff --numstat` for binary detection instead of `file`

The `file` command is unreliable for distinguishing binary from text files (marks shell scripts as "executable"). `git diff --numstat` shows `-` for binary files and is more reliable since git already has its own binary detection heuristics.