Terraform conventions for the water utility should load only when editing Terraform files. What configuration fits?

Terraform conventions for the water utility should load only when engineers edit Terraform files. The fitting configuration is a file under .claude/rules/ with a Terraform path glob in YAML frontmatter so Claude Code activates those conventions conditionally for matching paths.

Path-glob rules work because water-utility Terraform guidance—provider patterns, state backend expectations, module layout—is irrelevant when editing unrelated application or docs packages. Frontmatter globs such as **/*.tf keep the rules in version control for the whole team while charging context tokens only when Terraform files are in play. That preserves shared municipal standards without always-on noise.

Pasting Terraform rules into every subdirectory CLAUDE.md across unrelated packages fails by duplicating always-on or path-adjacent instruction into packages that never touch Terraform, wasting tokens and creating drift across copies. Keeping conventions only in a user-level CLAUDE.md for one engineer fails because teammates cloning the water-utility repo never receive the shared Terraform standards. Disabling all rules files and relying on verbal standup reminders fails by concept: verbal process is not executable, auditable project configuration and disappears across shifts and contractors.

Exam caveat: .claude/rules/ with path frontmatter is the conditional-loading mechanism; subdirectory CLAUDE.md and user CLAUDE.md solve different problems and are not substitutes for path-scoped team rules. Operational check: open a Terraform file and confirm water-utility Terraform rules load; open a non-Terraform source file and confirm those rules stay inactive.